IN- STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY FRANK W. DE WOLF, Chief EXTRACT FROM BULLETIN No. 33 FURTHER INVESTIGATIONS OF ILLINOIS FIRE CLAYS BY C. W. PARMELEE AND C. R. SCHROYER Technology and tests by C. W. Parmelee Geology by C. R. Schroyer PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 1921 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY FRANK W. DE WOLF, Chief EXTRACT FROM BULLETIN No. 38 FURTHER INVESTIGATIONS OF ILLINOIS FIRE CLAYS BY C. W. PARMELEE AND C. R. SCHROYER Technology and tests by C. W. Parmelee Geology by C. R. Schroyer PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 1921 Digitized by the Internet Archive in 2017 with funding from University of Illinois Urbana-Champaign Alternates https://archive.org/details/furtherinvestigaOOparm 5'5'J, £ I «? r* STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY FRANK W. DeWOLF, Chief Committee of the Board of Natural Resources and Conservation W. H. H. Miller, Chairman Director of Registration and Education Kendrick C. Babcock Representing the President of the University of Illinois Rollin D. Salisbury Geologist Fig. 43. Index map showing the locations of clay samples and the approximate position of the outcrop of the Cheltenham clay. FURTHER INVESTIGATIONS OF ILLINOIS FIRE CLAYS By C. W. Parmelee and C. R. Schroyer OUTLINE TAGE Foreword 8 Introduction: A general discussion of clays 9 The classification of clays 9 Purpose and difficulties 9 A proposed classification 10 Types and uses of clays 12 Kaolin and china clay 12 Secondary kaolins 12 Ball clay 13 Refractory clays 13 Plastic refractory bond clays 15 Architectural terra cotta clays 16 Stoneware clays 17 Sagger clays : 17 Sanitary ware clays 18 Paving brick clays 18 Face brick clays 18 Conservation of clays 19 The physical properties and the methods of testing the clays 19 Preliminary preparation 21 The test pieces 21 Formation 21 Drying 22 Raw clays: their properties and the methods of testing 22 Shrinkage 22 Linear 22 Volume 22 Water of plasticity 23 Shrinkage water 23 Pore water 23 Fineness 24 Slaking 24 Transverse strength 25 Bonding strength 25 Burned clays: their properties and methods of testing 26 * Pyrometric methods used 26 Burning shrinkage 29 Porosity 29 Fusion, or deformation tests 29 Distribution of Illinois clays 30 5 PAGE Clays of the embay ment area 31 Paleozoic floor and border 31 Correlation and division of the embayment deposits 31 Cretaceous system 35 Upper Cretaceous series 35 Ripley formation 35 Lithologic character 35 Tertiary system 36 Eocene series 36 Midway formation 36 Lithologic character 37 Wilcox group 38 Pliocene series 39 Quaternary system 40 Pleistocene series 40 Loess 40 Recent series 40 Alluvial deposits 40 Elevation of the Illinois embayment clays 41 Field and laboratory notes on the embayment clays 42 Union County, Mountain Glen area 42 Pits of the Illinois Kaolin Company 42 Pits of the French Clay Blending Company 45 Goodman pit 45 Location and methods of working 45 Geology 46 Mines of Frederick E. Bausch 48 Location and method of working 48 Geology 48 Elmer Gant mine 48 T. P. Sifford pit 49 Maddox and Nixon pits.., 49 Smaller pits 49 Comparison with the clays near Mayfield, Kentucky 51 Comparison with the clays of Lutesville, Missouri 51 Results of tests 52 Massac County 64 Paducah Pottery Company’s pit 64 Clays from the vicinity of Round Knob 64 Clay from the Obermark property 65 Results of tests 65 Pulaski County 67 Clays from the vicinity of Grand Chain 67 Clay from the vicinity of Caledonia 68 Results of tests 68 Alexander County 74 Clays from the Aetna Powder Company’s land 74 Results of tests s • • • • 74 Clays of Pennsylvanian age 76 Field and laboratory notes on Pennsylvanian clays 76 Monroe County 76 Results of tests 76 Madison County 78 Results of tests 78 6 PAGE Calhoun County 80 Results of tests 81 Greene County 82 Results of tests 84 Scott County 94 Results of tests . : 96 Pike County 98 Results of tests 99 Adams County 102 Brown County 102 Schuyler County 102 McDonough County 102 Results of tests 105 Fulton County 112 Results of tests 112 Mercer County 113 Results of tests 113 Rock Island County. 115 Results of tests 115 La Salle County 118 Results of tests 125 Grundy County 141 Results of tests 142 Johnson County 145 Results of tests 146 Tabulation of certain physical tests .. 146 Summary: Grouping of clays according to uses 149 ILLUSTRATIONS FIGURE PAGE 43. Index map showing the location from which clay samples were taken and the approximate position of the Cheltenham clay horizon 4 44. Hand plunger machine for molding briquets 20 45. Apparatus for saturating briquets in vacuo 28 46. Map showing the outcrop of the embayment deposits in Illinois with their relations to similar deposits farther south 32 47. Diagrammatic sketches of the “K” pit of the Illinois Kaolin Company 43 48. View of the southwest wall of the “K” pit of the Illinois Kaolin Company. . 