tWVERttTVOF ■^^BMArCHAMPAtGH fiBXOQV X asiuftitia DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 1 ( OCT 'Wv Tungsten and Molybdenum * Part I. NORTH-EASTERN AND EASTERN TASMANIA LOFTUS HILLS, M.Sc., Assistant Government Geologist Issued under the authority of The Honourable J. E. OGDEN, Minister for Mines BY < m ft? : : ■' (S a 3 in a 11 1 a . JOHN VAIL, GOVERNMENT PRINTER. HOBART 1916 ' . . I LOCALITY MAP Photo AlgrufJtrH fyJnhn Vail Goirnitnm t Printrr Unhurt Visum LOCALITY MAP by John Vail Cmvrmment PrtnUr linbnit Tumumia. Tasmania DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 1 Tungsten and Molybdenum Part I. NORTH-EASTERN AND EASTERN TASMANIA LOFTUS HILLS, M.Sc., Assistant Government Geologist Issued under the authority of The Honourable J. E. OGDEN, Minister for Mines {Tasmania: JOHN VAIL. GOVERNMENT PRINTER, HOBART B66226 1916 Vo4,| S' 5"3 T7S> / *~~(o TABLE OF CONTENTS. PAGE I.— INTRODUCTION 1 II. -GENERAL CHARACTER, GENESIS AND MODE OF OCCURRENCE OF WOL- FRAM AND MOLYBDENITE 3 IIL— QCCURRENCES OF WOLFRAM AND MOLYBDENITE IN NORTH-EASTERN AND EASTERN TASMANIA. (1) Molybdenite at Mt. Stronach 9 (2) Molybdenite and Wolfram in the Vicinity of Lottah H (3) Wolfram and Molybdenite at Con- stable’s Creek and Upper Scamander 12 (4) Wolfram at Gipp’s Creek 16 (5) Wolfram at Story’s Creek 19 IV. CONCENTRATION OF WOLFRAM AND MOLYBDENITE ORES 23 V.—CONCLUSION. (!) The Output from the District 30 (2) General Recommendations 30 PLATE. Plate I.— Locality Map Frontispiece Tungsten and Molybdenum Part I. NORTH-EASTERN AND EASTERN TASMANIA. I.— INTRODUCTION. The circumstances under winch the investigations described in this report have been undertaken are exceptional, and theretore the examinations and the character of the publication both differ from the ordinary work of the Geological Survey. The great demand for the steel- hardening metals, tungsten and molybdenum, brought about by the great European war, increased the price of the minerals wolfram } scheelite, and molybdenite, until the Imperial Government commandeered the whole output, and fixed the purchase-price. That price is high enough to warrant attention being paid to deposits which were previously unprofitable, and much activity in prospecting has resulted ; but the extreme necessity of obtaining greater supplies of these minerals has become so apparent that it was suggested by the Northern Tasmanian Science Sub- committee of the State Munitions Committee that the Geo- logical Survey should investigate the resources of the State in regard to these metals, with the object of determining whether the output could be increased. Accordingly, the writer was instructed to visit the local- ities in the north-eastern portion of Tasmania known to contain deposits of these minerals. The results of such examinations are here presented in concise form. No attempt has been made to supply complete geological data, the object being to indicate quite clearly whether the occur- rences are such as to warrant further prospecting, or, in the case of the mines already working, whether the output could be increased, and how. These descriptions and recommendations are preceded by a short account of the properties of the two minerals, wolfram and molydenite. 2 and their genesis and mode of occurrence, and the condi- tions uhder which they may be expected to occur are clearly indicated. In addition, a chapter is inserted describing the methods of concentrating such wolfram and molybdenite ores as occur in the district dealt with m this publication. . ,, £ ( It has been decided to publish this report as the first ol a new series of Geological Survey publications, to be termed “ Mineral Resources.” Each publication will deal with specific minerals or metals. In the case of the two metals, tungsten and molybdenum, which are treated of under the one head, it has been deemed desirable, in view of the urgency of the matter, to issue the publication deal- ing with them in several parts, as the investigations are completed in the various districts. Accordingly, this volume is Part I. of the “ Tungsten and Molybdenum portion of the “ Mineral Resources ” series of Geological Survey publications. . . The writer wishes to record his appreciation oi assist- ance of various kinds rendered by the following gentlemen during his field examinations: — Hon. A. W. Loone, Mr. H. Harvey, and Mr. T. Tucker, of Scottsdale; Mr. Simon Bakhap, at Lottah; Mr. W. A. Rattray and Mr. M. Hartnett, at St. Helens; Mr. Chas. Cheshire, at Scaman- der: Mr. S. J. Dunn, at Gipps Creek; Mr. J. Miller and Mr. D. MacLeod, at Story’s Creek. II. — GENERAL CHARACTER, GENESIS, AND MODE OF OCCURRENCE OF WOLFRAM AND MOLYBDENITE. (1) — Physical and Chemical Characters. (a) W olfram.—'SN olframite is a black, lustrous, opaque mineral, having a reddish-brown streak. Its habit is mas- sive, sometimes, however, assuming a bladed radiating structure. A marked characteristic is the perfect cleavage in one direction, by which the mineral is broken into flat plates. Wolframite is brittle, while the hardness is about H- This accounts for the readiness with which wolfram is reduced to slime by crushing, a property which is of great importance in itg concentration from accompanying gangue. The specific gravity averages about 7*3, which is approximately that of cassiterite or tin oxide. This fact is also of great significance in connection with concentra- tion. Both of these two facts will be fully discussed in Chapter IV. of this report, together with the important fact that all wolfram is slightly paramagnetic. Wolfram is a tungstate of iron and manganese repre- sented by the formula (Fe.Mn)W0 4 . It is an isomorphous mixture of the mineral hiibnerite MnW0 4 and ferberite FeW0 4 , both of which are known to occur as mineral species, but the whole of the occurrences dealt with in this report are the isomorphous mixture of the two, known as wolframite, or in its abbreviated form wolfram. Wolfram is sold on the basis of its content of tungstic acid W0 3 , the theoretical maximum being 76*5 per cent. The market quotations are on the basis of shillings per unit of W0 3 . The assay results of wolfram concentrates are always given in terms of tungstic acid W0 3 . The price per ton is, therefore, the W0 3 percentage multiplied by the quotation per unit. Thus, the price fixed by the Imperial Government at the present time for wolfram is 55s. per unit for a concentrate assaying not less than 65 per cent, W0 3 . A ton of concentrates assaying 67 per cent. W0 3 would, therefore, be worth in London — 55s. x 67 = <£184 5s. per ton. A concentrate assaying 73 per cent, would be valued in London at — 55s. x 73 = £200 15s. per ton. 4 (b) Molybdenite.— This mineral is silver-white to lead- erev in colour, and possesses a marked metallic lustre, it occurs in folis (leaves), scales, and also in a granular term. The folise are often flat, tabular, hexagonal crystals. Molybdenite possesses a marked basal cleavage, the thin laminae being very flexible, but not elastic. This mineral closely resembles graphite in its appearance, but the two minerals can be easily distinguished from each other by reason of the fact that molydemte when rubbed on p ^- celain leaves a greyish-green streak, ana mso by its chemi cal reactions for sulphur and molybdic acid. Molybdenite has a greasy feel; it is a “ d P / tially malleable. The result is that it is difficult to crush to a fine powder, although the hardness is on y . , 1 and 1-5, the mineral flattening out into flat plates which have a tendency to float upon water in spite the fact that the specific gravity is 4'8. This will be "bd^S fathering to a marked degree beinv quite bright, while the enclosing rocks show muca decomposition. At times, however, it alters on s ? rf * h to a yellow powder called molybdic ochre, which is th oxide of molybdenum. , -nr a it Molybdenite is the sulphide of molybdenum MoS 2 . is sold as a concentrate, which must not contain less than 90 per cent, of molybdenum sulphide. The basis !° f is the content of MoS,, which is regarded as the amt. The market quotations are in terms of shillings P e * ° MoS Thus, a concentrate assaying 91 per cent, MoS,, at the purchase price fixed by the Imperial Government, is 105s. x 91 = £477 15s. per ton ; and a concentrate which assays 9 1 per cent. MoS, is worth in London — 105s. x 97 = £509 5s. per ton. (2) Genesis. The two minerals, wolfram and molybdenite, are inti- mately associated as regards their genesis or mode of origin and, therefore, the factors governing their deposition will be most appropriately described under the one head. - detailed description is attempted, the leading points being very concisely indicated. ^ i •• The three minerals, cassiterite. wolfram, and mo v ite, are genetically connected wherever they occur in any 5 part of the world with granitic intrusions. That genetic association consists in the origin of both the granite and the three minerals mentioned above, along with their asso- ciated gangue minerals, from an igneous magma, which originally contained the component materials of them all. That magma, after being injected into a series of sedi- mentary rocks, began to cool, and a process of progressive differentiation was set up. That differentiation consisted in the segregation of the metallic portion containing the tin, tungsten, and molybdenum, together with non-metallic elements such as silicon, boron 5 fluorine, sulphur, &c., towards the centre of the massif. The remainder of the igneous material solidified as the granite rock, which, cool- ing and contracting along with the surrounding sediment- aries, ultimately provided passages for the escape of the enclosed metalliferous differentiate. In their passage along these open fractures in the granite and the surrounding sedimentary rocks, these metalliferous gases were subjected to a gradual decrease in temperature and pressure, becom- ing quickiy condensed to liquid solutions, still, however, under high temperature and pressure. The constituents of these gases and solutions were deposited as the decrease m temperature and pressure gave rise to conditions suit- able for their crystallisation. The first minerals to crystal- lise from the gaseous emanations were cassiterite bismuth- inite, wolframite, and molybdenite, together with the gangue minerals quartz, fluorite, tourmaline, &c. This part of the deposition of minerals from the magmatic emanations is known as the pneumatolytic phase. The lodes resulting from pneumatolytic processes are therefore confined to the outer margins of the granite massif and the immediately surrounding area of sedimentary rocks, and are characterised by the presence of the minerals cassiter- ite ? bismuthinite, wolfram, and molybdenite, and the gangue minerals quartz and tourmaline. It is thus seen that the geologic conditions under which wolfram and molybdenite occur are identical with those of cassiterite. In some cases, however, it has been demon- strated that wolfram in certain quartz lodes has been deposited from hot solutions, and not from gases. Thus, in Boulder Co., Colorado, U.S.A., the quartz lodes contain wolframite with no tin, in such positions relative to their original igneous source that the conclusion has been arrived at that they have been deposited from solu- tions in the deeper portion of the deep vein zone. In any 6 case, however, wolfram is never found far beyond the Ptt Th? mT^ral^moiybdenite also has been reported from ore-formations in all zones successively to near the surface, but the fact still remains that the important molybdenite deposits are confined, to the pneumatolytic, pegmatitic, or contact-metamorphic zones - (3) Mode of Occurrence. From what has now been described, it is obvious that tungsten and molybdenum ores will be found under, approx- imately, the same conditions as tin. Wolfram and molyb- denite Wnay therefore be looked for m granite country, and the surrounding metamorphic aureole. m In regard to the form of the deposit which carries the minerals, it may be stated that many widety different forms are known. Perhaps the most usual is that ot quartz veins in both the granite and the surrounding rocks filling the fractures along which the mineralising gases escaped. These quartz veins often persist for considerable distances, 1000 feet being quite usual, while 0< * asl ° nal 'y much greater lengths are observed as, fat ' 3 * chains at Story’s Creek, in the Ben Lomond district of this State The width of the quartz lodes is not very great, the average being from 1 to 2 feet. The constituent min- erals are Wolframite, cassiterite, pynte, bismutbmite an molvbdenite in a gangue of quartz, sometimes with the additions of tourmaline, fluorite, &c. The several min- erals occur as independent crystals or masses in the quartz, TtlmaS intergro^th of any two of the minerals being almost unknown, although they may occur in .contact When one of these veins is followed along its strike, it sometimes found that a preponderance of cassiterite occur^ ring at one locality gives place to an excess of wolfram at another. The occurrence of the wolfram m patches and bunches is characteristic of this type of deposit, so muc so that in many cases the exploitation of wolfram^bean^g lodes has been discontinued under the belief that *-be uessa tion of one patch of wolfram represented the complete dis- appearance of the wolfram values of the lode. Case ® ha ™ been known in which a few feet more driving along the lode after such abandonment revealed bunches of solid wolfram. It must be borne in mind by those exploiting wolfram lodes that this bunchy and patchy occurrence is 7 wholly characteristic, and that the secret of keeping up a continuous output of wolfram from such lodes is to keep sufficient stoping length of the lodes in work. So also in prospecting, there is no justification for discouragement when a patch of wolfram peters out, for search should be made along the lode for a recurrence of an ore-shoot. It must be noted that this alternation of rich patches and barren zones is characteristic along the dip, as well as along the strike. Another type of deposit is that of pegmatite veins or dykes, which consist of coarse aggregates of quartz and fel- spar, carrying the metallic minerals in blebs and patches, each mineral species generally occurring in separate crystal- line aggregates. This class of vein or dyke is, in reality, a variant of the quartz lode, and possesses the same general characteristics in regard to the distribution of the metallic minerals. The pegmatite dykes are rock differentiates from the original magma, carrying a concentration of the metallic components, and therefore are related to the quartz-porphyry dykes, which themselves carry tin in the form of cassiterite, and occasionally wolfram. A third form in which these deposits occur is that of 4t pipes ” of siliceous material, which do not occupy any well-defined fissures. These siliceous ore- bearing bodies have been followed down from small outcrops as irregular pipes of ore. These pipes of siliceous material are surrounded on all sides by granite, the whole of the lode being taken out in the width of an ordinary shaft. There is no sign of any fissure along which the mineral- bearing solutions might have been introduced, or which might be followed in the anticipation of striking other bodies of ore. The minerals molybdenite and wolfram occur in these pipes as bunches and patches, and, being very coarse-grained, are usually picked by hand after knapping. Such are the molybdenite and bismuth bearing pipes at Kingsgate, near Glen Innes, New South Wales, and the wolfram and molybdenite pipes at Wolfram Camp, Queensland. Finally, it remains to mention a rather exceptional occurrence of molybdenite in normal biotite granite as an original constituent, crystallising from the magma along with the quartz felspar and mica of the normal granite. The molybdenite in this case occurs as small patches in the granite, intergrown with the other components, and very sparsely scattered throughout the granite mass. Such is 8 the mode of occurrence on the greater part of the weetern slopes of Mt. Stronach, near Scottsdale, m this State, it doe P s not seem as if this class of occurrence is of any eco- nomic importance, the molybdenite being scattered throughout too large an amount of rock. Having now briefly indicated the general modes of occurrence of wolfram and molybdenite the particular occurrences m north-eastern and eastern Tasmania exam- ined during this investigation will be separately described. III.— OCCURRENCES OF WOLFRAM AND MOLYB- DENITE IN NORTH-EASTERN AND EASTERN TASMANIA. (1) Molybdenite at Mt. Stronach. Mt. Stronach is situated about 3 miles east of the Scotts- dale railway-station. It is reached by means of the main- road, from which a branch road leads to the foot of the mountain at 1A mile from the township. A foot track is available to the summit of the mountain. The whole of the mountain is composed of varying facies of Devonian granite. The occurrences of molybdenite are situated on the higher parts of the mountain and the west- ern fall, no molybdenite having been observed on the east- ern side. There is only one mineral section held for molybdenite in this district, and that is a reward section granted to G. L. Meredith, numbered 6948-m, with an area of 37 acres. It is situated on the western fall of the mountain, in the vicinity of the track leading to the summit. The only work done has consisted of a few shots put on a rather steep, smooth face of granite showing occasional splashes of molybdenite. These splashes vary in size from mere specks to masses a little more than half-an-inch in diameter. It is observed that wherever the molybdenite occurs in the granite at this point it has a reddish tinge, although both the rock carrying the molybdenite and that free from it are normal biotite granites. The molybdenite occurs as a primary constituent of the rock, no sign of any variation in the rock accompanying the appearance of the molyb- denite. Its occurrence in the rock is identical with that of the mica, with which at times it is confused. One sample collected from the locality shows quite clearly an intergrowth of felspar and molybdenite. There occur in this vicinity small irregular veins of pegmatite, but these do not seem to carry appreciable molybdenite, only one sample found by the writer showing that mineral. How- ever, so little work has been done that no definite opinion on the matter can be expressed, for it is in these veins that workable deposits of molybdenite may be found. To indicate the approximate contents of molybdenite in the granite on this section as visible on the surface, an area 10 n-nq ner cent MoS 2 , which represents a gross value 01 iZtii. to. . «*. *■* “2’rs/rt'S ... j; r t; o“. p ct.“S . •*« P . 8 ».tit. 5 ac n res h wh“h carries splashes of appreciable size, up to about 4 -mch, er _ r.. 6 rro..%friTS s_-si i~*J « S=S.K » Sr£rio‘^^ trtar? jns descried It may, therefore be regarded as unpayable, of the pinnacle, on a vacan^ range, is what is known £ H'rveVsIhow'It tLs point some® work has been done under a prospecting licence, tat i no The granite for a few inches on either side of these frac- tures shows some alteration, indicating clearly that they have been passages for solutions. The surrounding roik is the normal granite. There has not been sufficient work done to clearly show what the formation is, but it looks as if there exists at this point a pipe-like mass of siliceous material consisting of quartz and felspar, of undetermined dimensions, carrying appreciable values in molybdenite, copper, and silver. Samples submitted to the Government Assayer at the time the deposit was opened up gave the following results : — Sample No. 1 .. Sample No. 2 .. Copper. Silver. per cent. oz. Gold 41 65 Trace 3*3 6-0 Trace These figures cannot be taken, of course, to represent the value of the deposit as a whole, but there is no doubt that the values in molybdenite alone are sufficient to war- rant further work being done. The copper and silver values will be additional to the molybdenite, but their presence entails additional metallurgical treatment, which, however, as will be shown in Chapter IV., cannot be regarded as insuperable. Finally, therefore, in connection with the occurrences of molybdenite on Mt, Stronach, it may be stated that with the exception of one occurrence, there is no deposit which would justify further attention, and although there is a considerable amount of molybdenite scattered over the western slopes of the mountain, yet the obtaining of the whole of it would involve the removal of most of the mountain, an obviously unprofitable undertaking. The one exception referred to is Harvey's show, which decid- edly warrants further attention, and the writer would recommend that it be opened up by approaching it from lower down the slope. The extent and exact character of the formation will thus be seen, and the value determined sufficiently closely to decide the future policy. It is cer- tainly the only occurrence on the mountain which warrants present attention. (2) Molybdenite and Wolfram in the Vicinity of Lottah. It is known that several splashes of molybdenite occurred in quartz and pegmatite veins encountered while driving the old Lottah Mine tunnel, situated above the Lottah 12 township, somftoCce fl r ; P pr“t species gathered on the ^he occurrences to have been very sporadic, oo i/-] ooncerning this occurrence Lrth of the Lottah Mine there are reported to occur oectional splashes of molybdenite, but no definite forma- tions have been observed, and no work done. At the old Liberator Mine, 3 miles to the west of Lot- tah splashes of molybdenite occur in tin-bearing por- phyry exposed in the open cuts. Some large up to 1 inch in size, but these are very few “ SS% -ciated ^ Of molybdenite/ The Liberator cannot be regarded » potential source of molybdenite. Bak- On the Liberator section, now held by Mr. up This has only been surface-stripped ior a f«w c ^- — will be seen m Chapter iv. ; nto proposition, this occurrence ought to be looked A/TriT vtitYFNITE AT CONSTABLE S CHEEK (3) Wolfram and Molybdenue and Upper Scamander. There exists » an^rea ^J***^^ mander and St. tlelens, aDout carrying wolfram character ised b, «'•*" *“> is.;, ih.Lh.icd. .. b, ... dcraribri .I- 13 All these lodes on which any work has been done are con- fined to the sedimentary rocks. This wolfram-molybdenite belt or zone is about 4 miles long in a north-south direc- tion ; the width is undetermined, but is certainly greater than 1 mile at the southern end of the belt, although it> appears to be narrower at the northern end. The belt we are now discussing constitutes part of the tin-tungsten zone described by Mr. W. IT. Twelvetrees,. Government Geologist, in his bulletin on the Scamander Mineral District (Geological Survey Bulletin No. 9). They are genetically connected with the Devonian granite lying to the west, and represent the pneumatolytic phase of the ir.inerali&ation -which has given rise to the copper and silver deposits further east. Mr. Twelvetrees has described the occurrences on the Upper Scamander, but he did not visit the northern extension of the belt. The reader is referred to the' publication quoted above for general geological details. The northern end of the belt is best reached from St. Helens, for a good road is available to within 2 miles, whence the northernmost occurrence can be reached by means of a foot- track. The northernmost series of out- crops occur on an old 40-acre section numbered 4189-m, and shown on the Scamander mineral chart, which has recently been taken up by H. T. Roach and M. Hartnett as Section 7204-m. The country-rock on this section is a micaceous quartzite, representing the contact-metamorphio facies of the slates and sandstones, being not very far from the granite-contact. The strike of the quartzites is, approximately, north-west, south-east. The lodes strike nearly due north and south, and are almost vertical. They consist of quartz, with blebs and patches of wolfram and molybdenite, with some arsemopyrite. The width varies from about 1 foot upwards, one bulge 6 feet wide having been disclosed. The average width, as far as present work has shown, is, perhaps, 1 foot 6 inches to 2 feet, but so little work has been done that no definite figure can be given. What work has been done consists of a few shots and pot-holes at isolated points, and a little trenching. In one place a small open cut on the 6-feet bulge of lode referred to gave half a ton of wolfram, by hand-picking. This constitutes the total output from this section. An examination of the exposed portions of the lodes, of which there appear to be at least two parallel to each other, shows that the values of wolfram and molybdenite ar© 14 persistent and appreciable. Particularly is the percentage of molybdenite noteworthy. No figures of percentages can be given, but from the amount of the two minerals visible the lodes could be mined, and the minerals concentrated • at a profit if a sufficient length of lode is found to exist Not only is the molybdenite present m the quartz lode- filling but it occurs also in the quartzitic wall-rock adja- cent to the lode. The wolfram does not appear to occur under the same conditions, but is confined to the quartz- filling, and is often intimately associated with the molyb- de There is a very steep fall from the outcrops southwards and westwards to Constable’s Creek, amounting to about 200 feet from the uppermost outcrop. An adit driven northwards from ConstpbVs Creek would be vertically 200 feet below the outcrops, with between 300 and 400 feet of driving. This would be along the course of the lodes, and crosscutting would be necessary. Finally in regard to this section the writer would express the opinion that it deserves and warrants the expenditure of capital. It has a good prospect (if the lodes are at all persistent in length) of developing into a payable wolfram and molybdenite proposition. H The other sections in this belt on which any work has been done are situated in the Upper Scamander district the coun- trv intervening between these and Hartnett s section being unprospected. These sections can at present be reached from the Upper Scamander Ford, which is m communica- tion with Scamander Bridge (Yarmouth) by means of a eood road, by a foot-track some 4 miles in length, which, however, is of rather a steep grade. There ar « slx sec + tions held in this locality for wolfram and “^yMemte at the present time, five being in the name of I). MacLeod and one in the names of Greaves and Rubenach. These sections have been previously described m two official reports — one by Mr. G. A. Waller (then Assistant Govern^ ment Geologist), dated 4th June, 1901 ; and the other b} Mr W H. Twelvetrees (Government Geologist), m Geo- logical Survey Bulletin No. 9, dated 18th October 1910. The country-rock on these sections consists of slates ana quartzites, striking north-west and south-east, but there are less signs of contact-metamorphism than on Hartnett show, the granite being further away to the west. On Section 7176 -m (D. MacLeod) there are numerous small veins of quartz carrying wolfram on a steep northerly 15 slope of a spur running westwards from the West Pin- nacle. These veins coincide in strike with the bedding - planes of the slates, and seem to have been formed along them. They have been opened up by several small open- cuts, which have served to indicate that the veins are rather small and inconstant. In one lode, about 1 foot wide, with several parallel veins, there occurs associated with the wolfram several splashes of molybdenite. Not enough work has been done at this point however, to show the true character of the lode. It would be as well to drive a short distance along the course of the lode to determine its size and the molybdenite content. With the exception of a quartz lode about 9 inches wide and striking north-east to south-west seen in the creek at the foot of this slope, and which carries a few splashes of molybdenite, no other lode observed in this locality is known to con- tain that mineral. The most promising lode on this sec- tion, however, is one recently disclosed by Mr. C. Cheshire, which carries good wolfram values. It is 5 feet wide where exposed, and seems to be a more defined lode than any others visible in the immediate neighbourhood It is situated a few feet west of the wolfram-molybdenite' veins referred to above. It is worth further attention. On Section 7177-m (D. MacLeod), situated to the north of the previous section on the hill to the north of the creek referred to above, there occur a number of quartz lodes carrying wolfram. On the southern slope of this hill is a promising-looking lode. The strike is north- east to south-west, and the fracture thus cuts across the country, in contrast to the veins on the lastmentioned sec- tion. The lode is nearly vertical, with a slight inclina- tion towards the west. It has been trenched along its strike for about 40 feet, which shows a well-defined lode averaging about 18 inches with one bulge up to 3 feet. The quartz shows nice bunches of coarse wolfram occurring in the patchy manner so characteristic of that mineral. Excellent facilities for driving an adit to cut this lode exist, up to 200 feet of backs being obtainable. This lode is worth attention, as the metallic contents visible are cer- tainly payable. On the summit and northern slopes of this hill, still within Section 7177-m, are the old workings of the Carson De Beers Wolfram Mining Company, described by Mr G. A. Waller in the report above referred to. Several wolfram-bearing lodes were more or less opened up by this 16 Comoanv but operations ceased for two reasons-firstly, the price of wolfram was so low at the time (1900) that the values disclosed would be unprofitable; and secondly, owing to the directors becoming disheartened becau-'e several rich patches of wolfram did not continue, an expectation which, in view of the characteristics of wolfram lodes, was quite unjustifiable. Therefore, the reasons which were respon- sible for the cessation of operations 15 ye ars ago aP S &%-£££££ held by D. MacLeod, numbered 7181-M and which lies to the west of the two preceding sections, there occur two lodes about 5 chains apart These are on the eastern slope of a third hill, and good facilities for adit-driving therefore exist. The eastern lode is only 6 inches wide, but the other is larger, and of more importance. It is about 1 foot in width and has been opened up, and underhand stoped down to 15 feet for a length of 60 feet, and \ ton of wolfram taken out whic was obtained by hand-picking. The lode is well, defined, and is certainly worth, further attention. The writer wishes to definitely remove a misconception which seems to exist in regard to the wolfram occurring in this field. It has been stated that the wolfram is very low in tungstic acid. This is absolutely wrong as the picked wolfram from this field is as high as that from any other field in the Commonwealth. Wolfram is wolfram wherever it occurs, and the percentage of WO, in clean samples will vary by only a few units. Finally, in regard to this wolfram-molybdenite belt, it may be stated that work in the directions indicated above is quite justified under present conditions, and for other lodes between Hartnett’s show and the Upper Scamander, and also west of the latter, should be at once undertaken. The discoveries already made are certainly not the only lodes existing in the belt. (4) Wolfram at Gipp’s Creek. Gipp’s Creek is situated in the Ben Lomond district, lying in the southern footwalls of that mountain. It is reached by road from Avoca, from which it is distant about 15 miles/ The road ’s in good order except m “ places where the failure to provide proper table-drams haT caused several wash-outs. The grade is, on the whole, steep, but in no way excessive. 17 Mining has been carried out in this district for many years, but always in a small and rather primitive fashion. It was reported on by Mr. A. Montgomery, at that time Government Geologist, in May, 1892, and again by Mr. G. A. Waller in June, 1901. In both of these reports the occurrences of wolfram were regarded as quite subordinate to the tin. The present position, however, is that the wolfram is the more important mineral in the district. The country-rock is granite, through which run quartz lodes and greisenised bands carrying the minerals wolfram and cassiterite. The length over which these lodes extend is, approximately, 1 mile, and they have been more or less worked for, practice Uy, the whole of this distance. On the northern end of che belt, on a section now worked by Mr. ,S. J. Dunn, a considerable amount of alluvial ground has been worked, which carries mixed tin and wolfram, the former predominating. Some of this alluvial still remains to be worked, and to this Mr. Dunn is devot- ing his attention. On the eastern side of this section, however, there occur two parallel quartz lodes about 8 chains apart^ striking a little west of north and dipping to the east at about 45°. The lode on the east is just out of S. J. Dunn’s section, and averages about 9 inches in width, carrying nice tin values, with occasional bunches of wolfram. The other lode is within Dunn’s section, and is about 4 inches wide, but splits into stringers. These two lodes can be traced southwards into ground held by parties of working miners, and another lode lying to the east of them makes its appearance. These three parallel lodes in this locality carry predominant wolfram with only a little tin and, together with three additional parallel lodes lying nearer Gipp’s Creek to the west, have all been worked from the surface in very crude fashion to varying depths reaching a maximum of 40 feet, but averaging not more than 15 feet. Work in this primitive fashion, which mainly consists of underhand stoping until the water becomes too plentiful, is still continuing, but it seems as if this method of hand-to-mouth work is near- ing its natural end, and something more systematic will soon be needed to allow operations to be continued. The width of the lodes varies greatly, the average being in the neighbourhood of 1 foot. The wolfram values are patchy as usual, but the persistent length of the lodes is the sav- ing feature from the systematic mining point of view, the 18 centre lode of the first group of ^ree having been traced a^ortm to peter out as they approaeh the stee^ to^ the — ^ en ^ p£ d he h Which were abandoned by tha^ (Company PJ^ months ago. P ^ * thig point which is of the is ^£ m T ^r r r 1 tr^ - b = of wolfram was -ached JhatJhe^o^ ^ ^ XL had completely "disappear^ h» been ^nndantly s?3S s^p tifove ^^5 °f t backs l0de The lode should be followed southwards Enrt.^KKT-» t0 xTie^ri^ practically no tin in the old Tungsten Com- , i-i onrl it is a noteworthy fact that the amount P o rwoH at presen n lodes in this belt increases progres- leW in “elation to the tin contents from north (where Sts the main constituent) to south (where wolfram is the predominating mineral). Tungsten work- Tn regard to the lodes northwards ol the Tungsten worK invs anadltcan be driven northwards from ^ ^ near the tungsten workings, along the course of the lodes, bv which means up to 150 feet of backs can be obtained. The lode' can be penetrated by crosscutting from the main drive The time P has come for the exploration of these wolfram deposits on svsteinatic lines, and it is by such means of Attack, combined with efficient treatment methods, that an output commensurate with the size of the deposits can be obtained. 19 (5) Wolfram at Story’s Creek. Story’s Creek lies to the north-east of Gipp’s Creek, being distant therefrom about 5 miles. It is reached by road from Avoca, the first 9 miles of which coincides with the Gipp’s Creek-road. From the turn-oh to Story’s Creek (7 miles) the road, although of good grade, is in very poor order, there being many boggy patches. A few tons of metal would convert it into a good road. If machinery is to be carted over this road to Story’s Creek, eucli attention is absolutely essential. It may be at once stated that this district is decidedly the most important wolfram producer in north-eastern Tasmania. The country-rock consists of dark slates and quartzites -striking north-west to south-east, and dipping to the west at from 70° to 80°. The mining properties are situated on the western side of Story’s Creek, the southern continuation of certain of the lodes, however, crossing the creek. The whole of the ground is now held in the name of D. MacLeod, with the exception of three sections, aggregating 18 acres in area, held by W. Greaves, R. Byatt, and E. L. Egan, and situ- ated on the south-eastern corner of the mineralised belt. There are two main lodes, one striking N. 25° W., called the main lode, and the other called the No. 1 lode, striking N. 10° W. Both of these lodes dip to the west, the main lode having a dip of 37°, and the No. 1 a dip of 20°, which varies, however, at different points, being almost horizontal in places. Both lodes are of the same general character, namely, fissure -fillings of quartz carry- ing wolfram in bunches, blebs and massive aggregates, cas- siterite, and some pyrite. There is often, although not always, a seam of “ pug ” or “ flucan ” between the quartz and the country-rock. The wolfram and cassiterite occur in completely separate aggregates, no intergrowth of the two minerals being observed. The wolfram occurs some- times in large patches and bunches, from which cwts., and even tons, of clean ore have been extracted. Speci- mens weighing nearly 1 cwt. are quite common. The tin appears to be more plentiful on the hanging-wall of the lodes, but is by no means confined thereto. The pyrite also occurs in bunches in the quartz, and there is no inti- mate association with the other minerals. Both the wolfram and the cassiterite are invariably crystalline, 20 although complete crystals of the former are very seldom 3e These lodes were first reported on by Mr. A. f M°ni> • i SQ9 in his report, mentioned under PP J X Mr. G- A. Waller in 1901, but both ’of these gentlemen regarded the proposition as a both 01 rnese g to the wolfram as a contamma- UonTraf an Unimportant constituent. Mr. Montgomery refeirforTnstance P to the lode (No. 1) penetrated by Miers’’ tunnel as “carrying very little tin, wolfram ” At that time, also, very little work had been done, and the true size of the lodes was ^revealed. Since that time parties of working miners have held the ground and made handsome profits in mining for wcdfram or “ mixed ore,” as the mixed concentrate of tin wolfram is called. Their work on the surface, »^oon- sisting of underhand stopmg, has served tp demonstrate the Tength of the lodes, with the result that the No. 1 lode is seen to be 34 chains in length, averaging over this length for the depth worked fully 2 feet This lode is sometimes split into two or more branches, ^ut these umte to form the main lode, and the persistency of both the lode and its values is quite remarkable. Likewise the main lode has been worked for about 5 chains ously past where it crosses No. 1 lode, in Sec ion > but southwards of this it is split into many quarts ‘leader 8 all of which carry wolfram and tin, and most of which have been worked™ more or less. It is on a continuation of these quartz lodes that Greaves is now working, on the other side of Story’s Creek. For the last 34 years parties of working miners have owned and worked the lodei in this district until the difih culties which developed as increased depth was attained caused dissension, and the syndicate which now holds the greater part of the district stepped in, and are now initiat- ing that systematic working of the lodes which they fu y warrant. The wonder is how such a promising ' nln ™? proposition has been allowed to be neglected by capitalists. Since taking charge of operations, the present owners have driven a low-level adit and cut both No. 1 and main lodes. . , T , . 1U No. 1 lode has been driven on for 150 feet It is split into two veins, aggregating 3 feet, where cut by the adit, but is further split at both ends of the drive On the sur- face there were more branches, which came together at this 21 level, and the dip of the two branches here observable should allow them to unite a few feet deeper. The aver- age width of the No. 1 lode for the 150 feet is 2 feet 6 inches, and shows nice values in wolfram and tin. There are, several cross-faults in this part of the work- ings, striking nearly east and west, which displaces the lodes a few feet. The fault-line generally carries a foot or more of soft, puggy material, and serves a very useful purpose in crosscutting. One such fault was followed by the low-level ad.it, and another can be seen at the south end of the south drive on No. 1 lode. The main lode, where cut, measures 4 feet^ and shows high values. It is certainly a nice-looking lode. It has only been driven on for a few feet. When cut it gives a depth corresponding to 150 feet of lode for sloping. Miers’ tunnel, situated on the southern fall to the creek, about 15 chains south of the main adit, and approxi- mately on the same level, has been driven along No. 1 lode, which is here also in two branches, showing good values, and providing a very convenient means of attack- ing the southern portion of the lode. The crosscut from this tunnel, if continued for a few feet, will emerge a few feet above the level of the tramline, not many yards away from the mill -site. Stoping is in progress on No. 1 lode, but none has yet been done on the main lode. The material stoped is at present being treated in a very crude manner by hand, as will be described in the succeeding chapter. Steps are now being taken, however, to provide a suitable concentrating plant. A site has been chosen further down the creek, and a tramway already formed to connect with the low-level adit, below which future mining will have to be carried on by shaft- sinking. A haulage-line from the mill-site to the top of the ridge has been cleared and formed where it is proposed to erect an electro-magnetic separator plant. The capacity of the proposed concentrating mill will be 50 tons of crude ore per 24 hours. The motive power proposed is a suction gas plant, water-power not being available above about five horsepower, although there is sufficient for dressing pur- poses. The present output is 5 tons of concentrates per fort- night, the extraction by the crude methods employed varying from 2 to 5 per cent. The concentrates consist of, approximately, equal quantities of wolfram and tin 22 ore Since the present owners took charge the output of mixed tin and wolfram concentrates has been 79 tons. The 'two minerals present in these concentrates are pre- dent in about eoual proportions. The number of men employed is 45 and two shifts are worked. The manager is Mr. J. Miller. Such is the present position of affairs, and there is no distinct lode systems, the average width of nearly 3 bet on both lodes' already proved, and the metal contents proved by the extraction obtained by very crude methods are all very satisfactory indeed. As a matter of fact, the 34 chains proven length of one lode, and ^^ ^“en much greater length than 0 chains of the other, take in conjunction with the very fiat dip of both, warrant the entry if two separate companies to exploit them, although lost of the ground (330 acres in area) is now controlled most ot t e g \ wr iter would certainly recom- XTrXrt XX. i ..fh. p- sent time, either the provision of Xin asm tions When it is remembered that the S. & M. ’ the Middlesex district, has been worked at a profit for eight years on four parallel lodes averaging not more than Ttot ln wWth, with metal contents (tin, wolfram, and 1 toot m wiu , r cent and extending over a maximum length of 1200 feet, it is very clearly seen what ai^attrantive^proposition the Story’s Creek mine really is It is in the writer’s opinion, destined to prove the largest producer of wolfram in Tasmania, and, as pre- viously remarked, it is remarkable that its potentialities have not before been realised. Tn addition to the possibilities in regard to these .wo lode systems there exists the likelihood of locating other lodes between them and the granite-contact nearly a mile a Ts regards Ihf persistence of the lodes in depth it will be seen from the explanation given in Chapter IL th both the lodes and their values may be expected to tinue into the underlying granite. A considerable depth therefore, is available for future exploitation. IV.— CONCENTRATION OF WOLFRAM AND MOLYBDENITE ORES. In the Ben Lomond district (which provides the only present output of wolfram) the methods of treatment are very crude indeed. At Gipp’s Creek, the ore is mined, and the coarse wolfram knapped out and picked by hand. The rejects are built into a kiln with wood, and burnt. This causes the 1 breaking up of the quartz at the junction with the wolfram, freeing the. latter, which is picked by .hand, and the fine portion streamed. At Story’s Creek, the ore, as mined, is passed over a grizzly, and the coarse portion stacked for future treat- ment. The fines are treated in streaming-boxes, and a mixed tin and wolfram concentrate obtained, which is sent to Launceston fo:' electro-magnetic treatment, by which clean wolfram, assaying up to 74 per cent W0 3 , and clean tin concentrates, are obtained. Advantage is taken in mining of keeping separate from the remaining ore any rich patches of wolfram encountered. These are subjected to hand-picking, and sent away as clean wolfram. Such are the methods at present employed, and which have served a useful purpose in the past, but it is now necessary to replace this crude treatment by more efficient methods of concentration. It will be best to consider the different classes of ore under separate headings. The Wolfram and Tin-Wolfram Lodes of Gipp’s and Story’s Greeks . — As previously pointed out, the lode- material in these districts consists of separate crystalline aggregates of wolfram and cassiterite in quartz, together with some pyrite. The masses of both wolfram and tin *,re sometimes large, and there is no finely disseminated min- eral intimately associated with the quartz. The problem of treatment is, therefore, a special one, and must be dealt with accordingly. It may be stated without any equivocation or hesitation that the crushing of the material by stamps is sure to end in failure. As pointed out when describing the properties of wolframite, that mineral is very easily converted into slime when subjected to crushing, and the pounding of wolfram-bearing material in boxes until the whole of it will pass a certain screen is sure to convert a great part of the wolfram into fine slime, which, of course, is to be avoided 24 The object to be attained is to merely free the minerals from the gangue, and this can be easily accomplished by taking advantage of the crystalline character of the cas- siterite and wolfram, which allows of their separation from quartz at their junction when subjected to sufficient pressure. This is best accomplished by rolls, which simply “nip” the material, and do not “ grind ” it. In this way, the cassiterite and wolfram are freed from •he quartz. The reduction appliances must therefore consist of rock- breaker (reciprocating jaw type) and rolls. The mills should be of the gradual reduction type, and the concen- tration of ore, as soon as it is freed from the gangue, and without further crushing, should be the characteristic. In fact the mill should be designed on the same general lines as that at the S. & M. Mine, Middlesex, which treats a tin-wolfram-bismuth ore, from lodes of the same general character as these. This mill is described in detail in Bulletin No. 14 of the Geological Survey, pages 52 to 57 inclusive. The mills to be erected on this field should be on the same general lines. The present method of keeping bunches of wolfram separate from the ordinary lode-material as it is mined, should be continued, and bags should always be kept in the stopes for the reception of such picked material. An electro-magnetic separation plant is an essential adjunct to such a mill as that indicated above. Particu lars of such a plant are given in an article prepared by the writer, and published in Geological Survey Bulletin No. 14, pages 58 to 73 inclusive. The provision of such a plant at Story’s Creek is rendered necessary by the fact that the plant already operating in Launceston is work- ing at its utmost capacity, apart from the consideration of other economic factors. The plant should be on the same lines as that in Launceston, including the rolls and screens. The latter appliances are rendered necessary by reason of the fact that the coarsest jig product from the mill will be about J-inch in diameter, while the coarsest size treat- able by the electro-magnetic separator is one-seventh of an inch in diameter. It is inadvisable to design the mill to make the coarsest product of the latter diameter, for the reason given above, that the minerals should be separated from the gangue in as coarse a state as possible, to avoid sliming of the wolfram. In designing the mill this object should be kept in view, leaving the magnetic separation 25 tc take care of itself. Accurate sizing is also an essentia] to successful magnetic separation. The product from the concentrating mill will contain some pyrite, as it does at present, and the amount will certainly increase as depth is attained. A stage will soon be reached when it will be advisable to remove this pyrite, from a “ seconds ” product produced in the milling opera- tions. This will have to be done by first submitting the concentrate to magnetic separation, by which clean wolfram will be obtained, and a pyritic tin concentrate. The latter must be given a slight roast and again passed through the separator, when an iron product, which can be dumped, and a clean tin concentrate, will be produced. It would be a mistake to roast the mixed tin and wolfram concentrate before separation, as this would result in a loss of wolfram in the iron product, as Well as a contamina- tion of the wolfram product with iron. The Wolfram and Wolfram-Molybdenite Lodes of Con- stable’s Creek and Upper Scamander . — The lodes in this belt, which carry only wolfram with neither tin nor molybdenite, will have to be dealt with in a mill designed on the same lines as that indicated above, i.e. } gradual reduction, but there will be no need for the electro-mag- netic separator-plant. The concentrates produced in the mill itself will be at once marketable as high-grade wolfram . In those lodes, however, which carry molybdenite in addition to the wolfram, the treatment will be more com- plicated. The only method in general use in treating molybdenite ores up to quite recently has been hand-pick- ing the coarse flakes, the finer material being reserved for future treatment. Concentrating by water is impossible with this mineral owing to its tendency to float. Quite recently, however, the application of the flotation process has been successful in treating molybdenite ores. The following extract indicates the general outline of these processes: — ( x ) “ In the case of molybdenite ores, large scale results are obtained without the use of either acid or oil, the antagonism of the surface of the mineral itself to wetting action being sufficiently pronounced to enable it to be floated off under the conditions prevailing in practice. Even after having been crushed wet and passed through (') ti The Concentration ot Molybdenite Ores,’’ Minins: and Ensineerina Review, May fi, 1P12. 26 an ordinary wet ^ iS§H=a=SSi>=£ £«&rc ss -s mss m ° Vem ha n t larg^overflow 01 somewhat large over" m angue of the ore, and SSTSitSf**- w.™ «.<> *■*- ‘-V7” m «Tn the ‘ Engineering and Mining Journal for t t Henrv E. Wood describes what appears to b January , -ti y ■ rlifbeultv. The appar- practical method of overcoming usua i y f 0 rm of flota- atus used consists ^essentially o ^ the usual^tor^ ^ tion-box, with a h "hP er e { | d even l v over the width which serves to distribute the teed evenj from of the box. The ore— m this case d “ j £ this vibrating plate on gang „e of S“"; 'ih. “ «T«rz2 the take- 0 ^ Mt, ^Molybdenite overflowing with the atus. Instead ol the y ^ on to w hich it water, it is y ^ QY er the 0 ’ ve rflow-lip, the floats, and is earned p , f ree f rom mo lyb- water passing over the lip, g J was hed off the take- denite. The clean molybdenite is ^h^ 0 ^ ^ usual> off belt into a suitable receptacle. Tl e s g , passes out at the bottom of the box. “ The same author’s statement that the > ore ® ^ crushed dry is not, however, )t order experience. Where the ore m ^ sulphide from the »«■« 6 "“ 27 tides oi gangue, in order to allow it to sink, when it reaches the flotation-box, is considerable, and leads to much of the slime being carried over with the molybdenite. On the other hand, his advocacy of the ball mill, in one or other of its types, as a grinder for molybdenite ores is well justified, considerable experience with other crush- ing machines, both with and without screens, having shown the ball mill to be the most suitable machine for the pur- pose.” More recently, however, the Mineral Separation De Bavay’s Proprietary Company Limited have carried out a considerable amount of research on the application of the flotation processes to molybdenite ores, and the results obtained have been very satisfactory. One of the diffi- culties encountered in the treatment of molybdenite ores by flotation is the grinding of the mineral to sufficient fineness, owing to the fact that it flattens into flakes, rather than breaking down to slime. In any scheme of treatment provision must be made for the separation of these coarser flakes, as they are too large to be floated. Although the treatment of molybdenite ores is now suc- cessfully accomplished by flotation when the mineral is unassociated with others of value, the problem of treating a mixed wolfram and molybdenite ore presents certain difficulties. In the class of ore occurring on Hartnett’s section, for instance, the requisite condition of treatment to recover the wolfram is gradual reduction, as previously explained ; while the requirements in connection with the recovery of the molybdenite are fine grinding and sliming of the material. How are these two conditions to be com- promised upon .? If gradual reduction is decided upon the molybdenite will go partly in the concentrates and partly in the tailings, part of it being irretrievably lost in the dressing-water, unless provision is made to recover it. The tailings in this case could be submitted to flotation treatment. If the material is reduced to a fine state and first submitted to flotation, with subsequent concentration to recover the wolfram, much of the latter will be lost as slime. The recovery of a mixed wolfram and molybdenite concentrate cannot be regarded as undesirable, for these two minerals can be separated by electro-magnetic treat- ment. The exact method of treatment to be adopted will depend on the nature of the ore as it is disclosed in future operations, a great deal depending on the percentage and degree of coarseness or fineness of the molybdenite. When average samples of the ore are available, trial parcels can 4 •28 , Hesuatched for treatment, and the details of the latter decided upon. The difficulties can in no way be regarded SfSa'fSSSS 1-1 J._, .. £ - concentration is effected by means of shaking screens an * » The capacity of one of these plants is about 5Um^a r w ’orke d d by 6 Wo a general man- ag ‘‘ r The ore consists mainly of largo clean flakes of molyb- I ner cent molybdenite and bismuth. This is tea D> 6 per cent. crushed to about l-inch gauge* 0 The°nce passes by gravitation throu g h of rollers each set having screens to pick up the larg holes 1 /12th inch in diameter is placed, and the unaer SV 'SiteMSSTrf wat a The e t y aiUn g : S bwm^ “The oversize from the l/12th-inch screen is carried to a third set of rollers crushing to l,20th-mch gaug^ Much of the oversize from this screening is cleaned by hand-sieving. The first of this oversize, however is taken to a fourth set of rollers set close together and after crush- ing the material, is passed through a l/32nd-mch me ffi The oversize from this is a product containing 90 to 92 ner cent molybdenite. The undersize is a rich product, which is savedpending possible improvements m the treat- m Vnl„bdenite at Mt. Stronach.— As previously pointed out the only occurrence on Mt. Stronach ^hiclideserves further attention is that known as Harvey s show. T , 29 ore at this point carries chalcopyrite in addition to the molybdenite. The latter mineral occurs in flakes measur- ing, as far as can be seen at present, about J-inch in diameter. By fine grinding and flotation a mixed con- centrate of molybdenite and chalcopyrite could be obtained, which, after partial roasting^ would give clean molybdenite and a high-grade copper-silver ore. It is quite possible, moreover, that a separation of the molyb denite from the ohalcopyrite may be possible by means of differential flotation. Such a method of treatment can only be considered if considerable quantities of ore are subsequently exposed. It will probably be more expedient to adopt some such scheme of treatment as that outlined in the article by Mr. E. C. Andrews, quoted above, as the bismuth and chalcopyrite play about the same role in relation to molybdenite. If the occurrence develops into one of any size, there will be no difficulty in treating the ore. V . — CON CLU SION . (1) The Output from the District. There has been no output of molybdenite from this dis- trict whatever up to the present date. The output of wolfram is confined to that froni the i Lomond (Avoca) district, and a few pared. th * Upper Scamander. The exact amount is impossible of estimation, but may be put down at about 40C ' mixed concentrates from the former district, whicn cor responds to, approximately, 250 tons of clean wolfraim The output from the Upper Scamander has been o y about 5 tons of band-picked wolfram. , , The present output is confined to that from Gipp’s Creeks, which may be put down at, approximately, 12 P tons of mixed tin and wolfram concentrates per mont , equivalent to about 7 tons of wolfram per mon h. (2) General Recommendations. It now remains to briefly summarise the conclusions arrived at in the preceding pages in connection with Hhe various occurrences. The recommendations in r «g“d o future procedure are naturally influenced by the con ^deration of the desirability of obtaining the maximum supply of the metals tungsten and molybdenum, which the deposits are capable of producing, as soon " ^°^der The resume of the recommendations are presented under the headings of the various localities. Mt Stronach.— The occurrence known as Harvey s show is the only one deserving of further attention and P ; suectine of this occurrence is recommended. 11 an appre ciable body of ore is disclosed, then the consideration of treatment on the lines indicated m the P r ^ c ® d ^| d P ^ can be entered upon. The oulier deposits of molybdenite in this locality are quite unpayable, but search for d nite pegmatitic dykes can be made which may carry p y able molybdenite. Lottah. — The molybdenite occurrences observable in t is district are unpayable. The tin-wolfram deposi on e section held by Mr. Simon Bakhap m the vrcimty of the old Liberator Mine deserves further prospecting. Such, investigation is recommended. 31 Constable’s Creek and Upper Scamander . — The wolfram- molybdenite lodes on Hartnett’s Section 7204-m on Con- stable’s Creek show good values in both minerals, and active prospecting is recommended. The lodes on the sections at Upper Scamander are essentially wolfram deposits, molybdenite being only sparsely distributed, as far as at present observable; but from what can be seen with the very limited amount of work done, at least three of the wolfram lodes ought to be payable at the present market price. The investiga- tion of these lodes to start with is recommended. In addition, general prospecting between these sections and Hartnett’s, and also to the westward, is recommended. To enable such prospecting to be carried out, it will be necessary to construct a road to the Upper Scamander sections. The route for this road will be from the pre- sent end of the Scamander Road up the Scamander River to Fitzgerald’s Creek, following the course of the latter for about 1 mile, then turning northwards towards the hat ground on Section 7179-m. This seems to be the only practical route. Such a road is essential if these deposits are to be worked. Gipp’s Creek . — The systematic exploitation of a series of six parallel tin-wolfram lodes from a few inches to 2 feet in width, extending over about 1 mile of country, is decidedly justified, and is strongly recommended. The output possible from the present crude system of working is very small, whereas the deposits are capable of pro- viding an appreciable output if worked on systematic lines. Story’s Creek— This is certainly the most important district examined, producing, as it does, about 6 tons of high-grade wolfram per month, and being capable of greatly increasing that output. Two lode-systems, aver- aging about 3 feet in width — one being 34 chains in length, and the other over 5 chains, with several offshoots to the southwards — give potentialities which indicate an output exceeding any other wolfram-producing district in Tas- mania. The plant now proposed to be erected to treat the ore from D. MacLeod’s sections is designed to produce about 4 tons of wolfram (assaying over 70 per cent. W0 3 ) per week. The accumulated coarse rejects from the present crude methods, amounting to upwards of 1000 tons, and the development work already done, and that 'Contemplated on lodes already proved on the surface, will 32 be sufficient to keep such a plant going for an indefinite Sit treat thetixed^n and wolfram con- “ ifirtbus seen that S£ w srjg£ % gjs&x S,by virtueTf Their being the largest wolfram lodes in Tasmania, they fully justify. , r handling It is evident therefore that and treatment, the out 'P u materially increased, and siTfp" Js;“ r^r^r. *- the Stronach and Constable’s Creek districts. LOFTTJS HILLS, M.Sc., Assistant Government Geologist. Launceston, 22nd October, 1915. UMVERSinfO F ILLINOIS LIBRARt OCT 1 R it GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. 1.— The Mangana Goldfield, by W. H. Twelve- trees No. 2.— The Mathinna Goldfield, Part III. by W. H. Twelvetrees ’ No. 3. Thfe Mt. Farrell Mining Field, by L. Keith Ward, B.A., B.E. No. 4.— The Lisle Goldfield, by W. H. Twelvetrees No. 5.— Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees No. 6.— The Tinfield of North Dundas, by L Keith Ward, B.A., B.E. No. 7.— Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelvetrees and L. Keith Ward B A B.E. ’ ‘ ’’ No. 8.— The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward B.A., B.E ’ No. 9.— The Scamander Mineral District, by W. H. Twelvetrees No. 10.— The Mt. Balfour Mining Field, by L Keith Ward, B.A., B.E No. 11. — The Tasmanite Shale Fields of the Mer- sey District, by W. H. Twelvetrees No. 12.— The X River Tinfield, by L. Keith Ward B.A., B.E ’ No. 13.— The Preolenna Coalfield and the Geology of the Wynyard District, by Loftus Hills, M.Sc No. 14.— The Middlesex and Mt. Claude Mining Field, by W- H. Twelvetrees 1907 1907 1908 1908 1909 1909 1909 1910 1911 1911 1911 1911 1913 1913 34 No 15.— The Stanley River Tmfield, by L. L. igu Waterhouse, B.L •••; "i" , No 16.— The Jukes-Darwin Mining 16 . 1914 Loftus Hills, M.Sc No 17 . — The Bald Hill Osmiridium Field, by ^ w H Twelvetrees S5x5pi , «° 3E So. ,9. — The Zino-La»d SgM. ^ Read-Rosebery District, « t i 91 4 Read Group), by Loftus Hills, M.bc. ... N„ 20 -The Catamaran and Strathblane ■ Coal- N fields and Coal and Limestone at Ida Bay, Southern Tasmania, by 1915 Twelvetrees No 21.— The South Heemskirk Tmfield, y • m5 Lawry Waterhouse, B.h •_ XT 09 Catalogue of Publications issued by the NO. 22 ^government of Tasmania relating to the Mines, Minerals, and Geology of the State! to 31st December, 1914, compiled ^ by W H. Twelvetrees No 23 -The Zinc-lead Sulphide Deposits of the Read-Rosebery District, Part IL CR mg bery Group), by Loftus Hills, No . 24. - - 915 reports. No i -Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E 1911 - — 191 , Hills, M.Sc ; w No 4.— On Cement Materials at West Arm, by • igu H. Twelvetrees 35 No. 5. — On Some Gold Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6. — Reconnaissance of the North Heemskirk Tinfield, by L. L. Waterhouse, B.E 1915 No. 7. — Preliminary Report on the Zinc-lead Sulphide Deposits of the Rosebery Dis- trict, by Loftus Hills, M.Sc. 1915 RECORDS. No. 1. — Marine .Fossils from the Tasmanite Spore- beds of the Mersey River, by W. S. Dun 1912 No- 2. — 'Stichtite : A New Tasmanian Mineral : Notes by various authors, collected and edited by W. H. Twelvetrees 1914 No. 3. — Darwin Glass: A New Variety of the Tek- tites, by Loftus Hills, M.Sc . 1914 No. 4. — A Monograph of Nototherium Tasmanicum by H. H. Scott. Price 7s. 6 d 1915 MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. : North-Eastern and Eastern Tasmania, by Loftus Hills. M Sc. .. 1915 Part II. : Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc 1916 OCT 1 8 . y, t JOHN VAIL, GOVERNMENT PRINTER, TASMANIA. Tungsten and Molybdenum Part II. MIDDLESEX AND MT. CLAUDE DISTRICTS BY LOFTUS HILLS, M.Sc,, Assistant Government Geologist Issued under the authority of The Honourable J. E. OGDEN, Minister for Mines K 2Ta s man ta : JOHN VAIL, GOVERNMENT PRINTER. HOBART 1916 ■v ' - ■ . ; r n -■ '•'iViV : 4 asmattta DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURjflg No. 1 Ocr . 4 . '« 1 Tungsten and Molybdenum Part II. MIDDLESEX AND MT. CLAUDE DISTRICTS BY LOFTUS HILLS, M.Sc., Assistant Government Geologist Issued under the authority of The Honourable J. E. OGDEN, Minister for Mines Tasmania: JOHN VAIL, GOVERNMENT PRINTER, HOBART B67705 1916 . II ’ . S'S 3 Z'fr yiCil TABLE OF CONTENTS. PAOI I.— INTRODUCTION 1 II.— GENERAL CHARACTER, GENESIS, AND MODE OF OCCURRENCE OF WOLFRAM AND MOLYBDENITE 2 II.— OCCURRENCES OF WOLFRAM AND MOLYB- DENITE IN THE MIDDLESEX AND MOUNT CLAUDE DISTRICTS 3 (1) The S. and M. Mine, Moina 3 (2) The All Nations Mine, Moina 5 (3) Colling’ s (Poachin’s) Section 7 (4) The Squib (Gurr’s) Mine... 9 (5) The Iris Mine 10 (6) Ware and Smith’s (Urquhart’s) Section ... 10 (7) Properties on the Eastern Side of the Forth River 11 IV. — THE METHODS OF CONCENTRATION EMPLOYED IN THE DISTRICT 12 jo V.— CONCLUSION ... 13 (1) The Output trorn the District 13 (2) General Recommendations 13 Plate I. Locality Map PLATE. Frontispiece Tungsten and Molybdenum. Part II. MIDDLESEX AND MT. CLAUDE DISTRICTS. I— INTRODUCTION. This is the second of the “ Mineral Resources ” series of publications of thei Geological Survey. It constitutes Part II. of the set dealing with the tungsten and molybdenum resources of the State of Tasmania. Part I. was devoted to the occurrences in North-Eastern and Eastern Tas- mania, while this present volume treats of those in the Middlesex and Mt. Claude districts, situated in Northern Tasmania, about 25 miles south of the port of Devonport. The district has been previously subjected to a thorough geological survey by Mr. W. H. Twelvetrees, Government Geologist, and is fully described in Geological Survey Bul- letin No. 14, “ The Middlesex and Mount Claude Mining Field.” Consequently, the present investigation has been designed to merely supplement the complete bulletin and to specifically indicate the present position in regard to the production of the two metals tungsten and molyb- denum, as well as to discuss the future prospects. The report will be concise, and will contain no material that has already been dealt with in the abovemention ed bulletin, or in Part I. of the “ Mineral Resources ” series, and the reader will find himself repeatedly referred to either of these publications. The writer wishes to express his appreciation of hospi- tality and assistance rendered by the following gentlemen during the course of his field examinations: — Mr. W. E. Hitchcock, Moina; Mr. W. Goldsworthy, All Nations; Mr. B. J. Gurr, Moina; Mr. Warwick Castles, and Mr. C. Carlson. II.— GENERAL CHARACTER, GENESIS, AND MODE OF OCCURRENCE OF WOLFRAM AND MOLYBDENITE. There is no need to include in this publication the details under this head, as they have been fully delineated in Part I. of this series, and the reader is referred thereto before he proceeds to the next chapter. In addition, full details of the mode of occurrence and paragenesis of these minerals is contained in Mr. Twelve- trees’ bulletin above referred to, and reference to pages 32 to 37 of that publication will supply all the information available. With the general knowledge thus accessible, the descrip- tion of the various occurrences can now be proceeded with. "WoF/ii*,, oct i * t III. — OCCURRENCES OF WOLFRAM AND MOLY- BDENITE IN THE MIDDLESEX AND MOUNT CLAUDE DISTRICTS. (1) The S. and M . Mine, Moina. This is the pioneer and largest mine in the district. It has' been fully described in Bulletin No. 14, pages 45-52. In the period which has elapsed since that report was written (four years) considerable development has been carried out. It is only intended to describe here the results of this work and its effect on the future of the mine. There are four lodes worked on this mine averaging from 12 to 15 inches in width. At the time Mr. Twelvetrees made his examination, the No. 3 adit was the lowest level, and all of the four lodes had been driven on for varying distances. Since then, additional driving on Nos. 2, 4, and 5 lodes has been carried out, and new blocks of ore opened up, a great part of which has been extracted. During the last 12 months, however, a shaft has been sunk from the No. 3 adit level at the No. 6 lode, and connected with the: surface. The total depth sunk has been 150 feet below No. 3 adit, and levels driven along the No. 6 lode at 75 feet and 150 feet respectively. These are shown as the No. 2 and No. 3 levels respectively, the No. 3 adit being now known as the No. 1 level. The No. 6 lode at these levels maintains both its size and value, and this development undoubtedly places the mine on a very sound footing. The following particulars will give the posi- tion of the mine at the present time in regard to ore reserves : — No. 4 Creek Drive. — No. 2 lode, length 500 feet, height 87 feet. No. 3 Adit.— No. 2 lode, length 200 feet, height 154 feet. This block will be increased as driving along the lode is continued. No. 3 Adit.- — No. 4 lode, length 200 feet, height 50 feet. Main Shaft, No. 2 Level. — No. 6 lode, length 175 feet, height 75 feet. Main Shaft, No. 3 Level. — No. 6 lode, length 185 feet, height 75 feet. 4 Both of these latter blocks are being increased as driving along the lode is carried on. . A crosscut from No. 3 level is at present being driven southwards to cut Nos. 5, 4, and 2 lodes in that order, 150 feet vertically below the present workings on them. A distance of 89 feet has already been driven. It has been found impossible to express these ore reserves in figures, as the conditions of working are exceptional. For instance, if an average width of lode of, say, 12 inches is taken the figures obtained are quite valueless, tor the reason that in mining the lode it is found impossible to separate it from the country-rock, with the result that approximately 75 per cent, of the material milled is barren country-rock As the important figure to be con- sidered is that of the material which is to be treated in the mill, it will be seen that any estimate of ore reserves based on the width of lode is quite valueless As regards the future of the mine, however, the general statement is quite justified, that, on the evidence at present showing, five years’ full work is assured. In addition, the mine has possibilities much in excess of that, both m depth and in the longitudinal extension of the lodes. Since Mr. Twelvetrees’ visit, rock-drills have been installed, and have greatly reduced the cost of mmmg; in fact, in the hard ground the utilisation of suend: nils t is essential to the working of the mine at a profit. The drii s are worked by compressed air supplied by air-c^pressors driven by Pelton wheels for nine or ten months ol the year, and by an auxiliary steam plant during the dry season. The shaft is already equipped with a steam-driven winding engine. , , , •, The development footage to date is 9530 feet, and total material milled 55,585’5 tons, which gives 1 foot ol development work for every 5*8 tons of crude ore raised. A general idea concerning the length of the lodes and work done can be gained from the following: — No. 6 lode has been driven along for a total length of 800 feet, and stoped for a length of 800 feet. No. 5 lode driven on for 600 feet and stoped for 3U 1 00 ^ No. 4 lode driven on for 1400 feet and stoped for 1000 ^ 00 ^ No. 2 lode driven on for 900 feet and stoped for 800 f 0Bt The S. and M. has certainly been a consistent producer of the three metals, tin, tungsten, and bismuth, for the 5 past eight years. During that period the following ore has been produced : — Crude Ore Tons. Details of Ore Milled and Products Obtained. Picked Picked Bismuth. Wolfram. Tons. Tons. Firsts. Tons. Seconds. Tons. Slimes. Tons. Total. Tons. 55,585-5 640-55 274-35 53*55 2488 3*25 996*58 The details of the composition of the various products mentioned in the above table are given in Bulletin No. 14, and need not be repeated here. To indicate the contents of the material milled under present conditions, the following information is submitted, which represents the work done during the last 24 weeks : — Details of Recovery in Present Milling Practice. Crude ore milled ... Firsts Seconds Slimes Picked bismuth Tons. Percentage. 4880*00 ... 37-80 ... 0-774 44-90 ... 0-920 4-20 ... 0-086 0-35 ... 0-007 Total 87-25 ... 1-787 The crude ore thus provides 1787 per cent, of concen- trates of various kinds. This may be taken as the average of the material treated. The remarks in connection with this mine may be con- cluded by stating that the present output can be continued for at least the next five years, and that the success of the last eight years will continue. (2) The All Nations Mine , Moina. This mine is referred to in Mr. Twelvetrees’ bulletin as the Lady Barron, andi is described on pages 74 to 77 inclusive. It was originally known as the “ All Nations / * and has thus returned to its old name after many vicis- situdes. There is only one lode on this property, which is essen- tially a wolfram-bismuth one. Its characteristics have already been fully described in Bulletin No. 14. Since that examination, the spasmodic and unsystematic work which 6 has characterised all the operations since the discovery of the mine has been continued, and consequently the mine is in on better position than it ever has been. Such operations have consisted for the most part of underhand stoping and treating the crude ore by screening and streaming the fines. A small mill was erected, but was destroyed by fire about 12 months ago. Since Mr. Twelvetrees’ visit an adit has been driven at a depth of 40 feet below the No. 1 adit, and the lode driven on for 235 feet vertically below the approach to the No. 1 adit. All this has been stoped with the excep- tion of 75 feet. At present a winze is being sunk on a rich patch at this level. On the upper level the lode was driven on for 320 feet, and was stoped for 200 feet. On the surface the lode has been underhand-stoped for 550 feet. . , . , The mine has never been handled m a manner wmcn would give it a fair chance of proving its value. The mis- take has always been made of endeavouring to make it pay its way from the initiation of operations, with the almost total elimination of capitalisation. The result has been what could reasonably be expected, namely, complete failure to make of it a paying concern. The property suffers from several drawbacks, as compared with the neighbouring S. and M. Mine, notably the scarcity of water, due to its elevation, and the absence of facilities for adit-driving. These disabilities, however, cannot be said to render the mine valueless, as there are certain advantages which, although not very apparent, still exist, and when put to proper use should render the proposition a valuable one. These natural facilities become apparent on studying the adjoining section to the east (Ryan and Colling s), and the discussion of them will be presented after the occur- rences on that section have been described. It will be sufficient at this stage to state that above the present lowest level on the All Nations Mine there are the following blocks of ore remaining untouched : — Above No. 1 level, 120 feet long, with a maximum height of 80 feet. Between No. 1 and No. 2 levels, 395 feet long, with height 40 feet. It is perfectly obvious that instead of stoping a rich patch the work should be directed to driving at the No. 2 level along the lode to get vertically below the easterly outcrop of the lode, and so properly open up the above- 7 mentioned blocks. It must be constantly borne in mind that in wolfram-mining it is essential that considerable length of lode be operated on at one time, as this is the only way to ensure a constant output from lodes in which the values are sporadically distributed. This has been fully explained in Part I. of this series of publications, and the failure to realise this fact lias been partly respon- sible for the failure of this mine to progress. The width of the All Nations lode varies from 10 to 20 inches. The values are patchy, as is usual with wolfram lodes. It may be here remarked that it is impossible to arrive at the value of any wolfram lode by face-sampling, owing to the sporadic distribution of values, and attempts made to thus sample the All Nations Mine and others in the district are sure to result in misleading information. The only way to form an accurate estimate is by the test- ing of a large parcel representing some considerable length of lode. In the case of the All Nations lode the crushings put through in the past and present treatment are avail- able as an indication of the values to be expected from the lode as a whole. In this way the figure of 2 per cent, of concentrates may be stated as representing the value of the lode. The concentrates contain wolfram and native bismuth, with some carbonate of bismuth, and assay approximately : — Tungstic acid 68 per cent. Bismuth 4 per cent. The total output from this mine is impossible of estima- tion, but during the last 12 months, with the crude methods of working, has been 7 tons of concentrates. The future method of working this mine will be dis- cussed in connection with the following description of the neighbouring section (A. Colling’s). (3) Section 7207m (A. C oiling' s). This is described in Bulletin No. 14 as Poachin’s Section. Since Mr. Twelvetrees’ visit a short adit about 30 feet, on several quartz veins carrying wolfram in white conglome- rate country, has been driven. The precipitous slope to the Forth Biver is here traversed by outcropping quartz veins carrying wolframite. Where driven on, these veins seem to lie on the continuation of the All Nations lode, but no definite statement thereon is at present justified. The work so far accomplished has served to show that the 8 characteristics of the lode formation are those of small vertical veins, with flat offshoots connecting them, with the result that the whole of the face shows more or less wolfram, the country-rock itself showing bunches of wolfram occasionally. There are two main veins showing in the face at present, one 5 or 6 inches in width, and the other about 3 inches. The quartz veins are very rich m wolfram, with a little bismuth sulphide. The amount of mineral showing is certainly sufficient to encourage further work, but when viewed in relation to the All Nations property an important inducement for active work is realised. As previously pointed out, the drawbacks to the All Nations Mine are the lack of facilities for driving adits and the scarcity of water. If shaft-sinking were resorted to, the ore would have to be raised and subsequently lowered to a point where water is available. It is desirable to avoid this if possible, and investigation shows that there are two ways of doing so. The first suggestion takes advantage of the fall from the All Nations to the S. and M. A tunnel driven eastwards from the Bismuth Creek a few feet above the entrance to the No 1 . 4 creek drive would cut the western end of the All Nations lode in approximately 1500 to 2000 feet of driving, giving 200 feet of backs. This is quite a feasible proposition, but is not as desirable as the second suggestion, which will now be indicated. The country falls away rapidly from near the eastern boundary of the All Nations lease to the Forth Rivet— a total fall of about 1800 feet. Colling’s section is on this fall. As stated above, the lode formation partly opened up on this latter section is probably the continuation of the All Nations lode. If an adit were driven along Col- ling’s lode, it would therefore meet the most easterly end of the All Nations lode in about 1300 feet of driving, with some hundreds of feet of backs. In addition to this, the amount of backs can be increased by hundreds of feet if necessary, by starting lower down the hill, with a propor- tionately small increase in the length of the adit. The additional advantage also exists of opening up one lode formation while driving for a second, as contrasted with the driving along barren ground from the S. and M. lease. A good road passes through the easterly part of Colling s section, connecting with the Middlesex-road. Milling operations could be carried on below the workings in the Forth Valley, and water could be easily brought in from Bull Plain Creek. 9 There is a narrow strip of ground between the All Nations lease and Colling’s section, recently applied for by H. E. Walduck. The three sections concerned in the proposed scheme are the All Nations, Colling’ s, and Walduck ’s. It will thus be seen that by regarding the problem in a broad way, a proposition which at short range possesses marked disadvantages, can be attacked in a comprehensive manner and converted into one possessing very favourable features. The writer has no hesitation, on the evidence available, in recommending the adoption of such a scheme, the details which must be decided upon by a competent engineer experienced in wolfram mining. ' (4) The Squib (Gurr’s) Mine. This mine has been fully described by Mr. Twelvetrees in Bulletin No. 14. There are six lodes on the property, carrying varying percentages of wolfram, bismuth, and molybdenite. They occur partly in granite and partly in the adjacent quartzites. It has been observed that the value, as well as the size of the lodes, is greater in the granite. Four of the lodes were being worked by open-cut mining at the time of Mr. Twelvetrees’ visit, in order to take advantage of the numerous small stringers carrying metal. The whole of the. dirt was being milled in a small plant erected on the Narrawa Creek. Since that date, however, the open-cut system has been abandoned, owing to lack of haulage and transport facilities, and an adit is being driven at a depth of 100 feet below the open-cut, along one of the lodes in an easterly direction. Three hundred feet have already been driven, leaving 200 feet more before a point vertically below the open-cut is reached. The lode being driven on is small and broken, but at times shows good values in wolfram and bismuth. It is expected that the values and size of lode will increase when the granite is entered. Crosscutting will then open up the parallel lodes. Additional facilities for a deeper adit exist, giving a further 150 feet of backs. During the past 12 months 3 tons 5 cwts. of concentrate have been obtained, from which clean wolfram assaying 70 per cent. W0 3 , and 7 cwt. of bismuth ore assaying 40 per cent. Bi, have been extracted. There is quite an appreciable amount of molybdenite showing on this property, and the tailings in the mill show 10 the mineral freely. It is quite possible that the amount present could be profitably extracted by flotation of the crushed mill tailings, but the wisest plan to adopt is to await developments at the present adit level, and then determine by a bulk test of the mill tailings whether the extraction of the molybdenite would be profitable. The present scheme of operations is certainly justifiable, and there is certainly a prospect of a payable proposition developing . (5) The Iris Mine. This is an alluvial proposition, and was the first dis- covery in the district. Most of the ground is already worked out, but the present owners, Messrs. Adam and Davis, have acquired a mill lease adjoining to the north, until lately held by the Lady Barron Company, which contains a run of nice ground which ensures about five years’ work- ing at the present rate. During the last 12 months 6 tons of concentrate, con- taining tin and wolfram, have been obtained, and this rate of output should characterise the future. The great difficulty of working at this elevation is lack of water. (6) Section 7114m (J. Ware and IS. L. Smith)— TJ'rqu- hart’s Section. This section was described by Mr. Twelvetrees under the name of D C. Urquhart, the lessee at that time. Since his report an adit has been driven for about 30 feet on the lode below the lowest trench described in Bulletin No. 14. This has disclosed the lode, and shows it to be exceed- ingly rich, though small. In the face, it is split into two portions, one 6 inches in width and the other about 3 inches, making 9 inches in all. The lode is in granite country It carries values of wolfram and bismuth sul- phide in about equal proportions. A small parcel obtamed by dollying has been sent out, and amounted to 7 cwt. containing about equal proportions of wolfram and bismuth sulphide. In addition about 70 lbs. of hand- picked bismuth were obtained. At present two men working in a very crude fashion can obtain one bag of concentrate a week from the lode-stutf as mined. When it is remembered that this lode system has been traced for some chains on the surface, it is seen that there 11 is decided encouragement to actively prospect by continu- ing the present adit. As showing at present, the lode is as rich in bismuth as any in the field . (7) Properties on the. Eastern Side of the Forth Fiver. . Above the Lorinna-road, a little south of the Cage, on a section charted in the name of S. S. McLean, a tunnel has been driven for about 15 feet on a quartz lode in the granite, carrying wolfram and molybdenite. The width varies from 12 to 15 inches, and average samples are said to have returned over 2 per cent, each of wolfram and molybdenite. It would be as well, however, to place no reliance op such figures, as it is impossible to obtain a satisfactory estimate of the value of such a lode by taking face samples. At the same time, there is no doubt that the lode carries nice values in molybdenite and wolfram, and especially the former, for occurrences in such large flakes are exceptional in molybdenite lodes in Tasmania. The drawback to the proposition, however, is the extreme hardness of the enclosing rock. If it were not for that fact it would be an attractive proposition to a fossiker to break down the lode and obtain the molybdenite and wolfram by hand-picking and dollying. As it is, it is certainly worth while trying in this manner, but it is extremely doubtful whether a company could do any good at it. There are numerous other occurrences of molybdenite in this vicinity, but they are all so sporadic and indefinite in character that they do not warrant further attention. There has been no work done on any other sections since Mr. Twelvetrees’ visit, and consequently no mention of them is necessary in this publication. IV —THE METHODS OF CONCENTRATION EMPLOYED IN THE DISTRICT. These have been fully described in Bulletin No. 14, in two papers contributed by Mr. W. E. Hitchcock and the writer respectively. The former deals with the mining and milling methods at the S. and M. Mine, and the article contributed by the writer is descriptive of the electro-magnetic separation of tin, wolfram, and tungsten ores. These will be found on pages 52 to 73 of the bul- letin referred to. There is nothing new to add to these descriptions, except that several mechanical improvements have been effected in the S. and M. mill which increase its efficiency and smoothness of running. The most important point concerning the concentration of the S. and M. ore is in connection with the pyrite. The scheme adopted is to produce two grades of concentrate* — “ firsts ” nearly free from pyrite, and “ seconds ” con- taining approximately 50 per cent, thereof. The latter are treated by a special adaptation of the electro-magnetic process worked out by the writer, and converted into high- grade wolfram and tin-bismuth products corresponding with those produced from the firsts. The methods adopted at the S. and M. must serve as a model for the whole district. In regard to the recovery of molybdenite the only method applicable is that of passing the tailings from the concentrating mill to a tube-mill, and reducing them to slime before treating in flotation boxes, by which the molybdenite will be obtained as a float. The details of such a scheme should be left to the Mineral Separation De Bavay Processes Proprietary Company Limited, Mel- bourne. y._CONCLUSION. (1) The Output from the District. Tli© total output of wolfram from the district is impos- sible of exact estimation, but probably is not very far from 350 tons of concentrate, assaying 70 per cent, tungstic acid. The present output is approximately at the rate of 6 tons of wolfram per month. (2) General Recommendations. A brief summary of the conclusions arrived at in the preceding pages will now be presented, and it may be remarked that the urgency of the need of wolfram and molybdenite should influence the rate at which explora- tion on the lines indicated should be carried out. (1) The S. and M. Mine is working continuously and systematically, and cannot do better than continue its present scheme of operations. An output of approximately 27 cwt. of wolfram per week can thus be depended upon. Although molybdenite occurs scattered throughout this mine, there is no justification for an attempt to recover it, as it is too small in amount to pay. (2) The All Nations Mine and C oiling’ s Section should be worked in conjunction by driving an adit from the latter section along the lode to open up the All Nations lode at a depth. The milling plant should be erected some- where in the Forth gorge, and water brought in from Bull Plain Creek. In this way the properties can be sys- tematically worked, and will become important producers of wolfram. The present system of working is of no value either to the owners themselves or to the British Empire. (3) The present system of operations at the Squib Mine should be continued, and stoping initiated when the adit reaches a point beneath the open-cut. Investigations as to the possibility of extracting the molybdenite from the mill tailings should then be undertaken. (4) The Iris Mine cannot do better than continue the present rate of output. (5) Active development of the lode on Ware and Smith’s Section should be initiated by continuing the present adit. 14 C6') The molybdenite and wolfram lode on the eastern side of the Forth gorge should be taken m hand by one or two miners and worked by hand-picking. This is the only chance of working it at a profit. It will thus be seen that there are possibilities of increasing the output of wolfram from the district if sys- tematic work is immediately undertaken, and it is possible that an output of molybdenite may eventuate from the Squib Mine with a little from hand-picking on McLeans Section. LOFTTJS HILLS, M.Sc., Assistant Government Geologist Launceston, 1st January, 1916 GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. ■; BULLETINS. No. 1. — The Mangana Goldfield, by W. H. Twelve- trees 1907 No. 2. — The Mathinna Goldfield, Part III., by W . H. Twelvetrees 1907 No. 3. — The Mt. Farrell Mining Field by L. Keith Ward, B.A., B.E. 1908 No. 4. — The Lisle Goldfield, by W. H. Twelvetrees 1908 No. 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees 1909 No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E. 1909 No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelvetrees and L. Keith Ward, B.A., No. 8.— The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E 1910 No. 9. — The Scamander Mineral District, by W. H. Twelvetrees 1911 No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E 1911 No. 11. — The Tasmanite Shale Fields of the Mer- sey District, by W. H. Twelvetrees 1911 No. 12. — -The X River Tinfield, by L. Keith Ward, B.A., B.E 1911 No. 13. — The Preolenna Coalfield and the Geology of the Wvnyard District, by Loftus Hills, M.Sc. 1913 No- 14. — The Middlesex and Mt. Claude Mining Field, by W- H. Twelvetrees 1913 16 No. 15. — The Stanley River Tinfield, by L. L. Waterhouse, B.E 1914 No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc 1914 No. 17. — The Bald Hill Osmiridium Field, by W. H. Twelvetrees 1914 No. 18. — Geological Reconnaissance of the Country between Cape Sorell and Point Hibbs, by Loftus Hills, M.Sc 1914 No. 19. — The Zinc-Lead Sulphide Deposits of the Read-Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc. ... 1914 No. 20.— The Catamaran and Strathblane Coal- fields and Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees 1915 No. 21. — The South Heemskirk Tinfield, by L. Lawry Waterhouse, B.E 1915 No. 22. — Catalogue of Publications issued by the Government of Tasmania, relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914, compiled by W. H. Twelvetrees 1915 No. 23. — The Zinc-lead Sulphide Deposits of the Read-Rosebery District, Part II. (Rose- bery Group), by Loftus Hills, M.Sc, ... 1915 No. 24. Reconnaissance of the Country between Recherche Bay and New River, South- ern Tasmania, by W. H. Twelvetrees ... 1915 REPORTS. No 1. — Preliminary Geological Report upon the Mt. Balfour Mining Field, bv L. Keith Ward, B.A., B.E ' 1910 No. 2. — The Silver-lead Lodes of the Waratah District, by L. Keith Ward, B.A.,B.E. 1911 No. 3. — Preliminary Report on the Zinc-lead Sul- phide Deposits of Mt. Read, by Loftus Hills, M.Sc 1914 No. 4. — On Cement Materials at West Arm, by W. H. Twelvetrees 1914 17 No 5. — On Some Gold Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6. — Reconnaissance of the North Heemskirk Tinfield, by L. L. Waterhouse, B.E 1915 No. 7. — Preliminary Report on the Zinc-lead Sulphide Deposits of the Rosebery Dis- trict, by Loftus Hills, M.Sc 1915 RECORDS. No. 1.— Marine Fossils from the Tasmanite Spore- beds of the Mersey River, by W. S. Dun 1912 No- 2. — Sticlitite : A New Tasmanian Mineral: Notes by various authors, collected and edited by W H. Twelvetrees 1914 No. 3. — Darwin Glass: A New Variety of the Tek- tites, by Loftus Hills, M.Sc 1914 No 4. — A Monograph of Nototherium Tasmanicum by H. H. Scott. Price 7s 6 d. 1915 MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. : North-Eastern and Eastern Tasmania, by Loftus Hills M Sc. 1915 Part II. : Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc 1916 ilKWERSITY OF ILLINOIS LIBRARY OCT 18 IKK- JOHN VAIL, GOVERNMENT PRINTER, TASMANIA. a s m a itt a DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES ■ No. 1 ® WSRSITY OF ILLINOIS LIMAS’ Ul xj Tungsten and Molybdenum Part III. KING ISLAND BY L. LAWRY WATERHOUSE, B.E., Assistant Government Geologist Issued, under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania C a s m a n i a . JOHN VAIL. GOVERNMENT PRINTER HOBART 1916 «&$ ? * 7 , :A - ' ' 4 : ■ A' •.;’/ V. '. ' ' £L •/' 'V- V - v?; v ., • : • ' \ 'f* . ? ; . •’■■' 7_ 'I;';-'':'?,; , - • ' . , y ••• c: .. 'WCT-. rid, ■•■, ..'•■• ■■ : ' ' , , . •' U • 'W •**, V r'lW: y-jy+r; ; , : - . I - m • Wpy.:--. * < *3M& I* M a . ■ „;X S y t-v •*■ •«* 1 / ' .• t ,**•- M rjp f - L.C..;? A.'*- «,.ji 'aw A gm ,'i \|y ■ w. . v7 CJ 3 r .. - ' ' &| ! H - * / L •" .& • "■ - . .. ® asmaitta DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 1 Tungsten and Molybdenum Part III. KING ISLAND BY L. LAWRY WATERHOUSE, B.E., Assistant Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania {Tasmania. JOHN VAIL, GOVERNMENT PRINTER HOBART B70406 1916 S'S 5 77 %- y./ s TABLE OF CONTENTS. I.— INTRODUCTION AND GENERAL (1) Introduction (2) History (3) Area of Property (4) Situation (5) Access (6) Topography (7) Water-supply (8) Timber (9) Mining Facilities II.— GEOLOGY AND MINERALOGY ... (1) Rock Formations Developed (2) The Nature of the Ore-body (a) Mineralogical Composition (b) Structure ( c ) Mode of Origin III. — THE MINE WORKINGS IV. — ASSAY VALUES V.— COSTS ... VI.— TREATMENT VII.- RECOMMENDATIONS VIII.— SUMMARY AND CONCLUSION ... 146 ' Diversity oct Tungsten and Molybdenum. Part III. KING ISLAND. I.— INTRODUCTION AND GENERAL. (1) Introduction. This report forms one of a series of publications prepared essentially for the State Munitions Committee, in order to make available the latest information concerning the tung- sten and molybdenite resources of the State of Tas- mania. The present report (Part III. of the series) deals with a deposit of scheelite (carrying some molybdenite also) which occurs on King Island, in Bass Strait. Fur- ther information concerning the general geology of King Island will be found in a separate report by the writer, which will be issued as a bulletin of the Geological Survey of Tasmania. (2) History. The deposit was discovered a few years ago by a veteran Tasmanian prospector (Mr. Tom Farrell), outcropping on the sea-shore. It was developed by the King Island Pro- specting Association, and at the time of writing is under- stood to have been floated into a company known as “ The King Island Scheelite Company, No Liability,” with a nominal capital of '£50,000 in 100,000 shares of 10s. each. No official examination of the property has previously been made, although a report was recently furnished to the Prospecting Association by Mr. J. B. Lewis, of Mel- bourne. 2 (3) Area of Property. The property held bv the company consists of a mining lease (IOp^) of 78 acres, charted in the name of Alex- ander Campbell. This lease is on private property (owned by Mr R Cummins), but an option of purchase was given bv the owner over about 200 acres of ground, which would he required by the company as a site for battery and con- centrating plant, assay office, residences for manager anc men &c The ground adjoining the mining lease is also private property. (4) Situation. Kinv Island is situated in Bass Strait to the north- west of Tasmania, about midway between Cape Grim and Cape Otway! The mine is situated on the sea-coast in the P so“h -eLtern portion of the island, at the moutB of the Grassy River, and about^ miles -uthWof^p™ part n of rffiochT^ acres and e ^ e ^ in ^° “^ouvh 207 acres, both charted in the name of M. Parer, thou, owned by Mr. P. Cummins. (5) Access. Access to the property is given by the road from Currie there are other stretches which are loose sand or boggy sod and will need attention before any regular traffic (especially if at all in traffic the road would become practically p wet weather. The last few chains from the tablelano^ on which the north-western corner peg of and is situated, to the mine workings, slope rather s “ e M’ ■ no attempt has so far been made to grade a road, although this can be done without difficulty, a small amount of Si tTs1roCbt^" r} ;hat as the mine is developed, and becomes a producer of scheelite on a commercialscae, water-carriage will be utilised, as the property is favour- 3 ably situated in this respect. The mine is situated within a mile of the southern end of a wide bay, of which the northern point is known as Bold Head. The southern point is of granite, and towards its base is a site which could well be utilised for a jetty. Such a jetty would be exposed to winds from the south-east, east, and east-north- east, but splendidly sheltered from all other winds, and quite as favourably situated, from this point of view, as the Government jetty at the Fraser Bluff, a few miles fur- ther north. The prevailing winds on the island are from the west, and seldom cease blowing from this quarter. The shelter afforded by such a site as that suggested is excellent under these conditions. Adjacent to the actual jetty site is a small cove with a sandy beach, where machinery, &c., could probably be landed from a lighter under favourable weather conditions. The entrance to' this cove carries about 6 feet of water ; about 1 chain off, the depth increases to about 16 feet. A short distance south of this, at the base of the point, granite outcrops to the water’s edge, and there are several pro- jecting points of rock which might be utilised as a basis for a jetty. Some soundings were taken by the writer to obtain some idea of the practicability of a jetty scheme; the tide was medium to low at the time these measure- ments were taken. The most suitable position for a jetty appeared to be at one point where the granite on the shore was naturally fairly level, and where in the course of weathering several portions of the rock-mass had been separated from the main rock outcrop by encroachment of the sea, and now form tiny islands of rock. Such could, doubtless, be utilised if it were decided to erect a jetty at the spot. At about 1J chain (off this point the depth was 18 feet. At about and 3 chains, the depth regis- tered was 28 feet. There was found to be very little vari- ation at about the same distance off points on either side of the one particularly referred to above. The water deepens fairly gradually, 30 feet being registered at about 10 chains, and 45 feet at about 20 chains off shore. The water is deeper in places, however, and the bottom some- what irregular, for 55 feet was the depth recorded about 3 chains, and 50 feet 5 chains away from another point. Sufficient evidence was obtained to show that it would be practicable to construct a jetty which would easily berth steamers such as those trading to King Island at the present time. The bottom is evidently granite in this vicinity. 4 It has been stated in some quarters that the jetty recently completed at the Fraser Bluff will serve the scliee- lite mine. By air line, the distance between the two points is 10 miles. Bv road, however, the indirect route which must of necessity be taken considerably increases this distance. The route which would have to be taken at the present time would be along the main road towards Currie as far as a branch road running due north for several miles, and known as “ Crowe’s Road.” This road connects with the Pegarah Road from Currie to the Fraser. The total distance by this route would be about 17 miles, and as parts of the road are in a bad condition at the pre- sent time, particularly that portion between the Grassy and Crowe’s Roads, carting would be costly, and continuous traffic would be impossible in wet weather. Between 1 and 2 miles would be saved if a road should be constructed to connect up the branch road from Pegarah Road to J. Hunter’s block with that from the Grussv Road in to the Yarra Creek. There is a distance of about 11 mile between the end of these two roads, at present, covered with heavy timber. Thus it will be seen that with the present road facilities there is little to be gained, in point of distance, between cartage to the Fraser Jetty and carriage to Currie. The possibility of a tram connection with either jetty merits notice in'passing. A tram to Currie would follow approximately, the course of the present Grassy Road, and would be between 17 and 18 miles in length. A tram to the Fraser jettv would be constructed within a short dis- tance of the coast-line. The country here carries abun- dant dead timber, and much thick scrub and undergrowth. The surface is uneven, owing to the various creeks running down to the coast. This route was not examined in detail, but if at all practicable it is very unlikely that the line would be less than 15 miles in length, and from the gen- eral nature of the country the cost would be heavy. <6) Topography. The topography of the locality is such as to be favour- able to mining operations. The south-eastern portion of the island consists' of a plateau rising to about 400 feet above sea-level. It represents an old peneplaned surface which has been uplifted and modified by recent erosion. Along the coast this high ground slopes steeply to sea- 5 level, the seaward slopes being modified by the erosive action of various streams. There is usually a strip of level country a few chains wide along the foreshore, and small sand dunes have formed at intervals along this coastal strip, which is only a few feet above sea-level. The principal stream along this part of the coast is the Grassy River, flowing a little east of south, and this has out its gorge down to sea-level. This gorge is a typical young valley, and has steeply sloping sides. High up on the western bank of the river, a few chains from its mouth, is the north-eastern corner of the mining lease. The north-western corner is on the plateau, near its east- ern edge, at an elevation of 370 feet above sea-level. Between these two corner pegs, and in the north-eastern portion of the' section, is a creek flowing about south-east, which has also cut back into the hill. This creek does not carry very much water. The south-western corner of the section is on a terrace several chains wide, at an elevation of 200 feet above sea-level, and so intermediate between the higher plateau and the coastal strip. It is below the level of this terrace that most of the mining work has so far been carried out. The south-eastern corner of the section is truncated, the boundary-line of the section extending along the beach for 91> chains, and including the outcrop of scheelite ore originally discovered. Advantage has been taken of the topography in pro- specting the scheelite formation by driving adits into the slope of the hill, and the facilities offered are destined to play an important part in the future development of the mines. It is unfortunate that a sufficiently long period of time has elapsed since the uplift of the old base-levelled sur- face, to enable the Grassy River to erode its channel to such an extent. Had the river erosion reached a less mature stage, sufficient fall would have been available to permit of the generation of power. The grade of, the river-bed is too flat for some distance from the mouth to render this feasible, although the river will supply the water required for dressing purposes. (7) Water-supply. No records of rainfall in the immediate vicinity of the mine appear to have been kept, but judging from records from other parts of the island the average annual rainfall in this district would probably be about 35 inches. This amount 6 is fairlv well distributed throughout the year, and for no month 'is the fall negligible. The soil in the neighbour- hood is clavev. and is inclined to retain moisture for some time consequently the supply of water to the creeks is more regular thai would be the case with a very open sandv soil Under these circumstances it is not surprising to find that the Grassy River carries sufficient water throughout the vear for the purpose of ore-dressing and other operations "connected with the working of the mme. As noted above when referring to the topography, it is unfortunate that the river has not sufficient tall .o allow of the generation of power, so far as it was examined. A race of some length would be required to bring in water at a sufficient elevation for utilisation in connection with the plant, and it will probably be found more economy to in-tal a pump at a suitable point in the lower reach-s o( the river, and raise water to the selected machinery site. (8) Timber. Although there is no green timber of anv size in the neighbourhood, there is abundant dead timber standing, which will supply the demand which us likely to anse for some years to come. This timber was killed by an exten- sive bush-fire several years ago. It comprises mainly gu trees, with some blackwood, and in most cases the trees rise to considerable heights before branching, y 1€1 °S straight trunks of considerable size, which will be valu- able ~for structural purposes. On the island there is a tendency for the standing dead timber to rot after some years but at present much of it seems sound. ' There will be need of timber for firewood as well as for structural purposes, and the demands m tion can be supplied for some years without difficulty by timber in the immediate neighbourhood. . . One or more short tramlines will be required to tap the best belts of timber, and these will be constructed at com- paratively small expense along the brow of the ndge and the timber sent down to the works at a lower level by a chute. (9) Mixing Facilities. The propertv is verv favourably situated, and offers splendid facilities for economic mining The ‘°P°^P hl ™; features have been described, and it has been shown tha. / the land surface slopes steeply down to a narrow coast il strip a few feet above sea-level. It is on the face of this slope that prospecting operations have been carried out up to the present. The fact of the scheelite lode occurring below the surface soil on this steeply sloping hillside means that it may be not only tested, but also mined economic- ally. Adits may be driven on the course of the formation, and the advantages of driving in ore all the way are obvious. Crosscuts, should be driven at intervals across the ore-body to disclose its width, structure, and value. The advantages of working from adits in preference to shafts scarcely need comment. Nearly 200 feet of backs can be obtained by driving a low-level adit. This amount of backs, given a reasonably long shoot of ore, would represent a large tonnage with such a wide ore-body. Above 200 feet the hill rises more gradually, attaining a maximum of about 370 feet in the vicinity of the north- western corner of the section, but to obtain the Fame amount of backs here a much longer adit would be neces- sary than lower down the hillside. An advantage of being able to work by adits in this particular case is that the ore-body will at the same time be prospected and opened up, and that ore will be won from the prospecting drives unless it should be found advisable, as indicated elsewhere, to drive in the country- rock and crosscut across the deposit. Work carried out under the conditions existing on this property has the obvious advantage of ample space for tipping spoil. The topography, too, makes it possible to lower the ore by gravitation direct from the working adits to the treatment plant which would be situated at the foot of the slope. Tailings from the mill could be dis- posed of without any trouble after their valuable con- stitutents have been extracted, by depositing thmi on the beach below, to be distributed by wave action. A very important facility offered by the property is that a considerable amount of ore may be extracted by open- cut methods, which, of course, very considerably reduces working costs. The ore itself, as already opened up, undoubtedly would be economical to work on account of its comparative soft- ness, but this advantage may disappear when true unal- tered primary ore is encountered. II.— GEOLOGY AND MINED ALOGY. (1) Dock Formations Developed. It is necessary to deal briefly and in a general way with the rock formations developed in the neighbourhood of tho mine. Both igneous and sedimentary rocks are repre- sented ; the latter occupy the bulk of the area of the mining lease, although the south-eastern corner peg is actually on the contact of granite and sedimentary rocks. Granite outcrops for 7 or 8 miles along the coast to the south of the mine, and appears to extend inland for at least 2 miles. Old slates and sandstones extend to the north for some distance, succeeded by a series of tuffs and igneous breccias about 3 miles north of the mine. The granite is a handsome coarse-grained rock, carrying abundant phenocrysts of orthoclase felspar which give it a distinctly porphyritic facies; it is a porphyritic bjotite granite. It is very fresh, and shows no signs of crushing. At the contact granite porphyry occurs, with occasional large crystals of pink orthoclase felspar. The granite is traversed by occasional dykes of granite- porphyry and of aplite, representing probably some of the later phases of the igneous intrusion. The granite massif is also traversed by narrow dykes of dense dark-blue basic rocks. Two of these rocks were examined microscopically, and one occurring on the point south of the mine, where it is proposed to construct a jetty, proved to be a basalt, while a few chains further south was a dyke 6 feet wide of hornblende-lamprophyre. Closely associated with the scheelite lode and exposed in the No. 1 Adit is a dyke of aplite undoubtedly connected with the granite. It is a white rock, and is locally known as “ porphyry.’ ’ Microscopical examination shows that it is composed essentially of quartz, with some decomposed felspar and aggregates of muscovite mica. It carries both molybdenite and scheelite in places. The scheelite lode is in the sedimentary rocks, but within about 12 chains of the margin of the granite massif. As is to be expected in such close proximity to the intrusive gran- ite mass, the old sedimentary rocks are intensely altered. They appear sometimes as spotted schists, sometimes as very hard black flinty hornstones. The microscopical examination of thin sections of these rocks shows that there are developed quartz, albite, sericite, chlorite, biotite, and 9 magnetite — minerals typical of the contact metamorphic aureole of a granite massif. These rocks usually retain their banded structure, and although they have suffered intense alteration, they can as a rule be readily recognised as sedimentary rocks. In the immediate vicinity of the lode formation, bands of an intensely hard dense pink and green rock are developed. Microscopical examination of thin sections shows that these bands are composed essentially of aggregates of garnet in a groundmass of granular mono- clinic pyroxene, with a little interstitial quartz. This rock, on account of its excessive hardness and toughness, gives trouble in mining operations, for it is not only very diffi- cult to drill, but it shoots badly also. Fortunately, how- ever, the bands so far encountered in the workings carried out have not been more than a few feet in thickness. This rock is referred to below as garnet-pyroxene rock. The sedimentary rocks do not outcrop at many points in the vicinity of the mine, and no strike or dip can be assigned to the formation as a whole, nor is there any evidence of folding of the strata. In such close proximity to the huge intrusive mass of granite it is not surprising to find that the sediments are a good deal shattered. On the beach about 3 chains south of the originally discovered scheelite outcrop the sediments strike N. 21° E. and dip east at 49°. About 1 chain north of the outcrop the strike is east and west. There is no evidence available to fix the age of the sedi- mentary rocks, although the writer believes them to be of approximately Ordovician age. The age of the intrusive granite cannot be fixed, but it may perhaps be Devonian. It is uncertain how far these rocks may be correlated with similar ones developed in Tasmania, but this question will be dealt with in the writer’s general report on King Island, now in course of preparation. Where exposed in the mine the footwall country-rock strikes at different points at angles varying from N. 35° W. to N. 50° W., and dips south-west at angles from 35° to 55°: On the other hand, the hanging-wall, as exposed, appears to strike about N. 50° E., and dips south-east at 25°. This apparent anomaly is referred to below. A very interesting occurrence was noted in the open- cut at the entrance to the No. 2 Adit, viz. , of water-worn gravel and shingle. This was accidentally located between 7 and 8 feet below the present surface in sinking a shaft through the surface material. This shaft has since been filled up. The bed of gravel is said to have been between 10 3 and 4 feet in thickness, and to have been resting directly on decomposed garnet rock. The pebbles are of all sizes, from gravels to boulders 6 inches in diameter, and are thoroughly water-worn. They consist mainly of quartzites and of fragments of rock similar to those found in the adjacent country. The elevation is about 130 feet above sea-level. No other such material has been disclosed, and the occurrence of one small patch of water-worn gravel so high above sea-level is rather puzzling . It may be a remnant of river gravel accumulated by some stream when the sur- face contour was different from that of the present day, but the writer is inclined to think it forms part of a deposit of beach shingle. As mentioned elsewhere, the land surface in this vicinity represents an old peneplaned surface which had been worn down approximately to sea-level, and sub- sequently uplifted by earth movements, and again subjected to the degrading action of atmospheric agencies. No posi- tive evidence was obtained elsewhere as to whether this uplift was a simple movement or a succession of move- ments, but if the latter be true, a certain time-break between successive uplifts may be postulated, and during one of these intervals the shingle observed may have accu- mulated on the shore at sea-level, and have attained its present position by either a single movement or several movements, amounting to 130 feet. Further deposits may be disclosed as work proceeds, and they are of such geo- logical interest that their occurrence should be recorded. (2) The Nature of the Ore-body. It is not the writer’s purpose in this section to discuss the nature of the ore and the mode of origin of the deposit in minute detail, but rather to give a general description of the ore-body with a statement of what the writer believes to be its mode of origin. (a) Mineral, ogical Composition. The ore consists essentially of garnet (usually in well- formed crystals), showing a more or less defined banded structure. The other gangue minerals observed were quartz, epidote, calcite, monoclinic pyroxene, and actino- lite. The metallic minerals noted were scheelite, molyb- denite, pyrite, and bismuth; assays show the presence of tin, probably as cassiterite, although this mineral was not seen. 11 Scheelite (Tungstate of Lime, CaW0 4 ). — -This is undoubtedly a primary mineral. It occurs both in amor- phous masses and in definite crystals, doubly terminated tetragonal pyramids of small size being not uncommon. The largest crystal observed measured over 1 inch across. The colour is pale olive-green, streak white, hardness 5, specific gravity 5*91 . The mineral shows distinct cleavages, has a sub-adamantine lustre, and is translucent on thin edges. The scheelite frequently occurs in quartz veins traversing the garnet formation and the aplite, and molyb- denite is also often seen in these quartz veins. The two minerals are intimately associated. In several instances molybdenite was noted included in the heart of scheelite crystals, while in other cases masses of scheelite were sur- rounded by a rim of molybdenite flakes. The quartz veins referred to usually carry a little white mica, and in one case epidote was noted in addition to scheelite and molyb- denite. That scheelite is disseminated through the garnet forma- tion as well as being present in the noticeable quartz veins is shown by the assay results published elsewhere in this report. The mineral is present also in the white aplite exposed in the No. 2 Adit, although only in small quantities. Molybdenite.— This mineral has the usual physical characters, which do not call for special mention here. It occurs in tabular hexagonal crystals and plates, not usually exceeding one-quarter inch across. It is most abundant in the quartz veins which traverse the garnet formation, where it is not uncommonly accompanied by scheelite, and appears to be closely associated with the aplite dyke. Scattered flakes are seen in the aplite, and occasionally in dense gar- net-calcite lode material with no visible quartz. On the whole the mineral is not abundant in the lode, and although from time to time small quantities of high grade ore may be hand-picked from vughs and bunches in the quartz veins, molybdenite is at present not of great economic importance. Pyrite . — Pyrite is present in the ore, but in small quan- tities only, and in the ore at present opened up is not suffi- ciently abundant to be detrimental to the production of a high-grade concentrate. As the workings eventually extend to a greater depth, it is possible that the mineral may become more abundant, but there is no reason to believe that it is likely to prove a serious obstacle in the production of a marketable product. Bismuth . — At one spot only (in the No. 1 West Crosscut of the No. 3 Adit) was native bismuth seen in the mine 1*2 workings, when several small fragments were obtained by the manager : it probably occurred, at the locality men- tioned, in a quartz vein. Numerous assays made of samples from different parts of the mine showed that bismuth is not confined to this one locality . The details of these assays are recorded in a later part of this report. The occurrence of bismuth is important, because of the possibility of the mineral causing a penalty to be imposed on the concentrate if it exceeds a certain amount. Bismuth is exceedingly detrimental in steel manufacture, and a scheelite concentrate carrying much bismuth would not be accepted for steel-hardening purposes. The amount of bis- muth allowed at present is one-half per cent, in a scheelite concentrate, but tungstic acid is so urgently needed at present that probably slightly more than this amount would not render the product unsaleable, although a penalty might be imposed. Further reference is made to the pres- ence of bismuth in discussing assay values of the ore. Garnet . — The variety of garnet represented appears to be andradite. It is usually reddish in colour and translucent, and occurs in well-formed crystals up to about one-quarter inch across, the forms represented being usually a combina- tion of the dodecahedron and tetragonal trisoctahedron. Owing to the importance of the mineral when the question of treatment is being considered determinations were made of the specific gravity of the garnet. The values obtained varied from 3‘4Q to 4’ 19. The hardness is about 6 o. The garnet is attracted by the electro-magnet, and was found to be of about the same magnetic permeability as wolframite. This at once suggests a possible method of treatment. This question is dealt with elsewhere. (&) Structure. It is important to consider the structure of the cre-body as well as its mineralogical composition. Unfortunately, little definite information was available at the time of the writer's visit, and it is only in the light of further develop- ments that the structure can be clearly understood. The outcrop originallv discovered by Mr. T. Farrell is on the beach at high-water mark . at certain times it is covered bv drifting beach -sand. It consists of hard banded garnet - pvroxene rock carrving a little scheelite in places. These bands strike ab:ut N. 65° W., and dip vertically. A little work was done on the lode-formation just above high-water level and- a shaft was sunk 25 feet on the formation at a point 14 chain inland from the beach outcrop. From the 13 result of these workings it was assumed that the lode was really dipping vertically, and such an assumption was justi- fied at the time. About 6 chains inland, at the base of the hill, an adit was driven, apparently on the line of strike, but failed to cut the lode-formation. The ore-body did not outcrop at the surface. Higher up the hill another adit (No. 3) was driven on the lode, and, still assuming that the 'hp was vertical, two other adits .were commenced lower down (No. 2 and No. 1), and should have intersected the formation had it b.een vertical. The relative positions of these workings are shown in Plate II. Although in No. 2 Adit an aplite dyke carrying scheelite and molybdenite was disclosed, the ore-body as exposed above was not located. In No. 1 Adit hard garnet-pyroxene-calcite lode material was cut, but it is doubtful if this corresponds with the lode exposed higher up. These workings showed that the lode formation was not dipping vertically as was supposed. Crosscuts driven across the formation in the No. 3 Adit exposed both walls, and a study of these exposures yielded some important information. In the face of the short cross- cut north-east the footwall is just exposed, and strikes N. 45° W., dipping south-west at 35°. At three points along the main drive the readings were respectively, strike N. 50° W., dip S.W. at 55°; strike N. 35° W., dip S.W. at 55°; and strike N. 35° W., dip S.W. at 52°. From these exposures it would appear that average values for the foot- wall would be strike N. 45° W., dip S.W. at 50°. The hanging-wall was only exposed at one point, viz., in the face of the south-western crosscut from the No. 3 Adit, and here the strike appears to be N. 45° E., and dip S.E. at 25°. It is unfortunate that further exposures of hanging- and foot-walls were not available, as the strike and dip cannot be definitely determined from these particulars. The strike «md dip of the hanging-wall appear to be different from those of the footwall, but too much reliance cannot be placed upon a single observation. It is clear, however, that the iormation is not dipping vertically, as was assumed from an examination of the original outcrop. From the avail- able exposures of the footwall, the formation appears to be dipping (at the level of the No. 3 Adit) to the south- west at about 50°. Such being the case, it is easy to under- stand why the three lower adits (which were driven on the assumption that the lode-formation was dipping vertically) failed to cut the ore-body exposed above. Assuming the dip to be as above, the writer recommended the driving of a crosscut from the No. 2 Adit to intersect the formation 14 exposed above. This work was entirely successful, the ore- body being located, showing that the previous workings were too far to the north. The crosscut referred to was being driven at the time of the writer s examination, and the body of ore had not been cut through. The footwall here is not well defined. The aplite is m contact with an exceedingly hard banded garnet-pyroxene rock and this appears to" merge into typical garnet-calcite lode-material with irregular aggregates and veins of quartz carrying ric scheelite and a little molybdenite. The wall appears to strike about N. 10° W., and dip west at about 40°. These observations of the strike and dip of the wall of the ore-bodv vary considerably, but emphasise one important point, viz., the necessity for prospecting along the hne of strike, to determine definitely the structure of the ore body in order that future work may be planned to advan- tave. If the exposures of footwall and hanging-wall in the No 3 Adit as noted above represented true average values for these walls, it is clear that longitudinally the ore-body would taper out within a comparatively short distance ahead. As noted above, however, it is unsafe to attempt to predict on the evidence of the exposures available, since a purely local irregularity may account for the apparent discrepancy. „ , . „ If the ore-deposit be a replacement of a bed of more ol less impure limestone, as suggested below, it may be to some extent irregular in outline, though l ar f el y jJ e P ende ^ upon the form of the original calcareous bed. There is no evidence to show the size or extent of such a bed. Thus the small amount of information available to throw light on the true structure of the deposit serves to empha- sise the importance of prospecting to definitely prove the extent of the ore-body. There are indications that a small amount ot faulting may have taken place, to judge by fissures intersected m driving Thus in the No. 2 Adit, 1 1 feet beyond the winze is a fissure striking N. 55° W., and dipping south-east at 60° • this shows slickensides, and marks a change from hard banded garnet rock to shattered slate and quartzite suc- ceeded by garnet-pyroxene bands. In the lower (No. 1) adit a well-defined fissure, now filled with kaolin was inter- sected along the main crosscut south-west at 30 feet from the main adit, striking about N. 50° W., and dipping vertically; this fissure also marked a change in country. Again in a small crosscut driven from further along the course of the same adit, a similar fissure was noted, and has the same strike and dip as that just noted ; this also marks a 15 change to shattered country-rock. These three fissures apparently correspond, and mark a continuous fault-plane which may, perhaps, be continuous and correspond with the fissure intersected in the sharp elbow bend of the No. 3 Adit, which forms a regular water-channel. From the slickensides and shattered country-rock it seems evident that there has been some movement, but what influence this fault has upon the structure of the ore-body cannot yet be determined. It appears, however, to be in the footwall country. Other fissures were noted in some of the workings, but so far there is no definite evidence to show that faulting has modified the structure of the ore-body. (c) Mode of Origin. It remains to state briefly the writer’s opinion as to the mode of origin of the deposit. There can be little doubt that the deposit is genetically connected with the neighbouring granite massif, and that the metallic constituents were introduced with the granite magma, differentiation causing a partial concentration of these constituents in the still molten magma. These were expelled as gases at an extremely high temperature as the magma gradually cooled and consolidated, and penetrated the overlying sedimentary rocks which were at an extremely high temperature. The aplitic dyke may represent the main channel by which the metallic minerals were conveyed to their present position, the quartz and felspar represent- ing granitic material which was expelled with the metallics from the cooling granite mass. It seems likely that the ore-deposit was formed when the chemically active ana metal-bearing vapours and solutions came into contact with calcareous beds, which were almost completely replaced, the metals being deposited. The outstanding features which indicate that some such theory must be postulated to explain the mode of origin of the ore-body are: — (1) The banded structure of the deposit. (2) The occurrence of bands of country-rock altered to garnet-pyroxene outside the main body ot ore. (3) The miner alogical composition of the ore, and especially the presence of so many lime-bearing minerals (scheelite, garnet, diopside, calcite, epidote, actinolite). (4) The close association with the aplite dyke which itself carries metallic values. (5) The high-temperature minerals present. jjj THE MINE WORKINGS. vr Q mine plan was available on which the position of pr ?r“s.