44 49. View of Dr. Goodman’s mine in the NW. sec. 2, T. 12 S., R. 2 W 46 50. Sketch made at the mouth of the Goodman shaft 47 51. Map of the Mountain Glen area. The lands known to include deposits of clay having proven or probable commercial value are indicated by shading. 50 52. Sketch showing the clay body and its relations to the surrounding strata at the Paducah Pottery Company’s clay pit north of Choat 64 53. Abandoned fire clay pit at Golden Eagle 81 54. View of the Colchester Brick and Tile Company’s pit half a mile north of Col- chester, showing No. 2 coal near the top and stoneware clay at the base.. 104 55. View of the Utica Firebrick and Clay Company’s pit south of Utica; No. 2 coal overlies the clay 119 56. View of the clay pit at the west end of the Goose Lake area in Grundy County 142 TABLE 1. Subdivisions of the embayment deposits 34 7 8 ILLINOIS FIRE CLAYS FOREWORD Very early during the participation of the United States in the World War, the importance of a better knowledge of the extent and character of the refractory clay resources of Illinois was recognized. The cessation of importations of certain types of such clays which had previously been brought from enemy countries had made it imperative that domestic clays of suitable sorts should be discovered, if possible. Further, the general disturbance of the economic life by the war had greatly increased the costs and difficulties of transportation and emphasized the necessity for a more comprehensive survey of these clays than had yet been undertaken by the State. Consequently, Mr. C. R. Schroyer of the Survey was assigned the duty of visiting deposits, gathering the samples, and making the necessary studies of the geological conditions. Prof. Cullen W. Parmelee of the Department of Ceramic Engineering of the University of Illinois was given charge of the testing of the clays which was done in the laboratories of the department mentioned. All known clay deposits which gave promise of being of refractory value were examined and areas which had not been previously investigated were carefully searched. Fig. 43 shows the locations of all deposits sampled. The work was well advanced when the armistice was signed, but the cessation of hostilities was not considered a justification for termination of the investigation since it was recognized that the results would have very considerable permanent economic value. Therefore, the work has been somewhat extended and a few clays of a non-refractory type have been included since the samples were already at hand. Since the clays of the embayment area in the southern counties of the state have proved to be of unusual interest, it was thought desirable to study their relation to the very important deposits of the embayment area in western Tennessee and Kentucky. The authors of the bulletin, together with Dr. H. Ries of the U. S. Geological Survey, visited the deposits of western Kentucky and, accompanied by Mr. Wilbur A. Nelson, State Geolo- gist of Tennessee, visited those of the latter state. A visit was also made to the deposits at Lutesville and Glen Allen, Mis- souri, in order to determine what relation, if any, existed between that area and clay deposits in the southern part of the state. The authors therefore wish to express their appreciation of the assist- ance extended to them by the gentlemen named, as well as the many citizens of this State who have contributed in various ways to the successful prosecu- tion of this work. CLASSIFICATION OF CLAYS 9 INTRODUCTION: A GENERAL DISCUSSION OF CLAYS By C. W. Parmelee The Classification of Clays PURPOSE AND DIFFICULTIES It is possible to classify clays in many ways ; as for example, mode of origin, mineralogical character, physical properties, and uses, and several such classifications 1 have been published. The classification here presented is an attempt to correlate certain physical properties with uses. Difficulties are experienced in such an attempt because of the incomplete state of our knowledge of clays and clay products. We still have much to learn about the properties of the unburned and the burned clays and their products. Much information has been gathered through the agencies of the American Ceramic Society and other similar organizations, the various geological surveys, industrial laboratories, and research conducted at the various universities. Through cooperation of these various agencies, stand- ard methods of testing are being devised and standard specifications pre- pared, but the task is a large one and is made particularly difficult because of our ignorance of much that is fundamental relating to the material. One of the benefits which may be attributed to the recent war was the impetus given to the investigation of these problems. As consequences of this, not only has the knowledge of our clay resources been extended, but much has been learned about the requirements to be met by the raw mate- rials and also the conditions which the finished product should satisfy. A better understanding of these conditions has brought about a notable improve- ment in the products. Any economic classification of clays made at this time is to be regarded as only tentative, for the reason previously mentioned, namely, the incom- plete state of our knowledge of the properties of the raw materials which gives them especial value in the manufacture of certain products. Further, in the consideration of such a classification it must be remembered that with the exception of certain products of the cruder sort, it is the practice to blend two or more clays which are commonly of quite different kinds, with a view to obtaining mixtures which may be formed into wares without too much difficulty or loss, and which will possess the desired properties. Therefore, in the following classification, an attempt has been made to indi- cate what may be called the primary uses or, in other words, those for which the clay is particularly adapted. This does not exclude clays from uses for purposes not specified. For example, a superior fire clay may be suited for the manufacture of common brick. Its primary usefulness, however, may be regarded as for firebrick since it will be most valuable manufactured into that product. iRies, H., Clays; their occurrence, properties and uses: p. 23, 1914. 10 ILLINOIS FIRE CLAYS A PROPOSED CLASSIFICATION 1 The clays are classified for use according to the physical properties which give them especial value for specific purposes. I. Clays Burning White or Cream Colored, not Calcareous A. open burning clays, i. e., still distinctly porous at cone 15 1. Low strength, e. g., residual kaolins such as those from North Caro- lina 2. Medium and high strength, e. g., secondary kaolins such as those from Florida and Georgia Clays of the open burning type are of value in the manufacture of pot- tery because of their good color or because of the good strength and good color. These clays are frequently of a good or high degree of refractoriness. If of a good color, they may be used for special refractories such as pots for melting optical glass ; or the color may be of secondary importance and the clays may be valued for their refractoriness only B. clays burning dense, i. e., become nearly or completely non-porous between cones 10 and 15 a. Non-refractory clays : 3. Good color, medium to high strength, medium shrinkage. Uses : Pot- tery, including certain whiteware, porcelains, stoneware 4. Poor color, medium to high strength, medium shrinkage. Uses : Stone- ware, terra cotta, abrasive wheels, zinc retorts, face brick, saggars b. Refractory clays: 5. Good color, medium to high strength, medium shrinkage. Uses : Re- fractories, especially for glass, if they do not overburn seriously for 5 cones higher. Also uses stated in 3 C. dense burning clays, i. e., become nearly or completely non-porous between cones 5 and 10 and do not overlburn seriously at 5 cones higher than the tem- perature at which minimum porosity is reached a. Non-refractory clays: 6. Good color, medium to high strength, medium shrinkage ; usually reach minimum porosity between cones 5 and 8. Type : Ball clays. Uses : Pottery, whiteware, porcelain, and stoneware 7. Poor color, medium to high strength, medium shrinkage. Uses : Stone- ware, terra cotta, abrasive wheels, zinc retorts, face brick, saggars b. Refractory clays : 8. Non-porous or practically so at cone 5; do not seriously overburn for 12 cones higher ; highly refractory ; softening point at cone 31 or higher ; bonding strength minimum 325 pounds per square inch. Use : Graphite cucibles for melting brass. 2 9. Non-porous at about 1275° C. (cone 8), not overfiring at 1400° C. or higher. Strength and softening point as above 2 . Use : Steel crucibles 10. Become dense at about 1275° C. (cone 8). Do not overburn below 1425° C. Bonding strength, 250 pounds per square inch or higher. Soft- ening point, cone 29 or higher 2 . Use : glass pots 1 This classification relates only to the uses of clays for burned products and conse- quently no consideration is given to its uses as filler for paper or cloth, as a pigment, etc. F'or a definition of the terms “refractory" and “non-refractory” as used in this classi- fication and throughout the report, see page 13. For the terms “medium” and “high strength.’’ see page 22 et seq. 2 See page 16. CLASSIFICATION OF CLAYS 11 II. Buff Burning Clays A. REFRACTORY CLAYS a. Open burning, i. e., having a porosity of 5 per cent or more at cone 15 or above : Indurated — non-plastic or slightly plastic unless it has been weathered. Type: flint clay. 11. Normally aluminous; maximum alumina 40%. Use: Refractories 12. Highly aluminous ; alumina exceeds 40%. Type : Diaspore clay. Uses: Refractories, abrasives Plastic 13. Normally siliceous; maximum silica not exceeding 65%. Uses: Fire- brick and other refractory wares, terra cotta, sanitary ware, glazed and enamelled brick (see specific requirements for these below) 14. Siliceous; having a silica content above 65%. Type: Many of the New Jersey fire clays. Uses: Firebrick and other refractories b. Dense burning between cones 10 and 15, i. e., attaining a minimum porosity of 5% or less within that range: 15. Medium to high strength. Do not overburn for 5 cones higher than point of minimum porosity. Uses: Glass pots and other refractories; also used for firebrick, saggars and miscellaneous refractories, archi- tectural terra cotta, sanitary ware, enamelled and face brick c. Dense burning, i. e., attaining a porosity of 5% or less at cone 10 or lower: 16. See 8 17. See 9 18. See 10 These three classes, 16, 17 and 18, are used also for zinc retorts, fire- brick, saggars, and miscellaneous refractories, architectural terra cotta, sanitary ware, enamelled and face brick B. NON-REFRACTORY CLAYS a. Open burning, i. e., do not attain a porosity of 5% or less at any cone lower than cone 10 : 19. High or medium strength. Uses : Architectural terra cotta, stoneware, yellow ware, face brick, sanitary ware 20. Low strength. Use: Brick b. Dense burning, i. e., attain a porosity of less than 5% at cones lower than 10 : 21. High or medium strength. Uses: Architectural terra cotta, stoneware, abrasive wheels, sanitary ware, face brick, paving brick III. Clays Burning Red, Brown, or Other Dark Colors A. open burning clays, i. e., those that do not attain low porosity at any tem- perature short of actual fusion 22. Medium or high strength. Uses : Brick, drain tile, hollow blocks, flower pots, pencil clays, ballast 23. Low strength. Use : Brick B. dense burning clays a. Having a long vitrification range (5 cones) : 24. High or medium strength. Uses : Conduits, sewer pipe, paving brick, floor tile or quarries, electrical porcelain, cooking ware, silo block, art ware, face brick, architectural terra cotta, roofing tile 25. Low strength. Uses: As dust body in the manufacture of electrical porcelain, floor tile, building brick 12 ILLINOIS FIRE CLAYS b. Having a short vitrification range : 26. High or medium strength. Uses : Building brick, face brick, hollow block, flower pots c. Fusing at a low temperature, approximately cone 5, to form a glass: 27. Slip clays IV. Clays Burning Dirty White, Cream White, or Yellowish White 28. Containing calcium or magnesium carbonate or both. Never reach very low porosity. Have a very short heat range. Use : Common brick Types and Uses of Clays In the “Clay Classification/’ references are made to certain types of clays which have been found adapted to special uses. In the following brief descriptions an endeavor is made to state the characteristics of such. How- ever, the fact that a clay is designated a terra cotta clay or a sanitary ware clay, for example, does not necessarily mean that the clay constitutes a dis- tinct type, and the attempt has been merely to describe the kind of material which is sought for the use indicated. As a matter of fact, for many pur- poses it is quite impossible to define the characteristics closely. KAOLIN OR CHINA CLAY The true kaolin is residual in its origin. It has a low degree of plasticity, low strength, low shrinkage both in drying and burning, and after purification by washing is refractory. The term kaolin is used in this country for the same type of material as that designated by the English potter as china clay, and kaolins are used for the same purposes as china clays. Since there would be an advantage in introducing a distinction between the terms, it has been proposed to restrict the term kaolin to the crude material and china clay to that which has been purified for the market . 1 Kaolins do not always burn white. Some that are so badly stained that they are unsuited for use by the potter, may have considerable value if refractory. True kaolins have not been found in the State, nor is there much likelihood of such a discovery. The so-called kaolins of Union County are misnamed. SECONDARY KAOLINS These differ in origin from the true kaolins in that they have been transported from the place of origin by water and laid down in extensive beds. They are more plastic, stronger, and have higher shrinkages. They burn white, although not quite equalling the best residual kaolins. They are adapted to uses similar to those of the true kaolins. iMellor, J. W., A note on the nomenclature of clays : Trans. English Ceramic Soc. VIII, p. 23. TYPES AND USES 13 BALL CLAY These are highly plastic, strong clays which burn cream white or a very light buff and vitrify between cones 5 and 10, so that they are non- absorbent. No ball clays have been located in Illinois, although the so-called kaolins of Union County have the characteristics of this type. It is possible that some of the stoneware clays of the State may he of a sufficiently good quality after washing to permit their use for some of the purposes for which ball clay is