“ — «f •" w *"■> “‘rpSs'n , T rrs ? :siii"p2z:'-d srxK^ii m n»i. 8 s~ *«■ - . ATo 1 Adit —This was at the time of the writer s exami S.-JSS- — fl taTh^al^^ dipping vertically^ The approach is 23 feet in ^gth and ssi..i,i.. stst; ;U£ g ‘- °i sc. » t„, K « to* srtrccir STL. drive passed through similar decomposed white sandstones, meting Tto hard white quartzites carrying crystals of pyrite. S Here there is apparently a e ^ rep ^ e aip. bv a fissure filled with clay, striking N. 50° W-, and dip nLv vertically Beyond this the slates are much shattered they merge into soft clays (representing weathjed ^slates) S TT^ndX ping 3 ^ verticafty. ne ^not^e”^.0 ^feet on^ lrnrd -banded garnet X makes ii appearance. In the face ve^y har^ green garnet-pyroxene rock occurs. At 1 no feet from the main drive) a drive has been extended for 38 feet on a bearing N. 47° W a short crosscu bemg d iven north-east for 11 feet at a distance of 22 feet Lhe dnve exnoses well-banded garnet rock. Some bands ot gar rock are soft and partly decomposed; others are hard and contain abundant calcite and pyroxene (the la ttermineral only distinguishable microscopically), while other .bands again are intensely hard and tough, green and pmk in colour, and consisting of garnet and pyroxene^ In the lace lhe rock is hard garnlt-calcite, still showing a banded struc- 17 ture. These banded rocks have a general strike N. 70° W., and dip south at about 35°. In the 11 feet crosscut referred to, the strike is N. 60° W., and dip S.W. at about 30°. In this crosscut, 2 feet from the face, the garnet rock is traversed by a well-defined fissure — apparently a fault plane — striking N. 50° W., and dipping vertically. Beyond this the country-rock is a good deal shattered. This fissure apparently corresponds with that exposed in the crosscut from the main drive, as noted above. As described below, the garnet rock exposed in the No. 1 Adit carries low scheelite values; it appears, however, to be a distinct formation from that exposed in the Nos. 2 and 3 Adits higher up the hill. No work was being carried on in this adit at the time of the writer’s examination. No. 2 Adit . — This was driven into the hillside from a point about 136 feet above sea-level, or 30 feet above No. 1 Adit. A small open-cut had been taken out at this point for 20 feet, the width being 30 feet. The surface material carries scheelite, and with the soil is a good deal of garnet in crystals and crystal aggregates derived in the course of weathering from the ore-body a little higher up the hillside ; angular quartz is also noticeable. This material is 6 feet in depth, and rests on white aplite, which carries low tungstic acid values. From the face of this cut the adit is driven on a bearing of N. 47^° W. for 36 feet, when it bends to N. 14° E. for 26 feet to the face; 13 feet from the face a winze was sunk 10 feet. This was the condition of the adit when the writer first visited the property, but at his recommendation a crosscut was commenced from the bend in the drive 36 feet from the entrance, and had been driven 33^ feet on a bearing S. 44 \° W., exposing good ore. There is a considerable variation in the rocks passed through in this adit. Driving was commenced in aplite somewhat softened by weathering. This rock was traversed by a quartz vein 5 feet from the entrance, width 3 to 13 iucbes, carrying a good deal of scheelite. At 17 feet from vhe entrance the junction of aplite with decomposed sediment- ary rocks is to be seen striking N. 37° E., and dipping west at 26°. On the south-western wall aplite appears in the lower portion of the drive, junctioning with shattered and fissured metamorphosed sedimentary rocks above; the aplite itself is much jointed. Similar conditions prevail to the easterly bend in the drive 36 feet in. At 5 feet beyond this aplite appears again in dyke form, with walls which are sharply defined, although irregular (apparency 18 following certain joint-planes of the s^imentanes) The ad acent sedimentary rocks are much decomposed, but merge into bands of very hard pink and green gamet- P Tt X 13 e fe 0 et k from the bend, or 49 feet from the |ntrance, a winze was sunk in the western wall to a depth of 10 wet- This exposes banded garnet and garnet-pyroxene rock ^n contact with aplite occurring in dyke form. Quartz vel “ s ’ which sometimes carry a little scheelite, molybdenite, and ovrite traverse the garnet rock or occur at the junction of aplite and garnet rock; these are obviously connected genetically with the aplite, which continues underfoot From the^winze to within 2 feet of the f ace is hard banded aarnet rock Here a fault plane showing slickensides, with a strike N. 55° W. and dip BM. at 60 °, marks a change to shattered slate country with some bands of hard black quartzite and a little garnet-pyroxene rock. At the time of the writer’s final examination of the work 4 . — we » “* ” £ direction from the bend m the adit 36 feet trom tne entrance. At the collar of this crosscut aplite occurs dip- ping at about 25° and rising into the roof. This is m con P ct with a band of extremely hard green garnet-pyrox ne rock, which shows a banded structure , the . bands stoke about north-west and dip south-west at about 6 . feet from the collar of the crosscut is a quartz vein sho ® 1 “| in the roof about 12 inches in width, which carries a Hitt white mica good scheelite values, and richer molybdenite than was seel at any other spot in the mine. On the south- ed wall this quartz vein dips 2 .feet in a distance of 3 feet horizontally, and then rises again into the roof 4 feet tu ther along the course of the drive. This vein is appare y connected with the aplite intrusion . On jposite wa 1 at 10 feet from the collar, is a small dyke of aplite about 1 inches in width bordered by a vein of quartz with white mica and rich scheelite. At 17 feet in aplite dj sa PP earB ln the north-west wall ; quartz shows in the roof with scheelite garnet and mica. Banded garnet rock occurs here on the opposite wall, with scheelite. At 22 feet is ^ apparent wall, which is not very distinct but appears st "^ 0O few degrees west of north and dip west at 35 or 4U . There appears to be rather a merging into garnet lode material than a true wall, for from this point to the face the crosscut passes through crystallised garnet with calcite with irregular masses of quartz the whole trav ® rs ®| .^7 veins filled with soft decomposing micaceous material. 19 Sampling showed that this lode material carried good tungstic acid values, which is not surprising, as masses of scheelite are visible in places. No. 3 Adit . — This was the highest adit, and that in which most ore was exposed. Aneroid readings indicated that it is about 172 feet above sea-level, or 36 feet above the No. 2 Adit. It is a tortuous drive, and the work has scarcely been carried out to best advantage. An approach has .been cut on a bearing N. 37° W. for 64 feet to the entrance of the adit. At the entrance the floor is 21 feet below the surface. This is through soft decomposed gar- net rock near the surface, merging into harder material at a greater depth . The garnet rock is banded and is traversed by quartz veins frequently parallel with the banding, and carrying both scheelite and molybdenite. From the present entrance crosscuts extend east and west to the walls of the formation, exposing a valuable section of the deposit. The main adit extends 24 feet on a bearing N. 33° W. through banded garnet rock, frequently soft, but with some harder bands of garnet-pyroxene and occasional quartz veins. Bending to N. 72° W. the main adit extends for 38 feet through country rock, consisting mainly of slate with some harder garnetiferous bands. There is a well-defined quartz vein at the end of this length of drive, striking N. 10° E., and dipping west at 65°. Water is fairly abundant here, and a good deal of limonite is being deposited. The- drive now makes a sharp bend, and apparently runs on a course about parallel with that originally followed, as the bearing is S. 35° E. for 38 feet. This portion of the drive exposes mainly hard-banded garnet ana garnet-pyroxene rock. At 31 feet a quartz vein was noted, and this appears to mark the change to softer (more weathered) garnetiferous lode material similar to that exposed in the crosscuts from the entrance to this level. The last section of the adit, 14 feet in length, is driven on a bearing of S. 23° W. through similar material. It appears that at the face the adit is only about 10 feet from the south-western crosscut, so irregular has been its course. As noted above, crosscuts were driven from near the entrance to this adit, both north-east and south-west, expos- ing the width of the formation at this point. The former extends for 15 feet only, on a bearing N. 69° E., through soft garnetiferous lode material, exposing slate country rock (softened by weathering) in the face. The other crosscut bears S. 69° W. for 17 \ feet, when it bends further to the south, continuing for 45 feet on a bearing S. 36° W. before 20 bending still further south. The final length bears S. 4 W. for 18 feet to the face, where soft decomposed slate country-rock is again exposed. This crosscut passed through crystallised garnet material, only partly coherent in places, but sometimes harder and carrying calcite. The banded structure is not always noticeable, but is frequently traceable. A little quartz is visible in places; one vein runs for some distance parallel with the banding ot the ore (usually about horizontal), is one-quarter to 3 inches m width, and carries visible scheelite and molybdenite. Assay values quoted elsewhere show that the whole of the garnet formation exposed in these crosscuts carries scheelite. Lowest Adit (Collapsed ). — Near the foot of the hill, and about 6 chains from the shore, an adit was driven into the hill in the hope of cutting the ore-body, but only country rock (hard slates and quartzites) appears to have been passed through. This adit has now completely collapsed but is said to have been driven for 120 feet. The general direction was N. 74° W. Upper Adit (Collapsed ). — Higher up than the group of main workings, about 5 chains north-west of No. 3 Adit, is another adit, now completely collapsed. This is said to have been driven 30 feet from the approach, and to have just cut hard garnet rock. It is to be regretted that the for- mation was not completely exposed here. No. 1 Shaft . — This shaft was sunk on the scheelite deposit near the outcrop originally discovered. It is only about 120 feet from the outcrop on the beach which is covered at high tide, and on a terrace about 20 feet above sea-level. The shaft is partly full of water and quite inaccessible. It is said to have been sunk to a depth of 25 feet on a garnet formation carrying scheelite values. It is a little doubtful whether this formation is the same as that exposed in the adits higher up the hill. This question has been referred to when dealing with the structure of the ore-body. No 2 Shaft . — This shaft was sunk at the head of a small creek to a depth of 20 feet on a massive garnet formation carrying some fine scheelite. The shaft is situated about 4^ chains south-west of the No. 3 Adit, and at an elevation of about 150 feet above sea-level; it is now inaccessible on account of water. A grab sample from the heap of gar- netiferous material at the collar of the shaft showed as a result of assay 1*55 per cent, of tungstic acid. This for- mation appears to be a distinct one from that opened up by 21 the main workings. A trench (now partly full of water and inaccessible for sampling) exposes about 25 feet of similar garnet material to that exposed in the No. 3 Adit, with aplite just showing on the east side of the trench. No change in the formation is said to have been observed at the bottom of this shaft. No. 3 Shaft .- — This shaft was sunk on a terrace high up on the hillside about 10 chains north-west of No. 3 Adit. Aneroid readings show that the elevation is about 300 feet above sea-level. The shaft was sunk on what was supposed to be the line of outcrop of the main ore-body, but the result was negative, and work was abandoned after sink- ing 35 feet through hard metamorphosed slate country- rock, which sometimes showed faulting on a small scale. Garden Workings . — About 25 chains west of the main workings the approach to an adit was commenced at the head of a small creek. Solid rock was not exposed, but garnets are present in the surface material, from which small quantities of scheelite can be obtained on vanning. There appears to be in this vicinity an ore-body quite dis- tinct from any other exposed on the property, which should be prospected. UNIVERSITY OF ILLINOIS LIBRARY OCT 1 8 IV.— ASSAY VALUES. In the previous chapter a general description has been given of the different workings and of the nature of the ore and country-rock opened up by the workings. It remains to discuss assay values of the ore exposed on the property. All samples were taken by the writer, and were assaved by Mr. W. D. Reid, Government Assayer m the Geological Survey Laboratory, Launceston. In ail samples tungstic acid was determined, as this is the most important constituent. A little molybdenite was visible in some samples, but clearly it was not present m sufficient quantity to be an important constituent of the ore. Hence the metal was not determined in all samples, but only in sufficient of the samples to demonstrate the low values actually existing in the ore. Reference has been made in dealing with the mineralogical composition of the ore to the presence of bismuth and cassitente as impuri- ties and to the importance of these minerals should they be present in appreciable quantities. The official pro- clamation dealing with the purchase of wolframite and scheelite specifically states that neither bismuth nor tin must exceed b per cent, in the concentrate. It becomes essential, then, to determine the quantities of these impurities present, and this has been done m the case of all really representative samples of ore taken. It is of interest to note that although bismuth was detected by Mr. T. Farrell in one locality, the presence of tin m the deposit does not appear to have been suspected ; it proves to be fairly widely disseminated, although m com- paratively small amounts. . With reference to the actual constituent determined in the samples, it is of less value to know the actual schee- lite content than that of tungstic acid, as ore values are based on the latter constituent. Should the scheelite (Ca WO.) content be desired, however, it may be derived from the tungstic acid (WO a ) on multiplying by 1 24. Similarly, the molybdenite value (Mo S 2 ) may be obtained from that quoted for molybdenite (Mo) on multiplying by 1668, and the cassitente value (Sn from metallic tin (Sn) on multiplying by 127. The factors quoted are approximately correct. It sometimes happens' that there are replacing elements in the minerals which would vary the factors slight 1 y. With reference to the mode of sampling, the sample^ were broken as nearly as possible at right-angles to the 23 dip of the formation. Samples taken at this angle, but at 7-feet intervals when measured horizontally along the wall of a drive, would be 5 feet apart when measured at right-angles to the line of the samples. The occurrence of veins of quartz carrying visible scheelite, in places running parallel to the banding, might lead to grave discrepancies if samples were taken parallel to the banding of the ore. The results of sampling were as follow : — (W0 3 = Tungstic Acid, Mo. = Molybdenum, Bi. = Bismuth, Sn. — Tin.) No. 1 Sample. — From No. 3 Adit, south-western cross- cut face; hanging-wall country-rock. Result: WO s , trace. No. 2 Sample. — From No. 3 Adit, south-western cross- cut, eastern wall 7 feet from face ; hard crystal- lised garnet with quartz veins; width 7 feet. Result W0 3 , 2-80 per cent; Mo., O' 14 per cent, ; Bi., 0*17 per cent ; Sn., trace. No. 3 Sample. — From No, 3 Adit, south-western cross- cut, eastern wall, 14 feet from face; hard garnet rock with softer bands; width, 7 feet. Result: W0 3 , 1*30 per cent,; Bi., 0*01 per cent. ; Sn., 0’015 per cent. No. 4 Sample. — From No. 3 Adit, south-western cross- cut, south-eastern wall, 21 feet from face; lode- material similar to No. 3 ; width, 7 feet. Result: W0 3 , 0’88 per cent. ; Mo., 0*011 percent.; Bi., 0-045 per cent. ; Sn., 0*15 per cent. No. 5 Sample. — From No. 3 Adit, south-western cross- cut, south-eastern wall, 28 feet from face; material similar to No. 3; width, 7 feet. Result: W0 3> 040 per cent.; Bi., trace; Sn., nil. No. 6 Sample.— From No. 3 Adit, south-western cross- cut, south-eastern wall, 35 feet from face ; material similar to No. 3 ; width 7 feet. Result: W0 3 , 1*10 per cent.; Mo., trace; Bi., 0’025 per cent.; Sn., 0*017. No. 7 Sample,— From No, 3 Adit, south-western cross- cut, south-eastern wall, 42 feet from face; material similar to No. 3 ; width, 7 feet. Result: WO s , 1*22 per cent.; Bi., 0*013 per cent.; Sn., trace •24 No 8 Sample.— From No. 3 Adit, south-western cross- cut south-eastern wall, 49 feet from face; handed har’d and soft garnet lode material with some quartz ; width, 7 feet. Result: WO„ 1'83 per cent.; Mo., 009 per cent.; Bi., 0085 per cent.; Sn., 0'20 per cent. No. 9 Sample.— From No. 3 Adit, south-western cross- cut, south-eastern wall, 56 feet from face; similar material to No. 8 ; width, ( feet. Result: W0 3 , 1*66 per cent.; Mo., nil; Bi., 0*08 per cent. ; Sn., trace. No. 10 Sample. — From No. 3 Adit, south-western crosscut, south-eastern wall, 63 feet from face; similar material to No. 8; width, 7 feet. Result: W0 3 , 0*93 per cent.; Mo., trace; Bi., 0-026 per cent.; Sn., 0016 per cent. No. 11 Sample.— From No. 3 Adit, south-western crosscut, south-eastern wall, 70 feet from face; similar material to No. 8: width, 7 feet. Result: W0 3 , 2*51 per cent.; Bi., 0015 pe. cent.; Sn., 0‘ 30 per cent. No. 12 Sample.— From No. 3 Adit, northern cross- cut, south-eastern wall, 3J feet from adit; hard and soft garnet lode material. Result: W0 3 , 1*03 per cent-.; Mo., 0*027 per cent.; Bi., trace; Sn., Oil per cent. No. 13 Sample.— From No. 3 Adit, northern crosscut, south-eastern wall, hard and soft garnet lode, foot- wall side, 10^ feet from adit; width, ( feet. Result: W0 3 , 117 per cent.; Bi., nil; Sn., 0*012 per cent. No. 14 Sample.— From No. 3 Adit, northern crosscut face; footwall country-rock. Result: W0 3 , 0*20 per cent. No. 15 Sample.— From No. 3 Adit, south-western wall, 10 feet beyond crosscuts; bands of soft garnet with harder garnet-pyroxene bands and a little quartz ; width, 7 feet. Result: W0 3 , 1*71 per cent.;. Mo., trace; Bi., nil; Sn., nil. 25 No. 16 Sample. — From No. 3 Adit, south-western wall, 18 feet beyond crosscuts; similar material to No. 15 ; width, 7 feet. Result: W0 3 , 1*44 per cent.; Bi., nil; Sn., trace. No. 17 Sample. — From No. 3 Adit, south-western wall, beyond bend, 30 feet from crosscuts; very hard banded garnet-pyroxene rock; width, 7 feet. Result: WO„ 0'40 per cent. No. 18 Sample. — From No. 3 Adit, north-eastern wall, 31 feet beyond very sharp bend (21 feet from face) ; soft garnet lode material, with very hard garnet -pyroxene bands; width, 7 feet. Result: W0 3 , 1*00 per cent.; Bi., nil; Sn., O' 015 per cent,. No. 19 (Sample. — From No. 3 Adit, north-eastern wall, at final bend 6 feet beyond No. 18, and 15 feet from face; very hard garnet-pyroxene rock, with some softer garnet material; width, 7 feet. Result: W0 3 , 0'30 per cent.; Mo., trace; Bi., nil; Sn., nil. No. 20 Sample. — From No. 3 Adit, south-eastern wall, 6 feet beyond No. 19, and 9 feet from face; soft garnet lode material, with hard band, with quartz at bottom of adit : width, 7 feet. Result: W0 3 , 1*27 per cent.; Bi., trace; Sn 0’018 per cent. No. 21 Sample. — From No. 3 Adit face; hard and softer bands of garnet rock; width, 6 feet. Result: W0 3 , 0'70 per cent.; Mo., trace; Bi, nil; Sn., 0’012 per cent. No. 22 Sample. — From No. 3 Adit entrance, immedi- ately over junction with crosscuts, from subsoil (3 tt feet below surface) down for 6 feet across bands; soft oxidised material consisting mainly of coarse garnets. Result: W0 3 , 1'50 per cent.; Bi., nil; Sn., 0'013 per cent. No. 23 Sample. — From No. 3 Adit entrance, north- east wall, 12 feet south-east of No. 22, from 4J feet below surface to floor of adit approach, 12 feet; soft oxidised material consisting mainly of coarse garnets. Result: W0 3 , 1'90 per cent.; Bi., nil; Sn., 0*011 per cent. 26 No. 24 Sample. — From No. 2 Adit north wall, 10 feet from entrance ; hard fissured aplite ; height, 6 feet. Result: WO a , 0'41 per cent. ; Mo., 0'04 per cent.; Bi., nil; Sn., nil. No 25 Sample. — From No. 2 Adit, both walls, 20 feet from entrance, upper 3 feet; hard banded garnet and garnet-pyroxene rock, with some softer bands to their junction with aplite. Result: WO„ 0'20 per cent,; Mo., trace; Bi., 0-012 per cent.; Sn., nil. No. 26 Sample. — From No. 2 Adit, both walls 20 feet from entrance, lower 3 feet, immediately below No. 25 ; white aplite, with occasional softer bands. Result: WO a , 0-16 per cent.; Mo., 0'013 per cent.; Bi., nil; Sn., trace. No 27 Sample. — From No. 2 Adit 33 feet from entrance, on shoulder of drive and crosscut; top partly softened garnet rock, bottom aplite, with soft rock at floor of drive; height, 6 feet. Result: W0 3 , 055 per cent.; Mo., trace; Bi., nil • Sn. ' 3 ? frnpp No. 28 Sample.— From No. 2 Adit, winze 13 feet from face, from roof to bottom of winze west wall ; banded hard and soft garnet rock, with quartz and aplite 3 feet from bottom; height, 16 feet. Result: W0 3 , 0'40 per cent.; Mo., 0'02 per per cent.; Bi., nil; Sn., nil. No. 29 Sample.— From No. 2 Adit, new south-western crosscut, shoulder adjoining adit, 33 feet from entrance; upper 3 feet partly decomposed aplite, lower 3 feet soft banded garnet rock; height, b feet. Result: W0 3 , O' 41 per cent.; Mo., 0'16 per cent. No. 30 Sample.— From No. 2 Adit, new south-western crosscut, south-eastern wall, 7 feet from shoulder on main adit; top 12 inches soft micaceous pug with quartz, then banded garnet and hard garnet- pyroxene rock ; width, 7 feet. Result: W0 3 , 0*85 per cent.; Bi., nil; Sn., 0*014 per cent. 5 0 sseas Assiftant Government Geologist \ N \ 2.-— Assay Plan of No. 2 Adit showings Tungstic Acid Percentages. . . - ' ■ . ■ 27 No. 31 Sample. — From No. 2 Adit, new south-western crosscut, south-eastern wall, 14 feet from adit; upper 12 inches quartz, then hard garnet-pyroxene and softer garnet rock, 2J feet from bottom soft greenish country-rock with a little garnet; width, 7 feet. Result: W0 3 , 1*40 per cent.; Mo., trace; Bi., trace; Sn., trace. No. 32 Sample. — From No. 2 Adit, new south-western crosscut, soilth -eastern wall, 21 feet from adit; soft garnet lode material, with occasional harder bands and a little quartz ; width, 7 feet. Result: W0 3 , 1*35 per cent.; Bi., trace; Sn., 0*018 per cent. No. 33 Sample. — From No. 2 Adit, new south-western crosscut, south-eastern wall, 28 feet from adit ; soft garnet lode material, with some quartz and visible scheelite; width, 7 feet. Result: W0 3 , 9*56 per cent.; Mo., 0'16 per cent. ; Bi., nil ; Sn., 0*22 per cent. No. 34 Sample. — From No. 2 Adit, new south-western crosscut face, 33 feet from adit; firm garnet lode material, with soft bands and irregular masses of quartz ; height, 6 feet. Result: W0 3 , 2*53 per cent.; Bi., trace; Sn., 0‘30 per cent. No. 35 Sample. — From No. 2 Adit, new south-western crosscut roof, 7 feet from adit ; special sample of quartz vein, width 12 to 15 inches, showing richest molvbdenite seen in mine, and visible scheelite. Result: W0 3 , 2 75 per cent.; Mo., 2*51 per cent.; Bi., trace; Sn., trace. No. 36 Sample. — From open-cut at entrance to No. 2 Adit, 30 feet south of adit entrance, below surface soil, 6 feet below actual surface; sample of partly- weathered aplite exposed in bottom of cut; width, 8 feet. Result: WO,, 0*43 per cent.; Mo., trace; Bi., nil; Sn., nil. No. 37 Sample. — From No. 1 Adit, south-western crosscut, 46 feet from main adit (10 feet from face), south-eastern wall opposite north-western drive; very hard garnet-pyroxene rock, with soft bands of decomposing garnet lode material ; width, 7 feet. Result: WO 3 , 1*32 per cent. 28 No. 38 Sample. — From No. 1 Adit, 10 feet forward from No. 37, along north-western drive, south- western wall ; mainly very hard garnet-calcite rock, with some softer bands; width, 6 feet 6 inches. Result : W0 3 , 0’43 per cent. No. 39 Sample. — From No. 1 Adit, north-western drive, 20 feet forward from No. 37, south-western wall at collar of short crosscut; well-banded hard garnet-pyroxene rock and very hard garnet-calcite rock, with some bands of soft garnet ; widths 7 feet. Result: W0 3 , 0'64 per cent.; Mo., 0'03 per cent.; Bi., trace; Sn., nil. No. 40 Sample. — From No. 1 Adit, north-western drive, 30 feet forward from No. 37, south-western wall; similar material to No. 39; width, 7 feet. Result: W0 3 , 0 - 86 per cent. No. 41 Sample. — From No. 1 Adit, north-western drive; face (38 feet forward from No. 37) extremely hard and tough garnet-calcite rock, banded; width, 5 feet 6 inches. Result : W0 3 , 0’50 per cent. No. 42 Sample. — Sample from heap of soft garnet material at collar of No. 2 Shaft (20 feet). Result: W0 3 , 1'55 per cent. The accompanying diagrams (Figures 1, 2, and 3) show graphically the positions of the principal samples and their tungstic acid content as revealed by assay. The molybdenum, bismuth, and tin values are omitted from the diagrams to avoid complicating them too much. It is clear from the explanations given above that a general average of all the assay values is not justified to arrive at the average value of the ore exposed, as some of the samples are not samples of ore. Thus Nos. 1 and 14 represent hangingwall and footwall country -rook respectively, and carry only very low tungstic acid values. Then, again, some of the samples ( e.g ., No. 17) appear to be beyond the boundaries of the ore-body proper, and should be excluded in attempting to arrive at an average value. Several samples were taken from the garnet-calcite formation exposed in the lowest (No. 1) adit, and all carry scheelite ; but the writer is not satisfied that this forma- tion really forms part of the ore-body exposed in the adits *£ < £dUiru^ / fo-'G,. Assistant Government Geologist Fig. 1.— Assay Plan of No. 1 Adit showing Tungstic Acid Percentages. 29 above (Nos. 2 and 3), and hence he considers that these values should be excluded in estimating the average. The average value of the ore exposed in this adit is O' 75 per cent, tungstic acid (or £1 16s. Id. gross on the basis of the present price, 48s. Id. per unit). Another feature is worthy of comment. In the No. 2 Adit are several exposures of aplite (locally called por- phyry) from which samples were taken. The rock is associated with the ore-body, and itself carries low values (0'33 per cent, as an average of three samples taken), but cannot be regarded as ore. In the same adit some of the hard garnet-pyroxene carries very low values, but must be regarded as merely altered country-rock. It would be rejected in working the deposit on a commercial scale. No. 35 Sample, which was taken essentially to determine the actual molybdenite value of a quartz vein showing that mineral abundantly, can scarcely be regarded as typical ore, although several quartz veins were noticed in places between the actual lines of samples taken, carry- ing visible scheelite. In actual working, of course, such enrichments would go to raise the average value of the ore. Samnle No. 42 also appears to be from a separate formation and although nearly of average value, should be neglected in trying to arrive at the true average value of the ore-body exposed. Taking the average of 25 samples (viz., Nos. 2-13 inclu- sive; 15, 16, 18-23 inclusive; and 30-34 inclusive), the aver- age value of the ore sampled in the main formation is 1 * 69 per cent, tungstic acid. Of this aggregate amount, the 'writer considers that at least 80 per cent, should be •covered in treatment; i.e ., the net value of the ore is T35 per cent, tungstic acid. On the basis of 48s. Id. {.er unit of tungstic acid (the price guaranteed by the Com- monwealth Government) the ore has a net value at the present time of, approximately, <£3 5s. per ton. The values, other than those of tungstic acid, are worthy of comment. It has been commonly reported that tie ore is of value because of its molybdenum content, as well as its tung- stic acid. An inspection of the deposit showed that this was scarcely likely to be correct, and the assays made confirm this opinion. As noted above, Sample No. 35 was taken especially because the quartz was rich in molyb- 30 denite, to try and ascertain the real value of an ore which showed the ’mineral freely. The assay showed only 2'51 per cent, of molybdenum (Mo), equivalent to 4' 19 per cent, of molybdenite (Mo S 2 ). This sample, however, is not by any means representative. As recorded above, some samples of ore carry only traces (6 out of 12 samples of ore returning only “ trace ”), although only one assay gave a negative result. The average of these 12 samples, however, is only 0'024 per cent, molybdenum — a figure much too low to encourage the hope that it may prove payable. This figure would be equivalent to '04 per cent, molybdenite, and although at the time of writing the Government guarantees 93s. lOd. per unit of molybdenum sulphide for concentrates carrying 90 per cent, of the mineral, in practice the recovery would be too low to warrant any attempt being made to save the mineral, beyond hand-picking and throwing aside for treatment, when sufficient accumulated, any high-grade ore which might be encountered in the course of opening up and working the scheelite deposits. Richer patches of molyb- denite may be encountered in quartz veins traversing the formation, such as that exposed in the No. 2 Adit from which Sample No. 35 was taken. It is necessary to comment on the occurrence of bismuth and tin in the ore as revealed by the assay results quoted above : both metals are fairly widely distributed, although in small Quantities. In the 25 samples referred to above, bismuth is recorded as absent from 10, and present in traces only in six others. The average value for the 25 samples is '0126 per cent, metallic bismuth. According to calculations made, with a theoretically perfect concentration of the metal this amount of bismuth in the ore would bring the percentage in the scheelite concentrate to, approximately, '5 per cent., but as there is likely to be some loss, the amount finding its way into the concentrate is likely to be less than the limit mentioned. Theoretically, with an average ore value of 1'69 per cent, tungstic acid, and *0126 per cent, bismuth, if the concentrate be assumed to carry 70 per cent, tungstic acid, if 80 ner cent, of the scheelite be saved and 90 per cent, of the bismuth, the percentage of bismuth expected in the concentrate would be about '586 per cent. If only 80 per cent, of the bismuth were saved, the amount expected in the concentrates would be '521 ner cent. It must be borne in mind, however, that these figures are merely theo 31 retical, and the amount actually saved in practice may be considerably less than that calculated. With regard to tin (which is very probably present as cassiterite), only three of the 25 samples showed negative results on assay, although five others returned traces, the amount in the remainder ranging from Oil to '3 per cent. The average value is ‘0576 per cent, metallic tin. The tin is certainly not likely to prove of economic value, but. it may prove detrimental in the concentrate. An expression of opinion on this point, however, is not of much value in the complete absence of details of any practical concentration tests on the ore. Such tests are essential before any definite statement can be made. It is interesting, however, to try and anticipate the behaviour of the tin which is shown to be present in th$ ore. In the first place there is no positive evidence as to the form in which the tin exists in the ore, although it is most likely present as cassiterite in a very finely-divided form.. Then, again, there is nothing to show whether it is more intimately associated with one than another of the minerals of the ore. Should it, for example, be included in the scheelite, as traces of moly- denite are, it may be difficult to separate in the final stages from that mineral. Calculating theoretically, as was done in the case of bismuth, to try and get some idea as to the tin (supposing it to exist as cassiterite) likely to find its way into the concentrate, it is probable that the extraction will not exceed about 30 per cent, with such extremely fine ore. Assuming the average ore value to be 1'69 per cent, tungstic acid, and 0*0576 per cent, tin, with a concen- trate assaying 70 per cent, tungstic acid and a recovery of 80 per cent of the scheelite, theoretically the concen- trate might be expected to carry about 0*895 per cent, tin. It does not appear to the writer likely that more than 30 per cent, of this very fine tin will be saved, and it is not improbable (in view of the evidence afforded by the treatment of certain ores on the West Coast of Tas- mania in which the so-called “ slime tin ” is present), that the concentrate will be founa to carry only traces of the objectionable metal. On the whole, the writer considers it unlikely that bis- muth or tin will be present in the concentrate in sufficient quantities to be really detrimental. Even should the metals increase slightly beyond the amounts noted, the main product (scheelite) is so urgently needed that the 32 penalties are not likely to be heavy for the small amounts of the metals present. In the event of richer shoots of either metal being encountered, as the main concentrat- ing plant will be designed essentially to save a lighter mineral (scheelite) than either bismuth or cassiterite, it may be found possible to isolate a small quantity of heavy concentrate from the tables, which would be rich in the objectionable metals, and which would (if sufficient accumulated) be sold as a complex ore for special treat- ment, leaving the main bulk of the concentrate impover- ished to such an extent in these particular metals as to prove a high-grade scheelite ore, and command prices accordingly. It is extremely unlikely, however, that such treatment will be found necessary. Thus the bismuth and tin recorded, while not in their present quantities detracting materially, if at all, from the value of the ore as a tungstic acid product, indicate that a look-out should be kept for these metals in future work, and that the concentrate obtained from any parcels of ore treated experimentallv should be examined care- fully. UNIVERSITY OF ILLINOIS LIBRARY OCT i 3 1820 V.— COSTS. It scarcely comes within the scope of a geological sur- vey report to deal in any detail with costs of plant, of mining and of treating the ore, although some reference is necessary. Viewing the question broadly, it is clear that the deposit is not a small rich one, but that it is likely to prove a large and comparatively low-grade one. Such being so, it becomes important that working costs should be reduced to a minimum by carrying out mining and treatment operations on a moderately large scale. For- tunately, the mine is very favourably situated for eco- nomic mining (as noted elsewhere), and as open-cut methods may be employed, actual mining costs are likely to be low, and the property has other facilities, which have been referred to elsewhere. In the case of a property such as that under review, it is absolutely essential that adequate provision be made for prospecting *and developmental work. Certain recom- mendations are made below in this connection. At the present time little skilled labour is available on the island for mining work, although doubtless this will be remedied when operations commence in earnest on the property. The lack of skilled miners, however, is sure to make itself felt for a time, and will tend to increase working costs in the early stages above what will be found later to be a normal figure. Likewise, treatment costs are certain to be heavier in the earlier stages — which must, of necessity, be experi- mental to a large extent — than they will be under normal conditions when initial difficulties have been overcome. As to actual costs, although the writer cannot go into the matter, it may be advisable to give some estimate, and for this purpose thq yf pllowing extract is quoted from a professional report bv Mr. J. B. Lewis, mining engineer, Melbourne, published in the prospectus of the King Island Scheelite Company, No Liability: — “ Working Costs . — These would depend on what pro- portion of the ore could be worked by open -cut, and the amount treated. Open-cut working would adow the ore to be delivered at the treatment plant at 8s. to 4s. per ton. Stoping would cost 8s. or 9s. per ton ; crushing and concentrating, &c., 4s. 6d. per ton. If half the ore were 34 won by open-cut work and half by stoping, the average cost per ton would be 10s. or 11s. To this must be added prospecting and developing work; or we should be pre- pared for costs of 12s. per ton, with a plant treating 300 tons per week. Such a plant would be equivalent to a 10-head battery. Bags, freight charges, insurance, man- agement, &c., would probably add 3s. per ton. Stripping would doubtless more than pay for itself, as the material stripped would carry more mineral than would pay for its treatment. It is probable that after experience with the ore and the plant, the above costs could be reduced. Under similar circumstances costs have been obtained as low as 6s. per ton, in place of the 10s. or 11s., shown above; but all will depend on the plant being kept at its full capacity. Costs would thus be about £225 per week.” In the same report, under the heading “ Cost of Plant,” Mr. Lewis continues: — “ Cost of Plant . — A steam or gas plant generating elec- tricity, with separate motors for stone-breaker, battery or other crushing plant, concentrators, and pump for dress- ing and boiler water, and possibly for a conveyor convey- ing ore from mine to hopper over stone-breaker, would be the simplest, and possibly the most efficient, arrange- ment. Included in plant should be buildings for mine office, assay office, manager’s residence, and huts for men, there being no accommodation in the neighbourhood. For this a sum of £10,000 should be provided.” Mr. Lewis then estimates: — Per ton. “ Working costs, including all charges, £ s. d. management, &c 0 15 0 Interest on capital, 5 per cent., de- preciation, &c., 20 per cent 0 3 4 0 18 4 300 tons, at 18s. 4d. per ton £275 0 0 ” The above costs, as worked out by Mr. Lewis, and pub- lished in the company’s prospectus, are quoted without comment. It is interesting to contrast these working costs with actual ore values, as revealed by assaysi of samples taken bv the writer. Assuming for sake of comparison the ton- 35 nage upon which Mr. Lewis has based his costs — viz., 300 tons per week, of a gross value of 1‘69 per cent, tungstic acid, at 48s. Id. in Melbourne, if the extraction be 80 per cent., the value per week would be £975. If the extraction fell to 70 per cent., the value per week would be £853. The extraction should, in the writer’s opinion, more nearly approach 80 per cent, than 70 per cent., and might even slightly exceed the former figure with careful con- centration, after preliminary tests have shown the best methods to employ. Thus, on the costs quoted above, there is likely to be a considerable margin of profit if the ore maintains the average, as shown by assay. VI.— TREATMENT. The question of treatment of an ore of this descrip- tion cannot be dealt with in full detail in such a report as the present, when no experimental work has been carried out (owing to lack of facilities), but certain out- standing features and broad principles should be referred to. In attempting to concentrate one particular mineral, it is essential to pay attention to the minerals from which it has to be separated. As already described, the mineral which forms the bulk of the gangue of the ore is garnet, which usually occurs in crystal form, crystals varying from 1 / 16th inch across; aggregates of crystals are some- times much larger than this. The specific gravity of the garnet was found to vary between 3 ’40 and 4T9 (the variation is doubtless due to impurities included in the garnet, which could not be mechanically separated there- from). For the purpose of this discussion, the highest value (4‘2) may be assumed, as this provides the worst case with which it will be necessary to deal. As noted elsewhere, other outstanding features of the garnet are its hardness (aUout 6'5) and toughness. On the other hand the economically important mineral scheelite has a specific gravity of 5*91. It occurs in minute grains disseminated through the garnetiferous gangue, as well as in crystals of about the same size, and larger than the garnet, and in amorphous masses several inches across : it is appreciably softer than the garnet (hardness about 5), and is brittle. From these character- istics it is clear that the concentration, to be efficient, will need to be carefully carried out. There is not the difference between specific gravities of mineral and gangue as usually exists in an ore to be concentrated. The writer is of opinion, however, that the difference is suffi- cient to enable a satisfactory concentrate to be obtained, 'provided the crushed ore is. carefully classified. The classi- fication before concentration on tables will be found essential to ensure a satisfactory recovery of values, as particles of slightly unequal size of garnet and scheelite will be of so nearly the same weight that either an impure concentrate will be obtained by the admixture of garnet with the scheelite, or else there will be a loss of scheelite in the tailings with the garnet. 37 The difference in hardness and tenacity of the two min- erals, however, is also likely to have an important bear- ing on concentration. Given the same amount of crush- ing, the tendency must be for the softer mineral to slime, compared with the harder, and the relative tenacities increase this tendency. This suggests at once that after a coarse crushing, it may be possible to separate from the gangue some at least of the scheelite while still in a coarse state. In designing the treatment plant, provision should be made for this separation, for the more the scheelite is slimed, the heavier the treatment loss will be. For the preliminary crushing, a reciprocating jaw rock- breaker appears preferable to a gyratory crusher, as more slime would be produced by the latter style. The coarsely- broken ore would then probably be ground with rolls in preference to a stamp battery, for the same reason (to minimise sliming). After classifying the crushed material the coarse ore could be treated in jigs, by which the coarse scheelite would be saved. The size of the product giv- ing the most satisfactory results in this operation can only be determined by experiment. The tailings from the jigs will probably pay for grinding and treatment with the undersize from the rolls. The finer material will need careful classification before treatment on concentrating tables, and experiment will show whether a fine regrinding plant for the middlings is necessary. The final treatment for the slimes should be by canvas tables. It is almost certain that if these be made of sufficient size, the fine scheelite won from them will justify their installation, and that serious losses will occur without them or satisfactory substitutes. Suspecting from blow-pipe tests (no analysis being avail- able) that the garnet was an iron-lime garnet, fairly rich in iron, the idea occurred to the writer that this mineral might be attracted by the electro-magnet, and that if so, this feature might be utilised in treating portion of the concentrate, should such treatment be considered desir- able. In order to obtain some definite information on this point a sample was obtained by mixing the residual por- tions not required for assay of samples Numbers 2 to 13. 15, 16, 18 to 23, 31 to 37, and 42, described above, and submitting the bulk sample to Mr. J. K. Pound, M. Sc., manager of Messrs. Hinman, Wright, and Manser’s elec- tro-magnetic separation plant, this gentleman having kindly offered to test a sample. This test was witnessed T>y the writer, and the result is extremely interesting. 38 and may have an important practical bearing on the production of a high-grade concentrate. Mr. Pound has supplied the following notes on the test : — “ Notes on the Behaviour of Scheelite Ore from King Island, on Treatment by W ether ill Magnetic Separators. “ An average sample of Grassy River ore was received at the works of the S. & M. Syndicate Ltd., Cimitier e-street, Launceston. The works are equipped with Wetherill magnetic separators, and a description of the plant and process is given in the Geological Survey Bulletin, No. 14, page 58. The usual work carried on by the syndicate is the separation of wolfram from tin and bismuth ores. 11 The sample of scheelite was crushed and divided into two sizes — the coarse size of minus 5 and plus 11 mesh, and the fine size of through 11 mesh. This sample gave 11 lb. of coarse, and 30 lb. of fine, material . The coarse portion was treated on a Wether- ill separator, and it was found that the garnet in the ore was of, approximately, the same magnetic per- meability as wolfram, and was the sole magnetic min- eral in the ore. The result of the test was thus to give the garnet as the magnetic part, leaving the scheelite, quartz, &c., as the non-magnetic part. Prac- tically no garnet passes into the non-magnetic por- tion, and the garnet product is clean, save for a small amount of adhering matter. Of the fine portion of the sample, a small fraction was treated with similar results. The conclusion is that the garnets in the ore can be satisfactorily removed by ‘ magnetic separa- tion/ leaving the scheelite in the clean non-magnetic portion. The process promises to be commercially practicable on a scheelite-garnet concentrate, which could easily be obtained by dressing. (Signed) J. R. Pound.” The plant on which this test was carried out is usually employed for separating wolframite from cassiterite and bismuthinite (bismuth sulphide). The capacity of the plant is not large, and the cost of treatment would be too high to render it commercially practicable to treat crude ore of the average value of that already exposed in the mine. The separation of garnet from scheelite, molybdenite, and 39 quartz was undoubtedly clean, although in this case the garnet was magnetic and removed, while the scheelite (unlike wolframite) was non-magnetic, and went over the tail of the table. In order to determine what values were actually con- tained in the various products, the latter were submitted to Mr. W. D. Reid, Government Assayer, who reported: — “ Coarse material before treatment, 1 *85 per cent, tungstic acid; coarse non-magnetic portion, 7 '52 per cent, tungstic acid; coarse magnetic (garnet) portion, 0*31 per cent, tungstic acid; fine material before treatment, 1‘82 per cent, tungstic acid; fine non-mag- netic portion, 8*04 per cent, tungstic acid; fine mag- netic (garnet), O’ 22 per cent, tungstic acid.” These results are extremely interesting, as indicating that a comparatively clean separation of garnet from schee- lite and other minerals is possible. The low tungstic acid value in the magnetic product in each case is not surpris- ing, as some of the scheelite, quartz, &c., would adhere to the garnet particles, which would be attracted by the electro-magnet . It will be noticed that this is more marked in the case of the coarse than in the fine material, as would be expected, the finer crushing liberating more of the attached scheelite. The higher value of the non- magnetic portion in the case of the fine material than in the coarse (although the fine was slightly lower grade than the former), is also doubtless to be explained by the fact that the finer crushing would enable some of the garnet to be attracted by the magnet, which in the coarse material had passed over into the non-magnetic product, owing to the size of the attached particles of quartz, schee- lite, &c. There would not be any difficulty at all in producing a high-grade concentrate from the non-magnetic product, owing to the low specific gravity (compared with scheelite) of the quartz and accompanying gangue minerals. It is extremely interesting to notice as one result of tin* electro -magnetic test that the ore carries about 70 per cent, of garnet. If, then, it be found in practice that the scheelite losses are high in attempting to get rid of all the gar- net in the gangue, and produce a high-grade concentrate, it may pay to produce a concentrate carrying more garnet, in order to save more scheelite, and finally remove the garnet from this concentrate by electro-magnetic treat- 40 ment, when obviously a very much smaller tonnage would be treated than would be the case when dealing with crude ore. The treatment to be finally adopted can only be deter- mined after a certain amount of experimental work has been carried out. As to the bulk of concentrate produced, if 300 tons of ore be treated per week, and the concentrate assays 70 per cent, tungstic acid, the amount expected would be about 5J tons per week. In preparing for open-cut workings, it will be neces- sary to strip the surface material to expose the actual lode outcrop. Judging by the surface material exposed in the approach to No. 3 Adit, this surface material carries suffi- cient scheelite to pay for its treatment. The question of a machinery site need not be discussed at any length. The plant will be situated on the level strip on the foreshore, at the base of the hill-slope on which the mine workings are situated. This would be about 25 feet above sea-level. It appears advUable that before the exact site be decided upon, some further pros- pecting work be carried out to determine the trend of the ore-body below the No. 2 Adit. The position of the ore- body will largely determine the most suitable position for a main low-level working adit, and this, in turn, will be one factor which should be considered before the treat- ment plant be erected. With regard to water for the treatment plant and for boilers, this will doubtless be derived from the Grassy River, and, as noted elsewhere, it is likely that the most convenient plan will be to pump the water from the river to a main storage tank slightly higher than the plant, and distribute it from this tank by gravitation. Reference has already been made to the advantages offered on the mine for the economical handling of material, disposing of waste, and of getting rid of the impoverished tailings from the treatment plant. VII. — RECOMMENDATIONS. The foregoing description of the property indicates the general lines on which future operations should be con ducted. In the writer’s opinion the first work carried cut should have for its objective the pro/ing of the extent of the main ore-body, both laterally and vertically. Undoubtedly a very promising ore-body has been exposed, but it is essential that more work should be done, par- ticularly in view of the somewhat uncertain structural features, to definitely prove its extent. The most obvious way to attempt to prove the lateral extent of the ore-body is by surface trenching. The hill slope is flatter 'above the No. 3 Adit than lower down and it is worth while trying to trace the lode in this way. The surface overburden may, however, prove too deep to give satisfactory results in this way, although the overlying material is likely to carry abundant garnet, and to yield traces, at least (and perhaps payable quantities), of schee- lite. It must be made clear that there is no actual out- crop of the ore-body at the surface, and therefore this trenching, if carried out, will necessarily have to be along the approximate line of strike, as calculated from the ore- body exposed in the workings. But, in addition to any surface work, or replacing it, if both operations cannot be carried out, should be some underground work. Since payable ore has been exposed in both Nos. 2 and 3 Adits, it is advisable to follow this by continuing one or other of these adits. Since No. 2 Adit would give a greater amount of backs than No. 3, it might well be continued, although No. 3 has been driven fur- ther on the course of the ore-body. The plan to be car- ried out should be to drive either on or adjacent to the ore-body, and from this main drive crosscut at regular intervals to expose the full width of ore. It is important to extend these crosscuts beyond the apparent edge of the ore-body, because of the possibility of mineralised bands of country-rock occurring outside the main ore-body. Such work would give valuable information as to the true strike and dip of the ore-body, and would enable future work to be planned more confidently than can be done at the present time. For instance, this work would enable the position of the permanent deep adit (from which eventually the main mining operations will be car- 42 ried out) to be definitely fixed. This deep adit and winzes therefrom will, of course, yield valuable information as to the vertical extent of the ore-body. The question as to whether the adits should be continued in ore or in country-rock will need consideration. As exposed in the No. 3 Adit, the ore is soft, and would mainly be classed by the miner as “ picking ground.” The country- rock carries bands of green and pink garnet-pyroxene rock, which are to be avoided where possible on account cf their extreme hardness. Fortunately, such bands are usually narrow, and if they prove continuous for any length along the line of strike, it may be found practicable to drive along these as walls, although it will be essential to cross- cut through the bands as well as through the ore. Although the ore is so soft as exposed in the No. 3 Adit, it must be expected that the material will be harder as greater depth below the surface is attained, where the surface waters have not the same action in weathering the ore. An important reason why the ore-body should be opened up by cross-cuts, as recommended, is that further sections will be available for sampling. Mention has previously been made of the writer’s opinion that the No. 1 Adit exposes garnet rock (carrying scheelite), which may belong to a different formation from that exposed in the adits higher up the hill. Although this material is very hard and tough, it would, in the writer’s opinion, be worth while driving crosscuts in both directions from the present face. Such crosscuts would expose the width of the body of ore showing in the pre- sent face, and if the main ore-bodv be dipping to the south-west, as it appears to be in the adits above, this should be intersected if the crosscuts were continued, and a section across it at this level 'would yield useful informa- tion. Not the least* 'ii^portaiit* work to be undertaken in the near future is the prospecting of the scheelite-bearing formations on the property other than that already partly opened up. This work might well be undertaken simul- taneously with the exploitation of the main . deposit. So little is known of these deposits that no opinion can be expressed as to their value, although assays indicated that scheelite is present in encouraging quantities in at least one of the outcrops exposed. The nature of these ore- bodies is apparently similar to that of the one already partly opened up. 43 With regard to plant, this could probably be erected advantageously in units. Although a good deal of ore has been partly exposed, no definite tonnage can be cal- culated, and the condition of the mine is not such as to warrant the erection of a large and costly plant at the present stage, in the writer’s opinion. It is, however, especially to be noted that no work has been done to prove that large quantities of ores are absent, and that indica- tions are all very favourable. Exploitation work may con- fidently be undertaken. In the meantime plant might well be erected to commence, treating some of the ore exposed, such plant being regarded as one unit to be added to later on, as larger tonnages of ore of satisfactory values are proved. In erecting this unit, provision should be made for extension on the lines indicated. By working on some such plan, a start could be made to produce a marketable scheelite concentrate in reasonable time. If the ore exposed in the No. 1 Adit be typical of that which will be encountered in the deeper workings of the mine, it will probably be found advisable to instal an air-compressor and rock-drills; such, however, need not be considered at the present juncture. When work on the general lines indicated has been car- ried out, the future development of the property can be planned confidently, in the light of information obtained by this preliminary work. UNIVERSITY OF ILLINOIS LIBRARY OCT IS |S 20 VIII.— -SUMMAKY AND CONCLUSION. Before concluding this report, it is advisable to sum- marise the general conclusion arrived at as a -result of the examination of the property. An ore-deposit consisting largely of garnet has been partly opened up in a position which offers distinct advan- tages for economical mining. There is no treatment plant on the property, and no scheelite has been produced up to the present. Only a small amount of work has been done, and no ore has been blocked .out, nor has any ereat length along the line of strike been proved. The width, however, is considerable, being about 65 feet at right- angles to the dip, and 85 feet as exposed by horizontal crosscuts, and there is no sound reason for doubting the existence of a large tonnage of ore. The garnet formation carries scheelite, both disseminated through its mass, and in rich masses in quartz veins traversing the main forma- tion. The average value, as exposed, was found to be 1'69 per cent, tungstic acid, a value which at present prices is sufficient to yield reasonable profits under existing con- ditions. The richer masses of scheelite in the quartz veins may tend to increase the average grade of the ore above the figure quoted above. The ore carries traces of impuri- ties, but probably not in sufficient quantities to affect the value of the ore. At the worst, no more than a light penalty is likely to be imposed on the concentrate as a result of these impurities, and it is doubtful whether suffi- cient will be concentrated with the scheelite to justify even a light penalty. The ore does not appear to offer any special treatment difficulties, and a large percentage of the scheelite present should be saved. " Tests made indicate that, if necessary, electro-magnetic separation methods could be utilised to separate the garnet from the scheelite. While the structure of the main ore-bodv is not quite clear, owing to the small amount of work which has been done, recommendations have been made that work be car- ried out along definite lines to prove this, and open up more ore. Until this is done, it is not possible to estimate the amount of ore available, or the tonnage which could be treated per week, and therefore the actual scheelite output which will be possible is still a matter of conjec- ture. With very little more work it is likely that suffi- 45 cient ore would be opened up to justify the erection of a treatment plant, which should be in the form of a unit to be added to, as more ore is rendered available by develop- mental work. If 300 tons of ore be treated per week, as may be done a little later on if the ore-body opens up as it promises to do, with present values 5f tons of scheelite concentrate, worth about 70 per cent, of tungstic acid, would be produced per week. Such an output would be extremely valuable at the present juncture, not merely from the financial standpoint, but because of the difficulty of obtaining sufficient supplies of tungstic acid to meet the existing demand for steel-hardening purposes, and thus a double incentive exists for pushing on with the active development of the property. In addition to scheelite, the ore carries a little molyb- denite, but not sufficient to be of economic value. Associated with the main ore-body is a dyke of aplite which itself carries a little scheelite, but samples taken indicate that values are too low to prove payable. It is important to note that apart from th j main ore- body, at least two other scheelite-bearing garner forma- tions exist on the property, one at least of which carries payable values at the only point at which it is exposed. Both formations should be prospected, as bodies of ore may be opened up which will add largeiy to the available tonnage. It is generally understood that the King Island Scheelite Company, No Liability, has been floated, and that arrange- ments are being made to actively develop the property. Such work is heartily recommended. With a sound developmental policy, there appears to be no reason why this mine should not become an active producer of scheelite in the near future. The property has good prospects, and is worthy of the attention of investors — bearing in mind the warning given above, that the urgent need at the pre- sent time is for active developmental work. As indicated on the plans accompanying this report, some of the prospecting work has not in the past been carried out to best advantage. This is particularly true of No. 3 Adit, in which the face of the south-western cross- cut cannot be far from the surface, and in which the adit, after bending back practically parallel to itself, is within a few feet of the abovementioned crosscut. Past work has, however, been carried out without any survey (to the writer’s knowledge), and it would be advantageous to have- future work planned on more definite lines. 46 The writer here desires to point out that the plan of the property (Plate II.), and Figures 1, 2, and 3, repre- senting assay plans of the different levels, are sketch plans only; they are based on a rapid prismatic compass survey. The contours on Plate II. are only very approximate, being merely sketched in to give a general idea of the topographical features of the mining lease, and make no pretence of being accurate in detail. More detailed work could not be undertaken in the short time available. In conclusion, the writer wishes to record his apprecia- tion of the valuable assistance rendered during his exam- ination and sampling of the property by Messrs. Tom and Bert Farrell, and Chester Richardson. . Messrs. Farrell also supplied useful information concerning the property and the workings which they carried out. To each of these gentlemen the writer tenders thanks. L. LAWPY WATERHOUSE, B.E., Assistant Government Geologist.^ Geological Survey Office, Launceston, 31st May, 1916. piVERSITY OF ILLINOIS LIBRARY OCT 1.8-1920 OF the ' ^ 7 OF ILLINOIS ^GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. 1. — The Mangana Goldfield, by W. H. Twelve- trees 1907 No. 2. — The Mathinna Goldfield, Part III., by W . H. Twelvetrees 1907 No. 3. — The Mt. Farrell Mining Field, by L. Keith Ward, B.A., B.E. 1908 No. 4. — The Lisle Goldfield, by W. H. Twelvetrees 1908 No. 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees 1909 No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E. 1909 ,No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E. 1909 No. 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and . L. Keith Ward, B.A., B.E 1910 No. 9. — The Scamander Mineral District, by W. H. Twelvetrees 1911 ~No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E 1911 No. 11. — The Tasmanite Shale Fields of the Mer- sey District, by W. H. Twelvetrees 1911 'No. 12. — The X River Tinfield, by L. Keith Ward, B.A., B.E 1911 No. 13. — The Preolenna Coalfield and the Geology of the Wvnyard District, by Loftus Hills, M.Sc. 1913 :No. 14. — The Middlesex and Mt. Claude Mining Field, by W- H. Twelvetrees 1913 48 No. 15. — The Stanley River Tinfield, by L. Lawry Waterhouse, B.E 1914 No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc 1914 No. 17. — The Bald Hill Osmiridium Field, by W. H. Twelvetrees 1914 No. 18. — Geological Reconnaissance of the Country between Cape Sorell and Point Hibbs, by Loftus Hills, M.Sc 1914 No. 19. — The Zinc-Lead Sulphide Deposits of the Read-Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc. ... 1914 No. 20. — The Catamaran and Strathblane Coal- fields and Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees 1915 No. 21. — The South Heemskirk Tinfield, by L. Lawry Waterhouse, B.E 1915 No. 22. — Catalogue of Publications issued by the Government of Tasmania, relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914, compiled by W. H. Twelvetrees 1915 No. 23. — The Zinc-lead Sulphide Deposits of the Read-Rosebery District, Part II. (Rose- bery Group), by Loftus Hills, M.Sc. ... 1915 No. 24. Reconnaissance of the Country between Recherche Bay and New River, South- ern Tasmania, by W. H. Twelvetrees ... 