suitable. Ball clays are sedimentary in their origin. The drying shrinkage is ordinarily less than 10 per cent; the modulus of rupture as determined by the cross-breaking strength test varies between 200 and 500 pounds the square inch, with an average of 350 pounds ; the tensile strength per square inch varies between 125 and 150 pounds; the total shrinkage at cone 10 varies between 16 and 20 per cent. The water of plasticity varies between 27 and 43 per cent with an average of 32.6 per cent. REFRACTORY CLAYS Clays are designated as refractory if they are capable of withstanding high temperatures without showing signs of fusion such as deformation, i. e., loss of shape, or softening to a fluid state. Since all clays are able to withstand relatively high temperatures, and since no standard has yet been adopted, it becomes necessary to define more precisely what is meant by the term refractory clay. Purdy 1 and Bleininger 2 have suggested cone 26, and Ries 3 has named cone 31 as the boundary between the refractory and the semi-refractory clays with cone 27 as the lower limit for the latter clays. For purposes of this bulletin, all clays which fuse at cone 27 or higher are considered to be refractory and those which fuse at cone 33 or above are classified as highly refractory. The term fireclay has come to be used in a broader sense than is con- noted by mere refractoriness. It is now applied, at least in the middle west, to clays which have some of the characteristics of the true fireclays without regard to their ability to withstand very high temperatures. Commercially they have been divided into three classes which are known as No. 1, No. 2, and No. 3. The separation into these three grades has to a large extent been left to the convenience of the miner who wishes to make a distinction between materials but lacks the means for differentiating explicitly. Some attempt has been made to standardize these terms: for example, Bleininger 4 prescribes the lower limit of the softening temperature of No. 1 fireclay as iPurdy, Ft. C., and DeWolf, F. W., Preliminary investigation of Illinois fire clays*. 111. State Geol. Survey Bull. 4, p. 149, 1907. 2Bleininger, A. V., The testing of clay refractories : U. S. Bureau of Standards Tech. Paper No. 7, p. 15, 1912. 3 Ries, H„ The clays and clay industry of New Jersey: New Jersev Geol. Survey, Final Rept. Vol. VI, p. 311, 1904. 4 Bleininger, A. V., The testing of clay refractories: U. S. Bureau of Standards Tech. Paper No. 7, p. 44, 1912. 14 ILLINOIS FIKE CLAYS cone 32 ; and further, according to Purdy, 1 the time-temperature rate of vitri- fication is very slow so that it attains a low porosity only at a very high temperature, if at all. The term No. 2 fireclay is peculiar to the middle west. Not infrequently it is used by a clay miner to designate a grade which is inferior to the best which he is mining. However, the term is most frequently employed to desig- nate a clay which burns to a light color — a cream, buff, or light tan — and attains a low porosity at some temperature between cone 5 and cone 11. These limits have been arbitrarily set by the writer since, with the exception of some work done by Purdy 2 no attempt has been made to define the term with exactness. These clays are somewhat less refractory than the No. 1 grade and burn to a dense structure which makes them unsuited as the chief clay component for the manufacture of the best grade of firebrick. The fact that the term No. 2 fireclay in some cases connotes “second-grade” and the fact that use of this clay in the manufacture of this particular product is limited, should not be misunderstood and the class consequently under- valued, for amongst these No. 2 fireclays some of the most useful of the fireclays are found. The refractory clays of this class which have high strength are indispensable in the manufacture of crucibles, zinc retorts, and glass refractories, and those of good strength are necessary as the bonding agent for the No. 1 fireclays in the manufacture of the best grade firebrick. According to Mr. Purdy 3 the No. 2 fireclays may fuse as low as cone 16 and may be as high as cone 26, which is the minimum refractoriness of a No. 1 fireclay. Bleininger 4 states that “There is no sharp distinction between the No. 1 and the No. 2 fireclays, and any lower limits that may be set must be, in the nature of the case, arbitrary.” Further he states 5 that “cone 28 might be considered the limit below which a satisfactory bond clay should not soften.” This is not incompatible with the experience of Mr. Purdy 6 since he found that the “fusion point [of the No. 1 clays] in the majority of cases does not exceed that of the so-called No. 2 fireclays.” It would seem from the above references that there is much confusion in the use of the term No. 2 fireclay. In the opinion of the writer, the term should be abandoned in technical literature and its use otherwise discouraged for two reasons: (1) it carries with it an implication of inferiority which is most unfortunate since many of the clays which may be grouped under this class are quite as valuable and indispensable as those which we call the No. 1 fireclays; and (2) it makes no distinction between the refractory clays iRolfe, C. W., Purdy, R. C., Talbot, A. N., and Baker, I. O., Paving brick and paving brick clays of Illinois. 111. State Geol. Survey Bull. 9, p. 270, 1908. -Op. eir.. p. 272. 3 Purdv. R. <’.. and PeWolf, P. W.. Preliminary investigations of Illinois fire clavs : 111. State Geol. Survey Bull. 4, p. 139, 1907. 4 Bleininger. A. V., The testing of clay refractories: U. S. Bureau of Standards Tech. Paper No. 7, p. 45, 1912. 5 Op. cit., • p. 45. 6 Purdy. R. ("., and PeWolf, P. W.. Preliminary investigations of Illinois fire clavs : 111. State Geol. Survey Bull. 4, p. 139, 1907. TYPES AND USES 15 and those which are non-refractory. In other words, the term is used to include those clays which are not fireclays in the strict interpretation of the term. It seems to the writer to be more desirable to use a terminology such as proposed in the classification on pages 10 to 12. The use of the term No. 3 fireclays seems to be equally unfortunate. These have been described by Purdy 1 as seldom having fusion points exceed- ing cones 16 and 17. He differentiates them from the No. 2 fireclays on the basis of the rate of temperature-porosity changes. Since the basis of the distinction is not refractoriness and the type clay is non-refractory, it would therefore be better to avoid the use of the word fireclay. There are refrac- tory clays which have a rate of temperature-porosity change which would place them in this group. Because of other physical properties, they are adapted for use for specific purposes which gives them an especial value : for example, the crucible clays and those used for zinc retorts. It would seem a mistake to group this type indiscriminately with the non-refractory clays simply because of the rate of temperature-porosity change. The method of studying clays by means of the temperature-porosity changes has been found to be exceedingly useful, although the scheme of classification which Mr. Purdy proposed as based upon the rate of these changes has been subject to criticism by later investigators. 2 Some of the difficulties encountered were anticipated by him in the statement “it is possi- ble that broader limits will be determined when more and a larger variety of clays are tested.” Beecher 3 in his study of Iowa clays attempted to use the proposed classification but found several marked irregularities. It is difficult to understand these with our present limited knowledge of the mineralogical and chemical constitution of clays. However, it points to the necessity for broader knowledge of these matters. As previously stated, the method of study has been widely adopted and has been very fruitful. PLASTIC REFRACTORY BOND CLAYS These clays are used in the manufacture of crucibles, glass pots, zinc retorts, and miscellaneous glass house refractories. They are used in mix- tures with less plastic clays and with non-plastic materials. According to the investigations of A. V. Bleininger and his associates at the U. S. Bureau of Standards, 4 , 5 the requirements to be met by these clays are as follows : iRolfe, C. W., Purdy, R. C., Talbot, A. N., and Baker, I. O. ; Paving brick and paving brick clays of Illinois: 111. State Geol. Survey Bull. 9, p. 272, 1908. -Bleininger, A. V.. The testing of clay refractories : U. S. Bureau of Standards Tech. Paper No. 7, p. 44, 1912. 3 Beecher, Milton F., Iowa State College Eng. Exp. Station Bull. 40, p. 88, 1915. 4 Bleininger, A. V., Properties of American bond clays, etc.; U. S. Bureau of Standards, Tech. Paper No. 144, 1920. 5 Bleinin$rer, A. V., and Schurecht, H. G., Properties of some European plastic fire clays: U. S. Bureau of Standards Tech. Paper No. 79, 1916. 16 ILLINOIS FIRE CLAYS The siliceous clays and those for glass refractories should not soften below cone 30; for severe service the softening point should be above cone 31. In consideration of the clay having other desirable properties, some modification of this may be made ; for example, a very well known foreign clay which formerly was widely used softened at about cone 28. The water of plasticity varies between 30 and 45 per cent; the linear drying shrinkage should lie between 6.5 and 10 per cent; the plasticity should be high; the strength as measured in terms of bonding power expressed as modulus of rupture, obtained by testing a mixture of equal parts of the clay and grog is 325 pounds per square inch for Class A, and 225 pounds per square inch for Class B. A classification 1 made according to the burning conduct is as fol- lows : 1 — Burn dense at about 1150° C. (2102° F.) and not overfired at 1400° C. (2552° F.). Especially suited for graphite crucibles for brass melting. 