1915 REPORTS. No 1. — Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E. 1910 No. 2. — The Silver-lead Lodes of the Waratah District, by L. Keith W T ard, B.A.,B.E. 1911 No. 3. — Preliminary Report on the Zinc-lead Sul- phide Deposits of Mt. Read, by Loftus Kills, M.Sc 1914 No. 4. — On Cement Materials at West Arm, by W. H. Twelvetrees 1914 49 No. 5. — On Some Gold Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6. — Reconnaissance of the North Heemskirk v Tinfield, by L. Lawry Waterhouse, B.E. 1914 No. 7. — Preliminary Report on the Zinc-lead Sulphide Deposits of the Rosebery Dis- trict, by Loftus Hills, M.Sc 1915 RECORDS. No. 1. — Marine Fossils from the Tasmanite Spore- beds of the Mersey River, by W. S. Dun 1912 No- 2. — Stichtite : A New Tasmanian Mineral: Notes by various authors, collected and edited by W. H. Twelvetrees 1914 No. 3. — Darwin Glass: A New Variety of the Tek- tites, by Loftus Hills, M.Sc 1914 No. 4. — A Monograph of Nototherium Tasmanicum by H. H. Scott. Price 7s 6 d 1915 MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. : North-Eastern and Eastern Tasmania, by Loftus Hills. M Sc. 1915 Part II. : Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc 1916 Part III. : King Island, by L. Lawry Waterhouse, B.E 1916 JOHN VAIL, GOVERNMENT PRINTER, TASMANIA. a a mania "HIU\ DEPARTMENT OF MINES' GEOLOGICAL SURVEY MINERAL RESOURCES / No. 2 Cement Materials at Flowery Gully BY W. H. TWELVETREES, Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania C a s m a ti t a : JOHN VAIL 1 , GOVERNMENT PRINTER. HOBART 1917 B75771 DEPARTMENT OF flMH'pSj £ GEOLOGICAL SURVEY MINERAL RESOURCES No. 2 BY W, H. TWELVETREES, Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS. K.C.M.G. Minister for Mines for Tasmania JOHN VAIL. GOVERNMENT PRINTER. HOBART C a s in a lit a F75771 1917 TABLE OF CONTENTS. PAGE INTRODUCTION : 1 I. OCCURRENCES OF LIMESTONE 1 II. OCCURRENCES OF SHALE AND CLAY 4 III. THE MANUFACTURING PROBLEM 6 IV. GYPSUM 7 V. EXTRACTION AND MANUFACTURE 7 (а) Quarrying and Preparing the Stone for Burning 7 (б) Burning the Mixture 9 (c) Cooling the Clinker 10 (d) Adding the Gypsum 10 (e) Grinding the Clinker 10 (/) Storage of the Cement H VI. FUEL 11 VII. WORKS SITE * I 3 VIII. TRANSPORT TO SHIPPING PORT 13 IX. COST OF ERECTION OF WORKS 14 X. COST OF MANUFACTURE 15 XI. MARKETS i6 XII. CONCLUSION 17 Geological Map At end Cement Materials at Flowery Gully. Introduction. Among other localities in Tasmania which have been deemed suitable for the establishment of Portland Cement Works it has been necessary to examine that of Flowery Gully, between Beaconsfield and Winkleigh. Beds of limestone are extensively developed on Adams’ Hill, where the ground rises from the valley of Johnston’s Creek. The latter is a tributary of Middle Arm Creek, which it joins at the south end of the gorge of the Cabbage Tree Hill. Being between 7 and 8 miles from a deep-water port at Beauty Point, the position is attractive for works if the raw materials exist in company with the other necessary conditions. In con- sidering the suitability of the locality, the following points will be discussed : — 1 . The occurrences of limestone 1 and its suitability for cement-making . 2. The occurrences of shale and clay and their suit- ability for cement-making. 3. The manufacturing problem. 4. The source of a supply of gypsum. 5. Extraction and manufacture. 6. Fuel. 7. The works site. 8. Transport to shipping port. 9. Cost of erection of works. 10. Cost of manufacture. 11. Markets. I.— Occurrences of Limestone. A strip of limestone country, 1 mile long by §-mile wide, occupies Adams’ Hill, extending from the foot of the hill at Johnston’s Creek in a south-easterly direction as far as the Bookery Boad. The exposures terminate just a little- 2 south of the junction of that road with the main road to Winkleigh. The strike of the limestone is a few degrees east of south, and its dip is east of north. The older ferruginous strata on Dr. L. G. Thompson’s 24 acres must therefore underlie the limestone basin. The exposures of the limestone at the north-west end of the belt are at Quig- ley’s quarry %,t the northern boundary of Dr. Thompson’s 29 acres (A. E. Thomas), and just below the road going up Adams’ Hill on the 500 acres in the names of Evans, Thompson, and Douglas, known locally as the Bank pro- perty. The road ascending the hill between the 82 acres in the name of A. Douglas, and the 113 acres in the name of F. N. Beams, traverses the length of the belt and has limestone on each side of it, the bulk being on the 113 acres. Along the south-west side line of this property is a thin covering of waste from denuded Permo-Carbonifeous beds. The limestone is a bluish-grey, compact rock, veined with ealcite, and near Mr. Beams’ house possessing a subter- ranean cave channel known as the Winkleigh caves. These used to be resorted to by visitors: they have, however, been left to themselves and the depredations of tourists, and have now no particularly spectacular characteristics. The sur- face outcrops of the limestone occur as a series of rocky knobs at irregular intervals. The beds belong to the Gordon River and Chudleigh series, which are judged to be of Silurian age. Their trend does not assist in attempting to connect them with the lime- stone near Beaconsfield, on the east side of the Cabbage Tree Hill, but both doubtless belong to what was at one time one and the same basin of sedimentation. The limestone area on A. Douglas’ property is well timbered, that on Beams’ farm is all cleared land. The rock has been quarried for lime-burning on Beams’ land, where a kiln was operated by Mr. Lutwyche, but is now abandoned; and Quigley’s lime quarry has also been worked on the south boundary of the Bank property. All authorities agree that to warrant the erecting of a cement plant, the quantities of raw material available should be sufficient to enable work to be carried on for at least 20 or 25 years. In making a rough calculation of the tonnage of limestone to be worked here, the stone at Quig- ley’s and that on Douglas’ may be left out as reserves for the future, and the estimate be confined to the limestone on Beams’ farm, and more particularly to the hill rising from Lutwyche ’s quarry. Taking the block of ground' between this quarry and the Winkleigh Road as the mainstay of the proposed enterprise, with a maximum of about 270 feet 3 elevation above the quarry floor, its mean thickness for an area approximately of 6 acres would be about 100 feet. Its content at 168 lb. per cubic foot would be 2,160,000 tons, less, say, 720,000 tons for cavities, waste, and shrink- age; or net about 1,440,000 tons. This, at a consumption rate of 30,000 tons per annum, would last 48 years. Samples of this limestone were 1 taken on the present visit, and have been analysed in the Geological Survey laboratory by the Government Assayer (Mr. W. D. Reid), with the following results : — From Prom Lutwyche’s Quarry. From Caves. Quigley’s Quarry. Average. Calcium carbonate 95-40 95-65 94-75 95-26 Magnesium carbonate. . . 1-22 0-83 1-17 1-07 Iron and alumina ... ... 1-79 1-70 2-81 2-10 Silica 1-44 1*61 0-98 1-34 Moisture 0-13 0-18 0-20 0-17 ' 99-98 99-97 99-91 Previous samples were assayed by Mr. H. J. Colbourn, the Agricultural Chemist, at Hobart, as follows i — Main Outcrop. Outcrop at Face. Outcrop over- lying Caves. Calcium carbonate 95-45 94-00 93-72 Iron oxide and alumina ... 1-65 315 0-55 Insoluble matter 1-85 0-98 5-53 Moisture 1-05 1-87 0-20 100-00 100-00 100-00 A limestone with 75 per cent, carbonate of lime and 20 per cent, iron, alumina, &c., would be an ideal rock, and no admixture with clay or shale would be needed, but stone of this perfect composition is seldom or never found in nature, hence the proportions of lime and alumina have to be adjusted according to the nature of the limestone and clayey material used. The Flowery Gully rock is a high-grade limestone per- fectly suitable for the manufacture of Portland cement when mixed with clay or shale of proper composition. Its hardness does not exceed that of an ordinary crystalline or sub-crystalline limestone. A report has spread that it is too hard for cement manufacture, but this opinion must have been based on experience with the English wet process 4 of manufacture, in which the soft and moist materials (chalk and marl and mud) are ground and mixed wet. The ques- tion of hardness is purely one of crushing cost, and there would seem to be no difficulty whatever in crushing and pulverising the limestone at Flowery Gully. Its position on the scale of hardness does not exceed 3 and this degree of hardness does not offer the slightest obstacle to a crusher of the Gates type in reducing to a size fit for the grinding plant (ball or tube mills), in which the mixed materials have to be further ground in separate stages to a fine powder. To any maker, in the habit of treating only soft limes and marls the high-grade limestones seem hard, and from his point of view are undesirable in that respect ; but as a matter of fact they are being used satisfactorily for •cement-making all over the world. The Flowery Gully rock is a somewhat pure, dry limestone, but is not siliceous nor really hard. In the early days of the industry, the crushing and grinding machinery was not so perfect as now, and there was difficulty in reducing the so-called “ hard ” limestones economically, but this disadvantage no longer exists. The general composition of the rock in question is satis- factory. There only remains for the manufacturer to blend with it such proportions of clay or shale as will produce a cement of the composition aimed at, i.e., a mixture with an average composition of 75 per cent, carbonate of lime, 15 per cent, silica, and 5 or 6 per cent, alumina and iron. II. Occurrences of Shale and Clay. The clay and shale deposits of Flowery Gully are not all in one place and are of different kinds. 1. There is the general overburden of the limestone, a few feet thick, derived from the gradual weathering and decomposition of the underlying rock. It is mixed in places with the sheddings of soil from the adjacent ironstone and slates, and must vary a good deal in composition in different parts of the area. 2. There is the overburden of the slate and sandstone on A. Douglas’ property on Adams’ Hill. 3. There is an alluvial, somewhat sandy, clay on the floor of the valley of Johnston’s Creek. How far this descends is uncertain. 5 4. On the Bank property is a considerable area of Permo- Carboniferous mudstone shales. Some of these contain pebbles; some are fossiliferous and rather calcareous. Similar shales occur up the hill on McKercher’s property (formerly Ellis’). The composition of the clay- or shale ingredient is as important as that of limestone in cement-making. This is obvious when one realises that the deficiencies of the lime- stone in silica and alumina have to be made good by the addition of the clayey material. Whether clay or shale is used matters very little. Shale being soft, is easily ground. A frequent drawback to alluvial clays is their irregular com- position. They also often have a large organic content. Clays used for Portland cement generally have a silica percentage ranging from 55 per cent, to 70 per cent., the higher percentages being the more desirable. The iron and alumina should be about one-third of the silica percentage, or at most it should not exceed one-half. The selection of clay on a cement property devolves on the consulting engineer or works chemist, and the soundness of the cement will largely depend upon his choice and judg- ment. On the present visit samples of clay were taken from the following places and analysed by the Government Assayer as under : — Overburden near Road Quarry, Alluvial, Beams’ House. Adams’ Hill. Quigley’s Flat. Silica 68-56 77-74 79-04 Iron and alumina... 23-38 17-08 13-38 Lime 0-45 0-58 0-52 Magnesia 2-38 2-32 2-17 Loss on ignition 5-24 2-14 4-72 100-01 99*86 99-83 The high silica content rules out Nos. 2 and 3. The clay from the overburden lying on the limestone in the road- bank opposite Beams’ house is the only material of approximately correct constitution. The quantity of this, however, does not appear to be sufficient for manufacturing on a large scale. As regards quantities, the shales on the Bank property are more promising, but no samples were taken on this occasion, as the few exposures seen were pebbly or too calcareous. If works are contemplated, prospecting on that property should be directed towards the locating of beds of suitable material. The present 6 report does not aim at being other than a preliminary description of the proposition, stating what is to be seen at present, and pointing out what lies before those who are disposed to embark on the undertaking. Owners of lime- stone properties are often too prone to forget the important role played by alumina (as -contained in clay and shale) in cement manufacture. The limestone exposures are so obvious ; the clay, on the other hand, has to be sought and proved, and the right kind of clay is not always easy to discover. But the one is as essential as the other. III. — The Manufacturing' Problem. Portland cement is a mixture of limestone and clay or shale, ground fine and burned in a kiln to a stage of incipient fusion. The calcined mixture is then ground as fine as flour, when it becomes the Portland cement of com- merce. A little gypsum is added to the mixture to retard the setting. The average composition of the cement mixture is approximately 75 per cent, of carbonate of lime, 14 per cent, or 15 per cent, silica, and 5 per cent, to 7 per cent, alumina and iron oxide. It is evident that this composition can be obtained by using various proportions of various classes of raw materials, lime, silica, alumina and iron being the essential ingredients. The usual proportion of shale or clay used is one part to three of high-grade lime- stone, the ratio between the silica on the one hand and the alumina and iron on the other being from 2*5 or 3 and 3*5 or even 4 to 1. It is not always easy to find clay or shale with approximately this composition and otherwise suitable. Both the physical and chemical characters of the raw materials have to be studied and controlled by the works chemist. He has to see that the raw materials are of such a nature< that when mixed in certain proportions they are suitable for the manufacture, and he regulates the blending from the different quarries accordingly. Besides this, he controls by analysis the quality of the finished product. In doing this, the soundness, tensile and compressive strength, rate of setting, and specific gravity have to be determined, before allowing the cement to be placed on the market. For a plant producing 500 to 600 tons of cement per week (26,000 to 30,000 tons per annum), the following 7 quantities of material and coal ought to be available annually : — 30.000 tons of limestone. 10.000 tons of clay or shale. 500 tons of gypsum. 20.000 tons of coal. IV.— Gypsum. For the; annual production of 30,000 tons of cement, from 500 to 600 tons of gypsum would have to be imported, as no economic deposits of this mineral have as yet been ascertained to exist in Tasmania. Inquiry in the other States will be necessary as to the source whence it could be best obtained. Probably supplies would come from South Australia, where the present price is approximately 17s. 6d. per ton at Port Adelaide. The freight and charges would bring the cost at Flowery Gully to between 40s. and 45s. per ton. V.— Extraction and Manufacture. ( a ) — Quarrying and Preparing the Stone for Burning. The quarries of limestone and shale will be laid out so as to admit; of direct connection by tramway between the working faces and the rock-breaker. For the shale, if worked on the Bank property, an ordinary horse tramway will most likely be sufficient. The problem of the transport of the limestone from the quarries on the hillside would probably be solved by installing an endless-rope haulage. The principle of this method is that of an endless rope running round a drum at the loading and discharging ter- minals respectively, and’ travelling continuously in one direction. Or, for the upper benches when the work on them predominates, the desirability may have to be con- sidered of conveying the stone to the tramway bins on the level ground by aerial ropeway with automatic release: buckets, and driven by electric motor. This system of transport is peculiarly adapted to quick carriage with small or moderate loads; but it would not be applicable to quarries on the floor at Lutwyche’g workings. 8 The raw materials are suitable for the dry method of manufacture, and' it is assumed that this will be the process adopted. The stone will be passed through a rock-breaker of the Gates gyratory type, which is preferable to the jaw stone- breaker when the duty required is considerable. The material will be crushed to 2-inch size. The term “ Gates ” originates from the works of that name in Chicago, but is applied nowadays to any gyratory type of machine rather than to the particular make turned out by that company. The action is that of a cone which works on an eccentric and approaches and recedes alternately from the walls of the enclosing shell. This subjects the stone to powerful squeezes, and at last breaks it. It is without the excessive vibration of the jaw stone-breaker, and crushes to a 2,-inch size very evenly. Modifications of the original type are in the market, retaining, however, the essential gyratory action. It is, however, now accepted as good practice to adhere as closely as possible to the principle of crushing the raw materials in stages by separate machines, and in many works the jaw stone-breaker is used as the first crusher, reducing the stone to 5 or 6 inch sizes. The limestone at Flowery Gully, by analysis, does not contain more than 0 2 per cent, of moisture, and as about 1 per cent, or a little over is allowable in the dry process of manufacture, it would not seem necessary to instal a drying plant for this rock, if the stocks are kept protected from the weather. But it may be necessary to have driers for the shale and clay. These are essentially rotating drums, through which hot air from the kiln, or generated by separate furnaces, is caused to pass. After crushing and drying, the limestone and shale are automatically weighed and mixed in the proper propor- tions, and are then ready to be ground to a powder. Several types of grinders for this stage of the manufacture are in use at different works, but those which are most favoured are the ball and tube mills — the former for the first grind- ing, the latter for the second. Tube mills are hollow steel cylinders, 6 or 7 yards long and 4 or 5 feet in diameter. They are half-filled with quartz or flint pebbles, and as the tube rotates the pebbles rise on the sides, and, falling again, grind the mixture till the desired degree of fineness is reached. Ball mills are rotating cylinders or drums stepped inside and provided with steel balls which fall from one step to 9 another as the drum rotates, and grind the material to the fineness of grit. Tfie product prepared in this way for the kiln has been reduced to a size which admits of the bulk passing through a 180 -mesh screen. ( b ) — Burning the Mixture. The old upright kiln has given place in modern practice to the continuous rotary kiln, an English invention (Ban- some), improved and first successfully used by Americans about 28 years ago. This is a hollow steel cylinder lined with firebrick, or sometimes and partially with cement clinker bricks, 6 to 9 inches thick. It is usually 6 to 8 feet in diameter and from 60 to over 100 feet long. Up to recent years the standard length was 60 feet, but it has been found that the duty of the kiln is increased by increas- ing the length. Works have been provided with 150 feet kilns, 10 feet in diameter, but this extreme length is con- sidered in the trade as being the limit of efficiency; 120 or 125 feet in length and 6 to 8 feet in diameter are con- sidered normal dimensions for modern plants. F. B. Peck, in a paper on the “ Cement Belt in Pennsylvania ” (Econo- mic Geology, 1908, page 69), states that actual experi- ence has shown the average producing capacity of rotary kilns in barrels of cement per day is as follows : — 60 -feet kiln 200 barrels. 100-feet kiln 400 barrels. 120-feet kiln 500 barrels. 150-feet kiln 750 barrels. It is obvious that a long kiln will permit much of the heat to be saved which could not be utilised in a shorter kiln. A screw conveyor feeds the raw mixture into the upper end of the cylinder at a rate which is controlled by the kiln operator, who regulates the speed! according to circum- stances: this varies from one revolution in one minute to one in ten. The cylinder is usually driven by a variable- speed motor. The cylinder is slightly inclined (f or § inch to the foot). Under the influence of gravity and the rota- tion of the cylinder, the material slowly travels down the latter, and in the lower part of its passage is reduced to a state of semi-fusion by the heat from pulverised coal, which is blown by hot-air blast into the lower end. The tempera- ture in the fire zone is between 2600 and 3000 degrees Fahr. 10 The partly-fused product, consisting of chemically combined lime, silica, alumina, and iron, drops out at the discharge end in the form of lumps and nodules of white or red hot “ cement clinker, ” having a temperature of about 2000 degrees Fahr. The introduction of the rotary continuous kiln gave an immense impetus to the growth of the cement industry throughout the world, and no modern cement plant is without it. A kiln will run for six months before renewals of the lining are necessary. ( c ) — Cooling the Clinker. The hot clinker falls from the kiln into an inclined rotating cooler drum, the air current passing through the drum being the cooling agent. It. is. taken by a conveyor to the clinker store, where it remains for some weeks before adding the gypsum and subjecting it to a final grinding. (d) — Adding the Gypsum. Gypsum (sulphate of lime) has to be added to the clinker in small proportions as the latter passes to the grinding mill, in order to retard the setting of the cement, which otherwise proceeds too quickly. Between 1 per cent, and 2 per cent, is usually added; 3 per cent, appears to be the limit of usefulness, as when more than that proportion is used 1 , it is said to impair the strength of the cement.. After being crushed in a stone-breaker the crude gypsum is in some mills shovelled into elevators conveying it to the grind- mg^mill bins, or in others it is served automatically to the clinker as the latter enters the mill. ( e ) — Grinding the Clinker. This is effected in ball and tube mills, the latter being used for the final fine grinding. The product is as fine as flour, between 80 and 90 per cent, of it passing a 200-mesh sieve. It seems to be established that powdered clinker coarser than 180 -mesh size (180 holes per lineal inch) is deficient in the cementing property. 11 (/) — Storage of the Cement. The product is usually taken from the final tube mills by conveyors, and is then elevated to the hoppers in the storage house, where it remains until it has been analysed and subjected to the necessary tests. After this has been done it is drawn from the bins and delivered by means of conveyors and elevators to automatic bagging-machines, and is then ready for market. It may be mentioned, how- ever, that it is not taken from the bins until it has remained in them for some weeks or months to ripen. Certain chemical reactions may supervene, and have to be watched. VI— Fuel. It may be; expected that coal will be the fuel used for kilns and boiler furnaces, and will have to be brought from a distance. Petroleum and producer gas have been some- times used for burning, but the general practice is to employ coal. Where coal is too costly, the use of producer gas has to be considered, but Bleininger insists that it is never to be employed if it is at all possible to use coal, the percentage of heat losses being about 15 per cent, in favour of direct firing^ 1 ). The best coal for cement-making is that with a fixed carbon content ranging between 50 and 60 per cent., volatile matter between 30 and 40 per cent., and the less ash the better. A proportion of the ash always remains behind in the cement, and there should be no excess of ash if possible; but the ash may amount to as much as 15 per cent, without offering any difficulty, provided that it con- tains no particular constituent that would affect the pro- portions of the raw materials mixture. The fixed carbon percentage should not be high enough to make the coal anthracitic, for such coal (like powdered charcoal) is diffi- cult of ignition. The Tasmanian East Coast coal is quite suitable for the manufacture of Portland cement. Coal for the kilns may be received at the works as it is hewn from the seam or as slack. If it is lump coal, it has to be crushed by jaw stone-breaker or gyratory crusher, but if it is slack it is taken straight to the drier . All the coal when dried is reduced to powder in ball or tube mills till 90 or 95 per cent, of it will pass through (') « Manufacture of Hydraulic Cements,” by A. V. Bleininger. Ohio Geol. Sur. Bulletin, 1904, p. 298. 12 a 100-mesh sieve. The finer it is ground the quicker it will ignite, and even a poor coal can be used in the kiln if it is ground very fine. The drying and grinding are very important efficiency factors in burning. The powdered coal is passed in a screw conveyor to bins in front of the kilns, and thence drawn and blown into the kilns with hot-air blast. The coal actually consumed in the kilns is only a part of the aggregate consumption for all fuel and power require- ments. The purely kiln consumption has been reduced in recent practice, but usually figures out at about 30 per cent, of the clinker produced. But in making the necessary cal- culations the various power and works requirements must be taken into account. Eckel states : “ Every barrel (380 lb.) of Portland cement implies that at least 200 to 300 lb. of coal have been used in the power plant and the kilns.” ( 2 ). This is equivalent to 15 cwt. of coal for every ton of cement, but for an annual production of 30,000 tons of cement, allow roughly. 20,000 tons of coal. The Public Works Department of New- South Wales, in calculating the quantity of coal required for their pro- posed State works, estimates that to produce 30,000 tons of cement it will need 20,000 tons of coal for the kilns and works plant. The Tasmanian coal companies do not sell slack, and ordinary coal brought from Mt. Nicholas to Launceston and thence by boat to Beauty Point will not cost less than 25s. per ton at Flowery Gully. Slack coal from New South Wales will probably cost about 22s. per ton delivered at works site; or the small “ duff ” coal separated in Newcastle might approximate to 18s. or 19s. per ton. Evidence was given before the New South Wales Public Works Commission to the effect that the very fine coal (“ duff ”), resulting from double-screening, could be obtained cheaply at Newcastle, and would be suitable for cement works. Enquiries made by the writer show that the coal in question is screened through J-inch and J-inch apertures. It averages about 16 per cent ash. The Wick- ham and Bullock Island Coal Co. Ltd., Neath Colliery, has continuously separated the duff for years, and has been supplying it to brick kilns of a semi-Hoffman type. The cost, f.o.b. Newcastle, would be about 4s. 6d. per ton. No (*) (*) “ Portland Cement Materials and Industry in the United States,” by E. C. Eckel. United States Geol. Sur. Bulletin No. 522, 1913, p. 66. 13 instance' could be learned of its use in the manufacture of cement, and some tests would be necessary before its quality could be accepted as suitable. While in the district it was suggested to the writer that, there being so much timber in the neighbourhood, charcoal might be used instead of coal, but, as mentioned above, powdered charcoal is not easy to ignite unless the kiln conditions are incandescent. VII.— Works Site. The country at the foot of the hill in the valley of John- ston’s Creek is level, and a permanent stream flows through it. The works would probably be on that flat, and on the 500 acres of Evans, Thompson, and Douglas. The lime- stone would be taken to the kiln by tramway from Lut- wyche’s quarry, and perhaps by aerial ropeway from the higher benches. The conveying of this material to the works would involve a transport of about a quarter of a mile or a little over. The clay and shale transport will probably be about the same distance. The transport route from Lutwyche’s face is a singularly level and easy one. There is plenty of room on this flat available for all the buildings required in connection with the works and port railway, storage sheds for farmers’ freights, &c. VIII.— Transport to Shipping- Port. No serious difficulties exist in the way of establishing a good line of communication with Beauty Point. The dis- tance will be nearly 8 miles, approximately. A steam tram- way for over 3 miles of this, connecting the port of Beauty Point with Beaconsfield, is already in working order, and for the remainder of the distance the engineering work will meet with no obstacles. On the Beaconsfield side of the gorge the extension of the present tramway would necessi- tate some arrangement with private owners of land, but after passing through the gorge the line could be carried parallel with the road on the east side of Johnston’s Creek valley, where it would be on Crown land, and would not interfere with private property before approaching the south end of the valley. There, probably, the owners would 14 welcome facilities for conveying their produce to port or market. With sundry freight revenues from this line the transport charge for the cement to Beauty Point would probably not exceed 2s. per ton. IX.— Cost of Erection of Works. There is nothing in the existing conditions which would make the cost of works at Flowery Gully greater than that of similar cement works elsewhere in Australia. In 1914, Mr. E. J. Morston reported on the Flowery Gully pro- perty, and estimated that cement works with a capacity of 500 tons per week could be erected for about <£40,000 with suitable buildings, plus power plant for same, approximately £10,000 ; in all £50,000. Mr. F. Oakden reported to the New South Wales Govern- ment in 1912 on the cost of erection of State cement works at Homebush near Sydney, with a capacity of 600 tons per week (30,000 tons per annum), which he estimated would be £37,000, exclusive of railway sidings, earthworks, &c. Mr. L. Janicke, in the same year, reporting to the New South Wales Government on the cost of proposed works of similar capacity at the Homebush site, furnished an esti- mate of £41,000; while the New South Wales Public Works Department estimated from £58,000 to £93,000 for works with two plant units at various places in that State. In reporting for the Tasmanian Portland Cement, Lime, Brick, and Coal Company Ltd'., Ida Bay, in 1914, Mr. A. J. Willcoxson estimated the cost of a 30,000-ton plant at £33,000, exclusive of tramways and coal mine equipment. It will be seen from these figures that the installation of a modern cement-making plant is no light matter, even if restricted to one unit of plant. It is considered the best practice to have two kilns and two units, so as to avoid stop- page if anything happens to the kiln. The works can be laid out, according to expert evidence, so as to allow the addition of a second unit without interference with the first, and at a cost of not more than 60 per cent, of that of the first installation. For Flowery Gully the plant power would be electric, which is the accepted practice in all modern works. The power required for manufacturing by the dry process is 15 usually reckoned as from one to one and a half horse-power per barrel of cement, i.e ., from 600 to 800 horse-power for the proposed Flowery Gully works. If the power is derived from the State hydro-electric installation, the power fuel consumption will be considerably reduced. In England, however, steam power still has its advocates. X. — Cost of Manufacture. In the present state of trade and labour no reliable estimates can be framed of manufacturing cost, and the following must only serve to give a quite approximate idea of what may be expected : — 30.000 tons of limestone, quarrying, handling, £ and transporting to works, at 3s. 6d. per ton ... 5250 10.000 tons of clay or shale, quarrying, hand- ling, and transporting to works, at 2s. 6d. per ton ... 1250 500 tons of gypsum, delivered to works, at 45s. per ton 1125 20.000 tons of coal for kiln and power, at 23s. per ton 23,000 Total <£30,625 Roughly, therefore, it may be said that the materials and fuel will cost about £1 per ton of cement. Possibly the clay extraction may not exceed 2s. per ton, but the difference will not materially affect the total, as the govern- ing factor in the calculation is the cost of the coal. As mentioned above, the coal item can be advantageously modi- fied only by the eventual utilisation of the hydro-electric current. The manufacturing cost (labour, administration, repairs, bagging, and depreciation of plant) will fluctuate accord- ing to the varying current conditions, but good Australian authorities estimate it for cement works on this scale as ranging between 18s. and 23s. per ton. Taking 22s. under this head, the total cost will be brought to £2 2s. per ton at Flowery Gully and probably £2 4s. or £2 5s. at Beauty Point. 16 A comparison of this estimate with the estimated cost^ of other proposed sites in Tasmania and Australia shows the following figures : — At Ida Bay, in Tasmania, the cost of extraction and manufacture has been estimated as probably being £2 per ton. At Carlos Gap, in New South Wales-, at site, £1 8s. 8d. per ton. At Newcastle, at works site, £1 12s. 2Jd. to £1 17s. 8|d. per ton. At Homebush, near Sydney, £2 Is. 6|d. per ton, at works site . It may be mentioned that in the New South Wales estimates the coal item figures at 3s. 6d. per ton of coal at Carlos Gap and 14s. Id. per ton at Homebush. XI. - Markets. Supposing all the requirements of manufacture are satis- fied, the chances of success depend largely on markets and distribution. Competition has to be faced, and prices will be found to be governed by slight advantages of position which one works possesses over another. One is either nearer a port or the port is nearer a market, or railway freights are higher, or fuel has to be transported over a greater distance, or the consumption of the product within a given radius is not adequate, or a score of conditions may exist which will give one proposition a pull over another. Notwithstanding that the cement may be manu- factured profitably, the factors which bring about success are exceedingly complex. ♦ According to returns supplied to the Secretary for Mines by various public bodies (Hobart Marine Board, Launceston Municipality, Burnie and Table Cape Marine Board, Tas- manian Government Railways), their consumption of Port- land cement has been for the past five years at the rate of 3300 tons per annum; if we add an equal tonnage for the requirements of private builders and contractors, the aggre- gate yearly consumption will be, allowing for increased consumption after the war, within 10,000 tons per annum. Thus it appears that Tasmania cannot hope to consume in the immediate future more than one-third of the output of the proposed works, and would have to depend upon the mainland for taking the balance. It is easily seen, there- 17 fore how vitally important it is, when starting this industry in Tasmania, that the works should' be in the best possible position for coping with outside competition. The scale of output estimated in this report is at the rate of 500 tons per week more or less, which is that of a moderate- sized one-unit plant. If the capacity of plant were limited to 300 tons per week, which is a small output for cement works, the proportion which would have to be exported to the other States might then be' only about one-third of the total production instead of two-thirds, but the unit cost of production would be higher and competition more difficult to meet. The limited demand in Tasmania operates disadvan- tageous^ in deciding upon the size of the plant to be installed, for to obtain the very highest degree of efficiency at the minimum cost, a large installation is requisite, with a capacity of, say, 2000 or 3000 tons per week. The present markets, however, would not justify a larger plant capacity than 500 or 600 tons per week, which means a single-unit plant. XII. — Conclusion. In the pre-war period the cement industry throughout the world was developing at a rapid rate. The material is indispensable for the constructional engineer and builder in satisfying the multiform needs of modern life, and new uses are being found for it nearly every day. There is every reason for believing that an increasing consump- tion may be relied on as a certainty. Australia at present cannot meet its requirements from its own factories, but is compelled to import from abroad to supply the deficiency. This state of things will no doubt eventually be remedied by -an enlarged Australian output, and unquestionably it is desirable that Tasmania should, if possible, assist in contributing to the augmented produc- tion. The position at Flowery Gully is perhaps such that immediate advantage cannot be taken of the deposits there, but with the expansion of the hydro-electric scheme of dis- tribution, and perhaps a railway connecting the Govern- ment system of lines with Beauty Point, increased facilities for the supply of power and fuel may by and by consider- ably improve the working conditions. It is plain, however, that the starting of cement works is not a thing to be entered upon with a light heart, but requires for success the most careful consideration of both materials and 1 site, as well as Id the command and application of high technique and prac-^ tical experience. Year by year the requirements of the trade in respect of quality of product grow more exacting, and the highest training and practical knowledge on the part of those who control the manufacture are necessary to cope with the ever-increasing demands. Given the materials and a favourable site, the installation of Portland cement works in Tasmania is an attractive proposition. At several places in the island are large deposits of high-grade limestone, and the question of selec- tion of site is for the most part a pure matter of business insight and judgment. The use of cement has already become one of the great factors in the material progress of civilised life, and there can be no doubt that the estab- lishment of the industry in Tasmania is destined ere long to be an accomplished fact. It seems worth while taking some risk in achieving this. W. H. TWELVETREES, Government Geologist. Launceston, 5th April, 1917. 18 the command and application of high technique and prac- tical experience. Year by year the requirements of the trade in respect of quality of product grow more exacting, and the highest training and practical knowledge on the part of those who control the manufacture are necessary to cope with the ever-increasing demands. Given the materials and a favourable site, the installation of Portland cement' works in Tasmania is an attractive proposition. At several places in the island are large deposits of high-grade limestone, and the question of selec- tion of site is for the most part a pure matter of business insight and judgment. The use of cement has already become one of the great factors in the material progress of civilised life, and there can be no doubt that the estab- lishment of the industry in Tasmania is destined ere long to be an accomplished fact. It seems worth while taking some risk in achieving this. W. H. TWELVETREES, Government Geologist. Launceston, 5th April, 1917. GEOLOGICAL MAP OF LIMESTONE AREA AT FLOWERY GULLY LEGEND ■ . ' . ■ - . r' V — - ^ * - ■ r , - - v •- -•*• -V - : V ■ V GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. 1. — The Mangana Goldfield, by W. H. Twelve- trees 1907 No. 2. — The Mathinna Goldfield, Part III., by W. H. Twelvetrees 1907 No. 3. — The Mt. Farrell Mining Field, by L. Keith Ward, B.A., B.E, 1908 No.. 4. — The Lisle Goldfield, by W. H. Twelvetrees 1908 No. 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees 1909 No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E. 1909 No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelvetrees and L. Keith Ward, B.A., No. 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E 1910 No. 9. — The Scamander Mineral District, by W. H. Twelvetrees 1911 No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E 1911 No. 11.- — The Tasmanite Shale Fields of the Mer- sey District, by W. H. Twelvetrees 1911 No. 12.— The X River Tinfield, by L. Keith Ward, B.A., B.E -... 1911 No. 13. — The Preolenna Coalfield and the Geology of the Wvnyard District, by Loftus Hills, M.Sc. 1913 No. 14. — The Middlesex and Mt. Claude Mining Field, by W- H. Twelvetrees 1913 .$0 No. 15. — The Stanley River Tinfield, by L. Lawry Waterhouse, B.E. 1914 No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc. 1914 No. 17 . — The Bald Hill Osmiridium Field, by W. H. Twelvetrees 1914 No. 18. — Geological Reconnaissance of the Country between Cape Sorell and Point Hibbs, by Loftus Hills, M.Sc 1914 No. 19. — The Zinc-Lead Sulphide Deposits of the Read-Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc. ... 1914 No. 20. — The Catamaran and Strathblane Coal- fields and Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees 1915 No. 21. — The South Heemskirk Tinfield, by L. Lawry Waterhouse, B.E 1915 No. 22. — Catalogue of Publications issued by the Government of Tasmania, relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914, compiled by W. H. Twelvetrees 1915 No. 23. — The Zinc-lead Sulphide Deposits of the Read-Rosebery District, Part II. (Rose- bery Group), by Loftus Hills, M.Sc. ... 1915 No. 24. Reconnaissance of the Country between Recherche Bay and New River, South- ern Tasmania' by W. H. Twelvetrees ... 1915 No. 25. — The Gladstone Mineral District, by W. H. Twelvetrees 1916 REPORTS. No 1. — Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E ' 1910 No. 2. — The Silver-lead Lodes of the Waratah District, by L. Keith W T ard, B. A., B.E. 1911 No 3. — Preliminary Report on the Zinc-lead Sul- phide Deposits of Mt. Read, by Loftus Hills, M.Sc 1914 21 No. 4. — On Cement Materials at West Arm, by W. H. Twelvetrees 1914 No 5. — On Some Gold Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6. — Reconnaissance of the North Heemskirk Tinfield, by L. Lawry Waterhouse, B.E. 1914 No. 7. — Preliminary Report on the Zinc-lead Sulphide Deposits of the Rosebery Dis- trict, by Loftus Hills, M.Sc 1915 RECORDS. No 1. — Marine Fossils from the Tasmanite Spore- beds of the Mersey River, by W. S. Dun ... 1912 No- 2. — Stichtite : A New Tasmanian Mineral: Notes by various authors, collected and edited by W H. Twelvetree- 1914 No. 3. — Darwin Glass: A New Variety of the Tek- tite3, by Loftus Hills, M.Sc 1914 No. 4. — A Monograph of Nototherium Tasmanicum by H. H. Scott. Price Is. 6 d 1915 MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. : North-Eastern and Eastern Tasmania, by Loftus Hills. M Sc. .. 1915 Part II. : Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc 1916 Part III. : King Island, by L. Lawry Waterhouse, B.E 1916 No. 2. — Cement Materials at Flowery Gully, by W. H. Twelvetrees 1917 JOHN VAIL, GOVERNMENT PRINTER, TASMANIA. CPVjJ _9 kW&m 5>r^':V^V . j* y ^ ILLliiu . * *— ., 4 . asmania/yfAy 1 2 1921 DEPARTMENT OF TfttWeS- GEOLOGICAL SURVEY MINERAL RESOURCES No. 3 Phosphate Deposits in Tasmania BY W. H. TWELVETREES, Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania CTas mania: JOHN VAIL, GOVERNMENT PRINTER, HOBART 1917 ^ i^iumyp — j . 1 TASMANIA SCALE OF MILES 0 0 0 10 19 20 29 30 RAILWAYS PPOSPPATT OPPOSfTo # k Cape Rarron^lsland Clarke Island^^/ am w strait LOCALITY MAP 'Vphni by John Ion l Covrm merit Printed Bobo it Tasimuua Sasnutnia MINERAL RESOURCES No. 3 Phosphate Deposits in Tasmania BY W. H. TWELVETREES, Government Geologist 1 Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G „ Minister for Mines for Tasmania C a s m a n i a : JOHN VAIL, GOVERNMENT PRINTER, HOBART B76260 1917 Tasmania %/• flSlfy Of DEPARTMENT OF MINES 4fo]y ' u % % GEOLOGICAL SURVEY MINERAL RESOURCES No. 3 Phosphate Deposits in Tasmania BY W. H. TWELVETREES, Government Geologist' Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G . Minister for Mines for Tasmania Tasmania: JOHN VAIL, GOVERNMENT PRINTER, HOBART B76260 1917 TABLE OF CONTENTS. PAGE I. —INTRODUCTION .. 1 II.— MINERALOGY 1 III. — MINERAL PHOSPHATES 2 IV. — ORGANIC PHOSPHATES 3 V.— CONCLUSION 6 PLATE. t. — L ocality, Map Frontispiece Phosphate Deposits in Tasmania, I. — Introduction. The necessity for phosphoric acid in modern agriculture rests on the fact that phosphorus is an essential element of plant food. Consequently, the farmer is anxious to replen- ish his exhausted soil with fresh supplies of this important substance. It is taken up by the plant in solution ; the replenishment must therefore be in a soluble form. Tri- basic phosphate of lime is the form in which the neces- sary phosphoric acid is obtainable. This is insoluble in its raw state in water. It is consequently ground and dried and mixed with sulphuric acid. The resultant superphosphate is soluble and available for plant food. Owing to the consumption of sulphuric acid for war purposes, the manufacture of a soluble phosphate without making demands on the supplies of this acid is a special desideratum, Some methods have been devised to this end, but have not yet come into general use. The importance of ascertaining what are the natural supplies of phosphate rock in Australia has been realised by the Commonwealth Advisory Council of Science and Industry, and the State Gov0mments have been approached with a view of obtaining what information the geological services of the respective States may have available. The present report has been prepared in order to record briefly what is known respecting phosphate deposits in Tasmania. II. Mineralogy. Natural phosphates are derivatives of tri-basic phos- phoric acid (orthophosphoric acid) H 3 P0 4 . The phos- phatic ingredient of phosphate rock is tri-basic phosphate of lime (Ca 3 P 2 0 8 ). This figures in trade lists under the name of bone phosphate. The value of the crude rock is 2 dependent on its content of phosphoric anhydride (P 2 0 5 ), The latter is usually referred to as phosphoric acid. The division of phosphoric-acid-bearing rock into phos- phorites and phosphates is very loosely followed. The pneumatolytic apatite rock, which is the source of mineral phosphates, is called phosphorite; but the term has been extended also to the more compact varieties of any phos- phate rocks, reserving the name phosphates for the earthy varieties of lime phosphate. Pure apatite contains about 90 per cent, phosphate of lime, and is the sole mineral source of this substance. Apatite, when it occurs as fresh-looking crystals, is bril- liant, colourless, to greenish or bluish. The colour, how- ever, is variable, yellow, red, or brown shades occurring. It crystallises in the hexagonal system. The crystals become earthy and dull in the course of weathering. Pure fluorapatite contains 42*3 per cent, phosphoric anhydride and chlor apatite 40 ’9 per cent. The chemical compound known as organic phosphate of lime or rock phosphate is considered to be the result of the infiltration of phosphoric and carbonic acid-bearing waters into calcareous beds and the replacement of car- bon dioxide by phosphoric anhydride. When per- fectly pure, lime phosphate contains 45'81 per cent, phos- phoric anhydride (P 2 0- 5 ). III. Mineral Phosphates. (Phosphorites.) Veins and disseminations of apatite (phosphate of lime) are met with in some countries in basic and other erup- tives. Veins in scapolite rock are well known occurrences in Norway. Scapolite has not been reported in Tasmania, excepting as a scapolite-felspar vein in serpentine at Anderson’s Creek. 1 The nature of apatite veins is pegmatitic, and the genesis of the mineral is connected with pneumatolytic processes. The apatite mines of Canada and Scandinavia were at one time appreciable sources of phosphate supply, but their importance has diminished since the development of organic phosphate deposits in other parts of the world (United States, Tunis, Algeria, France, and Belgium). 3 t In Tasmania no apatite veins are known. This is some- what surprising, in view of the favourable conditions for their genesis. The mineral exists as a microscopic con- stituent of gabbro-amphibolite at Rocky River (Pre- Cambrian), of stanniferous granite at Crystal Hill, near Lottah, of metamorphic schist in the serpentine area of Anderson’s Creek, in basalt at Table Cape, and in other eruptive rocks. There are very considerable developments of serpentine and gabbro rock in different parts of the island, several of which are in positions favourable for pneumatolytic action (Bald Hill, Heazlewood, Meredith Range, Dundas, Trial Harbour, &c.). These rocks form the outer margins of granite masses, and might be expected to yield the lime-phosphate mineral, but examination of numerous rock samples has not revealed the presence of apatite in other than microscopic quantities. It may be, however, that further search will disclose apatite veins. Pro- spectors would do well to look out for these. IV. — Organic Phosphates. These embrace guano deposits and the leachings from them, and the deposits in calcareous sedimentary rocks. Wavellite, met with in the cleavages of slate, is a phos- phate of alumina, and is a precipitate from solutions car- rying phosphoric acid, which was previously disseminated in the sediments. It is used exclusively in the prepara- tion of phosphorus. On the hill slope east of the Den spur, near Lefroy, a few boulders of slate rock occur having a brecciated appearance, and containing (rather abundantly in places) spherules of greenish- white wavellite. Where broken across, these spherules show small discoid sections with a radiating structure, implanted on the surface of the slate. Although only these boulders are visible on the surface, there would appear to be a meridional line of .this coun- try , as the same mineral has been found further north. The improved appearance of the crops in the pad’docks where the boulders are seen is noticeable. Our ordinary limestones, such as we find in our Silurian and Permo-Carboniferous sediments, usually contain a small percentage of phosphoric acid, but not sufficient from an economic point of view. 4 For instance, an analysis of the dark-grey or bluish Silurian limestone at Mr. Blenkhorn’s quarry at Rail ton, made by Mr. H. J. Colbourn (the Government Agricul- tural Chemist), shows the following results: — Per Cent. Lime carbonate Combined water Phosphoric anhydride (phosphate of lime 2*2 per cent.) Magnesia Protoxide of iron Sulphuric anhydride Alumina Silica 75*10 0*55 1*02 0*54 2*88 4*66 3*05 12*20 ' 100*00 Mr. Colbourn remarks on this limestone as follows “ As an agricultural lime it must possess a high value, from the fact that it contains, apart from the lime, several important crop constituents in appreciable quan- tity, notably 1 per cent, of phosphoric anhydride, which is equal to rather more than 2 per cent. (2*2) of tricalcic phosphate of lime/’ Limestones of Permo-Carboniferous age occur in nearly all parts of the island, but do not contain sufficient phos- phoric acid to make the beds of commercial value. Some limestone of this age, highly f ossilif erous , situate 4 miles south from St. Marys, assayed by Mr. W. H. Baker, yielded the following: — J Per Cent. Phosphoric acid Silica Carbonate of lime Oxide of lime Oxide of magnesium Oxide of aluminium Oxide of iron Organic matter Water given off at 100° C 5*12 22*01 40*80 3*82 0*31 5*97 2*03 13*88 6*11 100*05 The most likely sources of supply are, perhaps, the shell limestones of the Straits Islands, where they happen to be ^on the present shore-line, and the rocky islets on the coast, irrespective of whether they consist of limestone beds or not. As a matter of fact, the rock on most of them is granite They are visited by numerous seabirds, ana receive deposits of bird guano. This guano decomposes partiallv, and its P„0 5 , combining with lime from the shells of molluscs, forms some of the tri-calcium phosphate which is found in the crustal portion of the underlying rock The undecomposed portion of the excreta hardens, and, with its lime phosphate, probably forms the loose lumps on the surface. Slopen Island is an exception, loi it is reported by Mr. R. M. Johnston, I.S.O to be com- posed of diabase, Permo-Carboniferous mudstones, and Mesozoic sediments. The calcareous content of the mud- stones would supply the lime for the necessary combma- Samples have been received from Sea Elephant Rocks (off the east coast of King Island), from White Rock Island between Freycinet Peninsula and Maria Island, from Slopen Island in Frederick Henry Bay, and from some islands in the Furneaux Group. Results of assays have been : — Per Cent. Sea Elephant rocks (granite) 11*00 phosphoric anhydride White Rock Island 13S0 Ditto (sand) 3*10 v Slopen Island (Permo-Carb.) 13‘56 The factor for converting P 2 0 5 into tn-calcium phosphate (phosphate of lime, Ca,P 2 0 8 ) is 2' 183 consequently the above assay figures would represent the following percent- ages of lime phosphate:— per Cent Sea Elephant rocks 24’01 White Rock Island 30' 12 Ditto 6 ‘ 7 ° Slopen Island 29' 60 In manufacturing superphosphates the percentage of phosphate of lime is reduced by 50 per cent., or, to put it in another way, double the above percentages would be necessary for the production of a superphosphate contus- ing the same proportions of lime phosphate. The propoi tions are insufficient to enable the material from these islands to compete with supplies reaching the manufacturers ,,of superphosphates from other sources. 6 The extent of these deposits is not exactly known, but from all appearances is very restricted both horizontally and vertically. Some of the rocks have been visited only infrequently by fishermen, and information with respect to them is limited. Information supplied by Mr. H. M. Rivett-Carnac, who has a wide knowledge of King Island, derived from long residence there, is to the effect that anywhere on the west coast of that island north of Currie layers of re-deposited lime may be found containing phosphoric acid up to 10 per cent. He considers the Pyramid Rock, between King Island and Hunter Island, a likely spot for guano. Mr. Rivett-Carnac also states that on Flinders Island, soutfi of White Mark, limestone occurs with a content of from 2 per cent, to 5 per cent, phosphoric acid. V.— Conclusion. From the preceding it will be gathered that the prospects of finding economic deposits of phosphate rock in the State cannot be described as very encouraging. The most pro- mising localities are the small islands off the coast, more particularly the east coast. Numerous sea-birds frequent these rocky islets, and are responsible for deposits of guano of moderate extent. Their numbers, however, cannot be so large as in warmer climes, and from all reports it seems doubtful whether deposits of any magnitude will be found. The lime' phosphate seems to be due to infiltrations from this guano, as well as to its consolidation, but, as far as can be learned, the phenomena are on a small scale. The conditions justify the collection of information but do not warrant any great expenditure at present in survey- ing these islets. As a preliminary step the fishermen who- sail the surrounding waters might be induced to bring in samples and supply some initial information as to the extent of the deposits and their nature, and the accessibility of the islands, before any official attempt at examination is made. It will be well to continue on the alert for possibilities, even if immediate results cannot be foreseen. There are some Tertiary limestones on the Flinders Group which vre slightly phosphatic, and the west coast, near Temma, may possibly prove to be phosphatic. Residents in these- remote localities might be asked to make observations and send in samples for assay. Prospectors may make a rough- 7 test of the rock in the field by taking with them a little nitric acid and molybdate of ammonium (powdered). A spot on the sample should be wetted with the acid, and a grain or two of ammonium molybdate dropped on it. If the molybdate powder turns a yellow colour, the pre- sence of phosphorus is indicated. Finally, a Government bonus, on a less extensive scale than the bounties under “ The Commonwealth Bounties Act, 1912,” for the discovery of a deposit of commercial value, might have the effect of stimulating local search for phosphates, both of organic and mineral origin. W. H. TWELVETREES, Government Geologist. Geological Survey Office, Launceston, 9th May, 1917. GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. 1 —The Mangana Goldfield, by W. H. Twelvetrees No. 2. — The Mathinna Goldfield, Part III., by W. H. Twelvetrees No 3. — The Mt. Farrell Mining Field, by L. Keith Ward, B.A., B.E No. 4.— The Lisle Goldfield, by W. H. Twelvetrees No. 5.— Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees ... No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E ; No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, bv W. H. Twelve- trees and L. Keith Ward, B.A., B.E. .. ; No. 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E ' No. 9. — The Scamander Mineral District, by W. H. Twelvetrees No. 10.— The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E No. 11.— The Tasmanite Shale Fields of the Mersey D’s+rict, bv W. H. Twelvrtrees No 12. — The X River Tinfield, by L. Keith Ward, B.A., B.E No. 13. — The Preolenna Coalfield and the Geology of the Wvnvard District, by Loftus Hills, M.Sc. ... No. 14.— The Middlesex and Mt. Claude Mining Field, bv W^ H. Twelvetrees No. 15. — The Stanley River Tinfield, by L. Lawry Water- house, B.E • No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc No. 17.— The Bald Hill Osmiridium Field, by TV . H. Twelvetrees No. 18. — Geological Reconnaissance of the Country between Cape Sorell and Point Hibbs, by Loftus Hills, M.Sc No 19— The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc No. 20. — The Catamaran and Strathblane Coalfields and Coal and Limestone at Ida Bay, Southern Tasmania, bv W. H. Twelvetrees No. 21.— The South Hoemskirk Tinfield. by L. Lawry Waterhouse, B.E No. 22. — Catalogue of Publications issued by the Government of Tasmania, relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914, compiled by TV. H. Twelvetrees 1907 1907 1908 1908 1909 1909 1909 1910 1911 1911 1911 1911 1913 1913 1914 1914 1914 1914 1914 1915 1915 1915 9 No. 23.- No. 24.- No. 25.- No. 1.- No. 2. No. 3. No. 4.- No. 5. No. 6. No. 7.- No. 1.- No. 2. No. 3. No. 4. No. 1. No. 2. No. 3, -The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part II. (Rosebery Group), by Loftus Hills, M.Sc. ”•••••• -Reconnaissance of the Country between Rech- erche Bay and New River, Southern las- mania, by W. H. Twelvetrees ••••• — • -The Gladstone Mineral District, by \Y H. Twelvetrees reports. -Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith W ard, jg ^ -The Silver-Lead Lodes of the War at ah Dis- trict, by L. Keith Ward, B. A., B.E •••••;••• -Preliminary Report on the Zinc-Lead _ Sulphi e Deposits of Mt. Read, by Loftus Hills, M.Sc. -On Cement Materials at West Arm, by W. H. Twelvetrees ••••”• VC- -On Some Gold-Mining Properties at Mathinna, by W. H. Twelvetrees V-'V’ m-* " -Reconnaissance of the North Heemskirk Tin- field, by L. La wry Waterhouse, B.E. •••••;••• -Preliminary Report on the Zmc-Lead Sulphide Deposits of the Rosebery District, by Loftus Hills, M.Sc records. -Marine Fossils from the Tasmanite Spore-beds of the Mersey River, by W. S. Dun -Stichtite : A new Tasmanian Mineral : Notes by various authors, collected and edited by W. H . Twelvetrees • • • ■ ■ • • • ~ ■ • • * ; : :* • • * -Darwin Glass : A new variety of the lektites, by Loftus Hills, M.Sc.. - —A Monograph of Nototherium Tasmanicum, by H. H. Scott. Price , 7s. 6d MINERAL RESOURCES. —Tungsten and Molybdenum — Part I. — North-Eastern and Eastern Tasmania, by Loftus Hills, M.Sc - Part II. — Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc. Part III.— King Island, by L. Lawry Waterhouse, B.E — Cement Materials at Flowery Gully, by W. H. Twelvetrees ;••••” • • • • • • — • , — Phosphate Deposits m Tasmania, by W. i i. Twelvetrees JOHN VAIL, GOVERNMENT PRINTER, TASMANIA 1915 1915 1916 1910 1911 1914 1914 1914 1914 1915 1912 1914 1914 1915 1915 1916 1916 1917 1917 » a I mammm „ f , U , SKS M/ <>" 1 2 1921 4f» y / u x STATE GEOLOGICAL SURVEY 0L a s in a DEPARTMENT OF iwik^sl 2 132 GEOLOGICAL SURVEY MINERAL RESOURCES ~~ ^ No. 4 . Asbestos at Anderson’s W. H. TWELVETREES, Government Geologist HOBART JOHN VAIL, , Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania fgf Casnianta; GOVERNMENT PRINTER, 1917 ® a s in a it t a DEPARTMENT OF MINES DEPARTMENT OF GEOLOGICAL SURVEY MINERAL RESOURCES No. 4 Asbestos at Anderson’s Creek BY W. H. TWELVETREES, Government Geologist Issued under the authority of Honourable Sir NEIL ELLIOTT LEMC^IS, K.C.M.G. Minister for Mines for Tasmania (Tasmania JOHN VAIL, GOVERNMENT PRINTER, HOBART B7M94 1917 TABLE OF CONTENTS U 3 PAGE I.— INTRODUCTION 1 II.— GENERAL GEOLOGY 2 III.— ECONOMIC GEOLOGY 4 (a) Serpentiriisation and the Formation of Asbestos 4 ( b ) The Relation of the Igneons Rocks to the , Asbestos Deposits 5 (c) The Minerals of the Field ... 6 IV.— 1 THE MINING PROPERTIES 9 C. B. Buxton’s Leases: 6479 -m, 70 acres; 6340-m, 10 acres; 6341 -m, 80 acres 9 Section 7232 -m, 80 acres (Paul Charriol) ... 14 V. — GENERAL METHODS OF ASBESTOS TREAT- MENT 17 VI. — COST OF ERECTION OF MILLS 20 VII. — COST OF ASBESTOS PRODUCTION AT ANDERSON’S CREEK 21 VIII.— REALISATION OF THE PRODUCT 22 IX.— EXTRACTION OF ORNAMENTAL STONE ... 24 Section 7414 -m, 80 acres (H. Conder) 24 X.— CONCLUSION 25 PLATES. Fig. 1. — Amphibole Asbestos from P. Charriol’ s > Section ••• *” l Frontispiece Fig. 2. — Chrysotile Asbestos from Buxton s I (Durabestos) Sections. Geological Sketch-map of Anderson’s Creek Asbestos Field At end of Report Frontispiece. Asbestos at Anderson’s Creek T. — Introduction. The renewal of interest in the asbestos field at Ander- son’s Creek, together with the special demand for the mineral by reason of the fact that it has a new applica- tion as material of war, has led to a re-examination of the points where operations are now being carried on — which, by the way, have been the sites of prospecting work from time to time during a series of years. The belt of serpentine rock in which asbestos occurs on each side of Anderson’s Creek is about a couple of miles in length from north to south, and 1J mile in width. Anderson’s Creek, a perennial stream, flows through the belt, and empties into the West Arm at about mile north of the northern boundary of the fibre area . The township of Beaconsfield is situate 2| miles east of it, and is connected with the field by means of a somewhat rough cart road. The following official reports have been published deal- ing with the district : — 1. Geological Surveyor’s Report of the Country near Ilfracombe, in the West Tamar District, by Charles Gould (Aug., 1866). 2. Report on the Asbestos Deposits, Anderson’s Creek, near Beaconsfield, by W. H. Twelve- trees (20th November, 1899). 3. Report on the Mineral Deposits of the Districts cf Beaconsfield and Salisbury, by W. H. Twelve- trees (13th March, 1903). Although the deposits have received attention at inter- vals, the attempts at development do not seem to hive attained profitable results. Recently, however, the Dura- bestos Company, or Sydney, and M. Paul Charriol, of Melbourne, have started work on them, and if the serious operations which are now in progress meet with success, the district will witness the birth of a new industry. A growing demand for asbestos fibre for building and other construction work is springing up ; it is being increas- 2 ingly used for roofing. It is also stated to be of use as a material of war, being employed largely in the construc- tion of new naval vessels, and as a protection against incendiary bombs. The High Commissioner for the Commonwealth in Lon- don has brought the present great demand for, and value of, asbestos, under the notice of the Australian Govern- ment, with a view of stimulating the Australian output. It thus becomes of special importance to investigate the possible sources of supply in this State, and the present examination of the Anderson’s Creek occurrences has been undertaken with this end in view. II. - General Geology. In this report, which is principally economic, the gen- eral geology of the field will be only lightly touched upon. The country to the west of the asbestos field consists of a mountain range hemming in the fibre area in that direc- tion, and terminating at Badger Head, in Bass Strait. This is known as the Asbestos Range, and probably owes its name merely to the proximity of the Anderson’s Creek field, for neither serpentine nor asbestos is known to occur in it. The range is composed of schists and slates of Pre- Cambrian age. The probability is that these ancient strata at one time occupied the present area of the ser- pentine, and extended as far east as Anderson’s Creek. On the Dan’s Hill meridian on the eastern boundarv of the serpentine, are sandstones and quartzites of the Bea- consfield series; these are of Silurian or Ordovician age. The country lying between them and the ancient strata referred to above is occupied by a serpentinised intrusion of ultra-basic rock, the home of the asbestos mineral. This intrusion is considered to be Post-Silurian and Pre-Permo- Carboniferous, i.e ., Devonian. A linear hill ridge of dark granular igneous-looking rock traverses the serpentine in a mean north-and-south direc- tion in the central part of the field. It is flanked on the east side by the chrysotile asbestos area, and on the west by serpentine, with bodies of hematite and mag- netite, which at one time were worked for iron ore. It is f-mile long by 10 to 12 chains wide, and the crest of the ridge rises into three or four domes or rounded summits. Where it has been cut through by the creek, a massive 3 ■cliff of bare rock is exposed. In the old days this ridge and its summits went by the name of the Settlers. Though frequently Very massive in aspect, the rock has in places a foliated appearance, and a directional arrange- ment of its constituent minerals is very marked under the microscope. Different opinions have prevailed as to the origin of the rock, some observers regarding it as a crushed aplitic or granitoid rock, while others interpret its char- acter as denoting a crushed fragmentary rock of the grey- wacke or arkose type. Dr. E. W. Skeats, who has kindly examined specimens of the rock, is of opinion that it was originally a rather coarse-grained sediment, containing quartz, aluminous or argillaceous material, and some partly decomposed fel- spars; i.e., a rock approaching an arkose or felspathic and argillaceous sandstone, and that its present characters are due to contact-metamorphism. The microscopic characters are those of a schist or gneiss ; the constituent minerals are biotite, muscovite, quartz, felspar, with minute grains of apatite, and occa- sionally a crystal or two of tourmaline. Indications of strain and crushing are present. A specimen was submitted to the late Professor Rosen- busch, who was unable to recognise in it the structure of an eruptive rock. For the present, therefore, the balance of probability is in favour of the rock having been a sedi- ment, crushed and reconstructed as the result of its pres- sure by, and inclusion in, the serpentinised rock-mass. There is also a small exposure of the same rock at the southern end of the old iron mines tramway, south-east of Scott’s iron hill. About ^-mile south of the southern end of the Settlers Range are signs of contact-metamorphic action, in the form of chloritic and vesuvianite rock. The eastern bor- der of the serpentine is not marked by any alteration of the adjoining sandstones beyond their induration, and on Dan’s Hill, by a little development of chalcedony. The latter is associated with some arsenical pyrites. Some pits have been sunk near the contact line in search of gold- bearing stone, and prospects are said to have been obtained at the time. A noteworthy feature of this field is the appearance at various points of small intrusions of granitic rock in the serpentine. One of these occurs round the south-east corner of P. Charriol’s Section 7232 ; another on the north side of the creek east of the tramway bridge; another a couple of hundred yards south-west of the bridge; another 4 in the southern part of the field, on Lot 730 (W. Barnes, 640 acres), 2 chains south of what used to be Gale’s gate, on the north boundary-line of the lot, and 5 or 6 chains east of Anderson’s Creek. The gate and fence have now been destroyed by fire, and the exact spot is difficult to locate. III. — Economic (Geology. ( a ) — Serpentinisation and the Formation of Asbestos. The serpentine rock of Anderson’s Creek is confined to an area which was previously occupied by the rocks known by the names of peridotite and pyroxenite. It is an alteration product of primary magnesian silicates, such as olivine and pyroxene. A very common view has been that the metamorphism occurred in the zone of weathering, and that meteoric waters were the agents of the alteration. This opinion has, however, in recent years, given place to a new con- ception. Bosenbusch, in his “ Elemente der Gesteins- lehre ” (1910), pointed out that serpentines strongly resist weathering, and adds that their high water content gives rise to the supposition that serpentinisation was effected in association with orogenic processes. Water is taken up from deep-seated thermal sources, the olivine of the fresh rock becomes replaced by serpentinous mineral, and finally the pyroxene follows suit; the specific gravity decreases, and the rock becomes a hydrous magnesian sili- cate. In the final stages of alteration, opaline silica and magnesia are common products. E. Weinschenk, in his “ Grundziige der Gesteinskunde,’ quotes a striking example from the Stubachthal of veins of perfectly fresh olivine intersecting completely serpen' tinised rock, which seems to show plainly that its serpentinisation was due to previous deep-seated causes. The purely bronzitic rock or pyroxenite is intersected by veins of asbestos only infrequently, but wherever the olivine-bearing rock has been converted to serpentine, small veins of asbestos fibre traverse it in every direction. The minutely-fissured olivine crystals have been penetrated by magnesian silicate in solution, and this has resulted in the gradual formation of serpentine. The excess solu- tion has found its way into, and remained in, the numer- ous joint-channels of the rock, where it has crystallised in the fibrous form as asbestos. Chrysotile-asbestos is prac- tically identical in composition with serpentine, a hydrated 5 silicate of magnesia. Amphibole- asbestos is an imper- fectly hydrated fibrous hornblende. ( b ) The Relation of the Igneous Rocks to the Asbestos Deposits. As in Canada, the serpentine at Anderson’s Creek is associated with varieties of granitic rock. Small isolated exposures of aplitic, graphic, and hornblendic granite arrest the attention, the more so as any normal granite massif is not known near the west bank of the Tamar. Perhaps the most reasonable explanation of the occurrence here is that both the serpentinised rock and the granitic varieties are the differentiated consolidation products of the same magma reservoir, the acidic intrusive material having remained fluid after the basic part had cooled. The consolidation of the different parts of the entire igneous complex was therefore not quite synchronous, though presumably in the Devonian period. Somewhat similar phenomena are recorded in connection with the asbestos-serpentine of Quebec. Mr. J. A. Dres- ser writes* : — Small bodies of granite, ‘seldom exceeding a few hundred feet in length, are very numerous in the peridotite in the vicinity of the asbestos mines at Thetford and Black Lake, where they are generally believed to be essential to the good quality of a deposit of asbestos. They occur as dykes, much folded and broken, and in a great number of small irregular masses, whose relations to the serpentine are extremely difficult to determine. In composition they vary from an acid phase near aplite in the smaller dykes, to hornblende granite in larger masses, and in some of the largest to hornblende-biotite granite.” It may be assumed that heated waters set in circulation hy the great granitic intrusion effected the serpeninisation of the cooling peripheral rock, and brought about the depQsition of the asbestos. The whole process may be figured in the following broad outlines : — 1 . There was the welling-up of the ultra-basic magma, probably the peripheral portion of the great granite magma. This consolidated as pyroxenite and peridotite. * On the asbestos deposits of the eastern townships of Quebec, by J. A. Dresser. Economic Geology, 1909, pp. 130-140. 6 2. The cooled rock was penetrated by protrusions of the granitic magma at various points. 3. The heated solutions set in movement by the above processes originated the serpentinisation of the rock-mass. Differential movements of the ser- pentine caused slickensided partings, and innumerable small channels and fissures were formed by shrinkage. 4. The wall-rock of the various channels and joints supplied the material, which crystallised as asbestos fibre. This operation was the end term of the entire alteration process. Investigators are not agreed as to exactly how the fibre was formed. Veins of magnetite intersect the ser- pentine, showing a fibrous crystallisation identical with that of chrysotile. It must be concluded that the granite and its apophy- ses have a casual connection with the occurrences of asbes- tos, for, according to the views expressed here, if t b ere had been no, movements of the acidic magma, the basic rock would not have been serpentinised, and asbestos would have been absent. (c) The Minerals of the Field. Asbestos . — This has become a popular group name for some minerals differing from one another in constitution, but bearing a certain resemblance in habit. True asbestos is a fibrous variety of amphibole ; while the Canadian com- mercial asbestos is chrysotile or fibrous serpentine. The group name is used in common parlance, and is applied by the trade to both varieties, distinguishing, however, amphibole-asbestos and chrysotile- asbestos. Both of these varieties occur in the Anderson’s Creek field, and both in serpentine rock. The amphibole variety, however, exists also in veinstone, consisting of aplitic granite. This is on P. Charriol’s section. The fibre is mainly parallel with the partings in the serpentine m which it is contained. It is several inches m length, has a cottony feel, and can be easily separated with the . lin- gers: cross-vein fibre also occurs. Some of it has a tamt. greenish tinge, but for the most part it is white', and resembles flax. When heated its hue is pure w i e. e 7 original amphibole mineral has been partly hydrated, and in recrystallising, has assumed the fibrous structure. As might be expected, its composition differs somewhat from that of chrysotile asbestos. It has less magnesia and water, has more iron ; and lime and manganese are con- stituents. Actinolite or tremolite, in minute colourless radiating tufts, is microscopically associated with the min- eral. Chrysotile asbestos is the fibrous form of serpentine. It is the silky, lustrous, greenish filling of narrow veins in serpentine rock. Its greatest development on the Ander- son’s Creek field is on the sections worked by the Dura- bestos Company. The chemical composition of the fibre is similar to that of the serpentinised wall-rock which encloses it. The strength and heat-resisting properties require co be determined by appropriate tests. Normal veins of chrysotile show the fibres arranged transversely to the vein-walls; sometimes these veins have been displaced so as to cause the fibres to overlap and assume the appearance of long fibres parallel, or nearly so, with the walls. This is termed in the trade “ slip fibre,” the length of fibre being only apparent. Some- times, however, without being slip fibre, the crystallisa- tion is in long threads, parallel with joint planes. This is seen in one of the Durabestos trenches, which shows a silky fibre several inches in length. The chrysotile on this field runs through the whole gamut of varieties, from a superb silky quality of the highest excellence, to the stiff vitreous-looking fibre of inferior grade. Chromite , — A hard, black, isometric mineral, with the composition FeCr 2 0 4 , oxides of iron and chromium. ft was formed at a very early stage of rock-consolidation, and is visible as minute granules or octahedra in the ser- pentine, though these do not appear to be profuse. At one time the mineral was believed to have crystallised during serpentinisation, but this is negatived by its occur- rence in fresh peridotite, and it is more natural to suppose that owing to its refractory nature it has survived the alteration of the original peridotite to serpentine. It is evidently associated with the iron ores of the district, as analyses of the ironstone show a content of chromic oxide up to 6 per cent. » Magnesite. — MgC0 3 , occurs as a white filling of joints in the serpentine rock, from which it is derivatory. It does not exist in sufficient quantity to be of commercial value. 8 Magnetite and II ematite . — These oxides, besides occur- ring as ordinary rock-forming minerals, exist in the iorm of beds or masses in the serpentine on Mt. Vulcan and Scott’s Hill, which have been worked as ores of iron. A full account of these occurrences will be found in the Departmental report of March, 1903.* They are associ- ated with asbestos-bearing serpentine. The slopes of the ironstone hills are strewn with nodular and concretionary boulders of brown hematite and magnetite, which below the surface are embedded in red ochreous drift. The latter seems to pass down into hematite and serpentine us clay, finally bottoming on hard serpentine, though doubt- less this floor cannot be considered as the downward limit of the iron oxide. According to the old bores, alterna- tions of iron ore and serpentine were met with (on Mt. Vulcan) to a depth of 176 feet. Pieces of fibrous mag- netite or “ needle ore ” are common in the surface soil, liberated, no doubt, from veins in the serpentine. Fibrous magnetite, with cross vein fibres, simulating the habit o chrysotile, occurs in the asbestos belt in narrow yeins_ 1 s deposition in this form would seem to be coeval with the formation of asbestos. M Merit e. — NiS. Capillary nickel sulphide, occurs in the serpentine on the Durabestos leases, as tufts of delicate radiating fibres of a brassy colour and lustre. Rhodonite. — MnSiO s This manganese metasilicate occurs in intimate association with scapolite m e o quarry on the hill. The scapolite stone shades off into pink rhodonite. Both of these minerals are to be regarded here as contact-metamorphic vein-products. Specimens of rhodonite are now difficult to obtain, the material broken out being buried under the tip. Scapolite .—Calcium-aluminium silicate . This mineral is seen if! the form of large white boulders lying ah the entrance to the old hill quarry. At one time it could be seen that their source is a vein in the quarry face about a foot in width, but the face at this spot is now obscured by talus. Mr. G. W. Card, of the Mining Museum, Syd- ney, has more than once examined this vemstuff, and his latest report is as follows: — - Microscopically it is a granular rock, an aggre- gate of scapolite and felspar (plagioclase) . The e xact * Repor^oxTthe^ Mineral Resources of the Districts of Beaconsfield and Salisbury, by W. H. Twelvetrees, 13th March, 1903. 9 optical characters do not help me much; there is no trace of cleavage, bnt some of the grains seem to show broad twin lamellae. Physical tests are fairlv definite : — Specific gravity (Walker’s balance) — 2*65. Hardness — 7, or slightly over. Fuses quietly at a good heat to a blebby glass. Na flame so strong it appears to indicate a sodium mineral. Silver nitrate throws down copious AgCl; chlorine must be present. The hardness I tested repeatedly; 6*5 is the highest quoted for scapolite, but your mineral seems to scratch quartz. ” Tourmaline . — Borosilicate of aluminium and other bases. The ordinary black tourmaline occurs very rarely in the metamorphic schist of the Settlers’ Hills. Its sporadic occurrence suggests some connection with the granitic intrusions in this field. It is not, however, any indication here of tin ore. Serpentine . — Hydrated silicate of magnesium. As a mineral it forms microscopic veinlets in the constituents of the serpentinised rock and veins in the rock-mass, as well as constituting the bulk of the rock itself. Picrolite . — A woody-looking magnesian splintery min- eral is sometimes associated with the asbestos, showing a columnar or incipient fibrous structure, but of no appar- ent value. It is met with both as a cross-vein filling and parallel with the vein walls. It varies in appearance nonx that of a harsh asbestos to a flinty-looking veinstuff. IV. -The Mining Properties. C. B. Buxton’s Leases — 6479m, 70 Acres; 6340-m, 10 Acres; 6341m, 80 Acres. These leases are situate 2^ miles west of Beaconsfield, on the east side of Anderson’s Creek. The woodcarters’ road from the timbered country on the creek passe* 10 through the sections and connects with roads to Beacons- field and Beauty Point. In the north-east corner of Sec- tion 6479 the country is Ordovician or Silurian sandstone, and the dark gneissoid rock of the Settlers crosses its south-west corner; otherwise, the rock of the sections is everywhere serpentine. The Durabestos Company of Sydney has been prospect- ing on the three leases as option-holders, Mr. Hartwell Conder, M.A., being the supervising engineer. Although prospecting work has been carried on here at intervals for many years, this may be said to be the first time that a serious attempt has been made under trained control to investigate and develop the resources of the area. The ground was taken up in 1899 in five leases (1772m, 1773m, 1774m, 1775m, and 1935m), by the Australasian Asbestos Company, which worked the deposits for over a couple of years, and shipped 374 tons of stone to the mainland, with a view of establishing a market before going to any great outlay in developing the property. The material exported consisted of impure fibre, matted and interlaced with decomposed fibrous serpentine rock. The fibre was long, and associated with a good deal of picro- litic stone. A mineralogical feature of this quarry was the occurrence of a patch or vein of scapolite, a foot wide, associated with, and merging into, pink rhodonite. A few boulders of the white scapolite are still lying about the approach. It was thought that the fibre might be found useful in making asbestic, an asbestos plaster in which the fibre is a substitute for hair. Laid over woodwork, this plaster renders the structure fireproof under ordinary conditions, and it was hoped that a strong Australasian demand would be created and fed by the Company's quarries. The market, however, did not eventuate, and the Company ultimately expended its capital, and died a natural death. The material broken out for use was found gradually to fall off in quality, the stone becoming harder and less fibrous. At the time, the price realised for it was £5 or £6 per ton after treatment in Melbourne, but as only the initial stage had been reached, permanent quotations could not be secured. A little south-west of the above workings a new quarry was started two or three years ago, and some vor k has been done in it recently. The face was found by the present option holders to be practically barren when they 11 came here, with the exception of a 10-ft. band of fibre- bearing rock in the north-west corner. A small pro- specting shaft was started here, and has been snnk to 27 feet from the floor of the quarry. From 17 feet down to the bottom some good fibre appeared, with a maximum length of \\ inches, but the rock is poorer at bottom. From what can be seen on the ore-heap, the fibre seems a good cross-vein chrysotile, ranging mostly between ^-inch and J-inch in length, and occasionally longer. The coun- try-rock is greenish serpentine, somewhat decayed by weathering and intersected by slickensided partings at steep angles. This quarry faces south, and is situate just below the brow of the hill in a favourable position for working. It has been worked into the hill northwards 75 feet by 44 feet in its widest part, and with a face of 15 feet in height. Over the top of the hill are the north-west quarries, which show narrow repeated ribbon-veins of chrysotile one- tenth to one-twelfth of an inch wide. These veins are, in places, no more than |-inch apart, and the formation has the appearance of being good milling rock, which would yield a fair percentage of short fibre. Its pre- sent value depends upon whether mainland dealers have more* than a limited range of requirements. In the flat country south of the hill quarries, a series of trenches has been opened, all of which expose bands or patches of chrysotile-bearing rock. These trenches yield a nice silky cross-vein fibre usually between ^-inch and Jr-inch long, and sometimes some fibre of superb quality 6 inches or 7 inches in length. The trenches may be dis- tinguished by the letters A, B, C, D, E, and F. A is a set of double trenches east to west, 330 feet and 80 feet respectively, situate in the southern part of Section 6479-m. There are two belts of good fibre rock in the long trench, separated by about 20 feet of lean rock. Some of the fibre from this trench is the best that has been yet seen on the field. B trench is 160 feet long, situate 200 feet further south, and is in pale-green serpentine rock, showing fibre from one-sixteenth to one-fourth inch in length. C trench is 100 feet south of the preceding, on the boundary-line between Sections 6340 and 6341. It has been driven a chain east and west. The serpentine is a little harder and the fibre not quite so plentiful as in the northern trenches. Some picrolitic fibre is noticeable on the gliding-planes of the rock. 12 D trench, with an old shaft, is 100 feet south; and 1L6 feet further south of this is E trench. About 200 feet south of the above is an old tunnel »hic* has been driven east, with a long approach. Some gc od fibre has apparently been obtained from this point, as evidenced by the existence of an old knapping-floor. South 4 of the tunnel are some knobs of hard bronzitic rock, and no further prospecting has been done in this direction. The asbestos area, however, continues, for fair chrysotile fibre occurs 200 feet south-east of the tunnel ; and ^-mile south-east are surface exposures of excellent fibre, J-inch and f-inch in length. This goes to show that almost any- where in this field prospecting would disclose fibre. A complete scheme of prospecting would mean the extension of the present plan of work to the whole of the ground, so as to make sure of locating ail the important patches. The present plan has, no doubt, been to carry out as much prospecting as possible, with a fixed limited outlay. As far as operations have proceeded, the indications are that the patches of fibre-bearing rock will be found to be numerous, but of small size. Their number, if they are in close juxtaposition, may possibly compensate for their size. If prospecting results are good, it may possibly pay for a time to break out and ship the fibre-rock to Sidney for the purpose of testing the market; but to restrict export permanently to hand-cobbed fibre or to small par- cels of selected stone would be prejudicial to the future of the property. The ultimate realisation of the asbestos resources here involves treatment on the spot, so as to turn to account all lengths and classes of fibre However, i would be premature to erect crushing and fiberismg plant at the present time, before the leases are prospected throughout, and a better idea gained of their capabilities of supplying the demands of a null, as well as of meeting the requirements of the Australian market generally. The fibre on these leases is, on the whole, chrysotile- usbestos of varying character, identical in appearance with that usually met with on the market. Some of it is the pale-green variety, separating when rubbed into very minute fibre; other varieties are white and more huffy ; another variety is the well-known slip fibre, several inches long, teasing out into lengths of 2 and 3 inches of soft silky thread The flexibility, softness, and length of the fibre at present being extracted appear to ^a^factory though perhaps not quite comparable with _ the finer Canadian varieties. The analysis of a sample in the Geo 13 logical Survey Laboratory by Mr. W. D. Reid, Govern- ment Assayer, gave the following results: — Per cent. Si0 2 - ... 42-80 MgO 41-86 CaO o-oo Ye O 5-04 ai;o 3 3 2-24 H.,0 - ... 8-46 100-40 The iron oxide content, 5 ‘04 per cent., is considerably higher than in the analyses of Canadian chrysotile fibre, as given by Cirkel. He quotes fibre from Thetford as con- taining only 0-87 per cent, iron protoxide, and 3'05 per ■cent. iron sesquioxide. The general run of Canadian hbre seems to be between 1 per cent, and 3 per cent, iron oxide. The remaining constituents in the Anderson s Creek analysis are in normal proportions. The adjacent iron ore deposit is suggestive of an exceptionally hign percentage of that metal being present in the serpentine ot the field. The presence of iron in asbestos increases its fusibility and diminishes its heat resistance. The veins, as a rule, do not show the parting in the middle which characterises many chrysotile veins in oth ;r parts of the world, so that the width of the vein cor- responds with the length of fibre. Some of the veins are accompanied by parallel veins of magnesite, talc, and ser- pentine mineral. . ,, Occurrences of hard and splintery picrolite, harsh ■(* lie feel, are frequent. White veins of this fibrous rock tra- verse the serpentine, looking like veins of dehydrated chry- sotile, but their minute structure does not support the inference. They may, perhaps, be interpreted as being veins of anhydrous asbestiform rock material, but exactly what process has originated them is at present uncer am. They seem to affect the bronzitic and imperfectly serpentm- ised rock, in preference to rock which has fallen a com- plete prey to serpentinisation. The width of the serpentine belt is so narrow that con- clusions cannot be drawn as to the relative fibre values of its central and marginal portions respectively. At pre- sent good fibre is being found towards both margins as well as in the centre of the belt. The pro a y .the whole of it has come strongly within the range of 14 ence of under-lying cooling granite, which has been favour- able for the asbestos-forming process. Perhaps the only qualification is that fibre is most likely to be met with where the serpen tinisation is most complete, and in this connection a favourable feature is that the mass of igneous rock is, comparatively speaking, so small that its serpen t- inisation is almost universal. Section 7232m (80 Acres— P. Charriol). This is situate a little over a mile from the preceding property in a north-westerly direction, 1J mile from the mouth of Anderson’s Creek, and J-mile west of the latter. Two roads give access to the lease — one, the Leonards- burgh-road, from Beaconsfield, and the other, a longer but better one, round by York Town, at the head of the West Arm. A short cut may be taken across the creek on E. Daily’s 48 acres, by means of a log. The country-rock between the creek and the quarry is serpentine, inter- rupted on the south-east boundary of the section by one of the intrusions of granitoid rock so characteristic oP this asbestos field. A quarry has been opened in the west part of the lease in rotten and fissured serpentine rock. Partings in the decayed rock, several inches wide, have a general dip towards the north, and are filled in places with long asbestos fibre, between 6 inches and 1 foot in length. A couple of tons of fibre have been broken out and selected from a formation width of 10 to 15 feet; other formations also appear in the face. The rock partings are open, and have admitted much surface water; in addi- tion to which the quarry has been filled with water for a considerable time, so that the fibre, as taken from the face,, is clammy, and somewhat discoloured. The analysis of the fibre, made by Mr. W. D. Peid v „ Government Assayer, is as follows:- — Per cent. Si0 2 54-88 MgO 18-94 CaO 12-15 Fe 2° 3 AU>, 2-60 h 2 o 1-20 99-81 15 The analysis of the amphibole- asbestos is a typical one of that variety, though the iron content here too is above normal. It is plainly different from the fibre worked on the Dura- bestos sections. The lime content, and its nearly anhy- drous nature, indicates that it belongs to the amphibole division, or asbestos proper. The trade name asbestos, however, includes also chrysotile, the hydrated fibre, which is asbestiform, and known as chrysotile-asbestos. The asbestos of this quarry resembles in appearance the hornblende asbestos of Gundagai, New South Wales. It has a cottony feel, and is easily separated by the fingers. Though the colour is greatly improved in drying by arti- ficial heat, the heating will have to be carefully watched, and its effect on the strength of the fibre determined, for heating has an invariable tendency to weaken asbestos fibre. It will be well not to push the process too far. With more cover it may be anticipated that the fibre will be stronger, and of a purer white. Besides this long form, a cross- vein white fibre occurs, |-inch to f-inch in length, with the habit of chrysotile, but with the' constitution of amphibole- asbestos. A rather peculiar feature in this quarry is the associa- tion with the asbestos of hard felspathic rock, which is found even in the heart of bunches of fibre, and is itself sometimes traversed by veinlets of asbestos. In the pre- sent wet and disintegrated condition of the face of the quarry, it is difficult to determine the exact nature of this association, but from appearances the rock is in the form of a vein or dyke, some inches to a foot in width, which has penetrated the serpentine; possibly from- somewhat allied rocks, which are seen on the eastern boundary of the lease. This vein-rock is preponder atingly felspathic, or again quartzo-felspathic, with the microscopic structure of aplite.* The only other rock-forming mineral in it, besides the introduced asbestos, is a little actinolite or tremolite. It is very hard and tough. At the south-east angle ox the section, surface stones are seen of a rock consisting entirely of felspar and long-bladed sections of hornblende. Some years ago samples of this rock were sent to Professor Rosenbusch, who recognised that it was an abnormal rock variety, but was unable at the time to assign to it a posi- tion in any of the accepted schemes of classification. * The felspar has the low extinction angles of the oligoclase-and-esine group. 16 Evidently the formation of asbestos took place during a late phase, for veins of it traverse both the serpentine and the aplite. In the upper part of the quarry, large splintery frag- ments of ^he asbestiform serpentine, known as pier olite, were found. The large pieces bear some resemblance to petri- fied wood. As is well known, varieties of picrolite are common in the serpentine of most asbestos mines. In Italy hornblende-asbestos occurs also in serpentine rock, and the experience there is stated to be that as the workings attain greater depth the fibre becomes softer and better. The descriptions of the lumpy bundles of long flax-like fibre in those mines read curiously like the occur- rence on Charriol’s section. Cirkel, contrasting the Italian hornblende-asbestos with the Canadian chrvsotile, says : — Both the Canadian and Italian varieties possess some fine qualities and characteristics, and each finds its special application. Manufacturers even say that in some cases a mixture of both gives better result, and is superior to the best quality of either of them used separately. ” Hornblende-asbestos is used for mill-board, and a fluffy variety of it for gas stoves. For engine and similar packing it should find a ready demand. Most of it is too brittle for spinning purposes. Not much can be said about the present deposit till it is opened up more. More than one band of fibre rock is exposed in the working face, and a fair quantity of material should be available. The conditions indicate the necessity for continuing the face into the hill and freeing the workings from the influence of surface water - Without incurring the expense of erection of a treat- ment plant, which at the present stage would be prema- ture, a small drying arrangement seems to be necessary in order to get rid of the superabundant moisture, but, as said above, it must be used with caution. An important task of the lessee is to assure himself of a market for his output. In this instance it is the prime condition of success. The work can then be laid out and the ground developed with some degree of confidence. The present quarry is apparently situated in a fibre-bearing belt, but for any continuous work, prospecting in advance is essential, for in this class of mining, formations of fibre are notoriously discontinuous and patchy, and success often depends upon keeping work going at one time on several patches. 17 V. -General Methods of Asbestos Treatment. Treatment methods vary in different countries and in different localities and mines in the same country, so that no particular practice can be quoted as typical. Dif- ferences of occurrence, nature of fibre, width of veins, hardness of rock, &c., make it impossible to adopt uni- form working schemes. Still, general principles have to- be followed. The process involves: — 1. The extraction of the stone from the quarry. 2. Where possible, handpicking the best fibre. 3. Drying and milling the short fibre rock. A perfectly satisfactory milling treatment has not yet been evolved, but improvements are continually aem g brought forward and old drawbaoKs remedied. Canada sets the milling practice for the rest^ of the world, producing over 80 per cent, of the world s fibre, and the best information regarding the principles of extraction and treatment must be gleaned from Canadian practice. Mr. F. Cirkel, of the Canadian Department of Mines, has collected much valuable information on this subject, and issued it in his admirable work on ‘ Cnryso- tile- Asbestos : Its Occurrence, Exploitation, Milling, and Uses ” (1910). Older information may be gathered from Mr. R. H. Jones’ book on “ Asbestos and Asbestic : Their Properties, Occurrence, and Use” (1897). A paper on “ Asbestos and its Production in Canada, by W. Moil- mann, in the “ Journal of the Canadian Mining Insti- stute ” (1902), may also be. consulted; likewise Notes on Plant in the Mining Districts of Canada,” by R E^ Corn- mans in the “ Transactions of the Institution of Mining and Metallurgy, Yol. XVIII., 1908-9). Cobbing. The rock broken down in the quarry is sorted, and the best pieces go to the cobbing-sheds. The fibre is there^ separated as far as possible from the rock with hammers and then with screens. The fibre so obtained is bagged toi market and sold as ‘‘ crude.” The separation of the fibre, however, is still very incomplete, and the stone > is not entirely eliminated. If there is not much crude fibre obtainable in this way, it answers better to pass all througn 18 the mill. Fibre §-inch and upwards is generally bagged, while shorter lengths are milled. As an example of a quarry where cobbing has to be car- ried on, the Takaha quarry, in New Zealand*, may be quoted:— J "The mining — or more correctly speaking, the quarrying — is carried on from open-cuts or benches on the hillside. Hand and machine drilling is prac- tised for the breaking of the rock in situ, and the explosives used are dynamite and gelignite. The dark-green serpentine is easily drilled; holes 8 to 10 feet deep are placed, and loaded in such a manner as to break out the rock in masses, as much as 4 tons in weight, with a minimum amount of fines. Heavy blocks beyond the capacity of the derricks are block - holed. Considerable skill is exhibited in the work of drilling and loading the holes,, as it demands a thorough knowledge of the direction of the various fissures and cracks. These blocks are lifted by crane on to trucks, and run to the dump; the fines are shovelled and the smaller blocks rolled into shallow wooden boxes (capacity, 10 cubic feet) placed on the ground. When filled these pit-boxes are hoisted on to truck-frames, built to tip their load in any direc- tion, and sent to the dump. When this work is suffi- ciently advanced, operations commence on the asbes- tos-bearing rock, enough powder being used to shat- ter without scattering the material. A rough sort- ing takes place ; slabs and pieces of fibre more or less free of rock are picked up, thrown into hand-barrows, and sent to the cobbing-shed, together with blocks con-* taining inch-fibre, or longer, which is easily separable from the rock; whilst the balance is paddocked for future mill treatment. The derricks consist of a mast stepped in a cast-iron plate, and held in position by six or eight galvanised iron guys. The 30 to 50 feet booms are so arranged that they can be raised or lowered at will; the hoisting-rope leads over a sheave at the outer end of the boom, thence two sheaves placed above and below the hollow pivot of the mast, through which it passes to the winch or horse-whim. This arrangement permits the derrick to swing a complete circle. At the cobbing-shed the fibre is freed from the adhering rock, lb. hammers being used for the * See “ The Mining and Engineering Review,” September, 1911. 19 purpose. The work is done on any piece of scrap- iron, steel, or even stones, offering a level surface about a foot square. The fibre is then graded, accord- ing to its length, colour, and purity; usually material 1-inch long and over is graded No. 1, and put up in 100-lb. bags for the market. Some operators include fibre of less length, which is one reason for the wide variation in the price of this grade. All The waste is retained for mechanical concentration. Cobbing is a very troublesome and expensive process. It is done in a rough and ready fashion, and the loss is enor- mous, as the adherent rock is firmly frozen to the asbestos; but so far it gives better results both as regards the extraction and cost, than any other known method. ” Drying. The next srep is to dry the rock, which, as it comes from the quarry, generally contains much moisture. Any steam-pipe or furnace arrangement as commonly used lor drying ores will answer the requirements, but the rotary drying cylinder is the appliance used m most works ct any size, although it has certain disadvantages m heat losses and excessive fuel consumption, which are, howevei, counterbalanced to some extent by its continuous a iou and its capacity for dealing with a large output. It is essentially a hollow steel tube, 30 feet long and 3 4 feet in diameter, rotating 6 to 8 times per T® w C t VmoSt- rounded by the fire, and the stone gradually loses its moist ure as it iorks its way slowly down the inclined rotating tube. Crushing. To crush the rock before drying is considered correct ractice, as it greatly assists the subsequent drying. It is, owever, only done in some mills. It is usually a f co1 ?" dished by a mill of the jaw stonebreaker type. The details f the process vary, a rough classification sometimes being Lcted P "nd the Joarser 4k recrushed in a second stone- r Generally a jaw stonebreaker effects the first crushing, if ter which the stone passes in some mills to a rotary rusher of the Gates type. A still finer crushmg is hen tchieved by rolls. The stone, as it goes to ^/further B pieces not exceeding the size of a nut. It is furthe. 20 reduced, and is then ready for separation into fibre and waste respectively. Fiberising. This part of the process of separation is known under the term “ fiberising.’ ’ The machines for effecting the separation are the so-called “ cyclones,” which consist of enclosed blades of the screw-propeller type revolving in opposite directions at a high rate of speed (2000 to 2500 revolutions per minute). The air movement caused by the revolution of these blades reduces the material by mutual concussion of the constituent grains to the size of small particles, J-inch and under. Cirkel says that hard and tough rock can be treated in a cyclone at the rate of 25 or 30 tons a shift, while soft rock can be dealt with at the rate of 40 or 50, or even 60, tons. The pulverised material is discharged on to shaking screens, one-sixteenth-inch mesh, in an air-tight box, from which an exhaust or suction fan draws the fibre off into collectors and settling chambers. The shaking screens separate the sand and small particles of rock from the fibre, which, having worked its way to the surface of the layer of material, is ready to be drawn off by fans into settling chambers. In the collecting or settling chambers the fibre is graded by means of revolving screens, the dust going off through escape holes. The dust carries extremely fine particles of fibre, and is sometimes collected for asbestic plaster. The above is an abstract of the general principles of asbestos milling, as gathered principally from Cirkel’ s exhaustive treatise, but the application of them varies in nearly every mill, according to conditions and require- ments. VI. — Cost of Erection of Mills. The factors which govern cost are so variable that an estimate for any particular mill can be framed only by the engineer consulted in the matter of erection. • As an illustration of the approximate cost of a typical mill, Cir- kel gives £10,000 for mill with two cyclone units and a capacity of 240 tons per day of 24 hours, plus about <£4000 for mine equipment and £3000 working capital. This is stated to be a moderate estimate, some plants hav- ing cost a great deal more. The sams authority states 21 that the number of cyclones governs the milling capacity, a cyclone treating 120 tons per double shift. Most mills have two or three cyclones. One to 1J horsepower per ton of rock treated is given by Cirkel as the power require- ments for asbestos mills. Commans says the larger mills have a capacity of 500 tons per day, and require one to one and three-quarter horsepower per ton of rock, 75 per cent, of which is absorbed by the crushers.* VII, Cost of Asbestos Production at Anderson’s Creek. At the present stage only an approximate forecast can be made, the percentage of fibre in the rock not being yet established, and very little guidance available for forming a proper idea of milling costs. Part of the out- put of stone being derived from the hill quarries and part from excavations in the flat country, the quarrying cost will be affected by the proportion of work carried out at the respective points. It looks as if fully one-half, if not more, of the rock broken will go to the spoil heap, perhaps a very small proportion be cobbed, and the rest milled. Some patches of rock would go straight to the mill, while intervening barren blocks of ground would have to be excluded. The rock milled might yield 5 per cent, of fibre, or possibly somewhat over that percentage. In Canada the extraction runs from 6 per cent, to 10 per cent, for ordinary cross fibre, and from 7 per cent, to 12 per ?ent. for slip fibre. Individual examples vary considerably Thus, in some Canadian mines, nearly the entire output of rock is milled, and yields 8 per cent, of fibre. Other mills are quoted as giving an extraction of 5 per cent. ; in another proposition 35 per cent, waste rock is rejected, and the bal- ance gives 8 per cent. At another (a slip fibre quarry) all the rock goes through the mill, and the extraction exceeds 7 per cent., and sometimes even attains 12 per cent. The general extraction in asbestos mills in different parts of the world appears to conform practically to these figures; thus, in Cyprus, the rock quarried contains from 8 per cent, to 10 per cent, of fibre; in Rhodesia, 6 per cent, to 10 per cent. ; in Wyoming, the milling rock runs * “ Notes on Plant in the Mining Districts of Canada,” by R. E. Coin- mans. Trans: Inst, of Mining and Metallurgy, Vol. XVill., 1908-9, p. 185. 22 from 5 per cent, to 10 per cent. As a whole, it may be said that the asbestos production of the world is from rock containing between 5 per cent, and 10 per cent, market- able fibre. As regards Anderson's Creek, supposing that half of the rock goes to the dump, and only a negligible proportion is cobbed, as mentioned above, the milling-rock might very well contain anything between 5 per cent, and 10 per cent, of fibre. Some samplings have given more than this, and in certain patches the whole rock seems to consist of fibre, but this is ascertainable only by crushing the material. Mr. W. B. Smith reported in 1910 that four samples of rock taken by him and crushed yielded 16 per cent., 17 per cent., 23 per cent., and 24 per cent, respectively, and that he considered that most of the asbestos-bearing rock contained between 15 and 30 per cent, of fibre. This estimate is probably excessive if applied to the formation in its entirety. On the other hand, there are belts of rock which are quite barren, and while these would be avoided in working as much as possible, some of them would have to be taken out in developing the quarries. If a 10 per cent, extrac- tion could be obtained, it would seem possible to produce the fibre at works site on the spot for something like <£8 or £10 per ton. If a lower rate of extraction ruled, the cost would be correspondingly higher. In Canada the cost seems to range between £4 and £7 per ton ; and the aver- age fibre content of the rock milled in 1915 was 5*71 per cent., as against 6‘03 per cent, in 1914. VIII. — Realisation of the Product. A difficulty met with in forming a satisfactory opinion with regard to the returns is that the grades of fibre in the asbestos trade are not standardised, and are different at different mines, so that little information can be gleaned from mere general quotations. In some cases the grades are regulated by the length of fibre, in others by its qual- ity ; but for the most part by length and quality com- bined. Thus, Cirkel states that No. 1 crude is a fibre about 1 inch long, and No. 2 from ^-inch to 1-inch. Other market grades comprise No. 1, of 1-inch length, and No. 2, aver- aging J-inch. “ Mill stock ” ( i.e ., fibre from milled rock), is classed in three grades; and besides this there is the dump sand “ asbestic.” 23 The crude fibre obtained by hand-picking commands the highest price. In 1915, the prices realised in the Quebec province of Canada, which produces practically all the asbestos of the Dominion, were for No. 1 crude long-fibre £-55 per ton; and for No. 2 crude, £24 10s. per ton; for the mill stock Nos. 1, 2, and 3, £13, £5 7s., and £2 10s., respectively. The asbestic was valued at 3s. 6d. per ton. These prices did not vary more than a pound or two from those ruling for three years previously. It should be, mentioned here that the mill products in the above state- ment are classed arbitrarily for statistical purposes in three qualities, namely £9 per ton and upwards; between £9 and £4; and less than £4 per ton respectively. (Mill stock Nos. 1., II., and III.) The hand picked crude is classed according to its value of £40 per ton, and upwards; or less than £40 per ton (Nos. 1 and II.). It is of inter- est to observe that the mean value of the total rock broken is 6s. per ton, and this seems to be a pretty constant figure. The crude fibre is stated to command startling prices in Australia, but reliable information about Australian prices is in the possession only of the firms who control the local market. The bulk of the chrysotile which would be won from the Anderson’s Creek field would probably range between \ and \ inch lengths. The production of fibre in Quebec from 1911 has been:— 1911, 102,224 tons; 1912. 111,175 tons; 1913, 136,609 tons; 1914, 107,401 tons; 1915, 113,115 tons. In the annual report for 1915 of the Minister for Mines for Quebec, it is stated that. — “ In the earlier part of the year the Jacobs and British-Canadian Mines suspended operations, most of the other mines only working half or one-third time. This temporary suspension dated from the beginning ' of the European conflict, and was the result of the closing of the German markets and difficulty in obtain- ing the necessary cargo space in vessels between America and Europe. The difficulty was diminished only when asbestos began to be employed for war purposes. On the other hand, since last spring the great demand for it on the part of American manu- facturers has eliminated the disease which threatened to paralyse this industry .... It is interesting to note that the demand for the higher grades of asbestos was greater in 1915 than in any previous year ; while 1913, a year in which there was the maximum activity in constructional work, witnessed the greatest consumption of all the lower grades.” 24 General confidence in the future of the trade prevails in Canada amongst those interested. At most of the mines the reorganisation of quarries and mills is under way ; improvements in haulage, in motive power, and in the con- centrating machinery are being effected, which it is anti- cipated will reduce the cost of the output and put the mine-owners in a position to cope with the increased demand which they believe they will have to face in the near future. IX. — Extraction of Ornamental Stone. Section 7414-m (80 Acres — H. Conder). This section is south of and adjoining the 80-acres lease 6341 -m, and has recently been taken up for prospecting the extension of the asbestos belt existing on the northern pro- perties. It is in serpentine rock, and with search, no doubt, fibre rock will be found on it. On it is a little bridge crossing over Anderson’s Creek, and 400 feet south of the bridge, though still east of the creek, is a quarry which was worked for a time by the Tas- manian Greenstone Company for ornamental building stone. The quarry has been opened in serpentine rock for a depth of from 15 to 20 feet. The derrick for lifting the stone is still there, and some blocks of hewn and squared stone 3 or 4 feet by 1^ and 2 feet are lying about the quarry ready for shipment. The attempt to establish an industry was a laudable one, and it is to be regretted that it did not meet with greater success. The stone is a dark-green mottled serpentine, and would take a good polish. Unfortunately, it is traversed by innumerable parallel partings, not more than an inch or two apart, which, while enhancing the beauty of the pre- pared stone, will inevitably cause the rock when sawn to break away into thin slabs, and it is probable that the same tendency will develop in the solid blocks if left exposed to the weather long enough. This feature is com- mon in serpentine rocks all over the world, and they are notorious for bad joints. This drawback makes it difficult to obtain good-sized slabs of serpentine rock for building purposes. Its weathering also is too irregular to mak ; it reliable for exterior work; but where it is sufficiently mas- sive it can be used for decorative ajid other interior work, for which it is highly prized. 25 Fiom the above it will be gathered that the quarry rock is none too good for the object which was in view; and in any case, on account of the want of uniformity in the physical characters of the stone in this field, it will be necessary to open up and test more than one quarry. With a greater population and an increased demand for ■decorative work and articles de luxe, a profitable trade of modest dimensions could probably be developed. At pre- sent the market has to be created, and care must be taken not to put the stone to a wrong use, which will militate against success later on. X.— Conclusion. The field is in that condition that it may develop into the source of a profitable industry. Present prices of asbestos and asbestos productions are encouraging. Information from the Commonwealth offices in London is to the effect that every particle of asbestos is now worth £ 20 per ton. In this case the market prices in Australia should be such as will enable the Anderson’s Creek ■deposits to be worked at a profit, if workable patches of any size can be exposed. Preliminary prospecting work on a large scale seems necessary in order to establish the tonnages available, and this must be done before the installation of a treatment plant can be thought of. The question of providing Government assistance in establishing a new industry of this kind deserves attention. The policy of the Government has been to assist mining by grants-in-aid and advances on the £ for £ principle, and it is to be presumed that the operators of asbestos pro- perties will enjoy their share of whatever votes may be passed by Parliament. In addition to this, the industry might be fostered by payment of a bonus of so many pounds sterling per ton upon the first 500 or 1000 tons of marketable fibre produced. Some fear has been expressed lest the asbestos veins should prove to be merely superficial phenomena, and cut out in depth. Against this may be set the fact that the formation of asbestos was a deep-seated process. In ^Canada, asbestos has been met with at a depth of 400 feet. The question of depth, however, need not disturb leaseholders, for the patches of fibre-bearing rock are so irregular that they will not be followed to any great depth. 26 Quarrying may be expected to be the extraction method' employed, as sinking is hardly likely to be remuneratiw except where the orebody is large and continuous, and the fibre of high grade. If prospecting discloses any broad’ zones of fibre rock, the outlook for the field will be bright. Present developments show the area in question to possess potentialities which it is possible that the work which is now proceeding may convert to payable actualities. W. II. TWELVETREES, Government Geologist. Launceston, 18th May, 1917. 26 Quarrying may be expected to be the extraction method' employed, as sinking is hardly likely to be remunerative except where the orebody is large and continuous, and the fibre of high grade. If prospecting discloses any broad 1 zones of fibre rock, the outlook for the field will be bright. Present developments show the area in question to possess potentialities which it is possible that the work which is- now proceeding may convert to payable actualities. W. II. TWELVETREES, Government Geologist,. Launceston, 18th May, 1917. GEOLOGICAL SKETCH MAP OF ANDERSON’S CREEK ASBESTOS FIELD LEGEND quaternary gravels , C DEVONIAN APLITIG GRANITE | DEVONIAN SERPENTINE .PRE-SILURIAN STRATA „ _ SCHISTOSE METAMORPHOSED ROCK OF UNCERTAIN ORIGIN . Asbestos Quarries 1 M | Asbestos trenches ! — - I UNIVERSITY OF ILLINOIS MAY 1 2 1921 GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. 1. — The Mangana Goldfield, by W. H. Twelvetrees 1.907 No. 2. — The Mathinna Goldfield, Part III., by W. H. Twelvetrees „ 1907 No. 3. — The Mt. Farrell Mining Field, by L. Keith Ward, B.A., B.E 1908 No. 4. — The Lisle Goldfield, by W. H. Twelvetrees 1908 No. 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees ... 1909 No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E. :..... 1909' No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelve- trees and L. Keith Ward, B.A., B.E 1909 No. 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., No. 9. — The Scalnander Mineral District, by W. H. Twelvetrees 1911 No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B E, 1911 No. 11. — The Tasmanite Shale Fields of the Mersey District, by W. H. Twelvetrees 1911 No. 12. — The X River Tinfield, by L. Keith Ward, B.A., No. 13. — The Preolenna Coalfield and the Geology of the Wynyard District, by Loftus Hills, M.Sc. ... 1913 No. 14. — The Middlesex and Mt. Claude Mining Field, by W. H. Twelvetrees 1913 No. 15. — The Stanley River Tinfield, by L. Lawry Water- house, B.E 1914 No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc *. 1914 No. 17. — The Bald Hill Osmiridium Field, by W. H. Twelvetrees 1914 No. 18.— Geological Reconnaissance of the Country bei veen Cape Sorell and Point Hibbs, by L ft us Hills, M.Sc 1914 No. 19. — The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc 1914 No. 20.— The Catamaran and Strathblane Coalfields and Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees 1915 No. 21. — The South Heemskirk Tinfield. by L. Lawry Waterhouse, B.E 1915 No.. 22.— Catalogue of Publications issued by the Government of Tasmania, relating to the Mines. Minerals, and Geologv of the State, to 31st December, 1914, compiled by W. H. Twelvetrees 1915 No. 23. — The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part II. (Rosebery Group), by Loftus Hills, M.Sc 1915* No. 24. — Reconnaissance of the Country between Rech- erche Bay and New River, Southern Tas- mania, by W. H. Twelvetrees 1915- No. 25. — The Gladstone Mineral District, by W. H. Twelvetrees 191(>- REPORTS. No. No. No. No. No. No. No. 1. — Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E • - 2. — The Silver-Lead Lodes of the Waratah Dis- trict, by L. Keith Ward, B.A., B.E. 3 — Preliminary Report on the Zinc-Lead Sulphide Deposits of Mt. Read, by Loftus Hills, M.Sc-. 4. — On Cement Materials at West Arm, by W H. Twelvetrees . 5. — On Some Gold-Mining Properties at Mathmna, by W. H. Twelvetrees •••• 6. — Reconnaissance of the North Heemskirk Tin- field, by L. La wry Waterhouse, B.E 7 4 — Preliminary Report on the Zinc-Lead Sulphide Deposits of the Rosebery District, by Loftus Hills, M.Sc. ••• 1910 1911 1914 1914- 1914 1914 1915- No. No. No. No. RECORDS. 1. — Marine Fossils from the Tasmanite Spore-beds of the Mersey River, by W. S. Dun 2. — Stichtite : A new Tasmanian Mineral : Notes by various authors, collected and edited by W • H. Twelvetrees 3 . — Darwin Glass : A new variety of the Tektites, by Loftus Hills, M.Sc.. ••• 4 — A Monograph of Nototherium Tasmamcum, by H. H. Scott. Price, 7 s. 6cl. . 1912- 1914 1914 1915- MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. — North-Eastern and Eastern Tasmania, by Loftu g Hills, M.Sc Part II. — Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc. Part III.— King Island, by L. Lawry Waterhouse', B.E No. 2.— Cement Materials at Flowery Gully, by W. H. Twelvetrees • • • • • ■ - • No. 3.— Phosphate Deposits in Tasmania, by W. ±i. Twelvetrees 1915 1916 1916 1917 191T JOHN VAIL, GOVERNMENT PRINTER, TASMANIA r* > • ! ' > A / VI C UWLUUlUftL, *’ '*?;> ' ™ ymiT * Of lUi^. . ® asmatiia 1921 DEPARTMENT QE . MINES GEOLOGICAL SURVEY MINERAL RESOURCES • No. 5 A Deposit of Ochre near Mowbray A ' •' 4 ‘* ‘ ' J by ; W. H. TWELVETREES, Government Geojogist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania (Tasmania: JOHN VAIL. GOVERNMENT PRINTER, HOBART 1917 / LOCALITY MAP Area dealt with in this publication . _ m Tkofo - A Ifjt 'uphtd hy John Vitit Government Printer- ffobart Tasmania. a s m a iti a DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 5 A Deposit of Ochre near Mowbray BY W. H. TWELVETREES, Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania (Tasmania: JOHN VAIL, GOVERNMENT PRI NTER ,&> HOBA RT B77236 1917 TABLE OF CONTENTS. PAGE X —INTRODUCTION • ••• 5 XX —OCCURRENCE OF THE OCHRE 5 III.— GEOLOGY AND MINERALOGY 7 IV — QUARRYIN 9 y. TREATMENT OF THE OCHRE 10 VL — PHYSICAL CHARACTERS OF THE PAINT 1C VII— CONCLUSION 15 PLATES. Locality Map Photograph of Paint Mine Hill... Frontispiece To face page 5 v* :i '( >.5 iii'Jn '! • '•! /.»t •. > c >? S .'■ -:>v , . >? ‘ i \ .«<• : -i > i ; : P ; / •« ; PAINT MINE HILL. A Deposit of Ochre near Mowbray. 1. — Introduction. On the old Paint Mine Hill on Russell's Plains, north of Mowbray, some preliminary operations are being car- ried on, with a view to the extraction of ochres and the manufacture of paint. As this will be a new industry for Tasmania, it was considered desirable that the deposit should be made the subject of examination, in order to ascertain whether its economic nature justifies the contemplated expenditure, and if so, to draw public attention to a new development of our mineral resources. Some 20 years or more ago an attempt was made to start working this mineral, and some of it was shipped to Melbourne; but for some reason the company was never floated. The proposition has now been taken up again, and with good chances of success. The site is between 3 and 4 miles due north from Laun- ceston, and about a mile east from Rocherlea railway- station, on the 2730 acres charted as granted to Wm. Faw- cett. Easy access is gained to it by the Lefroy-road, thence along the Lilydale-road as far as J-miJe past the railway-station; from this, a turn-off parallel with Bar- nard’s Creek leads to the hill. The summit is reached by a gentle ascent between 100 and 200 feet above the base. As will be seen from the above, the railway-station in the vicinity is most conveniently situated for freights; or if it is desired to transport by vehicle, there is an excellent road all the way to Launceston. II.— Occurrence of the Ochre. Immediately one begins to ascend the hill from its northern side, stones or lumps of earthy ferruginous material are seen lying about on the surface of the soil, suggestive of the occurrence of the ochreous deposit at this 6 level. In going up the hill from the northern end, float- ing pieces of ochre and oxide of iron are met with, becom- ing more numerous as the summit plateau is approached. The hill is a flat-topped one, and the surface seems ocbre- ous for a width of from 300 to 400 yards from east to west. If we assume that the ore-body is continuous from the summit to the northern end of the hill, its horizontal dimensions would be about |-mile long by, say, 300 yards wide. Enough work, however, has not yet been done to enable the superficial area of the deposit to be estimated properly, nor is its thickness known. It is highly pro- bable that it does not extend vertically to the horizon of the base of the hill, but follows a contour of hard rock at a certain depth below the surface. A few hundred feet of trenches and other excavations have been cut at the top of the hill, exposing red and yellow ochres of workable quality , but no cuttings are deeper than 5 or 6 feet. An old filled-in shaft, however, is supposed to be 30 feet down, but what it went through is unknown at the present time. The excavation in the floor of which it has been sunk yields first-quality red ochre. At one end of it, however, near the shaft, it is a little inclined to be clayey. At the other end the body of ochre is massive and compact. A small trench close to the north end of this main excavation shows good bright-red oxide, and on the west is also rich ochre. About 100 yards west of this is a low open-cut, where the first discovery was made. This also shows good red material, very suitable for treatment. Eighty yards east of the main excavation is a shallow trench, which exposes yellow ochre; with this, in places, is associated some white kaolin. Taking the evidence of all these trenches together, one may say that they indicate the existence of a more or less continuous bodv of ochre within the limits above men- tioned. Its nature may not be altogether uniform over the whole area. There may be exceptionally clayey patches here and there, but the extent of these can be ascertained only by prospecting or in the course of work- ing. Considering the comparatively small tonnage required for a moderate paint enterprise, there should be little difficulty in absolutely establishing the existence of the requisite quantities. From all appearances there is sufficient to supply the requirements of works for many years. 7 III.— Geology and Mineralogy. The geology of the country in which the deposit occurs is uniformly simple. The hill is part of the Mesozoic dia- base country, which flanks each side of t e va ey ° Tamar The ochreous deposit seems to occupy a basin or “iHptical channel in the hard fresh rock which sur- rounds it. but its real relations to the bedrock cannot b determined until more of it is exposed. It has some kind of resemblance to laterite, which m tropical and su - tronical countries is a common residual ferruginous clay, often occupying the summits of hills. Similar ochre is reported to exist further south along the continuation of the same hill system. G. P. Merrill, in his work on “ Pocks, Pock Weather- ing and Soils ” (page 299), gives an analysis of a very ter- ruginous^Indian laterite , l%h may be broadly -mpa^d •Ii. i-x , ~ ^™™ a if.irm of the Mowbray ochres. His figures are as follows: — Per cent. 37-576 A1 f) ) iyi 2 vj^ V 55-532 _r e 2 u 3 CaO . " MgO, alkalies, water, and loss ... ) 6-892 100-000 is The chemical composition of laterites, however, extremely variable, and does not enable any very precise definition of the rock to be made, beyond that it is a residual clay, in most instances due to rock-weathering processes. The typical conditions of its development are found in tropical and and climates. The Mowbray ochres have no doubt been formed by the softening Ind decomposition of the diabase rock, and if the St at the summit of the hill were sunk to a suffi^ cient depth the hard floor of the. bed-rock diabase would be struck. . , _ , Samples treated by Mr. W. D t Reid Government Assayer, in the Geological Survey Laboratory, gave the following results: — 8 Bed Ochre. Iron sesquioxide 45 ’28 Alumina 13‘72 Sili ca 32-40 Magnesia Lime . . . W ater . . . 1-84 0*91 5*60 Yellow Ochre. 