2 — Burn dense at about 1275° C. (232 7° F.) and do not overfire at 1400° C. (2552° F.) or higher. Suited for crucibles for steel and valuable for glass refractories if they do not overburn below 1425° C (2597° F.). 3 — Burn dense at 1425° C. (2597° F.) or higher. May overfire at 1450° C. (2647° F.) or above. Valuable for glass refractories. 4— Burn dense between 1150° C. (2102° F.) and 1300° C. (2372° F.) and have short heat range. Unsuited for refractory bond clay. The above classification applies to clays burned at the rate of 20° C. (36° F.) per hour above 800° C. (1472° F.). According to M. G. Babcock 2 the requirements of a zinc retort clay are: Considerable strength and bonding power ; a linear shrinkage between 4 and 6.5 per cent; a porosity-temperature range from 10 per cent at 1150° C. (2102° F.) to about 5 per cent at 1250° C. (2282° F.) ; it should not over- burn lower than 1400° C. (2552° F.) ; deformation point should not be below cone 30. ARCHITECTURAL TERRA COTTA CLAYS These are similar to the stoneware clays. They should be free from pyrites, concretions, soluble salts, gypsum, coaly forms of carbon, and other objectionable forms of foreign materials, because the clays are rarely washed before using. The presence of free silica in excess of 3 per cent in the form of grains which will not pass a 200 mesh sieve is considered objectionable by one firm of manufacturers. The red-burning clays are seldom used for this purpose since they are not as well-suited as are the light cream or light iBleininger, A. V., and Loomis, G. A., The properties of some American bond clays : Trans, of the American Ceramic Soc., Vol. 19, p. 606, 1917. 2 Babcock, M. G., Refractories for the zinc industry : Jour. Am. Cer. Soc., Vol. 2, p. SI, 1919. TYPES AND USES 17 buff colors for the type of decoration ordinarily applied to this product. The clays should have a good plasticity and be strong, but those which are sticky or rubbery when in the plastic condition are avoided. Since the terra cotta bodies are compounded of mixtures of clays and grog (i.e., ground burned clay), the manufacturer may control the shrinkages very readily, but it is desirable that the shrinkages of the clays used should be low or medium. The clays should slake readily when wet with water, so that they may be brought to a uniformly plastic mass without delay. Usually two or more clays are used in the batch. One of these at least should burn dense at some temperature within the ordinary range, namely, between cones 1 and 6, and the minimum porosity should be 10 per cent or lower. The clay should have a sufficiently long heat range at the cone temperature of minimum porosity so that there will not be any danger of overburning in the commer- cial kiln. These dense burning clays should not warp or crack in the drying or burning process. The other clay used will be of the open burning type. STONEWARE CLAYS These are sedimentary clays which have good plasticity and strength, burn to a cream or light tan color, and reach a low porosity between cones 5 and 9. They should be free from substances which will give rise to the formation of soluble salts. It is desirable that the clays be free from con- cretions, pyrites, coaly forms of carbon, and other substances which may interfere with the use of the clay, although washing of the clay, which is. frequently resorted to preparatory to use, will remove them. A comparison of the data regarding the stoneware clays used in different parts of the United States indicates that the physical properties are, on the average, as follows : The water of plasticity is from 18 to 37 per cent, though the usual amount is 35 per cent; the drying shrinkage varies between 5 and 13 per cent, and the average is about 8 per cent; the strength of the clay as measured by the crossbreaking test 1 varies between 125 and 400 pounds with the average at about 250 pounds per square inch ; the tensile strength varies between 100 and 300 pounds with an average of 150 pounds; the minimum porosity attained during burning is between 5 and 10 per cent, which may be reached between cones 5 and 10; the average burning shrinkage is prob- ably about 8 per cent. SAGGAR CLAYS Two types of clays are used in mixtures for the manufacture of these wares, namely, an open burning clay of good refractoriness, and a clay of lower refractoriness which will burn dense at a low temperature. It is desirable that both types should have good plasticity and good strength, although these properties may be the characteristics of only one of the clays used. It is important that the clays do not contain pyrites, concretionary il. e., modulus of rupture. 