42-62 8-78 39-52 1-50 1-28 5-80 The specific gravity was 2' 76 in a sample which was examined; this will vary slightly with the varying com- position of the pigment. Samples taken from the same trenches have also been assayed in Adelaide by Mr. A. Flounders, as follows: — Red Ochre. Yellow Ochre. Iron oxide 55*555 43*678 Silica 37-5 40-613 Alumina 4*166 9*195 Magnesium & calcium sal ts 1*388 2*683 Combined water 1*389 3*831 99*998 100*000 The quality of the material naturally varies from point to point, but the general composition is considered by paint experts to be such as will absolutely satisfy manu- facturers’ requirements. The specific gravity of the red ochre, as determined by the Government Assayer, is 2*76. The specific gravity bottle method is the most accurate one, but a modifica- tion of it is more usual in works practice, and with care can be made to give approximately correct results. It is more suited than laboratory methods for use in factorv work, the manipulations being quicker and more simple. A narrow, graduated tube or cylinder is filled to a meas- ured height with white spirit. This then receives a weighed quantity of pigment well stirred. Divide the weight of the pigment by the increase in volume of cylinder contents, and the result will be the specific gravitv of the pigment. If this is multiplied by 10 the weight of a gallon of the pigment is obtained. By this means the way is opened for interesting and important calculations of the specific gravity and volume of mixed paints. The specific volume is obtained by dividing the weight by the 9 specific gravity. Thus, take 50 lb. of pigment with a specific gravity of 3, mixed with 4 lb. oil, specific gravity 9. The total weight will be 54 lb., and the specific volume of the mixed paint, 17*10. The specific gravity of the paint can then be calculated by dividing the weight by the specific volume- 54 1710 3*15. A gallon of it will therefore weigh 31 lb. This example is merely an indication of ways in which these useful formulae may be, and are, employed in paint works. It may be mentioned here that ochres are earthy, pul- verulent forms of haematite and limonite. The Mowbray material varies in hardness and compactness, some of it being very soft and friable, or again harder and dense. It hardens somewhat after extraction from the trenches. Its softness generally will greatly assist its pulverisation, and in many respects it forms an ideal material for reduc- tion. With a specific gravity of 2*76, the weight of a cubic yard of the ochre will be, approximately, 2 tons, dry. IV . — Quarrying. The hill being fiat-topped, the position is not too con- venient for open-cut working, but sites for benches can be obtained by opening-up a little lower down the hill in one direction. Although the best body of ochre is at present exposed at the summit of the hill, it is quite pos- sible that stone of equal value may be uncovered at the base by prospecting, for ochreous material exists there, and it seems probable that it is in situ. From indications given by the few trenches which have been opened on the hill, it is likely that the quality of the deposit will not be found to be continuously uniform over any considerable area, perhaps not sufficiently so to enable a long face to be worked without selecting. It may be necessary to take out ochre from several points in order to avoid clayey portions of the deposit. These points will be located in prospecting. Prospecting for the hest spots will have to go on concurrently with the quarry- ing, so that there may always be a face or two to fall back on. The tonnage of ochre required, however, will be so 10 moderate that this prospecting need not be extensive, and certainly will not be costly. Vo — Treatment of ttie Ochre. It may be premised at once that treatment methods differ at different works, in accordance with the nature of the ore and the purposes to which the paints are to be applied. Various classes of raw materials require varia- tions in the sequence and kind of treatment ; and the methods to be adopted in each particular case have to be decided by whoever has technical control of the under- taking. Judging from the appearance of the Mowbray ochres, they can be easily prepared for paint manufacture by grinding in one of the mills of the edge-runner type. These mills, universally used in paint factories, are heavy iron or granite discs revolving vertically in a circular pan ; sometimes the pan itself is made to rotate. Several ingeniously devised varieties of these mills are in use, and developments of the different types are still in progress. VI. Physical Characters of the Paint. The paints directly obtained by simply grinding and mixing the raw oxides with linseed oil are pleasing shades of Indian red and stone colour or warm buff. The red oxide has not that brilliance which is associated with chemical instability, and yields an excellent protective paint, suitable for houses, fences, wagons, and all exterior work, and with the yellow crudes will form the base of decorative paints of various kinds. The expert opinion, given by Mr. Flounders, of Ade- laide, who is a practical adviser of repute, is to the effect that the pigment is of the finest staining capacity (especi- ally the red oxide), opacity, and texture; and the colour and toning are exceptionally pure and rich (pale buff and terra cotta). He states that they are the finest oxides handled by him, and the easiest to convert into paint, being very free from flinty grit and clay ; with a little judicious blending they will be equal to the best French ochres, which are the standard. The crude ochres have also been tested by the well-known Launceston firm of J. & T. Gunn Ltd., who report that 11 the test was most satisfactory, and that, in their opinion, they are equal to any that they have ever used. There was not sufficient time to test their lasting properties. With respect to the latter point, longer tests have been made elsewhere, which, so far, show the durability which might be expected from oxide pigments, which are notori- ously very permanent. The durability of a paint depends partly upon the absence of chemically active constituents in the pigment, and partly on the quality of the oil with which it is mixed. The analyses show that these ochres are practically composed of inert ingredients. Mr. Les. Cooper, painter, of Longford, has submitted the pigment to a practical test of some considerable dura- tion, and finds its durability satisfactory. He writes as follows, under date of the 17th May: — “ I have tried the samples of paint from Messrs. C. J. Weedon & Co. about five months ago, and find that it has stood as well as any paint that I have used. I have tested it on an iron roof; it has a very good flow and covering body, and has kept its gloss and body since putting it on. This refers to the two samples of paint — red and yellow.” The paint has also been tried in the Launceston Cor- poration yards and grounds. The tests have been under observation for six months, and have demonstrated its lasting properties. Mr. E. R. Mason, painter for the Corporation, says, under date of the 21st May: — “ I am much pleased with both paints. They are of excellent quality, very free, and very good in cover- ing power. I consider them superior to any imported paint that I have ever used, and I have had 40 years’ experience in paint-mixing and painting. If I could get this paint, I would not use the imported article.” The comparative ease with which the crude material can be ground to an appropriate fineness is a marked advan- tage. The ultimate degree of fineness which will be neces- sary depends entirely upon what uses the mixed paints will be put to. 'Victorian practice for ordinary oxide grinding seems to be to reduce the pigment to a size that will pass through a 146-mesh screen. This will be sufficient for the usual protective paints. For enamel paints and such like, much finer grinding would be requisite. The finer the raw material is ground, the less wear and tear falls on the machinery in the subsequent stages of manufacture ; 12 this, however, ought to be unusually light with these soft friable ochres. With fine grinding, also, the danger of “ settling out ” when mixed is greatly reduced. VII.— Conclusion. All the opinion which can be gathered up to the present goes to indicate that the deposit now being taken in hand is composed of ochreous oxides, which are both chemically and physically suitable for making paste and mixed paints of the highest degree of excellence. W. H. TWELVETREES, Government Geologist. Launceston, 10th July, 1917. GEOLOGICAL SURVEY OF TASMANIA. LIST OF PUBLICATIONS. BULLETINS. No. No. No. No. No. No. No. No. No. 1. The Mangana Goldfield, by -W\ H. Twelvetrees 2. — The Mathinna Goldfield. Part III., by W. H. Twelvetrees . 3. — The Mt. ' Farrell Mining Fieid, by L. Keith Ward, B.A., B.E. l 4- The Lisle Goldfield, by W. H. Tweivetrees 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast., by W. H. Twelvetrees ... 6. — The Tinfield of North Dunda^, by L. Keith Ward, B.A., B.E. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, by W. H. Twelve- trees and L. Keith Ward. R.A., B.R. ... ... 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E. ‘ 9. — The Scamander Mineral Distinct,' ’ty. ? wV H. Twelvetrees No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E. ........ No. 11.— The Tasmanite Shale Fields of the Mersey District, bv W. H. Ttyelvatrees No. 12.— The X River Tinfield,' by L. Keith Ward, B A B.E . No. 13. — The Preolenna Coalfield and the Geology of the Wynyard District, by Loftus Hills, M. Sc. ... No. 14. — The Middlesex and Mt. Claude Mining Field, by W. H. Twelvetrees, ir... No. 15. The Stanley River Tinfield, by L. Law ri rv Water- house, B.E No. 16. — The Jtikes-DaTwin Mining Field, by Loftus Hills, M.Sc. ........... .:..t:........’....f.. .......... No. 17.: — The Bald Hill Osmiridium Field, by W. H. Twelvetrees ........ ....i No. 18. — ‘Geological Reconnaissance of the Country ■be-* veen Cape Sorell and Point Hibbs, by . » : L ftus Hills, M.Sc. ’ No, 19. — The Zinc-Lead Sulphide Deposits of the Read- . Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc No. 20.— The Catamaran and Strathblane Coalfields and Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees No. 21. — The South Heemskirk Tinfield. by L. Lawry W aterhouse, B.E. No. 22. — Catalogue of Publications issued by the Government of Tasmania, relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914,,. compiled by W. H. Twelvetrees 1907 1907 1908 1908 1909 1909 1909 1910 1911 1911 1911 1911 1913 1913 1914 1914 1914 1914 1914 1915 1915 1915 14 No. 23.— The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part II. (Rosebery Group), by Loftus Hills, M.Sc 1915 No. 24. — Reconnaissance of the Country between Rech- erche Bay and New River, Southern Tas- mania, by W. H. Twelvetrees 1915 No. 25. — The Gladstone Mineral District, by W. H. Twelvetrees 1916 REPORTS. No. 1. — Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E. 1910 No. 2. — The Silver-Lead Lodes ,of the Waratah Dis- trict, by L. Keith Ward, B.A., B.E 1911 No. 3. — Preliminary Report on the Zinc-Lead Sulphide Deposits of Mt. Read, by Loftus Hills, M.Sc. 1914 No. 4. — On Cement Materials at West Arm, by W. H. Twelvetrees 1914 No. 5. — Oh Some Gold-Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6.— Reconnaissance of the North Heemskirk Tin- field, by L. Lawry Waterhouse, B.E 1914 No. 7. — Preliminary Report on the Zinc-Lead Sulphide Deposits of the Rosebery District, by Loftus Hills, M.Sc 1915 RECORDS. No. 1. — Marine Fossils from the Tasmanite Spore-beds of the Mersey River, by W. S. Dun 1912 No. 2. — Stichtite : A new Tasmanian Mineral : Notes by various authors, collected and edited by W. H. Twelvetrees 1914 No. 3. — Darwin Glass : A new variety of the Tektites, by Loftus Hills, M.Sc 1914 No. 4. — A Monograph of Nototherium Tasmanicum, by H. H. Scott. Price , 7s. 6d 1915 MINERAL RESOURCES. No. 1. — Tungsten and Molybdenum — Part I. — North-Eastern and Eastern Tasmania, by Loftus Hills, M.Sc 1915 Part II. — Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc. 1916 Part III. — King Island, by L. Lawry Waterhouse, B.E 1916 No. 2. — Cement Materials at Flowery Gully, by W. H. Twelvetrees 1917 No. 3. — Phosphate Deposits in Tasmania, by W. H. Twelvetrees 1917 No. 4. — Asbestos at Anderson’s Creek, by W. H. Twelve- trees 1917 No. 5. — A Deposit of Ochre near Mowbray, by W. H. Twelvetrees 1917 JOHN VAIL, GOVERNMENT PRINTER, TASMANIA . 'Jlmt bEOiii lasmanin "" DEPARTMENT" OF] MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 6 The Iron Ore Deposits of Tasmania BY W. H. TWELVETREES, Government Geologist and A. MCINTOSH REID, Assistant Government Geologist — ~~T \ r ~~* ' , ’' r Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania B90849 USIVEHSHTSF ILLiSUIS UihAft' 2 “ 1921 PRIOR, ACTING GOVERNMENT PRINTER 1919 T. G. i * ' -y- <.*i ® a a m a n i a DEPARTMENT OF MINES GEOLOGICAL SURVEY MINERAL RESOURCES No. 6 i rhe Iron Ore Deposits of Tasmania BY W. H. TWELVETREES, Government Geologist and ' A. MCINTOSH REID, Assistant Government Geologist Issued under the authority of The Honourable Sir NEIL ELLIOTT LEWIS, K.C.M.G. Minister for Mines for Tasmania TABLE OF CONTENTS. L— INTRODUCTION— by W. H. Twelvetrees II.— IRON ORE IN THE BEACONSFIELD DIS- . TRICT — by W. H. Twelvetrees (1) Introduction ... (2) Geology ... (3) The Settlers... (4) Ironstone Hills (Mt. Vulcan and Scott’s Hill) (5) Quality of Ore ... ... (6) Barnes Hill... ... (7) Concluding Remarks on the Anderson’s Creek Deposits (8) Sugar Loaf (9) Dr. Thompson’s Lode (10) Swift’s Hematite (11) Windred’s Oxide Deposit ... (12) Serpentine Paint Company’s Deposit ... (13) Conclusion Til— DIAL RANGE IRON LEASES— by W. H. .o > •4 Twelvetrees (1) Lease 8038-m, 80 acres, E. Hobbs; and Lease 8039-m, 80 acres, J, O’Neill ... (2) Penguin Creek Deposits (3) Iron Cliffs Lode (4) Manganese Ore at Dial Range and Pen- guin (a) Dial Range (b) Penguin IV.— BLYTHE RIVER IRON ORE DEPOSIT - by W. H. Twelvetrees (1) Introduction (2) Situation (3) Description of the Lode V.— RUTHERFORD IRON LODE— by W. H. Twelvetrees PAGE 1 4 4 9 10 11 18 25 26 27 28 29 32 32 34 36 36 41 44 46 46 49 51 51 52 52 64 iv PAGE VI. — IRON ORE IN LONG PLAIN AND ZEEHAN DISTRICTS— by A. McIntosh Reid 67 (1) Introduction 67 (2) Long Plain Iron Ore Field 67 A. Petrology 68 B. Geology 69 C. Economic Geology 70 D. The Mines . 72 (1) Rio Tinto Deposits ... 72 (a) Preliminary Statement 72 ( b ) The Ore-bodies. 72 (c) Analyses ’.. 76 ( d ) Estimation of Quan- tities ... ... ... ... ... 77 (2) Rocky River Deposits 78 E. Transport and Communication ... 79 F. General Remarks 80 '3) Iron Ore Deposits in the Zeehan District 81 A. Geology 81 B. Petrology ... ... 82 (1) Gabbro 82 (2) Serpentine 83 (3) Di op side (Lime - magnesia Pyroxene) 83 C. The Effects of Contact Metamor- phism ... .’ 83 D. The Mines 85 (1) Tenth Legion Deposits (Sec- tion 7925 -m, 10 acres, W. Thomas) 85 (2) Davern and Reynolds’ Sec- tion 87 (3) Section 1812 -m, 40 acres ... 87 (4) Davern’ s Prospect (Sections 7611-m and 7296 -m, both of 20 acres) ... ~. ... 87 * E. Genera] Remarks 88 VII. — THE IRON LODE ON NELSON RIVER— by W. H Twelvetrees 90 VIII MISCELLANEOUS DEPOSITS— by W. H. Twelvetrees 91 (1) Mt. Mueller or High Rocky 91 (2) Lewisham 92 (3) West Coast Range ... 92 V PAGE IX —ELECTRIC SMELTING— by W. H. Twelvetrees 93 X.— COST OF PLANT— by W. H. Twelvetrees 99 XI.— COST OF PRODUCTION— by W. H. Twelve- trees 101 XII. — FUEL — by W. H. Twelvetrees 104 (1) Charcoal 104 (2) Coke 106 XIII.— LIMESTONE FLUX— by W. H. Twelvetrees ... 109 XIV.— CONCLUSION— by W. H. Twelvetrees 112 LIST OF PLATES. Plate I. — Locality Map Frontispiece Plate II. — Geological Sketch Map of Anderson’s Creek Mining . / Area ... To face page 9 Plate III. — Ideal Section through Mt. Vulcan and Settler’s Range To face page 11 Plate IV.— Dial Range Iron Leases To face page 36 Plate V.— Penguin Iron Leases ... To face page 41 Plate VI. — Blythe Iron Field To face page 52 Plate VII. — Long Plain District : Rio Tinto Iron Mines To face page 72 Plate VIII.— Zeehan District : Tenth Legion Iron Mines ... To face page 85 IX. — Nelson River Iron Field To face page 90 Plate Zr S5i *■*/ & The growing attention and interest surrounding the ques- tion of the initiation of the iron industry in this island has led to the preparation of this publication. An endeavour has been, made to collect in one volume the various items of information with regard to iron ore deposts in Tasmania, which at present can only be obtained by referring to scattered descriptions, many of which are not easily acces- sible, and some, indeed, out of print. Some of the more important deposits have been revisited and subjected to renewed examination.. The chapter on iron ore in Lpng Plain and Zeehan Dis- tricts has been contributed by Mr. A. McIntosh Reid, who has lately examined the occurrences. Each author, while cognisant of the other's work, is responsible only for the contents of his own chapters. Iron is one of the most essential metals which minister to the wants of civilised man, and, singularly enough, has at the sam^ time_ perhaps the least unit value of any of the commercial metals. Statistically its output stands at the head of that of all the other useful metals; indeed, the figures representing the combined world production of all other metals are negligible compared with those refer- ring to iron. This means that its use enters into all the • departments of modern life, national and individual, and that the country which possesses large deposits of its ores, and the means of reducing them to metal, occupies an enviable position. History and experience teach that valuable iron and coal deposits are the founda- tions of a nation's material prosperity. The industry of iron and steel is the factor which dominates the manufac- turing world. I Various attempts have been made from time to time to estimate the iron ore reserves of the world, but the data 2 in many countries are very uncertain, and the figures put fdrward must be regarded as partaking somewhat of the nature of arithmetical feats, although for the moment nothing else expresses the possibilities. The world output . of pig iron annually amounts to between 60,000,000' and 70,000,000 tons. It has been thought that actual and potential reserves of ore amount to over 150,000,000,000 tons, which may contain between 60,000,000,000 and 70,000,000,000 tons of iron. In addi- tion, there are enormous possibilities, im the shape of undis- covered deposits, which must be taken into account when considering the future of the world’s supplies. Anyone who delights in making arithmetical calculations of dubious value can, by using these figures in a free way, make a show of forecasting the exhaustion of the world’s iron deposits at the end of a determinate period. But there are so many uncertain and elusive factors in the problem that the conclusion, which seems so obvious, is unsafe. The report of the International Geological Congress of Stockholm in 1910 on the ft Iron Ore Resources of the World ” estimated the world’s reserves as follow: — • 1 Actual Tons. Potential Tons. Europe 12,032,000,000 41,099,000,000 plus considerable America 9,855,000,000 81,822,000,000 plus enormous Australia ......... 136,000,000 69,000,000 plus considerable Asia 260,000,000 457,000,000 plus enormous Africa 125,000,000 many million tons Total 22,408,000,000 123,377,000,000 phis enormous It is almost certain that the actual reserves are still greater than indicated in the above figures. The modest position occupied by Australia in this epitome of the world’s resources is apparent, and causes one to think seriously of the future. # It emphasises, however, the necessity for making the most of the deposits available; that is to say, for testing them thoroughly, and utilising the raw material with the utmost care ancf to the last degree. The iron ore deposits in Tasmania are still in an unde- veloped state, and this makes it unsafe to calculate their extent on any other basis than that of potential reserves. 'N 3 On this basis the following figures represent an attempt to roughly estimate the possibilities of the islands — Potential Tons. Blythe River lode 17,000,000 Dial Range and Penguin 700,000 Beaconsfield and Anderson’s Creek.. 1,300,000 Long Plain 20,000*000 Zeehan District 2,900,000 Nelson River Unknown Total 41,900,000 A recent report by engineers engaged by the Common' wealth for the examination of the Blythe River lode is referred to later *in this bulletin. In their opinion, the lode-matter as a whole is too siliceous for a commercial iron ore. The view taken in the present publication is that until the ore -body has been effectively tested or developed, this opinion can be neither substantiated nor entirely disproved. In the meantime, the above provi- sional estimate is retained. The various deposits will be described in a conservative spirit, with the view of being helpful to readers anxious to learn the facts and possibilities in connection with the iron resources of the island. II. —IRON ORE IN THE BEACON SFIELD veyor, spent some months on Anderson's ureeK, opening up trenches and examining the deposits of ore. His report expressed the opinion that in the futnre the dis- trict would become highly important on account ot the abundance of iron ore of good quality, and favourably situated for working. a 4 - 4 - In 1872, in May, Mr. T. C. Just and Mr. Jas. Scott, M H A., visited York Town and the Iron Hills, with the result that they induced Melbourne investors to come into a smelting enterprise, and the Tasmanian Charcoal Hon Company was floated, on 400 acres of leased land with a capital of £80,000, in 40,000 shares of £2 each. Mr. MC Leonard was provisional manager. The present surveyed township north of the Iron Hills is called Leonardsburgh. The plan was to begin on a small scale, and make char- coal iron by the direct process in open Catalan forges, pro- ducing malleable iron blooms, to be forged into rough shaftings, &c., for the Victorian market. A jetty was built 310 feet out into the West Arm, and a wooden tram- way constructed up Anderson’s Creek to the mine, 5 to 6 miles distant. The company purchased 800 acres ot land, with a frontage on West Arm for a township, called Port Lempriere, after a leading Victorian shareholder. The first attempt appears' to have been m a f arl ^ ce designed to reduce the ore by a process invented by Mr. W. II . Harrison. Its foundation-stone was laid Decem- ber 6, 1872, but the trial was not persisted in. Mr. Har- rison communicated to the ^writer in 1902 the following nave iony, uwu ^ ~ ■ - — , T » j field, namely, on Brandy Creek, at the Sugar Loaf, and at Mt. Vulcan, Scott’s Hill, and Barnes Hill, on Ander- 5 information respecting what was done at the time of this trial: — ‘' About 30 years ago I was approached by the directors of that company, and engaged to erect a small trial plant (of a process which I patented) to see if a direct reduction of the company’s valuable iron ores could be effected on a commercial basis. I. accordingly put up a furnace on the mine, and, if I remember rightly, had only two or three days running, resulting in a considerable quantity of high-grade steel, from some of which a Mr. Grayson, a Sheffield cutler, of Melbourne, made a quantity of tools, pos- sessing very remarkable qualities. The tensile strength was far in excess of similar plates made from the then best manufactured steel procurable from Europe and America. From my steel, Mr. Grayson, under the hammer, made ribbons which could be tied into knots, and would nearly straighten out again to their orig- inal form. He made chisels to cut a groove along the course of a bastard file, the hammer-head of the chisel being so soft that it could be notched with a knife by hand. A bar of this steel could be cut and welded in the forge, like common wrought iron, without burn- ing or losing its splendid qualities. So much for the kind of steel which your iron ores can be made to produce. At the time I was erecting this plant, the directors made the acquaintance of a Mr. Gray, a blast- furnace man, from Melbourne. At his suggestion my researches were discontinued in favour of the old blast-furnace operations. The chrome in these iron ores was blamed as a factor of failure. As a matter of fact, chromic acid is a factor going largely to give the splendid qualities named above.” The company, having spent <£10,000 to £12,000 in pre- liminary work, was refloated in Victoria as the British and Tasmanian Charcoal Iron Company (capital £100,000), and a blast-furnace plant was ordered from Messrs. A. Barclay and Sons, Kilmarnock, B. Scott being appointed manager. The iron-cased cupola was put up at Port Lem- priere. The bricks for the chimney-stack of blowing- engine were specially made and imported from Victoria. All the common bricks used were made at the works, the clay being ground in a steam-clay mill. On June 17, 1876, Governor Sir F. A. Weld inaugurated the new works by blowing the furnace in. Although the company was 6 registered under the name of a charcoal-iron company, the fuel used was coke. The imported coke, which had to be lightered ashore, cost £3 per ton, so it was decided to import the coal and convert it into coke, which would then cost 25s. per ton. A range of 40 coke ovens was con- structed, with a capacity # of 1 ton each of coke per day. A trial charge of 20 of these was made with Bulli coal on September 4, 1876, and the results proved satisfactory. A new deep-water jetty, 600 feet long, was built at a cost of £1500, for accommodating vessels of any draught. A line to the mines, 6 miles long, of 4 ft, 8J in. gauge, was laid, with rails 50 lb. to the yard, and completed in May, 1876. Twenty wagons, each to carry 5 or 6 tons, were built on the works for the "transport of ore, &c. After the usual preliminary hitches, smelting fairly com- menced on the 25th October, 1876. For flux, Silurian blue limestone was brought by steamer from the River Don. The furnace was blown out about Christmas, having in two months put out between 2000 and 3000 tons of pig iron, or between 250 and 300 tons per week. Some of the softer sorts realised in Melbourne, £6 10s. per ton. On the 5th February, 1877, the furnace was again in blast, and was working well. It was cast three times daily, yielding about 13 tons of pig iron at each tapping. The presence of chrome appears by this time to have forced itself on the attention of those carrying on the enterprise. The first assays of the ore showed only small quantities of oxide of chromium. One assay yielded only traces, another T2 per cent., but when large quantities of ore were put through the furnace the objectionable ele- ment began to be noted in larger proportions, and the pig was found to contain from 2 to 10 per cent, of chrome. However, excellent cast steel was made in Melbourne from the purest varieties of this iron; a good deal of pig was nsed at Langford’s foundry, and some splendid castings were produced. For such articles as stamper-heads and shoes, and for all purposes requiring a combination of hardness and toughness, the iron was looked upon as the best that had come into the Victorian market. But it was soon seen that the local market for these purposes was essentially limited; and endeavours were made to secure an outlet for the product in England. Numerous experi- ments and trials, made at the large iron and steel works in England and Scotland, have been detailed by Mr. T. C. Just, in his “ Notes on the Iron Ore Deposits of the River 7 Tamar District. ” (*) It was mixed with other irons, tried for tools, wire, castings, chrome steel, &c. ; but the net results of trials made by the largest ironmasters in the United Kingdom proved unsatisfactory, the product being - too hard and brittle. The iron could not be worked by itself, was high in sulphur, was alloyed . with irregu- lar proportions of chrome, and produced brittle castings and excessively hard tool steel. The splen- did appearance of the' iron exhibited to the Iron and Steel Institute -excited such unqualified expres- sions of admiration that the- result of these trials caused deep disappointment. The company continued its shipments to Melbourne, but- the realisations dropped to about £5 5s. per ton for the soft grey pig, which was produced in small quantities. Trials were made with char- coal fuel; the fluxes also were varied, but without success. The bulk of the iron was white and hard, and as the Aus- tralian market, was too limited for the output of the fur- nace, it was decided, in August, 1877, to suspend opera- tions indefinitely. At that time 4000 to 5000 tons of iron were awaiting shipment. There was some idea of procur- ing a complete foundry plant from England, and estab- lishing a foundry in Melbourne for making gas and water- pipes, but this project apparently was not carried out. As far as can be gathered from the records of the time, the total output of the furnace was about 10,000 tons of pig iron, and the quantity of ore taken from the .* mine may be approximately reckoned as 20,0^0 tons. Mr. Just, who was a director of the company, strikes a melancholy note in his report of the operations. He says ( 2 ) : — “ Need I say that before admitting a failure we exhausted every known possible means* of manipula- tion. Mr. Robert Scott, the manager, was an old experienced ironworks manager in Scotland, and was largely interested in the success of the enterprise. Whilst the furnace was in blast, I spent weeks with him at the works, and discussed with him night and day the experiments which were put in operation. We had a skilled analytical chemist there for some time, carefully examining what went into the fur- nace and what came out of it. The closest super- vision was given, and details watched most minutely, but we never could get the iron sufficiently ( 1 ) Tasmanian Official Record, by R. M. Johnston, 1891 (pp. 464-469). ( 2 ) Tasmanian Official Record, by R. M. Johnston, 1891 (p. 470). 8 UJ Q O to o o - Q CO Z UJ > UJ H I— UJ z o < 2 CO CO 2 UJ O UJ QC o z o QC Ideal Section through Mt. Vulcan & Settlers’ Ran 11 T. C. Just thought that the rock was basalt, for he reported that “ at the Settlers there are several very curious mounds of basaltic rock/’ Parallel outcrops of identical rock occur at the south-east corner of Section UU7-m, 20 acres (formerly 6144, and previously 61431 at the southern foot of Scott’s Hill; 4nd inside the south-east corner of Mr. Williams’ land, on the west side of Ander- son s Creek (charted in the name of W. E. Baker). The crest of the main ridge has two domes south of the creek, and two north of it. . mooMtitueat minerals of the rock are magnesian mica (botite), quartz and felspar m equal proportions. The reispar is thoroughly decomposed. Minute grains of apa- tite are present, and an occasional crystal of tourmaline. Indications of strain and pressure are noticeable. The rock has a massive, igneous appearance in the field, with an occasional tendency to schistosity, which is more pro- nounced in microscopic slides. From the first, the Survey regarded it as being some modification of an acid eruptive though it has become gradually more and more inclined to interpret its characters as evidencing a crushed sedi- mentary of the greywacke type. The late Professor Rosen- busch, to whom a sample was submitted, professed him- self unable to recognise in the microscopic slide any sign o he normal structure of an igneous rock. More recently, Ur. E. W. Skeats examined it very carefully, and came to the conclusion that it was originally a rather coarse- grained sedimentary rock, consisting of quartz, aluminous. jSl argillaceous material, and Some partly decomposed febpars-; such a rock as an arkose or felspathic and th! rrT% San + and that its * present structure is the result- of contact metamorphism. At present the evi- dence, though not decisive, is rather in favour of its hav- ing been a sediment which was crushed and reconstructed mV s^XT 6 ° f the h6at and PreSSUre ° f th * ™ nd - No mineral veins have been -observed in this rock The magnetite veins of the district are confined to the serpen- the latter lr ° n an asbeSt0s ' havin S th eir genesis within (4)— -Ironstone Hills. * wb “ number— Scott’s Hill, named after Robeit Scott (mentioned above); and Mt Vulcan The former occupies Section 7707 -m, 20 acres, west of and djoimng 36 acres 1 rood purchased and in the name of 12 W E Baker (now owned by Mr. Williams) Mt. Vulcan ^blwS and 30 chains S.S.E. , occupying the 10-acre S tf F^-This hill supplied practically all the iron ore for the old furnace at Port Lempnere very little , if any having been used from Scott’s Hill. The whole width u u f rec i so il which indicates the iron formation h tu 1 500 feet and it continues through the entire r e c“f 10 acrt.’ At the foot of the northern slope is the principal quarry, which has been cut m ^ e i a little over a chain, showing a fence 170 leet m iengw. A chain and a half east of this is a smaller quarry m t "TheTe^nature of the deposit has been somewhat puzzling ever since Mr. C. Gould reported on it in 1866. He says : ( 3 ) “ ., '“In each case the main part of the deposit com- mences on the crown of a hill, and consists of large rounded boulders heaped on one another, or pr trading from the surface of :the soil. On fracture they art found to consist of alternate layers of brown hematite and earthy matter, the -ehness varying of » fhe relative portions 01 these wo, ana “g " muth that it wild be. unsafe from .urfaoe ^o^tifn of S “I ln“m;”with charting as accurately as I could the. whole area W by 70 broad, and is of an elongated form extend- ing’ to the north-east. In the other it is ^-rectan^ lar. To a cursory observer the appearance «£ these deposits is very anomalous, presenting, .... - Sfrc* 1st u .v sritti » more or ie g , Question. On extended exam- rt“ionT found that although the Moulders cr W ed of SnlTnes indicated on the charts by the small oval marking, and could be tra ced in those directions Paper No. 76. down the hills into the adjoining flat, and that many contained fragments of the magnetic oxide, together with other indications of their being of a derivative character. I therefore infer that the value of these deposits is very imperfectly represented by the surface masses, which I look upon as having been derived from the destruction of rich iron ores, such as magnetic oxide or crystallised hematite (probably the former). It is also likely that they are nothing more or less: than what miners call the back of strong lodes of magnetic oxide of iron, which would in that case be discover- able by mining operations conducted beneath the hills indicated on that vein. In fact, the drift below points to the existence of veins of magnetic oxide of some size, while the magnitude of the surface deposit renders it probable that that size would be considerable. I con- sider that eventually these spots' will become of great value.” The red hill drift or soil consists of loose earthy-brown hematite mixed with a certain proportion of red hematite and magnetite. The writer described it in 1903 as fol- lows:— ( 4 ) t ‘ The slopes of the hills, as well as most of the coun- ' try between them, are strewn with red hill-drift, con- sisting of brown hematite and magnetite. The drift passes downwards into layers of soft earthy hematite, sometimes hard and cellular, or partially crystallised and nodular, and into serpentine clay, the whole rest- ing ultimately on solid serpentine, which may in places be bedrock, in others wall-rock. Pieces of crystallised columnar magnetite are found in the red ochreous drift, and veins of the same mineral exist in the ser- pentine. Some of the iron ochre on the hill flanks is now being screened and shipped to Melbourne in small quantities. The tops of the hills show large boulders of iron ore lying upon and embedded in the ochreous • clay and drift. This is a common feature of all the deposits; the boulders are no doubt concretionary, and are exposed to the denudation of the surrounding soil. The quarries which have been cut in the hills show similar boulders at different depths, forming part of deposits of red and yellow earthy hematite. * ’ Particular search was made on this visit for pebbles or foreign rocks in the deposit, and especially in the boulders, as a little silica had been observed in them previously, sug- ( 4 ) “Report on the Mineral Resources of the Districts of Beaconsfieid and Salisbury,” by W. H. Twelvetrees, 8th May, 1903. 14 gesting transport, particularly as the country to the north has a thin covering of alluvial . lying on the serpentine rock. The difficulty experienced in obtaining satisfactory evidence leads the writer to the belief that the grains of silica which have been noticed in the boulders may have been chalcedonic and pertaining to the serpentine bedrock. Little nodules of magnetite and flakes of bronzite are occasionally seen, but none of these inclusions seem to be water-worn. The analyses reveal nothing which would indicate bog or lake ore. Bog ore is always limonite, hydrated oxide of iron, whereas this has an admixture of anhydrous ores (hematite and magnetite). It is also with- out the phosphorus content which characterises bog iron - ores, and the silica content is lower than is usual in the latter. - All the evidence points to the deposit being a residual mantle of ore resulting from the decay of the serpentine rock in situ. In this process the iron ores in the parent rock were in the main converted into limonite, some of them, however, surviving as hematite and magnetite. The chrome contents have been derived from the serpentinised rock, in which chromite is an original rock-forming constituent. Some dehydrating action has induced the formation of con- cretionary and cemented masses within the deposit, met with as boulders or flat tabular bodies harder than the sur- rounding unconsolidated granular pulverulent or clay-like material. In some parts of the serpentine area, especially in the part's where asbestos is abundant, veins of fibrous magnetite are very frequent. Sometimes magnetite and chrysotile asbestos are present, intimately associated in the same vein, leading the' casual observer to conclude that one material is a replacement form of the other. Minutely examined, however, the connections are seen to be abrupt, and cases of partial substitution are absent. The identical habit of the two minerals in such veins suggests that the fibrous crystal- lisation of both was contemporaneous. Other veins consist* of pure fibrous magnetite. These veins exist from the size of mere threads to a width of inches. The veins both of chrysotile and magnetite in all probability were genetically associated with the serpentinisation of the peridotite rock. The present quarry is in a semi-ruined state* owing to its long abandonment and the walls having fallen in to some extent. Visitors from the mainland occasionally view it, having heard of the iron deposits, but in its present con- dition it is not calculated to give a good impression of one of the iron shows of the State. It would probably be good 15 policy on the. part of the Government to pay a couple of men for three or four weeks to clean down the old faces and clear the floor of fallen overburden . The quarry would then be in a fit state: for inspection. About 170 feet: south of the main quarry is a small shaft some 20 feet deep in the soft limonite and ochreous forma- tion of which the hill consists; and 120 feet still farther south is Scott’s shaft:, on the crown of Mt, Vulcan. In this belt boulders of loose, and embedded boulders of consoli- dated, limonite, with enclosed fragments of fibrous (needle iron) magnetite, are plentiful. The summit of Mt. Vulcan is 200 feet above creek-level. As regards the persistence of the ore in depth down to the level of the creek, the old bores are really the only data which can be produced. Three bores were put down at the time of • the British and Tasmanian Charcoal Iron Com- pany— two on the hill and a third one somewhere' at its base. The No. 1 or Scott’s bore at the shaft was put down 176 feet, and the serpentine bedrock struck at 52 feet from surface. The register is as follows : " ft. in. Ironstone 24 0 Hematite g g Ironstone 5 g Heavy black sand, mostly iron 4 0 Soft ironstone 2 0 Heavy hard ironstone . 2 6 Brown hematite 7 g Decomposed serpentine 30 g Hard serpentine 5 g Serpentine mixed with asbestos 6 6 Serpentine and asbestos with magnetite... 2 0 Very hard serpentine and asbestos 0 6 Hard serpentine . 2. 6 Very hard serpentine 1 g Very hard serpentine with magnetite veins 9 0 Ironstone 5 g Greenstone 14 q Serpentine with asbestos 13 0 Serpentine with asbesos and iron ore 9 0 Iron ore q 2 Serpentine with veins of magnetite ...... 16 4 Iron ore, very hard, dense, and pure ...... 6 5 Serpentine with asbestos 1 g Serpentine 2 1 Total (feet) 178 0 16 No. 2 bore, also put down by Mr. Scott, showed much the same features. Its register is the following : — Bore No. 2. ft. 19 in. 0 Sand with ironstone pebbles M £ cni ptiitft * • 5 : s 6 6 TYp-phth P*T*f^Pyllst/OTLG 24 6 X/ubl/IB Uv/oCU glvuaiotui.iv . Serpentine 12 6 Total (feet) 70 0 Total (feet) 70 0 Water prevented further boring. Bore No. 3. ft. in. Ironstone ^ ^ Clay with iron pebbles ... 19 0 Oxidised conglomerate and magnetite — 10 6 Pure magnetite 1 6 Decomposed greenstone 29 0 Hard rock, supposed to be ironstone, broke auger 8 0 Total (feet) 87 6 These bores support the view that the brown iron ore- body consists of a mantle about 50 feet in thickness, lying at that depth on serpentine rock veined with magnetite, from which it has been derived by decomposition. A good many fragments 'of fibrous magnetite can be picked up on the surface of these hills, and veins of the same mineral may be 'seen in the serpentine , which has been worked for asbestos by Mr. W. B. Smith west of Nichols’ Bridge over Anderson’s Creek. Whether the magnetite veins below the ironstone deposit are suffi-. ciently numerous or wide enough to permit of profitable working once the oxide mantle has been removed is, how- ever, problematical. For the present, at all events, this mantle must be regarded as the commercial asset of the proposition. The dimensions of this mantle, horizontal and vertical, need to be ascertained and verified before any sound cal- culation of quantities can be made. The surface indications on Mt. Vulcan embrace the whole of the area of the 10-acre section; and on Scott’s Rill the whole of the original 17 40-acre section. But from the width of the belt along which the surface boulders are most numerous, one would judge that the best part of the Mt. Vulcan deposit is from 200 .to 300 feet wide— that is, if the boulder-bearing part of the deposit is taken as being the most solid and concen- trated. But it is very evident, that the carrying out of a comprehensive boring scheme, which need not be very expensive, is necessary to define the limits of the whole The 10-acre lease could be quickly bored with a hand- drill with auger bits, drilling holes 100 feet apart along meridians and lines of latitude. Where necessary the dis- tance could be reduced to 50 feet. The depths to bedrock would no doubt be variable, but would probably not exceed 50 feet. Sampling results from these holes would furnish reliable data for calculating tonnages and values ; and until some such work is accomplished, estimates can be no, other than speculative guesses. Mr. Robert Scott made an estimate of furnace ore derivable from Mt. Vulcan in the following terms :- “ By further explorations and borings I found that the quantity of hematite ore might saf ely be estimated at one million tons, or sufficient to produce 20,000 tons of cast iron annually for the next 25 years.” This might well be if the hill consisted of iron ore down to creek level, but for the reasons mentioned above the writer is of the opinion that it is highly probable thaUthe mantle of ore is not more than 50 or 60 feet thick, in which case a generous estimate of the Mt. Vulcan deposit would not exceed half a million tons. The same quantity possibly exists on Scott’s Hill, so it is likely that nearly one million tons of ore cover these two hills. The bulk of this consists of fines, only a small proportion being consolidated, and the quality is far from being uni- form throughout. The deposit no doubt rests on a mass of serpentine containing Yeins of magnetite, tyit, as said above, for the present- the commercial valfie of the ore resides in the mantle deposit. Scott’s Hill.— A small cut or two may be seen on the low elevation known as Scott’s Hill, 30 chains north of Mt. Vulcan'. These were only trial excavations, and it does not appear that any supplies from this hill were taken to the furnace The ore is red and yellow soft limonite, very little of it really hard. The hill is low, from 80 to 100 feet high, about 25 chains in length, from north to south, and 10 % 18 chains wide. The general occurrence is similar to that on Mt. Vulcan, though the ore is generally softer and more inclined to be ochreous. On the west side is a long open drive, from which material has been taken by the Ser- pentine Paint Company for its factory in Launceston, but this enterprise will be discussed later in the present report. (5) — Quality of Ore. Samples of iron ore from Mt. Vulcan were submitted by the writer .in 1903 to Mr. W. F. Wa**d, the Government Analyst, who reported as follows: — Per Cent. Iron as peroxide ... 75*80 Silica 5*40 Sulphur 0*13 Phosphorus Minute trace Chromium oxide ... 5*90 Alumina 4*30 Loss on ignition ... 7*30 Total * 98*83 per cent. 53*06 metallic iron Mr. Just reports an analysis of the pig iron from Mt. Vulcan ore made by Dr. R. C. Moffat as follows : — No. 1. No. 2. Per Cent. Per Cent. Metallic iron 89*72 97*82 Metallic chromium 9*27 1*43 Sulphur and phosphorus ... Traces Traces Nickel, cobalt, manganese. . — . None Tin, antimony, molybdenum Nitride of titanium I Traces Titanic acid ... t / Silica Oxides of vanadium and car- 1 ^ 1*01 0*75 bon > 100*00 100*00 Specific gravity 7*55 6*10 The same year (1877) analyses of the Mt. Vulcan pig iron were also made by Mr. E. Riley, London, who was 19 considered one of the best authorities on iron in England. The figures were as under : — t No. 1. No. 2. Per Cent. Per Cent. Carbon 4-200 3-270 Silicum . . -976 124 Sulphur •207 •562 Phosphorus -055 •054 Iron 88-343 9P362 Chromium 6-287 4143 Mai^anese Nil Nil -Copper Traces Traces 100-068 99-515 Samples taken by the writer on this visit have been assayed by Mr. W. D. Reid in the Geological Survey Laboratory, Launceston, as follows: — Mt. Vulcan Mt. Vulcan Scott’s Hill. ;; •: . / • ~ (cemented (loose material); material). Per Cent. Per Cent. Per Cent. Iron .54*2 40- 1 56-3 Alumina 6-93 19-22. 5-87 Silica 3-30 7-60 2-96 Chromic oxide 2-53 2-71 1-80 Sulphur 0-16 0-09 0-12 Phosphorus Trace Trace Trace Loss on ignition .... 9-80 13-30 8-60 In. chromiferous ores the oxide of chromium is reduced in the smelting process, and the chromium passes into the pig iron, uniting with the earbdn and iron and forming a double carbide of those elements, very hard and. brittle. One per cent, of chromium is stated to have the effect of making the ironjpuite hard, and 2 per cent, unfitting it for foundry ^purposes, leaving a market outlet only for certain steel works purposes. ( 5 ) As the chrome content rises, more of it enters the slag. In 1903 the writer , sent the analyses of some of the Mt. Vulcan ores to some of the large ironmasters of the- United V) But see what is reputed later respecting foundry iron from the Mayari chromiferous ore. 20 Kingdom, who replied with their opinions. Messrs. John Brown & Co., of the Atlas Works, Sheffield, reported that the composition is too' variable for any reliable work to be done with it, but that if ithe pig were as good as Swedish, and with a regular percentage of chrome, armourplate makers could use it. Krupp’s agent' in London at that time stated that it was not suitable for their works.. Messrs. Cammell & Co., Cyclops Works, Sheffield, wrote that the results of the smelting of such ores had not been very satisfactory, owing to the 'irregularity and great density of the iron produced; also' to the great expense of smelting. The Barrow Hematite Steel Co. Ltd. stated that they were not aware that any great advance had been made during recent years in the way of utilising ores which contained a percentage of chromium. The previous year they had made experiments with an ore containing from 2 to 4 per cent, of chromium, with the object of using some ores of this class from Greece, but the result was most unsatis- factory, for they had to give ’.up all ideas of using ores of that kind, even in small quantities. In 1897 Mr. W. C. Dauncey, C.E., in a paper on the iron deposits of Tasmania, read before the Royal Society of Tasmania, suggested that a mixture of two ores — chrom- iferous and non-chromiferous — might be made in smelting, or a percentage of the chromium pig could be added to the pure pig when melting for the production of steel. The latter could be done by melting pure pig in the Bessemer converter, and adding the necessaary quantity of chrom- iferous pig; then agitate to ensure perfect mixing, and cast into ingot moulds. He -considered that a ready sale could be got for the produce, “ providing buyers' knew that they could buy such material, and could rely upon getting a steel containing the necessary percentage of chromium, and not varying between a maximum. and a minimum with a wide range. ” > - . - It must be admitted that the outlook some years ago was not promising with respect to the possibility of utilising the Anderson’s Creek ores. The writer, however, is of opinion that at the present time the position has become more favourable. This view is founded on the fact that iron ores containing low percentages of chromium are now being mined and marketed in different parts of the world. This particular Tasmanian type of iron deposit is not quite unique. Elsewhere there are also occurrences of iron ore with a low percentage of chromium, and what is more to the point, some of them are being utilised. The Ander- 21 ion’s Creek deposits may be particularly compared with the brown ore-bodies of the island of Cuba Re % dua ^“ a r S , " of ore described as mantle or blanket deposits, occur m that island, forming a bed derived from t^ecomposrtion of serpentine rock, into which it passes at depths vary g up to fifty or (in a few cases) a hundred feet It consists of red and yellow iron oxides, hydrated and anhydrous with a certain proportion of magnetite. These are in a loose and finely divided condition, ^ s tatoce of shot-like concretions m the upper park of, the mass V seminated through the mantle are. “ d pisolitic recemented masses. The lower part of “ft Ldy is largely comp-d^of^yellow from a the C grass roots down to the surface of the unaltered rock Th! estimated tonnages are enormous, amountag to nearly two thousand million tons of ore . Like our And > sdn’s Creek deposits, these'Cuban ore-bodies contain a small percentage of chrome — P7 per cent., 1'8 per cent., 2 p cent., and 2'39 per cent.— a somewhat lower content than that of the Tasmanian ore. _ . . - In a paper on “ The Characteristics and ^Origin of tto Tirnwn Iron Ores of Oamaguey and Moa, -Cuba, Dy w. ttated that thelpennsylvania Steel Company and the Maryland |t!l Company 7 have successfully used %"erous Cuban ores and established their value. Further, in a paper in the s am e volume on the “ Iron Ore Depute of the Moa District, Oriente Province, Island of Cuba, by J. S. Cox, Jun., the author makes the following mteres - ing remarks : — “ l n the furnace the high alumina content compli- cated the slag ' calculations , and, since pig iron was pro- duced, the elimination of the chromium was to the production of satisfactory steel. ^ detailed description of how these several problems have bee ^ met would form a paper of Some length. ^ is sufc cient here to say that th© Pennsylvania Steel Com pany, the parent company of the Spanish- American Iron Company , has worked out practical solutions of all these difficulties in the case of the Mayan ores, and the results are applicable to th© similar Moa ores (p. 87) , “ Partial or oomplete elimination of the chromium and the production of a satisfactory steel were accom- 22 plished after patient experiment. Steel rails made trom this ore have demonstrated their superiority over ordinary rails by actual use on the Horseshoe Curve oi the Pennsylvania railroad. For more than a year the Pennsylvania Steel Company and the Maryland bteel Company have manufactured commercially! from Mayan ore a steel which, by reason of its nickel con- tent and low phosphorus, is superior to the ordinary Bessemer and open-hearth products (p. 88). An average result of 59 analyses of the Mayari ore referred to is given at page 111 of the volume quoted from as follows: — ^ y Silica Per Cent. T79 Alumina O t A 9-63 Iron 47-fiO Chromium, nickel, and cobalt . . • f UU 2.- 95 rks analysis of the ore as mined is as follows Per Cent. Iron, natural 36-5 Iron, dry . 50-34 Silica 3-75 Alumina io-o Phosphorus .... o-oi Sulphur 0-18 Moisture 27-50 Combined H 2 0 10-50 Manganese 0-64 Chromium ' 1-40 Nickel and cobalt 0-72 The Anderson’s Creek ore differs from the above in con- taining less alumina, more chromium, and no nickel. The nickel of the Cuban ore has no doubt contributed to the high quality of its steel, and the chrome remaining in it has probably assisted in the same direction to a less extent. The absence of nickel from the Tasmanian ore may be a disadvantage. , . ■ In the “ Mineral Industry for 1912 ” (p. 495) it was stated that a new and natural alloy of iron, nickel, and chromium attracted much attention, and was being sold under the name of “ Mayari Steel.” The product was essentially pig iron smelted from the Mayari ores of Cuba, and then purified in an open-hearth furnace. This steel is being used where extreme strength or hardness combined with ductility is desired, and has been in demand for rails, shafts, tools, springs, &c. Some of the iron ore deposits in Greece are in the form of beds resting on a floor of serpentine rock, and the ore contains from 2 to 3| per cent, of chromium. Grecian ores are exported to European furnaces, but there is only a limited demand for -the chromiferous varieties. Other-occurrences of chromiferous iron ore are mentioned in the literature of the subject. Thus the Clealum iron ores of Washington are lenses of hematite and magnetite lying on an oM eroded surface of serpentine rock, from which it is supposed to have been derived; the occurrence, however, is not strictly parallel, as the formation is believed to be sedimentary. A feature ’in its composition, however, is that it carries from 1*9 to 5*2. per cent, of chromic oxide. ( 6 ) Another occurrence is on Staten Island, New York, where some small deposits have been described as consisting of brown iron ore resting on serpentine rock, from which it has been derived as the result of subaerial depay. It, too, contains from 1 to 2‘81 per cent, of chromic oxide. It was reported as being mined in 1886. ( 7 ) The writer has been in communication with the Bethle- hem Steel Company, Bethlehem, Pennsylvania, which a few years ago took over the Pennsylvania Steel Company, which latter company in turn controlled the Maryland Steel Com- pany. The one operation on the Mayari ore is now being -directed from the office of the Bethlehem Steel Company. Some interesting information has been received from the latter company with reference to this ore. The' company’s Cuban deposits are being worked at the rate of about 350,000 tons of nodules per annum, though just at present there is a temporary stoppage of operations in consequence 1 of a scarcity of shipping. Steel rails are not at present made from Mayari ore, its use being generally confined to steel that can be heat treated. It is claimed that by a slight modification of the open-hearth process this steel is pro- V duced without the necessity of adding the alloying elements in the furnace or ladle, hence insuring uniformity m their distribution throughout any heat. ( 6 ) “ Cuntiibulions to Economic Geologs , 1907,” United States Qeol. Surv. Bulletin 340 (p- 325). C) Ibid. (p. 328). 24 The pig iron produced^ from the ore is a chrome-nickel iron having the following general composition : — Per Cent. Carbon 4-57 Manganese *9 Phosphorus *047 Sulphur -oil Nickel 1-3 Chromium 2*66 Vanadium -05 Titanium ......... i... -18 Copper , *035 , Silicon *80 It is a hard, dense, and brittle metal, a little heavier than ordinary pig iron. It has a large crystalline struc- ture, somewhat similar to spiegel iron, cannot be drilled, and breaks up considerably when handled. In practice itr is mixed with the different foundry irons im order to obtain the composition required. The makers state that in the general run of foundry work for miscellaneous castings an addition of 10 to 15 per cent, of the pig to the regular foundry mixture will produce excellent castings.- They state that chilled rolls containing 20 to 30 per cent, of Mayari pig have given three to four' times the service of ordinary chilled rolls, and that the presence of chromium and nickel in the iron give it a peculiar adaptability for chilled work of any character. It is not recommended for all purposes, but for castings where closeness of grain, chill, strength, or service is essential. The raw ore is described as being very similar to a loose non-plastic clay, a description which might also be applied to the Anderson’s Creek ore. The best furnace results have so far been obtained by submitting the ore to a preliminary treatment. Nodulising it in kilns is the process principally employed, though it is believed that sintering will eventu- ally be found more satisfactory, on account of saving in fuel and the more open and porous character of the material: produced. The nodulising kilns are 125 feet long, 10 feet in diameter, and turn out about 8 tons of finished P? r hour - Powdered coal is used as a 'fuel, about 400 lb. being required to produce a ton of the nodules. 25 (6) — Barnes' Hill. This hill is on the 640-acre Lot No. 730, about 1J mile south-east from Mt. Vulcan, and £-mile east of Anderson’s Creek. A fair bush road connects with the main road to Beaconsfield. All round the base of the hill, and ascend- ing its slopes, is the familiar red ironstone soil. The hill itself evidently has a subtratum of serpentine rock, inter- sected here and there by veins of asbestos and fibrous mag- netite. It is flat- topped, and in the limonite soil, both on the hill flanks and at its summit, soft boulders of iron ore are abundant. The strongest line of these appears to run north and south for a distance of 1200 feet, with a width of 300 to 400 feet. Outside these limits the stones of iron ore are scattered more sparsely, but the belt of red soil is still wider, and it is probable that the whole area of the occurrence is as much as 1000 feet square. The nature of the occurrence is similar to that at Mt. Vulcan. Some solid boulders of concretionary ore have been exposed by shallow excavations, and cuts a few feet deep have been put into the ground' without showing any change in the character of the deposit. There are no proper data avail- able for estimating the thickness of the mantle of ore, and in the absence of these it will be best to refrain from attempts to calculate tonnages. Quarries can be opened out with ease on the western brow of the hill, and the out- put sent down by tram to any level selected for the hori- zontal tramway to connect with Mt. Vulcan; or, if desired, a connection can be effected with the Sugar Loaf. When operations are resumed in the neighbourhood, this ore- body ought to form an essential part of any scheme. The ore is chromium-bearing, as will be gathered from the following analyses : — (No. 1 analysis was made by Mr. W. F. Ward, Govern- ment Analyst, of samples taken by the writer in 1903; No. 2 was made by Mr. W. D. Beid, Government Assayer, of ^samples taken on the present visit.) No. 1. No. 2. Per Cent. Per Cent. Iron ... 50*54 47*80 Silica... 6*50 3*80 Sulphur ... 0*14 0*11 Phosphorus Traces Traces Chromium oxide ... 6*90 4*25 Alumina 4*00 11*88 Loss on ignition ... 8*70 11*81 26 Judging from the fine body of iron ore on this hill, the veins of magnetite whence it was derived must be unusu- ally numerous, but to what extent they are developed can only be ascertained when the Works bottom on the ser- pentine. (7) Concluding Remarks on the Anderson's Creek Deposits. That the chromium content offers a difficulty has to be conceded, but a similar difficulty has apparently been over- come in other parts of the world, and with the approach- ing establishment of the iron industry in Australia and Tasmania, these fine deposits of ore, surrounded by abun- dant timber, near ample supplies of limestone flux, and within easy reach of deep water, ought not to be suffered to lie neglected just because some trials many years ago were not successful. With new trials, based on the most recent advances in metallurgical technique, the result might now be very different, and the undertaking is com- mended to any who are prepared to go thoroughly into the matter and assist the State to ‘turn these ores to practical account. The location of the furnace will depend largely on what plan of work is finally' adopted. If it is intended to reduce the chromium content to some extent by blending with the Sugar, Loaf chrome-free ores, the furnace would probably be erected where the old Ilfracombe Company’s furnace still stands on Hind’s farm, at the base of the Sugar Loaf (Lot 571, 640 acres, John Munro), close to the Sugar Loaf iron lode. The Anderson’s Creek ores would then be trammed to that locality. Inexhaustible supplies of high-grade limestone exist about 1J mile to the south. A tramway-line would have to be constructed from the fur- nace to Beauty Point for the transport of the iron to the port. If, however, work is started at Mt. Vulcan, the furnace will probably be again erected on the shore of the West Arm. In this case it would be open to use coke as fuel if desired; while at the Sugar Loaf considerations of cost would most likely dictate the employment of charcoal. In either case, the State hydro-electric current would be a valuable asset in the process of reduction to metal. 27 (8) — Sugar Loaf. Two miles south-east of the Barnes' Hill deposit is the Blue Peaked Hill, or Sugar Loaf, where there is a well- known lode of brown hematite, which was worked in 1872-3 by the Ilfracombe Iron Company, and was known by the name of the Ilfracombe Iron Mine. The old Ilfracombe . Sawmill Company had a tramway pussing this spot, and this probably gave rise to the name “ Ilfracombe " being adopted by the mining company, and attaching to the ore. In Mr. J. Hines' field, on Lot 571, 640 acres, in the charted name of John Munro, is the shell of the company’s blast furnace, which appears to have been the oldest furnace in the district. It was erected under the direction of a manager from Victoria, but it is said that as a consequence of faulty construction, the metal could not be got to flow. After abortive attempts, and spending nearly £10,000, the company sus- pended operations in 1873. At the foot of the range is an old ore pile, indicating that open heap calcination of the ore was resorted to, with a view of driving off the contained water previous to smelt- ing The lode courses up the hill in a direction N. 30 degrees E., and the outcrop shows some very large masses and boulders protruding through the rather dense scrub. The latter prevents the actual width of the lode from being ascertained on an ordinary visit of inspection. Mr. Gould, who reported on it in 1866, estimated the horizontal length of the outcrop as 286 yards, and its average width 66 feet. He calculated the tonnage above water-level as 705,800 tons, or, deducting half for inferior quality, a net quantity of 350,000 tons of rich ore. The average quality of the ore over a large portion of the lode he estimated as being from 55 to 60 per cent. The quality deteriorates towards the upper end of the outcrop, and the lode also seems to be breaking up in that direction. Facilities exist for open-cut working, and the ore could be broken out cheaply. The country-rock being sandstone and grits, the ore is, as might be expected, free from chromium. Samples taken by the writer on his previous visit, when analysed by the Government Analyst, yielded 56:8 per cent, metallic iron-, and contained no appreciable titanium. The 28 Government Assayer’s report of assay of samples taken on the present inspection is as follows: — Per Cent. Ferric oxide 78‘84 = Iron 55*2%. Alumina 3-28 Silica 6-20 Chromic oxide ... . Nil Sulphur ... 0-08 Phosphorus b. ... ... ... Trace Loss on ignition ... 11-40 99-80 difficult to forecast what plan of working the Anderson’s Creek deposits will be found the most suit- able, and as they are the governing factor in the initia- tion of work, and the tonnages available at the Sugar Loaf are not large, it is somewhat premature to attempt to outline what part the latter will play in the general industry of the district: Possibly the ore may be utilised in blending with the chromif erous ores, eventually press- ing into the service tonnages below water-level, which Mr. Gould estimated would increase the quantity available at the rate of 20,000 tons for every yard in depth. In that case, the choice would lie between erecting the furnace at the Sugar Loaf and bringing the Anderson's Creek ores to it, and putting up the smelter at the West Arm and transporting the Sugar Loaf ore to it. (9) — Dr. Thompson’s Iron Lode. At the base of Adams’ Hill, at Flowery Gully, is John- ston’s Creek, on the east bank of which are two lots, owned by Dr. L. Grey Thompson, 29 acres and 24 acres respect- ively. Alr’eady in Mr. Gould’s time an occurrence of brown iron ore on the 29 acres was known, which was judged by Mr. Gould to be in the form 'of a lode running east and west, and having a width of 5 or 6 feet. It is not easy to verify the accuracy of this statement, as the ore lies scat- tered about the hill in loose boulders, and forms small cliffs of impure ore mixed with country-rock, with steep faces to the valley on the west. The ore may be characterised as an impure brown hema- tite, not sufficiently high in grade to be profitable by itself* 29 g,nd probably in insufficient quantity for separate treat- ment; but if smelting is started at the Sugar Loaf, some of it might be tried in the furnace there, with a view of ascertaining its practical value. Samples of the best-looking ore were taken and assayed by Mr. W. D. Reid, Government Assayer, as follows: — Per Cent. Ferric oxide Alumina Silica ... Chromic oxide ... ... ... Sulphur Phosphorus Loss on ignition 78*98-= Iron 55*30 % 4*02 8*05 Nil 0*10 Trace 9*00 100*15 (10)— Swift’s Hematite (now H. J. Windred). This deposit is on a 14-acre section (No. 7988-m), east of Brandy Creek, Beaconsfield, held under lease by H. J. Windred. In the eastern portion of the lease are the old excavations made by the Tamar Hematite Iron Company in 1874-5. The history of this undertaking is of interest as showing what was done at that time in the way of smelting on a small scale for a short period. The company extracted about 1000 tons of concretionary brown hematite and impure ironstone from shallow trenches and excavations in the surface beds, and smelted the ore in a charcoal furnace which was erected on the shore of Middle Arm (Swift’s Jetty). The furnace was lighted on the 1st January, 1875, and after a few initial mishaps, was soon got into satisfactory running, showing an output capacity of about 5 tons of iron per day. Five hundred tons of excellent pig was produced during the first half of 1875. A trial casting of the iron was made at Peters’ foundry, in Launceston. Two tons of it were run into moulds of fly-wheels for chaffcutters, tram- way wheels, small wheels for the Launceston and Western railway, panels and rails for palisading, various parts of ovens, &c. It proved easy to melt, presented no sulphur trouble, and was pronounced soft and highly creditable in respect of fracture and grain. It was considered tougher than the Scotch iron, which was tested at the same 30 time. In these trials the pig was sorted so_as to separate the very hard or white iron. The softest was selected for the castings, and was smelted without any mixture with other irons. When run, it proved soft enough to take the finest impressions in the moulds. The castings made in Melbourne were also stated to be superior to those obtained from the ordinary Scotch pig, but as the Company could not obtain superior prices in Melbourne., they shipped a couple of hundred tons to Glasgow to try the home mar- ket. It was estimated that they could produce and land pig iron in London at a cost of from £4 to £4 10s. per ton. The parcel sent home was sold at £6 7s. 6d., and was reported “ of good quality, though rather tough/' The analysis was — Per Cent. Iron ... 94-40 Combined carbon 0'96 Graphite 3 ’08 Silicon 0*89 Sulphur 0*22 Phosphorus 0"09 Manganese 0'24 Loss 0*12 100-00 A drop in the market value of pig iron to the extent of 50 per cent, took place, and the furnace was blown out in June, 1875. The published reasons for suspension were various. The depression in the iron trade was one; another was that it was intended to raise fresh capital and add to the plant. Mr. A. H. Swift, the manager, died in February, 1876, and work was never resumed. No doubt the fall in prices affected the enterprise materially, added to which was the small scale on which work was conducted. The deposit was never opened up extensively, and it is still impossible to say what quantities are avail- able beyond the limited exposures in the shallow work- ings. From the excavations, all that one is able to judge is that a bed of about 5 feet of impure brown hematite, pass- ing below into 2 feet of denser ore, rests on a couple of feet of pebbly wash, which goes down into pipeclay. The 2-feet bed seems to Lave been taken for the furnace, and most of the impure overburden thrown aside. 31 The ore of this deposit is a brown hematite or limonite; its occurrence is manifestly in the form of a bed laid down in a lake or estuarine basin, which at one time may have stretched away as far as the Middle Arm. Its downward extension is evidently limited by the wash and pipeclay which is met with beneath it. The northern part of the lease shows a widespread cover- ing of unconsolidated iron oxide. The Native Paint and Oxide Proprietary in 1890-2 shipped 1000 tons of oxide from this ground to Melbourne. It was largely used for gas-purifying, and at that time realised from 27s. 6d. to 42s. 6d. per ton. Between the road and the northern boundary a good many holes have been sunk in the material, disclosing flat tabular masses of hydrated iron ore at different horizons in the loose oxide. The deposit passes northwards beyond the boundary of the section. It is not to be supposed fhat the iron formation covers the whole area of the lease, but it may possibly extend over a third or more. Mr. Windred is at present endeavouring to exploit the deposit for ochre and iron ore. If smelting works ar0 erected for the Anderson’s Creek ores on the West Arm it might be arranged to supply moderate quantities of this ore to supplement them, as there would be only a short road connection with the tramway. Samples taken on the present visit have been assayed in the Geological Survey laboratory, with the following results : — Old Workings. Unconsolidated Stratum. Per Cent. Per Cent. Eerric oxide 66-84 = Iron 46*8 °/ 0 43-56 = Iron 30-5 °/ 0 Alumina 5*20 15*32 Silicia 17-20 31*20 Chromic oxide...... 0 - 07 Nil Sulphur 0-13 0-14 Phosphorus ....... . Nil Trace Loss on ignition ... 10*40 9*60 99-84 199-82 The loose ferruginous deposit is of a colour which is suggestive of a possible value for paintmaking. Some tests would be necessary to ascertain whether the bulk of the material is free enough from grit to permit of its use for this purpose. Excessive silica in a paint impairs its opacity or body, and excessive alumina impairs its 32 brilliancy. The varying assay results indicate the neces- sity for a careful examination of the' quality of the deposit as a whole. The property is very conveniently situated for working and transport to Beauty Point, the shipping port. (11) — Windred’s Oxide Depo&it. This has been referred to in my report on iron ores. It is west of Brandy Creek, on the ground worked by the old Tamar Hematite Iron Company for the production of pig iron. On a portion of the lease- is a covering a few feet thick of loose red iron oxide, of a colour-shade which suggests that it might be _of use for paint-making. (12)— Serpentine Paint Company’s Deposit. This company holds a ‘20-acre mining lease (7707-m) on Scott’s Hill, and a 5-acre machinery site (7854-m) west of and adjoining the former. The hill (which, in fact, is little more than a gently rising ridge from the valley on the west) consists to all appearances of soft red and yel- low limonite, resting on and derived from serpentine rock. The subaerial decay of this rock, with its contained veins of fibrous magnetite, has led to the conversion of the lat- ter to the hydrated iron oxide, which is so useful for the manufacture of paint. The oxide forms a bedded or blanket deposit of essentially the same nature as that pre- sent on Mt. Vulcan to the south. Associated with it also is a similar chrome content, derived in like manner from the chromite veins existing in the serpentine. Embedded in the red soil on the flat top of the hill are consolidated concretionary stones and boulders of limonite, somewhat harder than the surrounding material, but identical in com- position. Here and there scattered fragments of the familiar fibrous “ needle iron ” are noticeable on the sur- face. The history of work on these deposits extends back to over 30 years ago. The Chromate, Asbestos, Paint, and Gold Mining Company operated previous to 1888, and the Native Paint and Oxide Proprietary in 1890-2. The latter company shipped about 500 tons of iron o^ide from here, principally for gas-purifying. The present company has extended the old open drive from the west side-line of the 20-acre section in a south-easterly direction 33 into the hill to a total length of 250 feet. The maximum depth attained in the course of this drive is 25 feet, and the deposit has been tested to a further depth of 14 feet, making about 40 feet thickness proved. In driving fur- ther into the hill this thickness will increase. It will pro- bably be comparable with that of the deposit on Mt. Vul- can. As the deposit is a bed, and not a lode, its width is not limited to the width of the cutting, and far greater quantities will be obtainable than are likely to be required by the present enterprise. If iron-smelting is initiated in connection with the deposits on these hills, there is no rea- son why the two industries should not be carried on con- currently, as the tonnages necessary for ,the paint require- ments will be infinitesimal in comparison with the ore sup- plies taken by the iron furnace. It is not surprising that various attempts have been made to turn the paint deposit to account at different times, for the variety of permanent oxide colours in the material is striking. Yellow, red, green, and brown are elements of the colour scheme^pre- sented by the Components of this bed. These metallic oxides form the basis of the iron pigments of commerce. Among the chocolate and dark-red varieties are to be found some of the most stable types of ferric oxide. Native oxides, unlike manufactured or calcined materials, possess the character of permanency, and, with suitable blending, lend themselves to the preparation of pigments with any desired degree of opacity and staining power. The pre- sent company controls three mines with different raw materials in each, which has the advantage of enabling it to command a market for varying types of product. The Serpentine Paint Company, in founding a new Tasmanian industry, has established a paint factory on the wharf in Launceston, where it makes, not only the oxide paints, but lead and chemical paints as well, meeting the requirements of the entire paint industry. The following account of the process of manufacture is extracted from a communication emanating from the Company : — V The crude oxides are purified by jevigation or air separation, the specific gravity being made use of to separ- ate the various grades of colour. In the levigating pro- cess the slimes are furnace-dried, and then ground to a very fine powder. This passes to a pug mill, and is incor- porated with pure linseed oil ; it then goes through the granite rolling machine, thus precluding any chance of burning the pigment and changing the colour ; . thence it passes through steel roller mills, where it is reduced to the 34 consistency of stiff paste, and finally emerges as paste paint of the very finest quality. “ This paste is conveyed to the mixing -vat and the neces- sary quantity of linseed oil, turpentine, and a very small proportion of drier added to make it liquid paint. Hotary planes, electrically driven, thoroughly mix the paint, which is taken to the finishing cone mills, whence it is run directly to the containers, ready for market. This thorough mixing secures perfect suspension and absence of deposit on the bottom of the tin. The company guaran- tees that no adulterant of any kind is used in the manufacture.” The following is an analysis of the raw oxide from the cutting : — PerCent. Ferric oxide ... 75’98 = Iron 53*2 Alumina ... 4*94 percent. Silica ... ... ... 5'25 Chromic oxide ... ... ... 3- 62 Sulphur ••• ... 0‘09 Phosphorus ... Trace Loss on ignition 9'96 99*84 The absence of grit in the raw material is highly favour- able for easy grinding and ready conversion into paint. Another point which may be remarked is the non-exist- ence in the ore of chemically active elements which would be apt to impair the permanence of the paint. It is prac- tically an inert substance, and with due attention to the quality of the oil can yield a pigment permanently resist- ant to moisture, light, an$ climatic changes. Satisfactory tests of permanence and spreading power and other neces- sary qualities have been made of the manufactured paints, and the whole process of manufacture is under the super- vision of a trained works chemist of repute in the paint world . It is to be hoped that the placing of a good local article on the market will meet with general support in Tasmania, and that Government departments will not be backward in encouraging the new industry with their orders. (13) — Conclusion. It behoves the Government to do all in its power to sup- port and foster the development of a new industry such as 35 paint-making, particularly as it is essentially based on the use of our natural resources. We have the suitable raw material, but it cannot be reckoned as an item of our mineral wealth unless it is profitably employed. Success in this enterprise depends largely upon what amount of patronage and support it can secure, and especially upon how far the local support will obviate the necessity for seeking trade outside the State. We have now an oppor- tunity for testing the genuineness of the demand for local manufactures. Ill— DIAL RANGE IRON LEASES. (1)— Lease 8038-m, 80 Acres, E. Hobbs; and Lease 8039-m, 80 Acres, J. O’Neill. These leases cover the old leases 5088-93m, 50 acres, W. Jones, and 5o89-93m, 50 acres, F. S. Denney, They are situate high up on the steep western flank ot the Dial Range, within a couple of hundred feet of the crest, towards the south end of the range, and about b miles from the sea-coast at Penguin. They are approached by a good metalled road running from Penguin to Riana through the farms occupying the fertile basaltic table- land which everywhere skirts the North-West Coast- line, and is the source of prosperity of this part of the is.an . Incidentally, the question is sometimes put m respect ot the comparative qualities of the soil derived from basaltic lava— the so-called chocolate soil— and that produced by the disintegration of the diabase rock of the Tasmanian Tiers. The latter soil forms large tracts of relatively poor land *%hi\e the former is renowned for its fertility througSbut the State. Yet the chemical composition ot both iM6i4 identical. The probable explanation is that the ba^l^ with its loose glassy base, breaks up into its constitiibift elements with sufficient rapidity to admit ot the formating a deep soft soil before wind and weather agencieir? Lave time to carry the disintegration products away ; y^ilelthe physically resistant diabase rock weathers so slowMthat the resultant soil is carried off almost as soon as it is firmed, leaving behind a thinly-covered surface ot hard solid rock. . in The surface of the Penguin tableland rises gradually towards the south until, at about 800 feet above sea-level, the southern boundary of the 100 acres charted m the name of L. Biggins (now Stone’s farm) is reached, where the main road is left and the ascent of the range is com- menced by means of a zig-zag foot-track, which leads direc to the iron leases. The air-line to the ore-outcrop is about 1 mile from the road in an easterly direction ; the actual ascent begins at about half a mile. The Penguin Creek is crossed at the foot of the mountain. The footpath has been well cut, and the grade is easy. At the base the basalt soil gives place to the Silurian conglomerate rock ot the range. III.— DIAL RANGE IRON LEASES. (1) — Lease 8038-m, 80 Acres, E. Hobbs ; and Lease 8039-m, 80 Acres, J. O’Neill. These leases cover the old leases 5088-93m, 50 acres, W. Jones, and 5u89-93m, 50 acres, F. S. Denney, They are situate high up on the steep western flank of the Dial Range, within a couple of hundred feet of the crest, towards the south end of the range, and about 6 miles from the sea-coast at Penguin. They are approached by a good metalled road running from Penguin to Riana through the farms occupying the fertile basaltic table- land which everywhere skirts the North-West Coast line, and is the source of prosperity of this part of the island. Incidentally, the question is sometimes put in respect of the comparative qualities of the soil derived from basaltic lava — the so-called chocolate soil — and that produced by the disintegration of the diabase rock of the Tasmanian Tiers. The latter soil forms large tracts of relatively poor land, <#hile the former is renowned for its fertility throughout the State. Yet the chemical composition of both islneafl^ identical. The probable explanation is that the baisilfef ^yith its loose glassy base, breaks up into its constittf§ifl| elements with sufficient rapidity to admit of the f ormatiqn^ of a deep soft soil before wind and weather agenciejg; have time to carry the disintegration products away; ^hile^the physically resistant diabase rock weathers so slowly^ that the resultant soil is carried off almost as soon as it is llrmed, leaving behind a thinly-covered surface of hard solid rock. The surface of the Penguin tableland rises gradually towards the south until, at about 800 feet above sea-level, the southern boundary of the 100 acres charted in the name of L. Biggins (now Stone’s farm) is reached, where the main road is left and the ascent of the range is com- menced by means of a zig-zag foot-track, which leads direct to the iron leases. The air-line to the ore-outcrop is about 1 mile from the road in an easterly direction; the actual ascent begins at about half a mile. The Penguin Creek is crossed at the foot of the mountain. The footpath has been well cut, and the grade is easy. At the base the basalt soil gives place to the Silurian conglomerate rock of the range. 37 Some stones of iron ore are present in the conglomerate on the track before reaching the west side-line of the leases, but the main body of the deposit is situate a few hundred feet inside the lease boundary. The ore-body consists of red. hematite (ferric oxide), non-magnetic, and appears to be a replacement of the conglomerate-bedded rock. It has a linear direction extending north and south, and showing outcrops at intervals through both leases. Its surface has not been exposed sufficiently to admit of accu- rate measurements of its width. A good deal of it seems to be 3 or 4 chains wide, and on the northern lease its width may be greater, as ferruginous soil is noticeable for several hundred feet. The exposures on the northern lease, 8038-m, may be described as follow: — Some ironstone is seen loose in the soil on the northern boundary-line of the section. Following a southerly direc- tion from this across the lease through dense scrub in the valley, one ascends a hill which is crowned with a knob of hard iron ore. Numerous- boulders show ore of variable quality, some of it very massive and good, but mixed with other stone of lower grade. The surface indications here are very encouraging, and a good deal of ore could no doubt be got from this point. Its position, too, is favourable for trans- port down the creek to works or rail. South of the creek, but still on the same lease, is a short adit which , has been driven into the steep hillside r whete there was formerly a small excavation. Ironstone boulders occur at surface, some of them consisting of very pure ore, while, in others the replacement of the conglomerate has been imperfect, showing partly-changed pebbles. Another little tunnel has been driven near the dividing- line between the two sections for some 50 feet in a south- westerly direction, but the formation in the end is some- what indifferent in quality ; some of it consists of fair iron ore, but the rest is stony. In this part of the lease the surface is ferruginous for a width of about 500 feet, but the scrub requires to be cleared and the ground examined by trenching in order to establish the nature and value of the formation. There is evidently a parallel ironstone formation on this lease, exposed in a creek bank on the western side-line at about 7 or 8 chains from the south-west corner peg. The extent of this has not been ascertained. 38 Passing now to Lease 8039-m on the saddle or flat crest of the hill south of the boundary between the two sections, a large flat outcrop of great boulders of iron ore occurs in the surface-soil. The ore is of excellent quality ; a good deal of it is massive, but shows the replacement process. Being at the summit of the spur, it could be quarried in either direction, and transported either down the creek ^o the east or to the tableland on the west, according to the working plan adopted. It is difficult to say what width the formation has at this spot, but it is probably at least 2 or 3 chains. , , . , Further south, half-way through the section, and on the same ore-line, boulders of dense hematite appear, showing occasionally specular iron ore. Judging by the stone at surface, the usual width seems to be maintained. The ore will break in mining into good lump -ore suitable for the furnaces, and the usual deleterious ingredients ot many iron ores are distinctly low. The proportion of phos- phorus on the whole does not exceed the Bessemer limit, and the sulphur percentage is quite low. Owing however, to the ore-body being the result ot replacement of conglomerate, which has taken place to a variable extent throughout the ore-belt, some of it showing a complete substitution, while in other parts the substitu- tion is only partial, the relative proportions oLiron oxide and silica vary irregularly. The result is that the grade is far from uniform throughout the formation, and it any ot the imperfectly transmuted stone is included in sampling, the silica percentage is at once augmented and the iron percentage diminished. Siliceous boulders of ironstone are scattered m the soil between the different outcrops and cuttings. Towards the edges of the formation the conglomerate is seen to have suffered very little alteration, and in calculating the quan- tities of ore for smelting allowance will have to be made for this. Still several of the outcrops seem to carry a pro- portion of good-grade ore, and in working the deposits favourable places in the belt would have to be selected. The scrub or overburden, or both, covering the ore-body for such a great part of its length makes it impossible to take an average sample ; and some expenditure is neces- sary in the way of trenching down into the solid forma- tion before an approximate idea can be formed of values. All that one can do for the moment is, on the one hand, to select some good samples, showing what the formation is capable of yielding in more or less quantity, and on the ! 39 Iron. Silica. Phosphorus. Sulph ur. Per Cent. Per Cent. Per Cent. Per Cent. .. 68 0*5 traces traces .. 66 1*6 traces traces .. 69 0*8 traces 0*15 .. 58 6*8 traces traces . other hand to take such general samples where -there hap- pen to be exposures as may be judged to correspond with what will be met with in bulk. Selected samples were taken by the writer in 1903 and assayed by Mr. W. F. Ward, Government Analyst, with the following results : — Northern lease Ditto ... Southern lease Ditto ... General samples taken on this occasion indifferently from all parts of the formation have been assayed by Mr. W. D. Reid, Government Assayer, as follows: — Moisture Iron. Silica Phos- Sulphur. at phortis, 110^ C. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Northern lease ... 50*86 23*40 0*05 0*095 0*15 Southern lease ... 63*84 8*60 0*08 0*03 0*02 Ditto 54*50 19*20 0*001 .0*085 0*12 The highest grade on the southern lease was from the outcrop at the top of the hill where the track leads up to the formation, and this leaves nothing to be desired. The other samples show an excess of silica. A grab sample from the Knob outcrop on the northern lease resulted in a very siliceous assay, viz. " Per Cent. Iron ... ... ... ... ... 42*56 Silica ... ... ... ... 30*90 Phosphorus... ... ... 0*032 Sulphur ... ... 0*10 Moisture at 110°C. 0*21 In fact, any variety of ironstone may be obtained, accord- ing to the more or less perfect replacement of the con- glomerate. The more siliceous ore would require to be pre- pared for smelting by crushing and washing. It is impos- sible to say what proportion the siliceous .ore bears to the quantity of ore of standard quality ; this can Only be ascertained by systematic trial Work and sampling. It would seem that in mining a selection would have to be made as far as could be judged of ores of 50 per cent. 40 am i Howards A certain amount of improvement could probably be effected by the use of picking belts Between L and 60 per cent, ore is good grade, and it the JJiai Range ore can be raised to that extent a little extra the smltom bouncy the continuation of the belt are said to occur on M . Counsel’s land, which is very likely. The ore at this southern end of the section seems ei to widen out considerably, or else parallel ^ belts exist. Some verv good stones of ore may be picked out from here, buronthewhole it looks as if the grade might not prove in be so high as at the northern end. As regards the quantities available for the furnace no commercial calculation can be made until the w^e Wth of the formation is ascertained, and t g exposed by clearing off the scrub from the surface and testing the outcrop 111 along by means .of drenches and ^pite; Even then its behaviour m depth will be o y P fectly known. At present only a very rough idea can _be formed of its possibilities, and even m order to no this some vital assumptions have to be made. The leng^ width of the belt of smeltable ore have to be ^ the grade If it turns out that a belt of workable ore 2 feet wide exists for a third of the, total length through the two sections the quantity of ore down to a depth ot 5U feet would total about 600,000 tons This, at 50 per cent iron, would be equivalent to 300,000 tons metal or, if at 60 per cent., 360,000 tons. These figures cannot, how- PATPr be used until the data are established. . The way in which the iron industry will .be moated on the North-West, Coast is at present so uncertain that any forecast of the exploitation of the Dial deposits must be attended with uncertainty. The latest, developmen s sug gest that they will be worked as an independent enter- prise. Operations will no doubt be commenced °" 1 1 moderate scale The smelter would probably be near Pen gut te meek route being the one used ^r transporting ore to the furnace. This route would^permit of t he Pen guin Creek iron deposits being tapped, and contribute g moderate quantities of high-grade ore to the ^era out- nut A route across to the Leven, and so to Ulverstone, has been mentioned, but the advantage of this yis ^ not apparent, except for shipping purposes. The natural tall for the output is down the Penguin Creek valley. J. A. Owens 4! The whole subject of starting work is bound up with questions of competing works, fuel, and power, as well as the class of product aimed at. The future .of these pro- perties will inevitably be governed and regulated by the result of expert investigation of these conditions. The decision as to what class of iron will be specialised in — iron for steel-making, foundry or cast-iron, or iron for puddling or wrought-iron— -will influence the scale of operations. Operations for making steel on a large scale will not be contemplated, and work will be restricted to the manu- facture of some special lines of iron and steel, for which a market can be secured without having to deal with any ruinous competition. This, as well as the size of the deposit, will necessitate a small production, and the question whether it can be made profitable is one which will require careful study. Ihe questions of fuel and flux are discussed in another part of this publication. Charcoal fuel is more suitable for small furnaces using electric power than for the more trying conditions of large blast furnaces, and for exploit- ing these moderate-sized deposits electric furnaces would be eminently adapted. (2) — Penguin Creek Deposits. Along the course of the Penguin Creek, at about 3 miles from its mouth, a good deal, of hematite ore is found in the stratified Silurian quartzite or sandstone and slate west and north-west of the Dial Range. The creek appears to have formed its channel in this wide ferruginous belt of country for about a mile or so. Mr. A. Montgomery reported on these deposits in 1895. He noticed already at that time that a few trenches had been made on Hudson’s and Brown’s land, exposing the quartzite bedrock on the former, and he was of opinion that very large quantities of excellent ore could be won at small cost. He considered that the deposit had no con- nection with the Iron Cliffs lode, though it is almost on the line where the latter might be expected to be met with. The Iron Cliffs ore is a brown hematite, while the Penguin Creek ore is an anhydrous red hematite. Mr. Montgomery’s samples, chipped here and there from the best-looking blocks of ore, yielded on assay 98 per cent.' of peroxide of iron (68*60 per cent, metallic iron), 1*6 per 42 cent, silica, and 0'2 per cent, sulphur wfiich is a pure iron well adapted for making high-quality .^el. When Mr Harcourt Smith visited the deposits m 1898 he found them being operated by the -Tasmanian Irom Company (Mr. J. C. 8 Ellis), who were shipping ore from the forma- tions on Hudson’s and Good’s properties. In 1903 the writer examined the workings, and visited them again l 1905, at which time, owing to severe Australian competi- tion, the output, which was being shipped to New y-outh Wales for flux in smelting-furnaces, had been temporarily reduced to about 150 tons per week. Mr. Ellis worked the quarries from 1897 to 1909. At the end of that period the smelters got their main supplies elsewhere and Mr E is had difficulty in retaining a market for his full output. In addition, dispute with landholders resulted m his being deprived of his tramway facilities, and this led to the abandonment of the enterprise, after sending away alto- gether 40,000 tons of ore. - . , A horse-tram, two-thirds of it steel and the remainder wood with steel strips, had been laid down from the quarries to the wharf, a distance of 3^ miles, along the creek which it crossed and recrossed several times by means of little bridges. Thirty tons of ore a day were carried m two trips, and the ore was loaded into lighters for trans- mission at Devonport into boats for New South Wales. The ore was selected so as not to assay less than 6b per cent., and it mostly ran from 66 per cent, to 68 per cent., with 2 to 3 per cent, silica. . Samples taken in 1903 from the various quarries then in work were assayed in the Government laboratories, as follows: — . . „ ,, (1) Surface (2) Hudson’s (3) Good s Work (side Quarry. Cutting (above road). Iron ••• Silica Sulphur Phosphorus... of tramway) 69*00 0*4 Trace Trace 68*00 0*6 68*5 0*6 Attention was called at that time to the remarkable free- dom from detrimental impurities, such as sulphur and phosphorus, and the low silica content. On tlm present occasion there was hardly the same opportunity of taking samples which would do justice to the deposits, as work has ceased, and only abandoned and more or less worked- out quarries were available for inspection. The samples taken showed, nevertheless, a remarkably pure ore. they 43 w e re^as sa y e d by. Mr. W. D, Reid, Government Assayer, as follows: — ■ Iron ... ... ... Silica .. Sulphur. . . Phosphorus ... Moisture at 1 10° C. Hudson’s Quarry. Her Cent. 67-71 2-20 0-025 0-026 0-13 Good & Craw- ford’s Quarry. PerCent, 65-24 1-90 0-098 0'03 0-13 The worked deposits extend for 1J mile along the creek m the form of replacement bodies of ore and boulders and nodules in a less pure soft ferruginous, matrix extending from c^eek -level up to the surface of the basaltic tab le- land. The boulders sometimes attain a great size, some having been found weighing as much as 25 tons. The softer matrix in which they lie is often clayey, and was too impure for shipment. The working plan followed was to open out quarries at selected points, where pure boulders or other solid ore occurred. To illustrate the irregular occurrence of the best hard ore, from a cut south of No 1 -,°^ ly ^ USt below the half a dozen boulders yielded 100 tons of ore. Further up the creek, too, on the east side, about 508 tons of, ore were taken out of the surface-soil, boulders of 5 and 10 tons first-class hematite being very common. The structure of the deposit indicates that the ore has replaced sandstone or conglomerate, and, as might be expected, the quality varies from place to place, a good deal of it being earthy and siliceous and associated with Iimomte Occurring with the ore is a white friable saccharoidal sandstone ydnch has here and there been con- verted into quartzite. A kernel of this stone was found m a boulder of iron ore. Signs exist of the conversion of sandstone into the ore of the deposit, and the nodular lorm m which some of the ore occurs suggests an original pebbly sandstone or conglomerate. This excludes any rela- tion with the Iron Cliffs outcrop, which is that of a lode, t /-X • extr f mel y difficult to form an opinion as to the quantities^ of workable ore still available. Of course, Mr Fills selected for his purpose only the very best ores, and the consequence, is the workings are patchy and irregular A good deal of the ore which he rejected would be suitable lor the furnace; but even so, the irregularity of the deposit militates against laying out work with any reliance on con- tinuity . There is no doubt a good deal of ore which is still 44 ”sr. re ... « *» •«•' «*f » ?- h t“3S rc^^s. ”« sa^sft^s: tlip rifle-range, shows some iron ore 20 or ou teet m Mr Ellis worked here for a time, and shipped some of the ore E Somr 0 f it is siliceous, but in parts it is -rj P"- A sample taken on the present visit assayed m the Geolog Survey laboratory yielded as follows . Iron Silica Sulphur... Phosphorus... Moisture at 110° C. Per Cent. 68-82 0*84 0-021 0-001 . 0-14 This is an excellent sample, of unsurp^abl? quaU^. Traces of ~ SetaS ounces ,"C SXfe - *• 55ft •££: £ atrasc sat r«?«s * b ” if the industry is started in the neighbourhood. (3) — Iron Cliffs Lode. Th “ “ ‘J v •M’L.’S feet in width, on pass es through Anderson’s 60 wards s0 P il; except where exposed in a acres, cov 'V, , 23 acres, where the ore has an creek, and into Ba arv te S and is sometimes man- g-aniferous. 0 Samples taken from the surface on this land 45 assayed 59 per cent, iron, 5 per cent, silica, and only traces of sulphur and phosphorus, Southwards from Anderson’s the lode passes into the sections held by Pullen and Mitchell, O’Byrne, and Paton. Samples from the large outcrop on Pullen’s, assayed by Mr. W. F. Ward, Government Analyst, yielded : — Sample No. 1. Sample No. 2. Pei Cent. Per Cent. Iron ... ... 48-0 57*0 Silica ... ... 18*4 7-2 Sulphur ... ... 0'15 Traces Phosphorus Traces Traces Samples from the deep tunnel (about 450 feet below the outcrop), and where a clayey iron gossan has been driven into, were assayed by Mr. W. F. Ward, Government Analyst, and appear to have yielded 16 grains gold per ton, with traces of silver and copper. It is evidently a lode formation, and the hydrated oxide, which forms the part of the lode now accessible, is most probably the result of oxidation of some metallic sulphide. As a brown iron ore its grade and quality are good. Mr. Ellis sent away some shipments from it, but :the silica content, though not at all tod high for iron-smelting, was too high for his requirements, and, being limonite, the contained water made it not sufficiently remunerative for his purpose, as only the very highest grade was suitable for his market. The utilisation of this ore-body will, no doubt, eventu- ally lie in supplementing ore-supplies to smelting-furnaces in the Penguin Creek valley. Taking the whole ore-body as it exists on Pullen’s and O’Byrne’s leases, there is no doubt that quantities of ore could be easily mined and delivered to furnaces in the Penguin Creek valley. As far as can be judged at present, a 50 per cent, grade might be obtained, and the output would belong to a class of ore easily reducible. The whole of these cliff and creek deposits are capable of forming valuable auxiliaries to the Dial Range proposition. The local conditions for smelting works somewhere along ,the creek are excellent; Penguin itself is on the sea-board; it would be neoessarfi to restore shipping facilities by repair- ing the breakwater, and with the iron industry started, the district would be a busy centre. The writer is indebted to Mr. Richardson for accompany- ing him over the Penguin deposits. 46 (4) Manganese Ore at Dial Range and Penguin. (a) Dial Ram,ge. A deposit of manganese ore occurs on the 63 -acre lease, 7162-m, at the northern base of Mt. Duncan, charted in the names of J. Payton and J. Revell. It appears to have been discovered by Mr. Robert Revell in 1905. A belt of boulders and stones of ore runs up .the hill in a southerly direction or a little east of south, and an open drive has been put in on the formation for a distance of about ^-chain, an -r V™ "u?;.vi.ion.l pi» i» .h. C.m- bro-Ordovician to the Silurian. time or another about The pofsS'rf The - SScs s u iron ore property, 1 or | teri F al down to river- non-cuprferous hematite-bea ^ th ma l level, the absence m rather contra-indicate proportion of limoni e m depth - a large number the existence of a.. copper . disclosing the presence ;Sw p c: "is .«* » -P-,- 1 ' T£1“m*h’» .C P V*i» *»“ “» ■i “u-t «. speaking, with the acid mag > re i a tions, however, are manifestation and outco • TVip ore is not mag- n- ,h ~ irrrrrSm s by way of - J^ojfthe successive stages of . deposition, the lating specifica y de d as having been metasomatic. . process may be regard ° s jde of the river The lode is prominently sh °™“ { thfe . slo p es 0 f the by a series of huge crags projecting s J on the mi> f (jw “s. — s», fc,»a .... ..... .... .< 54 the main line of outcrop. This eastern lens seems to be of a decidedly siliceous nature. Its continuation northerly is obscure. The main lode runs north from the river for about three-quarters of a mile, 26 chains of which are below a capping of olivine basalt of Tertiary age. This sheet of lava is between 100 and 150 feet in thickness. The lode emerges from below the northern edge of the lava and continues half-way through Section K)61. The width of the lode north of the river and at different horizons varies a good deal. At the river itself it is not more than 30 feet wide, while higher up. and some chains north of the river the width of outcrop is 50 feet, and north of O’Keefe’s quarry the solid ore at surface at different points measures from 80 to 100 feet across, widest at the northern end. ; . The lode-width at the point where the river flows across the formation has been taken by the Commonwealth engineers^ 8 ) as an indication that the lode is thinning out in depth along its entire course, but it is doubtful whether this assumption is sound. The explanation suggests itself that the river may mark the thin end of a lens, which was chosen by the stream as a path of least resistance. On the south side of the river the lode occurs as lenses showing in the form of large crags, not always on the same line, and separated by areas of intervening country-rock. The base of the lowest crag is between 140 and 150 feet wide. At the top of the crag a trench exposes the Ore and ore-ground for 4 chains. Higher up is what is known as the “ Purgle Crag,” a mass of dense lumpy iron ore, projecting in a striking way from the hillside. The crag is over 100 feet in width, siliceous ore extending further west, concealed below the overburden of soil. In the crag itself is excellent ore. Still greater widths have been ascribed to the ore -deposit on this side of the river, but these probably include inter- vening bands of iron-stained country between parallel iron formations, of which there are some signs. Further, there is a siliceous upper crag to the east — possibly a parallel lens. The origin of the Purple Crag is not quite clear. The view advanced that it is merely a surface formation deserves examination, although appearing somewhat improbable. Those familiar with the features of the Tas- ( 8 ) In a recent examination on behalf of the Federal Government. 55 manian conglomerates and breccias of this age will recall similar occurrences of brecciated ore without adopting for them a recent origin. Such may alternate with other^beds in which the replacement has been imperfect. Na-turaliy, the view adopted in the present case will inevitably affect the tonnage-estimate considerably. Samples which the writer took from the Purple Crag m 1900 yielded on by the Government Analyst 68'6 per cent, iron, 1 8 p cent, silica, 0-09 per cent, phosphorus and traces only ot sulphur. The sampling carried out by the Commonwealt engineers in 5-feet sections shows results ranging from 57 ? 96 per cent, iron and 1292 per cent, silica to 66 56 per cent, iron and 2’26 per cent, silica. Sneaking generally,- there is so much siliceous lode- material and § iron-stained country-rock on the south ^side of the river that a good deal of work is necessary in - order to ascertain the boundaries and actual average JoM the ore-bodies. The old estimates and the present Com- monwealth estimates have, m the absence- of this work, merely a partial and tentative value. But the apparent Lsesdn this area cannot be excluded from ^-^era- tion of the Blythe River lode as a whole. The develop ment of high-grade hematite ore on Rutherford s P r °P® r *y further south shows that the ore-belt is not restricted to the north side of the river, but continues a considerable distance beyond the limits of the Company s leases. The tunnels which have been driven intoddie lode on the north side of the river are three m number, viz. lhe old Central tunnel at between 500 and 600 feet from the river and 280 feet above the level of the water (aneroid measurement) ; Mr. Darby’s lower tunnel at the river; and his upper tunnel below one of the northern outcrops. The central tunnel, as was pointed out by the writer in a levies report, was driven in a badly-chosen spot^ m a poor-looking part of the line between two large crags of ore which project from the surface on this side of the hi . Tt 6 isa crosscut tunnel through the ore-bed which is here c 4 L t ““ The tunnel £ only 50 feet below the out- wViicb had nothing to recommend it, consisting of cr< ?P’ , . ■ i The ore cut was of inferior grade, the t impre°smiTleft on the writer’s mind being that perhaps 10 p^ S might be good ore, the rest being earthy and iUceous The best ore assayed 56'7 per cent, iron and IsTper cent, silica. Going southwards from here the out- 56 crop increases in width, till at a point about 400 feet above the river it is about 80 feet wide. The lower tunnel was driven opposite to the old bridge which used to cross the river at that spot, and was put into the hill 225 feet on the western or footwall side of the lode, which latter has been tapped by seven crosscuts. The lode underlies to the south-east, passing beneath about 40 feet of soft slate country, which is succeeded by a jaspery ridge, and 80 feet of siliceous and brecciated iron ore, most of which is earthy and stony, though some of it looks of fair quality. This may be taken to be the eastern parallel lode. Outside the entrance on the writer's previous visit was an old pile of ore broken from the outcrop, consisting . of solid hematite free from visible silica. There were also piles of good ore from the crosscuts, especially from the 77-feet crosscut. The first crosscut has been driven at 30 feet from the tunnel-mouth for a distance of 12 feet, the last six of which were in dense ore without visible silica. The second crosscut, at 45 feet, was driven east 6 feet to the ore, and then stopped. The third crosscut, at 66 feet, was driven 6 feet in ore of a jaspery and stony nature, the assay showing 46 per cent, iron and 34*2 per cent, silica. The fourth crosscut, at 77 feet, was driven 17 feet in hard solid ore, assaying 65 per cent, iron and 7 per cent, silica. The fifth crosscut, at 142 feet, cut into ore for 6 feet, assaying 67*2 per cent, iron and 3*8 per cent, silica. The sixth crosscut, at 167 feet, was 25 feet in ore. Some good ore can be got from this crosscut, assaying 68*1 per cent, iron and 2*4 per cent., silica, but patchy. On the whole, the material is -impure and lumpy, and in the face cherty with a hackly fracture. At 189 feet the ore was merely cut into for a foot, and appeared good and solid. At 199 feet good-looking ore was just exposed by a cut into the wall of level (assay 65*5 per cent, iron and 2 per cent, silica). Siliceous material showed on the western wall. The seventh crosscut, at 225 feet, was driven in ore 13 feet. Some of this was good, assaying 68*7 per cent, iron and 1*6 per cent, silica, but most of it was lumpy and suspiciously hackly with a short fracture. Some of the 57 lode-matter is rather fine, and would have to be cautiously mi R tiUbe n^iced re that in no instance has - crosscut W driven right through the lode; the latter has sometimes been tapped for a few feet only, or even merely exposed bv a cut The object appears to have been to obtain assurance that the lode was descending from surface “ strength Some good payable ore has been disclosed, bu assoefated with siliceous material. The assays of samples taken bv the Commonwealth experts across the lode at entrance to the tunnel yielded 54 per cent, iron and 31 per cent, silica. Such results are possible from a given section of the lode if in a cherty zone. The upper tunnel is situate m the northern part of the lode about 600 feet vertically above the lower one . cut the lode at about 80 feet below the outcrop, and has traversed the ore-body for 84 feet without passing through it A few yards more driving would probably have taken ft' through lode. The ore is solid, and has he appear- ance of being good, though the writer s samples did not yield the best results, giving 59'8 per cent, iron and W4 per cent, silica. Soft siliceous and earthy P atc ^ es and one of these has been entered at the end of tunn . This tunnel also shows that the surface outcrop is noi t an encrusting Capping, but that the lode defend, wi h The enclosing strata. The trenches north of the tunnel snow dense ore associated with silica. The Commonwealth exoerts formed the opinion that the ore m this tunnel very cherty and siliceous throughout, though they ' say some of the ore looked fairlv good, and some nice clean ore is showing in one or two places on the surface immediately over the tunnel. The results, they say, go a long w y towards proving the irregularity and non-continuitv of the better grade of ore exposed on the surface. Their C0 ™P ® - sampling showed 54-3 per cent iron and ?5.per.P^^ A small quarry in the northern part of O Keefe s b acres shows some very good-looking hard hematite, from which the writer got samples assaying as “och as 68 4 per cent, iron, with only 2'2 per cent, silica. The thousand tons of ore which were sent away by the company aresaid to have been broken from this quarry. As usual there is . some mottled siliceous ore with the higher-grade hematite, and- the samples taken by the Commonwealth - experts averaged 56’4 per cent, iron and 19-11 per cent, silica If the fine outcrops fire worth anything, as an indication, they encourage the hope that actual work will show that 58 all along the line adequate quantities of payable ore will be found available for many years to come. It is true that the trench work and close sampling carried out by the visit- ing experts in certain parts of the lode seem to justify the opinion that the average silica contents are unduly high, so far as v those samples and trenches are concerned, but the real question is what proportions obtain in the lode as a whole. This must remain a matter of opinion until the lode is thoroughly tested and opened up in the course of work- ing. It will then be possible also to determine how far it is practicable to reject excessively siliceous and waste stuff without going to too great expense. Mr. Darby’s opinion was that there may be half a ton of refuse in 1 ton of ore, or equal bulk of each. Mr. Darby gives the results of analysis of an average sur- face-sample taken from the whole deposit, and these may be placed by the side of an analysis given by the Common- wealth experts of a composite sample from proportional parts of 23 samples of fairly-good ore from different parts of the lode, as follow : — Mr. Darbv. Commonwealth Bxperts. Per Cent. Per Cent. el: on] = W. f 1? j = Silica .'. 7*312 7 76 Alumina ...... 1*750 ; : , 0*620 Lime 0*068 0*165 Magnesia...... 0*071 Trace " Sulphur tri- - >• oxide 0*060 = sulphur 0*024% 0*135 = sulphur 0*054°/ Phosphorus pentoxide 0*083 ='% phosphorus 0*036% 0*11 9 = phosphorus 0*052% Titanic acid 0*03 N1 Copper.. Trace Trace Arsenic ...... Trace ; Manganese... Trace 0*078 manganous oxide Chromium ... Absent Nil Combined water % 0*324 0*54 Moisture 0 160 0*13 These analyses of the good ore at the Blythe do not differ essentially from each other. The crucial question after all is one of tonnage. The writer, on his recent visit, took samples of good hematite exposed at and near the quarry on O’Keefe’s section in the northern part of the lode, and from the southern end of the outcrop. These were assayed by Mr. 59 W. D. Reid, Government Assayer, with the following results : — Iron Silica... Sulphur Phosphorus. Moisture at 1109*0. Northern South of River Bank, Samples. River. South Side. Per Cent. Per Cent . Per Cent. 66'10 69-00 64-36 5*20 1-20 6-20 0'063 . 0-057 0-07 0-002 0'02 0-002 0-12 0-14 0-08 Some of the more siliceous ore on the south side of the river was taken for assay, and yielded the following result : — Per Cent. Iron ... ... 44' 63 Silica ...... 32*80 Sulphur 0'04 Phosphorus O'OOl Moisture at 110° C. 0’16 Such stone is too impure for treatment in the furnace From various reports it can be gathered that some of the ore is of excellent quality. Mr. J. R. M. Robertson, of Sydney, reported in 1891 to Messrs. Henry Law and Co. : — I know of no deposit of iron ore so pure, and con- sequently so admirably fitted for producing the high- est and best brands of iron and steel.” The “ Australian Mining Standard ” of July 20, 1891, contains an account of experiments made at Halliday s Engine Works, 20 Erskine-street, Sydney, with a 4-cwt. sample of Blythe River ore : “ Mr. Brazenhall informs us that he charged an ordinary foundry furnace with .3 cwt. of the Tas- manian iron ore and about 14 lb. of limestone, and ran the iron smelted into pigs. He afterwards made cast- ings of various descriptions from the pigs thus pro- duced, and had a cast mandrill put into the lathe to show that the iron was not too hard for machining. The iron proved of the very highest quality, of exceed- ingly fine and close grain, and very tough. In addi- tion to the cast-iron, a small quantity of puddle bar- iron was secured, owing to the furnace not being - entirely adapted for producing, cast-iron, and wrought- iron has been worked up with the most satisfactory results.” 60 Mr. A. Montgomery, M.A., Government Geologist for Tasmania, in 1894 reported in that year as follows: — “ As -it was quite impossible for me in the unde- veloped state of the mine to obtain a sample of the ore which would at all fairly represent its average bulk value, and as such a sample would indeed be of no particular use, inasmuch as in actual working a lot of lean ore would be necessarily rejected, I only took^ a few samples of the best-looking boulders in the river for analysis. They may be looked 1 upon as fairly representing the best ore, but from inspection I should judge that many thousands of tons of equally good stuff could be readily obtained. What the average yield of such first-class ore from the bulk of the deposit would be is, as already remarked, only to be ascer- tained after it has been opened out by trenches and cuttings. “ The samples taken were forwarded to Mr. W. F. Ward, Government Analyst, in Hobart, with instruc- tions to have 1 them carefully examined for all impuri- ties likely to interfere with the quality of the iron to be made from the ore. He reports the analysis as fol- lows : — Per Cent. Iron peroxide 95 ‘2% = iron 66 ‘4% Silica ... ... ... ... .. 4-8% Phosphoric acid . Traces This ore is of excellent quality, being- practically free from all impurities with the exception of the silica. It resembles the well-known Cumberland red hematite, so long used for the production of steel by the Bessemer process.” Mr. Montgomery goes on to say that, according to these analyses, the Blythe Biver hematite is one of the finest and purest in the world. The estimates of quantity which have been made by various observers at different times must be regarded as subject to the limitations which inevitably attach to the consideration of imperfectly tested properties. They are as follow : — 1894:, Mr. A. Montgomery, 30,000,000 tons gross. 1900, Mr. J. H. Darby, 24,500,000 tons net. 1901, Mr. W. H. Twelvetrees, from 17,000,000 to 23,000,000 tons net. 61 1919, Messrs. Boyd, Gibson, & Young, 9,000.000 tops, the bulk of which is regarded as being - too siliceous for an iron ore at the present, day. The following will indicate the bases adopted for these estimates : — Mr. Montgomery says: — “ The deposit must be one of the largest also, containing many millions of tons. The data for cal- culating its size are very insufficient, but taking them such as they are, a rough calculation may be made which will serve to give some idea of it. On the south side of the river, the ore is seen for a horizontal dis- tance of about 8J chains, and rises to a height of 280 feet above the stream; on the north side it rises to % . 500 feet above the river in about 50 chains horizontal distance, and then falls a little, say to 400 feet for another 16 chains. Taking the width of the ore-body at 66 yards, these measurements give the cubic con- tents of the deposit under the visible outcrop. the level of the Blythe River as slightly over 10,000,000 cubic yards r or, at 3 tons to the cubic yard, 30,000,000 tons. It is not to be supposed that the ore terminates where the outcrop disappears under the superficial basalt, or that it only goes down to the level of the Blythe Biver. ( 9 ) A good deal of the bush has been cleared away since the above report,, and the width of the lode has been ascer- tained to be less than was surmised. Mr. Darby reported that as he only saw the crosscut of the deposit made by the Blythe Biver and the solid ore blasted out in a few places, he was unable to state how many million to^is are actually to be obtained but could sav that after thoroughly examining the surface, there are overwhelming indications at many points m over a mile of country of an immense deposit of hematite. He proceeds : — - “ In estimating the probable quantity of ore, I have taken the river bed as the bottom, although it is nearly certain to extend down much further, and have meas- ured the width of the deposit where The sides ere well defined . T h e' - cubical co ntent of the deposit, which ( 9 ) Report of the Secretary for Mines, 1893-4 (p. xxu.). 62 I have thought it advisable to divide by two, at 3 tons per cubic yard, yields 24,500,000 tons of selected ore/’ The estimate of 17,000,000 tons marketable ore made by the writer was based on a horizontal lode length of 90 chains, and average widths and height above river level for separate sections, deducting 50 per cent, for waste rock. Taking the lode length as a mile, and the width as 100 feet, nearly the same result is obtained. These three estimates, it will be observed, are rough and tentative, and assume the existence of concealed sec- tions of the ore-body, besides involving personal opinions as to the average nature and quality of the ore. The estimate of Messrs. Boyd, Gibson, and Young, however, belongs to a different category, being confined to segments of the lode, on which some prospecting, however imper- fect, has been carried out, and making some pretension to the valuation of definite blocks of ore. Being a buyers’ valuation, all portions of the lode which cannot be demon- strated to contain sufficient usable ore are cut out, and, of course, potentialities and so on are not admissible. These necessary limitations, while meeting the requirements of an intending purchaser preclude the consideration of the general prospects and possibilities of the lode from the standpoint- of its eventual contribution to the iron resources of the State. The additional trenches and excavations made under the direction of the Common- wealth experts have, as far as they have gone, given results not altogether reassuring; that is to say, they have shown the existence of more siliceous ore than was expected, and they indicate the necessity for the lessees to exercise care in deciding where they will open out in starting production. The company’s advising engineers will, no doubt, in the first instance, lay out a well-con- sidered prospecting scheme, and then locate the sites for their quarries. It is possible that a quarter of the whole tonnage exists to the south of the river, but very little is really known of the ore-bodies on that side of the Blythe, and they suffer untjer the disadvantage of being less access- ible than the northern part of the lode. The lessees will probably look ahead for 20 or 25 years, and, if aiming at a moderate metal production with the aid of the State hydro-electric current, say, perhaps, 100,000 tons annually, they will require to assure themselves of an ore-supply to the extent of 4,000,000 to 5,000,000 tons, or double that quantity if they desire to double the production. It is 63 regrettable that so many years have elapsed without open- ing up and practically establishing the value of the pro- perty. The possibility of reducing the average silica content by selection and blending will have to be investigated. The mere presence of siliceous ores does not invalidate the claims of an iron property to serious attention. Some of the Lake Superior ores, as shipped, contain as much as 34 to 40 per cent, silica, but the proportion is brought down by mixing with the purer grades to an average of under 10 per cent. ( l0 ).' The facilities for ore-raising are good. Points for open- cut workings, can be easily selected in the solid crags and outcrops of ore standing out on the hill-sides, and the ore sent down at no unusual expense to river-level for despatch to works. If the smelters are erected at the mouth of the Blythe, the old tramway route from the mine (some 6^ miles) can be used for laying down rails and connecting with the Government line at the coast. There would be a further transport of the finished product over a distance of 5 miles to Burnie, where interstate ves- sels can load with ease. ( ,0 ) The Gedogy of the Lake Superior Region,” by C. R. V. Hise and C. K. Leith. United States Monograph, Yol. LII., 1911 (p. 273). V. — RUTHERFORD IRON LODE. This is situated about 2 miles south-west of the most southerly exposure of the Blythe iron lode. It is on the northern half of 320 acres purchased land charted in the name of T. S. Rutherford, a block which as been recently subdivided. The northern subdivision comprises 158 acres, and it is in this part that the lode outcrops occur. Between here and the Blythe River lode are undulating farm lands, with the exception of two mineral leases of 60 and 47 acres respectively, which have been worked by the Price Copper Mining Company, No Liability, with indifferent results. The farm lands have the basaltic soil characteristic of much of the North-West Coast. The Rutherford main outcrop unquestionably marks the general continuation of the Blythe ore line. The south- ern outcrop of the latter disappears below the covering of basalt inside W. H. Atkinson’s 186 acres, and, on this interpretation, reappears in the central knob of ore in Rutherford’s 158 acres. The cutting on the Main-road has intersected a soft ferruginous formation about 10 feet wide, south of which is a knob of ground strewn with boulders of rather soft brown hematite. A shaft has been sunk 40 or 50 feet without getting anything very solid; there is a possibility that it was put down a little too far east to strike the lode exposed in the cutting. This cutting lode may not actu- ally be the continuation of the main Blythe lode, or, again, despite its dissimilarity, it may be the tail end of one of the Blythe lenses. Further south, on lower ground, are some boulders of hard hematite, indicating an outcrop, and still further south, in about the centre of the block, the lode rises to a hill some 60 feet above the creek-level. This part of the outcrop shows an excellent hard hematite, in appearance indistinguishable from that of the Blythe. The outcrop appears as if it might be slightly off the Blythe line of lode, but this may possibly be due to difference of level or to the development of the ore-bodies in the form of more or less discontinuous lenses. There is an old shaft near the top of the outcrop on this knob, but the bottom of it is not now accessible. Reports are to the effect that this shaft was not very satisfactory^; it seems to have been sunk in Somewhat soft ground, which may have been outside 65 the edge of one of the ore lenses. It would be desirable to prospect the whole line of country with a view of estab- lishing the nature and extent of the ore-body. The hill at the base is 9 or 10 chains across, but in the absence of work it is impossible to state the true width of the lode. At present the width of the boulder-strewn surface is the only criterion, and may lead to erroneous conclusions. Some crystallised and micaceous hematite of excellent quality occurs on this line a few chains furthef south, and stones of iron ore are met with in the soil right up to the south boundary of the 158 acres. The lode-line, therefore, shows signs of traversing the block for over -J-mile, and in addition there is the doubt- ful section of the lode near the road. As the solid out- crops are marked by hard knobs of ore only at intervals, it may well be that the lode is of unequal value at diff erent points, especially if the general occurrence is lenticular. Typical specimens of good ore were broken from different parts of the lode, and these have been assayed by the Government Assayer in the Geological Survey laboratory with the following results : — No. 1. ‘No. 2. Typical Ore. Micaceous Ore. Per Cent. Per Cent. Iron 68-94 67-06 Silica ... ... P53 2-16 Sulphur o-oi 0-03 Phosphorus 0*05 0-06 A sample taken in 1903, and assayed by Mr. W. F. Ward, Government Analyst, gave the following results: — Per Cent Iron ... ... 58'00 Silica ... 2:40 Sulphur Traces Phosphorus 0*05 From the assays it will be seen that the ore has a high metallic value, and is specially low in silica and sulphur. The phosphorus is not excessive for an ore of that grade. The pieces of Sample No. 1 were chipped off the solid outcrop on the central hill. In all probability it will be found that there exists a good solid mass of approximately this quality. Sample No. 2 comes from a little distance to the south, .and all one can say is that it looks as if the 66 lode were continuous between the two points. This is also a very good-quality ore. A systematic sampling, however, can be carried out only when the lode is cut into at regu- lar intervals. The above, nevertheless, a*e sufficient to indicate a deposit which contains ore of exceptional purity. The property is connected with the ooast by a good road, the distance being a little over 7 miles to Wivenhoe rail- way-station. If work is started at the Blythe, the best way of developing the Rutherford ore-body, if prospecting results are satisfactory, would probably be to mine the ore and deliver it to the Blythe furnaces. VI. -IRON ORE IN LONG PLAIN AND ZEEHAN DISTRICTS. (By A. McIntosh Reid.) ( 1 ) — Introduction . In the following pages an account is given of the results of an investigation into the origin, nature, and extent of the magnetic iron ore deposits of the Western Division. It has been deemed advisable to present this account in two parts. One paper deals with the ore-bodies of the Long Plain district^ the other with those in the vicinity of Mt. Heemskirk, in the district of Zeehan. Only the easily accessible of the commercially important deposits were examined, and of these the largest only in detail. Several examinations of the ores of these fields have already been made by the Geological Survey. The early investigations of these occurrences were in relation to the associated silver and gold bearing copper, lead, and zinc ores, and not as to their value as sources of iron; but in later reports consideration was given to the economic fea- tures of the iron-bearing portions of the deposits. The last official examination of the Rio Tinto and Rocky River ore-bodies, in the Long Plain district, was made by W. H. Twelvetrees in 1903; and G. A. Waller, in 1902, investigated the large magnetite ore-bodies on the Tenth Legion property, and also the magnetic iron outcrops on Davern’s leases, both of which lie in the western part of the Zeehan district. Long Plain district is in the County of Russell, between Waratah and the sea-coast; Zeehan district lies in the County of Montagu, 25 miles southward from Long Plain. (2) — Long Plain Iron-ore Field. The deposits of magnetite described in these pages, as well as many others smaller in extent occurring in this locality, have been known for many years. They were originally discovered by Surveyor-General Sprent on one of his early expeditions through the western districts. It was considered at the time that the huge outcrops were cappings of tinstone deposits, and when this anticipation was not realised, the prospects were abandoned. How- 68 ever, several years later prospecting was resumed on the associated pyritic ore-bodies, which were found to con- tain chalcopyrite, gold, and silver. Subsequent^ large exploratory works were undertaken by wealthy mining companies at 'Rio Tinto, Rocky River, and at intermediate points • but in no occurrence were the metals sought alter sufficiently concentrated to be of economic value. These immense magnetic deposits have been repeatedly noted by the Geological Survey, but their possibilities as sources of iron have not been fully realised until recent time. this investigation has shown that the extent of high-grade mag- netic iron is much larger, both in the Rio Tinto and Rocky River areas, than anyone had reason to anticipate. The Rio Tinto portion of the iron field lies 25 ; miles by road south-westward from Waratah, and 20 miles from the port of Corinna, on the Pieman River. A fairly well- graded road has been constructed from Waratah over the Magnet Range to the edge of Long Plain, whence it is connected with the terminus of the road leading from Corinna by a 10-mile track. . The iron, ore occurs in disconnected masses contained . in a belt of metamorphosed gabbro- amphibolite, i-mile wide by 25 miles long, running 8 degrees west of north and south of east. They lie for the most part on the eastern side of Savage River, but cross the valley at Rio Tinto, and extend northward to Specimen Reef goldfield. Southward they continue on the western confines of Long Plain, cross the Whyte and Rocky Rivers near their confluence, and extend beyond Paradise River. The surface of this area is a tableland (Long Plain), 1100 to 1200 feet above sea- level, which is portion of an old Tertiary erosion channel. Much of the surface is gently undulating, with shallow serrated stream valleys, but in the vicinity of Savage River the effects of erosion are more pronounced. A. PETROLOGY. Although the rocks which contain the magnetite deposits of the Long Plain and Zeehan districts differ m composi- tion and in structure, as well as in age, yet in many respects they are remarkably similar. The former are described as hornblendic, serpentinous, quartzose, and tal- cose schists belonging to the Pre-Cambrian, while the lat- ter are gabbro-amphiboUtes of Devonian age. Generally the metamorphosis of the Pre-Cambrian schists of Long 69 Plain has been intense; but in certain parts the horn- blendic rodk occurs devoid of banding, foliation, or schist- osity, having the macroscopic appearance of gabbro- amphibolite. These formations were examined by y W. H. * Twelvetrees, Government Geologist, who makes the follow- ing comments:- — (- 11 ) feet in a south-easterly direction. -Ore is cut at 147 feet, and a few feet farther ahead is a band of chalcopyrite. From this point the tunnel passes through actinolite schist containing magnetite and pyrites. No. 2 lode lies east of No. 1, and has an outcrop of hematite and magnetite. A tunnel driven 386 feet along its course shows the lode 17 feet wide, composed of gossan, with native copper and cuprite and much siderite. Between these two pyritic ore-bodies, 12 chains north of the bridge, another lens (No-. 3) of clean magnetite is exposed on the ridge of the steep hill leading towards Speci- men Reef. The' surface outlines are obscured by clayey material. and vegetation, so that its size could not be ascer- tained. Ore-bodies Nos. 4 and 5, which follow, are the most extensive and richest of them all. No. 4 commences at f-mile north of the bridge in Section 4649-m, at an eleva- tion of 1000 feet above sea-level, and continues through Section 4648-m along the ridge of a steep hill in a general meridional course for 2000 feet. It is fully 100 feet wide, and consists of clean magnetite of an extremely dense tex- ture. No impurities of any kind could be detected by eye in this ore, and its quality is shown by analysis No. 17. No. 5 ore-body is of equal quality, and is perhaps even greater than its predecessor, from which it is separated by a band of schist 200 feet wide. It lies a little eastward of No. 4, following the ridge northward for 1500 feet and 76 southward into Savage River valley. The western fall of the hill to Hall’s Creek slopes at a very high angle, exposing a very long face of massive magnetite. In some cases the ore occurs in aggregates of almost perfect octahedra, m others rhombic dodecahedra are common A remarkable feature of this outcrop is the quantity of float ore strewn over the surface, in pieces about 4 inches m diameter, of extraordinary regularity. Sample No. 16 was taken from this ore-body. . „ , , Q n North of this outcrop basalt occupies the surface but dU chains farther on still another occurrence is found, this is a dome-shaped mass erf considerable extent, essentially similar in composition and nature to those already Several Other deposits are known in this locality, but they are not of any considerable extent, and were not examined. (c) Analyses. The composition of the ore may be gathered from the following analyses made by Mr. W. D. Reid, Government Kind of Ore 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Magnetite . . . Magnetite ... Magnetite ... Magnetite **... Magnetite Magnetite Hematite... Hematite-:.. Hematite Magnetite ' & pyrite Magnetite & Hematite... Magnetite^ Magnetite^ Magnetite Magnetite Hematite.. Magnetite 64 -00 1 ; 68 * 30 69*20 69*13 68*80 68*6S; 63*4 69*3J a* d dl °P ^ rocks containing the magnetite deposits, with slates anct Tartzites along the northern boundary and m the north- IsT quarter, ®The border of the granite outcrop is 3o Ch Tt tretdr— of a very large lenticular " magnetite, extending from a^ point 3 chains d ^ Kynance boundary, through Section 7925-m, to the bank of Pine Creek. It occupies the crest of a sharp ridge 250 feet high, trending north 60 degrees west. Near the centre of the section the lens contracts, and- below this point a tunnel has been driven southwards from _P 86 Creek, a distance of 312 feet, completely intersecting the ore-body at 120 feet below the outcrop. The tunnel passes through quartzites and slates for 182 feet, intersect- ing a narrow chlorite vein containing idiomorphic crystals of pynte at 132 feet, and entering magnetite-diopside rock at 185 feet. The magnetite-bearing rock gives place to massive diopside at 239 feet, and continues fox 36 feet, after which it passes through a second band of magnetite,’ 20 feet thick, finally entering diopside rock again. There is a gradual transition from ore to rock in this ore-body but only thin bands of clean ore occur. Associated with the magnetite are tremolite, serpentine, diopside, calcite actmolite epidote, chlorite, and a little vesuvianite and garnet. This ore-body could be easily explored by driving east and west from the crosscut. The length of this lens along the outcrop is 1400 feet and the actual width about 50 feet. The apparent width’ as determined by the talus material, is much greater. In some parts the ore is coarse-grained; in others, it is hard and dense, and remarkably pure. Very large octahedral and rhombic dodecahedral crystals of magnetite are developed m the massive ore-body. An idea of the quality of the ore may be gathered from the following analyses • — No. 1 Kind of Ore. ! Iron. j Phosphoric Acid. Sulphur. Titanium. Silica. 1 Magnetite °/ / o 60*18 % I race ! ~°/T~ 0*20 °7 Nil ° vO/ / o 2* 1*2 2 Magnetite 70*7 Trace 0*10 Nil 3 i Magnetite 69*6 Trace ' ! 0*47 No. 1 sample was taken from the tunnel below the oxidised zone; Nos. 2 and 3 are representative of the mas- sive ore at the outcrop. Phosphorus occurs only in traces sulphur m negligible quantity, and titanium is entirely absent. Tests for silica show a very low content. It is noteworthy that there is little or no increase of sulphur in the ore at depth. ‘ r It is impossible to arrive at a close estimate of the quan- tity of ore extractable by quarrying, for there are no reli- able data upon which a safe calculation can be based Under the circumstances, it has been decided to consider i recoverabIe from tbe ore-body to a depth of ? n qnn mvi f r’ t ' At thls d6ptl1 the quantity works out at 1,900,000 tons. 87 Eastward, in the Kynance property are several smaller ore-bodies; and westward, mst ovet Pine tteek anot^^ deposit projects above the level of the pla . y not important. ( 2 ) — Davern and Reynolds’ Section. This is a 10-acre section situate 15 chains north-west from the Tenth Legion. It encloses a large dome-shaped mass of magnetite-hematite ore etandmg nut 6C fee ^ above the level of the button-grass plain. The hill, 850 feet long and 250 feet wide, is coiriposed wholly of hard, dense o e of remarkable purity. The quantity of ore recoverable above drainage level is 160,000 tons. A branch from the Zeehan-Comstock tramway extension ^could be constructed very cheaply and on easy grades right up to the base of the hill. Thus the ore could be loaded direct and shipped without preliminary treatment. A grab sample o pieces of ore taken indiscriminately from the outcrop con- tained: ~ Percent. Iron 66-72 Alumina 1 61 Phosphoric acid Irace Sulphur 0 49 Silica 2 57 (3) — Section 1812-m, 40 Acres. This is a vacant section lying |-mile south-eastward from the Tenth Legion Mine, and adjoining the Kynance Mine on the south This deposit appears to be of precisely the same type as those already described. It occurs under similar conditions, and follows the northern boundary of the gabbro dyke, trending a little south of east. Like = the others, it occupies a sharp narrow ridge, which extends westwards to the edge of the plain. This ore ,body is about 40 feet wide, and fully 1000 feet long^ ^ove the 150-feet contour it is computed there are 800,000 tons ot high -grade ore. /4A Davern’s Prospect (Sections 7611-m and 7296-m, both of 20 Acres). These properties are situated about a mile west of south of the Tenth Legion. The margin of the gabbro passes 88 through the south-eastern corner of the section, while that of the granite passes through the north-western. Between them the country consists of intensely indurated slates and nornstones. On the north side of a creek, which flows diagonally through the section from the north-west corner to the south-east, a large body of massive magnetite is exposed. The dimensions of this deposit have not been ascertained, owing partly to the heavy vegetable cover; but it outcrops prominently here and there for 1000 feet! and appears to be fully 40 feet wide. Float ore forms a deep talus over a far greater area. This ore-body can be easily exploited to a depth of 206 feet, at which level there exists 850,000 tons of fairly high-grade magnetite. On the south side of the creek a number of trenches and open-cuts have been put in on irregular masses of sphaferite (zinc-blende) and magnetite which occur in the gabbro marginal rock associated with chlorite, phlogopite, tre- molite, actmolite, &c. In some places the sphalerite is almost pure for several feet in width, and then it changes abruptly to magnetite without any distinct parting divid- ing the two; in others blebs occur sporadically distributed throughout the igneous rock. The facilities for the exploitation of the ore-bodies are excellent, and very little development is necessary to pre- pare the mine for continuous operation. E. GENERAL REMARKS. These mines possess decided advantages over those in ~ neighbouring districts, in that they are easily accessible and can be operated without any considerable outlay on developmental works. By means of a short branch from the Comstock Tramway, rail connection with the seaport of Strahan, 35 miles distant, can be obtained. The route of the proposed extension of the Zeehan-Comstock Tramway to South Heemskirk district passes within a mile of these mines, all of which could be linked with the main tramway by means of short spur lines. A trial survey was made three years ago by the writer for the purpose of ascertain- ing the most economical and advantageous route to the South Heemskirk tinfields. Leaving the Zeehan-Comstock Tramway at the Summit, 2J miles from Zeehan, this route follows the Colonel North line for a half-mile, from which point it deviates south-westerly, passing by the Tasmania Mine, thence north-westerly along the old tramway towards the T.L.E. property, thenoe south-westerly parallel to 89 Trial Harbour-road to the foot of the steep incline, whence it crosses the road and passes below the iron mines on t e south side of Heemskirk Range. i_: s The aggregate tonnage of magnetite, figured on the oasis of actual ore in sight and available by quarrying methods of extraction, is probably far too small rather than o lar»e Exploration has not yet demonstrated The size and the nature of the deposits at depth, but it rs considered that their vertical extension is beyond that at which econo- mical mining can be earned on. The outstanding featur of the ore-deposits is the almost entire absence of de - terious impurities in the ores. Occurring m basic igneous rocks, the percentage of silica is naturally low; phosphorus and sulphur also are present in only insignificant amounts, traces only of chromium and titanium occur ; and copper is entirely absent. So far as exploration has y et S°“®’ there seems to be ho evidence of increased sulphur at depth. These deposits are conveniently situated to supply tiie immediate demand for high-grade iron ore, and they are of sufficient magnitude to meet all the requirements of the market for many years. The ore can be produced at a minimum cost without the necessity for heavy initial expenditure in the preparation of the deposits for exploita- tion Thus* all the essentials are here for the economical pro- duction of high-grade iron ore on a large scale. VII.— THE IRON LODE ON THE NELSON RIVER; Mr. L. Keith Ward, B.A., in Geological Survey Bulletin No. 10, on “ The Mount Balfour Mining Field ” (1911), describes a massive iron lode some 6 miles north-east of Whale s Head, Boat Harbour, on a group of sections situate on the Nelson River. The mineral sections, from north to south are 2760-m, 40 acres; 292-3-m, 40 acres; 2942-m, 35 acres; and 273 1-m, 40 acres. Mr. Ward states that, in the central portion of 2923-m the outcrop is over 100 feet in width, and consists of gossanous material containing much hematite. The hematite becomes rapidly the most abundant constituent as the lode is followed southwards along its course. The out- crop may be traced through Section 2942-m without inter- ruption. Mr. Ward says it is here massive, and consists of hematite mixed with crystalline magnetite and a small amount of quartz, for many chains maintaining a high degree of purity. He concludes by remarking that as an ore of iron this lode merits systematic prospecting ; trenches could be cut across^ at regularly-spaced intervals, in such a manner that wgfth could be accurately ascertained at a number of jjintsggand an opportunity exists for a tunnel across the l^e>from the Nelson River gorge. Outcrop is said to be 300 feet above sea-level, and Engineering difficulties of any magnitude would prevent ge^pre from being carried by rail to Whale’s Head Boat Igarbcmr. Plate IX NELSON RIVER IRON FIELD > viii. MISCELLANEOUS deposits. Numerous occurrences of iron ore, but none of them of great importance at present, have been recorded from various^ other parts of the island . v. , , n Deposits of brown iron ore exist in the swampy button- grassland in the Florentine Valley. The large deposit marked on the Buckingham charts as Iron Blow on Frodsham’s track, 2 miles east of The Florentine River is an impure yellow hydrated oxide of iron, mixed with quartz and'quartzite wash! with a N.W.-S.E course, and a width of several chains. It has been trenched upon in ferru- vinous swamp clay and drift to a depth of from feet At the bottom of the deepest excavation the material is very clayey and. contains stones of quartz and kaolin. Boulders of the ore are strewn over dhe soil. (1) Mt. Mueller or High Rocky. On the plain crossed by the Gordon River track smith- west of Mt Mueller and half a mile, from one of the st which form the headwaters of the Styx River boulde of brown iron ore are profusely scattered °yer th f SUr £_^' About 150 feet north of the track the Great Western Rail- way Company opened a trench 40 feet long, 2 to 5 feet wide, and 6 feet deep, exposing _ concretionary limomtein yellow sand. The ore cut into is impure, and the bed is irregularly arched and has in it both vertical and horizontal partings * The trench is in soft sandy material, but boulders of hard limonite lie on the surface. South-west of the track is a knoll of limonite boulders, some of which enclose patches of soft sandstone or even sand Below the knoll to the west are large boulders of conglomerate and white sandstone similar in character to the patches in the ore. These sandstone boulders are wal ter- worn into fantastic shapes, with pot-holes. The sand the ore must have been derived from the strata from whic the boulders were dislodged, and was pobably deposited in a lake, the water of which drained into the valley of the Upper Weld, which lies here in a panorama below the tr Lower down the hill to the west boulders of : iron ore continue to occur in the soil and for half a mite further west where, in the myrtle and horizontal forest, the Great Western Railway Company trenched and drove an abortive adit for about a chain to test the formation underground. The adit is driven in from the track in a south-easterly direction across ferruginous chocolate-coloured greasy clay slate, dipping about 45 degrees south-easterly. At 10 feet behind the end soft white clayey slate was passed through, and white indurated sandstone forms the face. No iron ore appears to have been met with. Some loose specimens of limonite on the track show veins of quartz 'traversing them, and may possibly belong to the Silurian conglomerate beds, but the iron blows generally m this part of the country are, as far as the writer is able to judge, deposits of bog ore, and too impure to be used for the production of iron. (2) — Lewisham. A development of ‘impure iron ore occurs here, but the quantity is unimportant, and ^though samples may be col- lected with an assay value of 50 per cent, and upwards, the bulk is too low in iron to be of use. (3) — West Coast Range. Hematite ore-bodies exist at various points on the West Coast Range, but are apt to be contaminated with iron and copper pyrites, and have at present hardly any value as sources of iron. IX.— ELECTRIC SMELTING. European and American reports suggest' that electric processes for smelting iron ore and producing pig- are not universally applicable in a commercial sense, but that they may be adopted with advantage where^ the conditions are favourable, that is to say, where cheap hydro-electric power is available and coke economy is desirable. . ™ , • Mr T Bibby in a paper on Iron and Steel Biectr Fu^ci,” rS in. JanLry this year before the Man- chester Association of Engineers, says: ■‘On the average, the blast furnace consumes one ton of coke per ton of pig iron produced. The eiectric furnace consumes one-third of a ton of coke, and requires one-third horsepower year per ton ot pig produced For the cost of the two systems to balance, we must be able to supply one horsepower per year at the cost of two tons of coke.” Judging by this, the conditions in Tasmania would appear to be eminently favourable for the new process The history of attempts at electric smelting does not go further back than twenty years. The first experiments were in Italy in 1898-1901, with the Stassano furnace Then during 1901-5 tests were carried out in the Keller furnace in France; and in- 1904-6, with the Heroult fur- nace at. Saul te Sainte Marie in Canada This furnace was also in operation at Heroult m California from 1907 onwards. In 1907 came the experiments of the Electro- Metal Company of Domnarfvet in Sweden, followed by trials in Norway, and commercial operations m Sweden m The following references will illustrate the gradual pro- gress made since these dates in the electric smelting of iron ores : — r . Rodenhauser, in his work on “ Electric Furnaces m the Iron and Steel Industry ” in 1912 quotes (p. 372) Craw- ford, of the Noble Electric Steel Company, of Heroult, California, as follows: — “ While it is hardly agreed with the prophecies made by some that electric furnaces for producing pig iron will eventually be competitors of blast furnaces, even in the regions where economic: conditions make the latter possible, Crawford feels that where electric 94 power can be obtained cheaply, and where coke and freight rates are high, and for making superior grades of iron, electric furnaces will enable many large bodies of iron ore to be worked which would otherwise remain idle, and, that the electric iron furnace, both of the shaft type and of the long and narrow type, each in the field best adapted for it, will make steady pro- gress/ } In the “ Mineral Industry for 1913,” Mr. Stoughton (p. 429), while noting that the commercial manufacture of ferro-alloys in the electric furnace continues to increase, admits that the smelting of iron ore to produce pig iron has not yet justified the early expectations of its advocates. In the “ Mineral Industry for 1914/’ Mr. James Aston succeeds Mr. Stoughton as author of the iron and steel articles of that work, and gives some hint of the reasons for the very slight advance made in electric iron smelting. He says (p. 438) : - — _ “For the production of pig iron from the ore the electric furnace has proved rather disappointing during the past year. Development proceeded to the point where with charcoal available as a reducing agent, and electrical energy at reasonable cost, pig iron could be produced at profit in competition with existing sup- plies. However, developments of any magnitude, or out- side of zones of special local conditions, pointed to the necessity of large furnaces, and especially of a type adapted to the use of coke as a reducing agent/’ The dependence of successful electric smelting on the price of coal or coke and freight charges is emphasised by J. B. C. Kershaw in his “ Electro- thermal Methods of Iron and Steel Production ” (1913, p. 42) : — Though the electric iron smelting processes may therefore make headway in those localities where all the conditions favour their development, and where the price of pig-iron is artificially increased by freight charges, they are unlikely to undergo extension or development in other lands or localities so long as cheap supplies of coal and coke are available for the ordinary blast furnace, process of manufacture.” The general position of electric smelting in Scandinavia in 1914 has been described by Dr. A. Stansfield in his bul- letin entitled “ Electro- thermic Smelting of Iron Ore in 95 Sweden ” (1915), published by the Department of Mines, Canada. From his remarks it appears that at that time most of the iron ore in Sweden was smelted m small blast furnaces with charcoal fuel. The excellent quality of the iron produced has resulted in high prices being obtained, and consequently in the development of a profiteble indii^ try. The Electro-Metals furnace was well established in Sweden, and was replacing the charcoal blast furnace. The 4000 -horsepower furnace at Domnarfvet was putting ou about 30 tons iron daily, using charcoal fuel; attempts to employ coke were, up to that date, not very successful. He proceeds to remark : — “ The smallness of the-scale on which these furnaces ' " operate may not be harmful in the charcoal-iron indus- try, because quality rather than quantity is aimed a , and because charcoal furnaces must always be ot moderate dimensions. Such furnaces, however can- not compete commercially with a modern coke blast- furnace of 400 or 500 tons daily output It must also be remembered that attempts to use coke instead of charcoal in the Electro-Metal furnace have so far been unsuccessful, though it is expected that the difficulties encountered may be overcome by building the fur- nace shaft somewhat wider and lower. This change is needed, because coke is far less bulky than charcoal, and the charge is therefore less open and obstructs the passage of the gases up the shaft ” (p. 7). Dr Stansfield describes the small Tinfos furnace operating in Norway as one of the few types m which the use of coke was possible. A gas coke was imported from England, containing T2 per cent, sulphur, but the furnace capacity is small, the output of pig being only 10 tons This author, in reporting oft the outlook with regard to electric smelting in Canada (p.-8), comes to the conclusion that there is no evidence to show that it can be undertaken on a large scale in competition with existing blast-furnace industry. The reasons for this are stated as (1) the high cost of production, (2) the difficulties connected with the use of coke as a fuel in the Swedish furnaces, and (3) the small size and output of these furnaces. He adds that much of the Swedish metal is used to produce special qualities of steel and wrought iron, and that the possibility of develop- ing a high-grade charcoal iron industry would have to be investigated before beginning in Canada a large production of a rather expensive product. 96 The statements reproduced above with reference to elec- tric iron reduction furnaces represent the outlook up to 1915. Since then experiments have continued to be made, and the electric process has been substantially improved. It is perhaps still true to say that unless coke is costly and power cheap, the electric furnace will not compete with the blast furnace, but when the reverse is the case, it conies into its own. One great advance which appears to have been made in the interval is the adaptation of the furnace to the use of coke. The Electro-Metals furnace no longer suffers the disadvantage of being restricted to the use of charcoal fuel, but some more precise information on this point is still desirable. Coke would be the best material to use in the electric furnace if it were not for the impurities which it contains, but that charcoal suffers from crushing more readily than coke, and that the size of charcoal blast furnaces in Sweden is limited by this drawback. One of the important improve- ments which have been introduced in this furnace is the possibility of securing a very uniform development of heat across the whole section of the furnace by transformer arrangements , making it practicable to increase the maxi- mum size of the units which can be built with commercial success. This type of furnace is making headway in Sweden, and is also being installed in Italy and Japan. It seems’ therefore', that a standard type is now being evolved, in which the shaft and charging arrangements are not very different in character from those of the ordinary blast- furnace. There is a wide hearth or crucible, as it is called, into which the iron in a spongy condition descends together with the flux, fuel, and gangue. Powdered ores are apt to clog, and the furnace works best With crushed ore 1 inch to 2- inches in diameter. Electrodes of amorphous carbon enter the crucible through ijs roof and are embedded in the charge. In the large furnaces a three-phase current is supplied from three transformers, and each transformer is connected to two opposite electrodes. The resistance of the charge to the electric current which passes between the pairs of electrodes creates the heat. The consumption of electrodes is met. in a simple way bv dropping them a little further into the charge at intervals of a few days; it has been found that from 1 six to nine kilos per ton of pig are consumed gross. The role of the current is strictly to pro- vide the heat which brings the charge to the temperature necessary for reduction and- melting. Thus this process permits the coke consumption to be decreased to the quan- 97 tity requisite for reduction, namely, one^third of a ton per ton of pig produced, in lieu of one ton as already men- tioned. Thus at the outset two-thirds of the sulphur and other impurities in the fuel are excluded from the furnace charge. It may be added here that the higher temperature obtainable in the electric furnace admits of a more basic slag, which facilitates the elimination of sulphur from the iron, a circumstance of high value in connection with steel- making. Electric pig iron, whether made with coke or charcoal, is consequently superior m quality to blast fur- nace pig. . The above remarks refer to furnaces for producing iron from iron ore, and not to electric steel furnaces for making steel from pig or scrap or for refining steel. The latter are in widespread use, and are being continuously improved and otherwise developed. The possibility of producing pig steel direct from iron ore in the modern electric furnace seems to have been established, and if there is a demand for steel the question of adopting this process instead of converting the pig iron to steel in a second furnace would have to be considered. Sir John McCall, the late Agent-General for Tasmania in London, went into the question of making steel direct from Tasmanian ores, using coke as fuel. He suggested restriction of manufacture to some special class of article, such as wire-fencing steel, &c. One gathers that the capital expenditure for plant would be £200,000. This is on the assumption that work will be initiated on a fairly large scale. A bulletin on the . commercial feasibility of the electric smelting of iron ores' in British Columbia, by Dr. A. Stans- field, has been issued this year by the Department of Mines in that province, and is replete with valuable information on the whole question of electric smelting. The author reports that this process has passed the experimental stage, and that the furnace adopted in Sweden and elsewhere as the standard commercial type is that of the Electro-Metals Limited. In Sweden the normal product is a white or low-silicon iron, though the company consider that a foundry iron can be made, at a somewhat higher cost. Moreover, Dr. Stansfield is of opinion that this type of furnace can be used, as the white iron can be made suitable for the foundry by adding ferro -silicon. He remarks that coke and charcoal can be used as fuel if desired, mixed in certain proportions. Attention is drawn to the circum- stance that commercial electric furnaces happen to have run nearly entirely on magnetites (with a slight admixture of hematite to facilitate smelting), but it is thought likely that hematite ores will be found to smelt more readily. The author’s final conclusion is that with the present methods of electric smelting the industry in British Colum- bia may be expected to prove successful commercially, but that it will depend ultimately on the production of special qualities of iron and steel, and will be unable to compete with the blast furnace in the production of ordinary grades of pig iron. ( 14 ) ( u ) “ The Commercial Feasibility of the Elective Smelting of Iron Ores in British Columbia/’ by A. Stansfield Brit. Col. Dept, of MinesT^Bulletiu No. 8, 1919. X.— COST OF PLANT. This in Tasmania will vary considerably according to the locality in which works are erected, and will be further influenced by the scale on which the mmeowners propo* to work. All that is useful for the moment is to cast an eye over costs in other countries and States. ' A well-known American author says : — ( ) “ As a general thing a fumaoe is not built unless its projector can see a profit of V50 dollars as a m.ni- mum for a 500 tons furnace costs, with its site and all complete, about 1,000,000'dollars (£200,000) m nor- m/timi; its output is, say, 170,000 tons per _y* and T50 dollars per ton profit on this is 255,000 dollars (£51,000) per year, equal to 25^ P® r Capital can scarcely be raised for a smaller return than this in so variable a business. The following estimate may be quoted as giving s°™e idea of what a smaller blast furnace would cost. The Roval Commission on 'State. Iron and Steel Works in Queensland recommended last year that the Government proceed with the erection of a blast furnace having capacity of 150 tons of iron ore per day, to ? e ^ 6r wl * by product recovery, coke ovens, and mine equipment the initial cost not to exceed £150,000, and further ^ms to be expended if circumstances warrant an extension ot the W °Mr E C Saint-Smith, of the Geological Survey of Queensland, estimated also for this Commission that a smelting plant designed to handle only 100 tons of ore per day would not cost more than £100,000, including by-pro- ducts, coke ovens with a limited surplus coke production, and mine equipment. . . Thus, with £150,000 outlay, 60 per cent ore ° produce 27,000 tons of pig iron per annum working 300 days in the year; or, in the case of 50 per tons. With £100,000 outlay, the yield would be 18,000 and 15,000 tons respectively. Turning now to the cost of an electric smelting plant, some late 8 information is that received from the Electro- Metals Limited, kindly placed at the w riter 8 disp os al by (»)TTiTjohnsoii7^ Operation, and Products of the Blast Ftfrnaee,” 191 8 (p. 515 ). 100 Mr. J. H. Butters, General Manager of the Tasmanian Government hydro-electric enterprise. This is to the effect that the cost of a 4000 -horsepower furnace, capable of an output of over 12,000 tons pig iron per annum, would (excluding buildings) be about £25,000 f .o.b. London or other English port; but this is for the furnace only, and would be exclusive of crushing plant, coke ovens, store- houses, tramways, &c. Information from another source is to the effect that there are several single-unit furnaces working satisfactorily in Sweden, and the cost of the iron produced is not seriously greater than from the larger plant. Dr. Stansfield, in his 1919 bulletin, gives an estimate of the cost of a three-furnace plant producing 27,000 tons per annum at from £70,000 to £80,000, inclusive of land, wharf, tracks, and rolling stock. Half of this quantity would probably be for steel-making and the remainder for foundry iron. Dr. Stansfield states that the Swedish fur- naces do not seem to have been used regularly for the pro- duction of foundry iron, and that there is some doubt regarding their suitability for this purpose. They produce usually a white pig iron suitable for. chilled castings or for steel making. XI.— COST OF PRODUCTION. At the present stage this cannot be definitely stated, as all the factors stand in need of investigation, Basic figures as to the cost of producing the iron can only be arrived at after decisions have been made as to the site of smelting furnaces, means of transport from mine, whether blast fur- nace or electric smelting is to be adopted, whether charcoal or coke is to be used as fuel, and whence the supplies of fuel will be derived, what deposit of limestone will be utilised. The figures will vary, too, sightly with the locality of the ore which is to be mined. For such a universal article as pig iron the cost of pro- duction is practically standard. In present blast-furnace practice pig costs between <£4 and <£4 10s. per ton. Mr. E. C. Saint-Smith estimates that it could be produced in Queensland for £4 5s. At present this figure has the value of an estimate, and may possibly be exceeded a little in actual practice. The matter of most interest in this connection, so far as Tasmania is concerned, is what prospect electric smelting has of competing successfully with the blast-furnace method. The items of cost are comprised in four groups, viz. : : — Raw materials, electric current and consumption of elec- trodes, labour, and overhead charges. In a general estimate of the cost of the ore, fuel, and flux, allowance must be made for different local conditions. Thus ore from the Blythe lode, delivered to the mouth of the river, will cost less than Rio Tinto ore delivered to the Pieman; and. ore from near the summit of the Dial Range, delivered to furnaces on the Penguin Creek or at Diver- stone, will cost more than ore from Anderson’s Creek, delivered to the West Arm. Then the percentage of the ore will also make a difference. Sixty per cent, ore, at 6s. per ton, would mean 10s. per ton of pig iron; while 50 per cent, ore would enter for 12s. These possibilities must be taken into account when considering ths figures put forward below. The cost of the electric current in Tasmania cannot yet be definitely stated as delivered to points on the North- West Coast, but at the outset it will be safe to assume that it will be in the neighbourhood of £4 per horsepower year ; and the consumption per ton of pig may be estimated at from 0*3; to 0 4 horsepower. Dr. Stansfield, in his bul- 102 m letin,( 16 ) gives Gronwall’s estimate in 1914 as 0'39 HPY per ton of electric white (coke) pig iron, and 0‘42 HPY per ton of electric grey (coke) pig iron for 60 per cent. ore. Apparently Electro-Metals have brought down the con- sumption, as they quote 0*3 HPY for their present furnaces. This would make the cost £1 4s. per ton of iron prduced. As for the electrodes, Gronwall in 1914 estimated their consumption at from eight to nine kilogrammes per metric ton of iron. No quote is obtainable for Tasmania at the present time; the price would probably be riot less than £30 per ton of electrodes; say, 5s. per ton of pig. Electro- Metals state that the electrode situation is at present abnor- mal, but that it is expected that prices will fall to an extent which will reduce the cost to, say, 2s. per ton of pig. Prices of coal and coke are also at present exceptional and unstable. The furnace-owners would probably make their own coke in coke ovens near the works. Coke, at present prices, would cost from 55s. to £3 per ton; but some reduction of these figures may be expected. Limfestone flux may be reckoned at 12s. 6d. to 15s. per ton of stone delivered. The remaining items are labour, repairs, and general charges. Labour at English rates of wages is estimated at 5s. per ton, which may be doubled for this country. Summarising the foregoing figures, the following general result is reached as the cost of a ton of pig iron to be pro- duced by electric smelting in Tasmania : — Per Metric Ton. 60 per cent, ore, or 1*6 ton, at 6s. per ton at furnace 7 cwt. coke at 55s. per ton at furnace 4 cwt. limestone at 15s. per ton at furnace . . . Electric energy ^ 0*3 horsepower at £4 per horsepower year • 9 kilos, electrodes at £30 • •• Labour, repairs, and general charges Total ••• £4 6 0 Some items may be found to be slightly different in actual working; and, as said above, mine-owners will have to adjust the figures for raw materials according to the situ- atidn of their mines, but it is extremely pro bable that the ( 16 ) « Electiothennic Smelting of Iron Ores in Sweden,” by A. fetnns- field : Onada, Dept. Mines, 1915 (pp. 4ts49). £ s. d. 0 10 0 0 19 0 0 3 0 1 A 0 0 5 0 15 0 103 cost will prove to lie somewhere between <£4 5s. and £4 10s per ton. If it is possible subsequently to obtain a reduction in the price of the electric current, so much the better. ( 17 ) , These costs may be regarded as satisfactory! from tne point of view of the utilisation of the hydro-electric supply of current, and even if they were higher, the adoption of electric furnaces for steel making would still dictate the use of electric energy . If a properly organised charcoal-burning industry could be established, and regular and adequate supplies assured, one unit of the smelting plant might be run on charcoal fuel and special brands of iron produced. riT\ power at £2 per horsepower y°ar, and ore at 10s. per ton, and the cost of electrodes reduced to 4 cents a lb.. Dr. Stansfield is of opinion that foundry iron could be produced in Br tish Columbia by the electric process tor about £4 16s. per ton. The quantity of limestone will vary with the ore • in some cases it may amount to as much as 10 cwt. per ton of pig. In British Columbia Dr. Stansfield considers 8 cwt. of charcoal would be required for ioundry iron. XII.— FUEL. Whether smelting in connection with the Beaconsfield deposits is being considered, or along the. North-West Coast, or at Corinna, or Balfour, Zeehan, &c.,- the fuel question is an important one, for it is the heat cost which in the last instance determines the site for the works. The reports indicate that there is no doubt about the commercial applicability of the electro-thermal process where condi- tions are favourable, and these may be taken to be emi- nently so in Tasmania. Accordingly, blast-furnace smelt- ing is a subject which will be discarded from this report. Mr. J. Bibby, in a paper on “ Iron and Steel Electric Furnaces,” read in January this year before the Man- chester Association of Engineers, says : — “ On the average a blast furnace consumes one ton of coke per ton of pig iron produced. The electric furnace consumes one-third of a ton of coke and requires one-third horsepower year per ton of pig pro- duced. For the cost of the two systems to balance we must be able to supply one horsepower per year at the cost of two tons of coke.” The lay reader may wonder why coke or charcoal should be necessary when electric energy is employed, but this question may be answered at once by calling to mind that the electric current supplies only the heat, while the carbon is required as the reducing agent ; that is, an agent which will separate the iron from the oxygen with which it is combined. Consequently, coke or charcoal is always neces- sary. (1) — Charcoal. The Savage River and Heemskirk deposits, by reason of their remoteness, are at a disadvantage as regards coke supplies compared with Beaconsfield and North-West Coast properties, and the employment of charcoal may well be taken into consideration. For electric-smelting furnaces charcoal is an excellent fuel, and has always an advantage over coke in one respect, namely, in that it is almost free from sulphur; though it may be mentioned here That with these furnaces the sulphur, if in moderate proportions, whether in coke or charcoal, is practically eliminated and an almost sulphur- free pig produced. At present the cost of charcoal in Tas- 105 mania -seems to be a trifle higher than the cost of coke, but if quality of iron rather than quantity be aimed at, the selling price which the product will command will admit of a somewhat high fuel cost. This matter is dealt with in Sweden, in the. most thorough manner. The large iron companies, "have their own forests, and exploit, them m t most scientific and systematic way. The. best timber is utilised for pulp, the next best is used for building pur- poses, and the balance for charcoal-making. The large forests do not. consist of large trees :. the size is usually 8 or 10 inches in diameter. The branches' and twigs too small for charcoal burning are gasified and the gas used m the manufacture of special steel. The- very high-grade products which give Sweden a special position in the iron market of the world are based upon its pure iron ores, its hydro- electric power, and charcoal fuel. The conditions for a similar specialised high-class industry exist in Tasmania; it is worth while investigating them and seeing how tar they can be taken advantage of. i „ One drawback to the use of charcoal is the acreage ot land required for the growth of timber within easy reach of the smelting works. Although Tasmania is locally endowed with abundant forest growth, a steady depletion in any one district would make it necessary to continually go further back for supplies till at last the cost would tend .to become prohibitive. . The yield of wood suitable for charcoal burning obtain- able from Tasmanian forest lands naturallv varies in dif- ferent parts of the island. Mr. Robert Sticht, General Manager of the Mt. Lyell Mining and Railway Company,! states that the average timbered portions of the West^Coast will cut from 60 to 80 tons of 80 cubic feet each of 6 feet split firewood per acre. The experience of some burners points to a yield of 20 tons wood per acre in some localities. As about 50 per cent, of the wood consists of water and 25 per cent, of volatile matter, only about 25 per oent. of it will be represented by the charcoal which is obtainable, and perhaps it will be safe to say that the charcoal yield will be about 20 per cent. Thus the yield of charcoal per acre may be estimated as ranging from 4 or 5' tons to 15 or 16 tons, according to the forest growth. • The ruling costs for charcoal in comparatively ' small quantities appear to figure out at about 6d. per bushel of 15 lb. weight, which is equivalent to £3 15s. per ton. There are, however, considerable differences in the quota- tions, charcoal at Moina costing £3 14s. per ton; at Ben Lomond, £3 12s.; on the north coast, £S; on the east 106 coast, £5; and on the west coast, from £3 to £6. Of course, these prices must be understood as being based on trivial quantities and on the usual primitive pit or stack method of burning, in which the yield is admittedly poor. Kiln or retort burning, with an output of by-products, would probably make charcoal available at works for something below £2 per ton. Incidentally, it may be mentioned that if charcoal fuel were adopted it might mean the starting of an imporant charcoal industry. At present it is difficult to forecast what choice of fuel will be made in the case of individual enterprises. (2) — Coke. Good iron furnace coke must be low in sulphur and ash. The presence of much sulphur in it involves the production of a sulphurous pig iron, to avoid, which more limestone flux is needed in smelting, and necessarily more fuel. A satisfactory coke will contain from 0‘5 to over 1 per cent, sulphur, and furnace-owners generally are averse to the use of a fuel which exceeds 2 per cent, or so of this objec- tionable element. At the same time a good deal of iron is made with inferior coke. Despite manipulation of fluxes, and though some of the sulphur is certainly driven off by the heat of the furnace, it may be accepted that the total quantity contained in ore, fuel, and flux is not substantially reduced in the blast furnace. Here the electric furnace has the advantage. A good coke for blast furnace use has to be sufficiently hard to resist the unavoidable pressure in the furnace, but the electric furnace is not so exacting in this respect. It would be desirable to institute some 1 experiments with a view of seeing whether any of the Tasmanian coals can yield a coke which would be suitable for electric smelting. Among' the coals to be tested would be the coals' from the Mersey seams, that from the Preolenna field, the coal from Catamaran in Southern Tasmania, and the East Coast coals. As a rule, the latter do not yield a firm, coherent coke, though their sulphur content is very satisfactory, the Nicholas Range coal having not more than from 0'5 to 0’6 per cent. There are great irregularities in the coking pro- perties of the East Coast coals, some of them coking well in the laboratory. Such tests, however, are insufficient. It might be possible to achieve some result by mixings coal from different fields, say, the Preolenna and Mt. Nicholas fields ; and again it is well known that coking iin the by-product oven instead of the bee-hive oven has often con- 107 verted non-coking coal to a coking variety . partly because in the former the coal is closely confined, while m the latter it lies loosely. Some of the Denison Elver coal has yielded a very firm coke on assay, and the Launceston Gas o - pany has obtained an excellent marketable coke from • jL On the other hand, a small sample from the same seams was tested at the Thornhill Collieries m England, and viplded only a very soft and friable coke. 7 The Mt. Nicholas and Cornwall coal has been assayed ^at various times with indifferent results, A laboratory coke has recently been obtained by assay from coal at the west .end of the Mt Nicholas Range (the old Durham seam, now Silk- stone) ; and the coal in the seams at Mt. Rex gives a c °^ 6 which is described in the assay reports, as good and firm. The Dalmayne coal, too, yields a good assay cok^ Trials have been made lately in the United States and Canada with pulverised coal in copper and nickel blast furnaces and, it is reported, with satisfactory resu s. IhL can be applied to the electric shaft furnace, it willmean much for Tasmania, as even if the coal of this island shou not prove capable of yielding a suitable metaliurgical ooke, “could still be utilised in the furnace. It is indeed said that almost any coal can be used for this purptee.^ T progress of the trials which are proceeding on the A “« rl £ continent will no doubt be carefully watched. Electro- Metals Limited stjate that they have not yet used pulverised coal in lieu of coke, as the necessity has u°t a risen birt of their patents covers the employment of it to convert the CO 2 into CO on its introduction to the crucible m t g SrcuStton system. A number of their furnaces are now working'on coke most satisfactorily , and they areaow«- pleting a plant for Genoa where six furnaces will work en The y older°coal in Tasmania, that of the Mersey and Preolenna seams, suffers under the drawbacks of a high sulphur content, though making good coke That °L MeVsey basin contains about 3 per cent, sulphur; the Preo lenna ranges up to 4 and 5 per cent., while Ihe Eas Coast coal carries only from 0'5 to 06 per cent. If it is desired to draw on the firstmentioned fields for supplies, trials will have to be instituted to see how far and at what cost the sulphur contents could be reduced Coal-washing plants ■ are on the increase, and nuts and slack and dirty coal generally are frequently washed with a recovery of P cent. Although the primary object m washing is Reduce the quantity of dirt, the process involves “^dentally -the elimination of part of the sulphur. A further reduction 108 / of sulphur takes place during coking, but how far the sulphur content in the Tasmanian high-sulphur coal can be reduced before employment in the furnace is a subject which invites study. If anything approaching to a normal content can be obtained, the remaining sulphur can be eliminated during the electric smelting process. It may be -recalled that with electric smelting two-thirds less sulphur enters the charge than is the case in ordinary furnace prac- tice, for only one- third of the fuel is needed, and this makes the work of elimination easier. The possibility of mixing native coal with coke for the furnace charge has likewise to be considered. While a posi- tive opinion on the applicability of Tasmanian coal to iron ore smelting by the electric process cannot be expressed, there is some possibility in this direction, and there exist strong reasons and encouragement for investigating the whole question. 7 ' •• - !; 7 •- 1 I ■ ‘-i r a -7. • " V • • XIII — LIMESTONE FLUX. Tasmania abounds in good limestone suitable for use in smelting, and it is believed that all the large deposits of iron ore likely to attract the attention of ironmasters are not far from limestone occurrences. This substance produces lime in the furnace, which acts as a base, forming a fusible slag. The quantity required will vary with the impurity of the ore, and may fluctuate between 4 and 9 cwt. per ton of pig. It is claimed that the Electro-Metals type of elec- tric furnace, with average quality ores, may be assumed to take 350 lb. per' ton of pig. On the other hand, other inquiries give figures up to 9 cwt. The sources of supply in each case will be a matter for the .works owners to consider. The Rio Tinto mines would •derive their, flux from limestone beds which are said to exist near Corinna; these occurrences have not yet been officially verified. The limestone near Zeehan would conveniently supply furnaces treating the ores from the Tenth Legion and that vicinity. The ores of the Beaconsfield district would easily draw supplies from the large deposits at Flowery Gully; while the great limestone properties at Gunn’s Pains are the nearest to the Dial Range and the Blythe. Some limestone is being worked in the Don Val- ley by the Broken Hill Proprietary, connecting with the Government coast railway. Purchase or exploitation would depend on what arrangements are possible with the Broken Hill Company. . At Mole Creek are unlimited quan- tities of limestone, and near the Government western line of railway. Freight to the Blythe would be over 72 miles by rail. The Flowery Gully limestone is quite near to the Sugar Loaf iron lode, and is about 8 miles from Beauty Point on the Tamar, where at present deliveries in small quantity cost about 14s. a ton. This rate could no doubt be greatly reduced. ,A steel, tramway exists for over 3 miles of the distance between the deposit and the port on the river: a connection for the remainder of the distance would have to be effected by the construction of a. tramway. . Daily’s . quarries, in, the neighbourhood of Beaconsfield, could also supply a certain quantity of good-grade limestone for a furnace on the West Arm . Average analyses of the 110 Flowery Gully stone by the Government Assayer show the following composition : — Per Cent. Calcium carbonate ... Magnesium carbonate Iron and alumina — Silica Moisture 95*26 107 2-10 1-34 0-17 The nearest limestone to the Blythe River lode is that reported at the Upper Blythe Bridge, on Addison’s pur- chased land west of the bridge, and an examination was made by the writer recently of the spot where some of it had been uncovered in the road bank and used for metal- ling the road. The rock is now buried below the soil, and only a few loose' boulders can be seen. Notwithstanding this, judging from the surface contour, it is probable that the hill does contain beds of limestone concealed by a heavy overburden of basaltic soil. Since the visit referred to, an occurrence of limestone has been reported further up the road on Grealey’s land. An occurrence further east, in the valley of the Leven, is that at Gunn’s Plains, at the mouth of Walloa Creek. This place is 4 miles south-east of Riana township, or 9 miles south-east of the Blythe River in a direct line. After leaving Riana there is a good road for a couple of miles to Kaine’s farm, and a pack track thence to the mouth of Walloa Creek, which flows into the Leven at the north end of Gunn’s Plains. Or one can motor all the way from Ulverstone on a good road. The limestone covers about 100 acres of Wells’ land and about 60 acres of Rogers’ land, part of the lot charted m the naftie of Mary Kent. These beds form part of a broad belt of this stone crossing the plains in a south-easterly direction. The actual strike of the strata seems to be N.W.-S.E., and the dip to the north-east. The beds on Wells’ land are exposed along the side of the road west of the creek. They can be worked cheaply, and are conveniently situated for loading the stone for trans- port. When Wells’ stone is finally exhausted, the solid mass of rock on Rogers’ land up the creek, where it is exposed in lofty vertical cliffs, will be available for supplies. Altogether there are 120 or 130 acres of limestone land on these lots, which would supply the rquirements of any smelting works indefinitely. Ill Samples of the rock have been assayed by the Govern- ment Assayer in the Geological Survey Laboratory, with the following results : — Par Cent. Calcium Carbonate 90*25 Magnesium carbonate •• 0 iy Silica Ferric oxide and alumina • i 1 < Moisture . 0 18 100*09 A high-class lime is being made from it by Mr Wellard, and finds a ready market in quantities at Is. 6d. per bag. A disadvantage which the locality possesses as a source for outside supply is the present cost of getting the stone to the railway. By the new road it will probably cost 6s or 7s. a ton to carry it to Preston, and thence by rail to Penguin from 2s. 6d. to 3s. Works in the Penguin Valley would most likely find the stone costing them, delivered, m the neighbourhood of 10s. per ton. At present rates the railway freight from Penguin to the mouth of the Blythe is 2s lid. per ton, but this would no doubt be considerably reduced for quantities. The present motor transport to Ulverstone from the plains is 10s. per ton, but it ^ ques- tioned whether that could be made to compete with the railway. With modern quarrying methods and reduced transport rates, the conditions point to the selection of the great deposits of limestone at Gunn’s Plains as a source of supply for any furnaces erected along the North-West Coast between Burnie and Ulverstone; and the costs may not be more than 2s. or 3s. per ton of pig iron. XIV.— CONCLUSION. From the preceding it will be gathered that Tasmania possesses deposits of iron ore of a varied nature ip. different parts of the island. With three exceptions, however:, no commercial use has so far been made' of them. These are the chromiferous ores of Anderson’s Creek, the brown hematites of Brandy Creek, and the high-grade hematites of the Penguin Creek Valley. The metal from the Ander- son’s Creek beds was placed on the market for a short time, until the increasing chromium content interfered with the sales. Small quantities of the Brandy Creek iron were disposed of satisfactorily, but, with a drop in the market, the outlook was not encouraging enough for the owners to continue their venture. The demand for the Penguin ores fell off when the buyers found more convenient sources of supplies of flux on the mainland, and the difficulties with landowners hastened the suspension of operations. The remaining deposits have so far not been exploited for one reason or another. Either they are not sufficiently near shipping ports, or are unfavourably situated for deliveries of fuel and flux, or the desired capital has not been forth- coming. Doubtless the absence of serious attempts to prospect and open up the properties, with a view of dis- closing their actual value, has to some extent discouraged the approach of investors. It may in fact be said that all the properties referred to are in this undeveloped state. While there is much in their visible features to support a hopeful view of their possibilities, ah entirely inadequate amount of work has been done on them for establishing a basis for commercial calculations. Their values, there- fore, may be characterised as latent and potential. In this sense the iron resources of Tasmania are of no mean order. This becomes apparent when one takes into account the area of the island and compares this and the extent of the deposits with the average of those of the iron-bearing countries of the world. Professor Hj. Sjogren, in his sum- mary of the Stockholm Congress reports, works out a ton- mile factor for the world’s reserves. Striking a mean between different estimates of the supposed actual and potential supplies of iron ore throughout the world, rang- ing from 90,000,000,000 to 130,000.000,000 tons, there emerges approximately a total of 110,000,000,000 tons, which, over an area of 50,554,630 square miles, is equivalent to 2175 tons per square mile. In this total, Tasmania, 113 with an area of 26,000 square miles and potential reserves of 42,000,000 tons, figures with 1615 ton-miles. This, therefore, is below the world average, but not depressingly so. . . In the utilisation of these potential stocks the provision of electric energy by means of the State hydro-electric instal- lation must always be regarded as an indispensable factor, as the future of the deposits is inextricably bound up with electric smelting and electric steel production. Electric furnace units of moderate size can easily be installed at various centres, thus responding to the needs of widely separated deposits. The Savage River and Zeehan magnetites are above all most suitable for electric smelting, for nearly all electric iron furnaces so far have been run on magnetic ores, and the commercial feasibility of the pro- cess has been practically and absolutely demonstrated. As hematites smelt in the blast furnace more easily than magnetites, they also will be readily reducible in the elec- tric furnace. The Government is prepared to arrange for the delivery of power at reasonable prices. The costs of fuel and flux will not be prohibitive, though the question of fuel will involve aiixious consideration. Electrodes will by and by be purchasable at normal prices. Labour will probably not fall below its present level. Taking all these factors into account, electric iron ore smelting presents itself as a workable proposition. The quantities required for ^electric furnaces do 1 not necessitate the enormous ton- nages customary in blast-furnace practice, and in one locality or another, according to all appearances, it is safe to say that enough ore exists to support the industry in Tasmania for very many years. Moreover, the intimate relation which is admitted to exist between the manufac- ture of iron and steel and the economic status and future of a nation or country justifies any attempt to exploit the deposits wherever the indications and conditions promise a reasonable chance of success. W. H. TWELVETREES, Government Geologist. a. McIntosh reid, Assistant Government Geologist. Geological Survey, Launceston, 4th November, 1919. GEOLOGICAL SURVEY OF TASMANIA LIST OF PUBLICATIONS. BULLETINS. No. 1- — The Mangana Goldfield, by W. H. Twelvetrees_ i907 No. 2.— The Mathinna Goldfield, Part III., by W. H. Twelvetrees 1907 No. 3. — -The Mt. Farrell Mining Field, by L. Keith * Ward, B.A., B.E 1908 No. 4. — The Lisle Goldfield, by W. H. Twelvetrees 1908 No. 5. — Gunn’s Plains, Alma, and other Mining Fields, North-West Coast, by W. H. Twelvetrees ... 1909 No. 6. — The Tinfield of North Dundas, by L. Keith Ward, B.A., B.E 1909 No. 7. — Geological Examination of the Zeehan Field, Preliminary Statement, bv W. H. Twelve trees and L. Keith Ward, B.A., B.E 1909 No. 8. — The Ore-bodies of the Zeehan Field, by W. H. Twelvetrees and L. Keith Ward, B.A., B.E 1910 No. 9. — The Scamander Mineral District, by W. H. Twelvetrees 1911 No. 10. — The Mt. Balfour Mining Field, by L. Keith Ward, B.A., B.E ." 191] No. 11. — The Tasmanite Shale Fields of the Mersey District, by W. H. Twelvetrees .'. 1911 No. 12. — The X River Tinfield, by L. Keith Ward, B.A., b.e. : mi No. 13. — The Preolenna Coalfield and the Geologv of the Wvnyard District, by Loftus Hills, M.Sc. ... 1913 No. 14, — The Middlesex and Mt. Claude Mining Field, by W. H. Twelvetrees 1913 No. 15. — The Stanley River Tinfield, by L. Lawry Water- house, B.E 1914 No. 16. — The Jukes-Darwin Mining Field, by Loftus Hills, M.Sc 1914 No. 17. — The Bald Hill Osmiridium Field, by W. H. Twelvetrees 1914 No. 18. — Geological Reconnaissance of the Country between Cape Sorell and Point Hibbs, by Loftus Hills, M.Sc 1914 No. 19. — The Zinc-Lead Sulphide Deposits of the Read- Rosebery District, Part I. (Mount Read Group), by Loftus Hills, M.Sc 1914 115 No. 20. — The Catamaran and Strathblane Coalfields ami Coal and Limestone at Ida Bay, Southern Tasmania, by W. H. Twelvetrees No. 21. — The South Heemskirk Tinfield, by L. La wry Waterhouse, TB.E No 22.— Catalogue of Publications issued by the Government of Tasmania relating to the Mines, Minerals, and Geology of the State, to 31st December, 1914, compiled by W. fl. Twelvetrees •* No 23 —The Zinc-Lead Sulphide Deposits of the Itead- Rosebery District, Part II. (Rosebery Group), by Loftus Hills, M.Sc No 24.— Reconnaissance of the Country between Rech- erche Bay and New River, Southern las- mania, by W. H. Twelvetrees No. 25 — The Gladstone Mineral District, by W. H. Twelvetrees 1915 1915 1915 1915 1915 1916 No 26— The Tin Field of North Dundas, by Hartwell Conder, M.A. Camb., A.R.S.M., London ... 1918 No. 27. — The Bangor Mineral District, by W. H. Twelve- trees 1918 No 28 —The North Pieman, Huskisson, and Sterling Valley Mining Fields, by A. McIntosh Reid ... No. 29.— The Mining Fields of Moina, Mt. Claude, and Lorinna, by A. McIntosh Reid 1919 No, 30.— The Mt. Pelion Mineral District, by A. McIntosh Reid 1919 No 31 — The Zinc-Lead Sulphides of the Read-Ros,ebery District, Part III, (Metallurgy and General Review), by Loftus Hills, M.Sc. 1919 REPORTS. No. 1. -^-Preliminary Geological Report upon the Mt. Balfour Mining Field, by L. Keith Ward, B.A., B E 191® No. 2. — The Silver- Lead Lodes of the Waratah Dis- trict, by L. Keith Ward, B.A., B.E 1911 No. 3. — Preliminary Report on the Zinc-Lead Sulphide Deposits of Mt. Read, by Loftus Hills, M.Sc. 1914 No. 4.— On Cement Materials at West Arm, by W. H. ^ Twelvetrees • • 1914 No. 5. — On Some Gold-Mining Properties at Mathinna, by W. H. Twelvetrees 1914 No. 6.— Reconnaissance of the North Heemskirk Tin- field, by L. Lawry Waterhouse, B.E. 1914 116 No. 7 —Preliminary Report on the Zinc-Lead Sulphide Deposits of the Rosebery District, by Loftus Hills, M.Sc. ...... 1915 « RECORDS. No. 1.— Marine Fossils from the Tasmanite Spore-beds of the Mersey River y by W. S. Dun .. 1912 No. 2.' Stichtite : A new Tasmanian Mineral : Notes by various authors, collected and edited by W. H. Twelvetrees ^914 No. 3— Darwin Glass: A new variety of the Tektites, by Loftus Hills, M.Sc 1914 No. 4. — A Monograph of Nototherium Tasmanicum, by H. H. Scott. Price, 7s. 6 cl. . 1915 No. 5.— On the Occurrence of Tetrad i um in the Gordon River Limestone, Tasmania, by Frederick Chapman, -A. L.S., F.R.M.S ... 1919 MINERAL RESOURCES. No. 1.— Tungsten and Molybdenum- Part 1.-"— North-Eastern and Eastern Tasmania, by Loftus Hills, M.Sc 1915 Part II.— Middlesex and Mt. Claude Districts, by Loftus Hills, M.Sc 1916 Part III. — King Island, by L. Lawry Waterhouse, B.E 1916 No. 2.— Cement Materials at Flowery Gully, by W. H. Twelvetrees 1917 No. 3. — Phosphate Deposits in Tasmania, by W. H. Twelvetrees 1917 No. 4. — Asbestos at Anderson’s Creek, by W. H. Twelve- trees 1917 No. 5. — A Deposit of Ochre near Mowbray, by W. H. Twelvetrees 1917 No. 6. — The Iron Ore Deposits of Tasmania, by W. H. Twelvetrees and A. McIntosh Reid 1919 ilKiVtBSi'iY OF iLLIMIS LIBRARY FEB 2 - 1921 ACTING GOVERNMENT PRINTER, TASMANIA.