18 ILLINOIS FIRE CLAYS matter, or other foreign material which may cause damage to the wares placed in the saggars for burning. The shrinkages of the clays are not important since the mixtures contain a very considerable amount of grog and, moreover, small variations in size are of no moment. Unless the saggars are to be used at very high temperatures, it is not necessary to use high grade refractory clays. It is quite essential, however, that the clays should be suitable for use in mixtures which are subjected to heavy loads at high temperatures. Knowledge of the fundamentals of good saggar making is as yet in a rudimentary stage, and there is a great divergence in the practice of potters in the choice of materials and their proportions. SANITARY WARE CLAYS The clays used in the manufacture of such wares as bath tubs, wash trays, and sinks, are similar to those used in the manufacture of terra cotta. PAVING BRICK CLAYS The requirements to be met by these clays are good plasticity so that they may be formed as brick by the auger machine ; little or no tendency to laminate; good strength; safe drying properties so that they will not warp or crack during that process ; a low carbon and sulphur content so that they may be readily and safely oxidized during the burning process ; little or no concretionary material ; the color of the burned ware should be a good red in order to meet the usual requirements of the trade, although paving bricks are made also of clays burning to a light color; the minimum porosity should be approximately 5 per cent or less and this should be attained with a suffi- ciently wide heat range so that there will be no danger of overburning in the ordinary commercial kiln ; the product must develop a sufficient degree of toughness to meet the usual tests ; the linear drying shrinkage may vary considerably, but the ordinary maximum is 8 per cent and the average is 6 per cent; the water of plasticity of typical paving brick clays is 17 per cent. FACE BRICK CLAYS Clays of a great variety are used for this purpose and the requirements which must be met may be stated only in a general way. For the purpose of manufacturing by the plastic process, which is that most generally used, the clay must be of a sort which will flow readily through the die of the brick machine. No marked development of lamination should occur. The clay should have a fair or good strength in the dry condition. It should dry readily and safely without a tendency to warp or crack. The usual shrinkage is from 6 to 8 per cent, although it varies widely. The appearance of a scum, whitewash, or efflorescence of any kind at this or subsequent stages in the manufacture is objectionable. The clay should be practically free from minerals of a harmful kind, size, or quantity, as for example, calcium carbonate in its various forms, pyrites, and concretionary iron. The clays should burn hard and strong without warping, blistering, pitting, etc. CONSERVATION 19 They should attain a low per cent of absorption at a temperature which is commercially practicable. This varies widely according to the type of mate- rial and may be said not to exceed cone 8 and usually lies below cone 1. The clays should have a sufficiently wide heat range to permit the necessary degree of vitrification without danger of overburning and the variations in color throughout the burn should be of a sort both as to shade and variety as to permit satisfactory grading. Conservation of Clays We have been accustomed to regard the supply of our better grades of clays as practically inexhaustible. Considering the great area of the whole country and the large portion still unexplored economically, this may be accepted as true. However, in those states which are most largely given over to industrial pursuits, it is scarcely wise to make this assumption. While it is true that we have large areas with great tonnages in the process of utilization and other areas known and unknown yet to be exploited, still we should not evade the fact that in some important districts the end is in sight. It is wise, therefore, to have in mind the importance of conserving the supply of the better grades of clays. This may be done by obtaining a complete knowledge of the extent and character of our clay resources ; by a more precise knowledge of the requirements of the raw materials for the manufacture of the various wares; by less wasteful methods of mining; by the use of methods of purification to render clays serviceable which would otherwise be unavailable for use ; by the adoption of the practice of blending clays from certain areas or districts so that there would be a more complete utilization of the output from small mines of the region or of certain strata of clays ; by the avoidance of the practice of using superior material, either the raw material or the finished product, where an inferior grade would suffice. As an instance of the importance of a more adequate knowledge of our clay resources, we may cite the diaspore deposits of Missouri. For many years flint clay deposits in certain counties of that state have been operated. A peculiar rough type of clay found in those pits was regarded as detri- mental or worthless, and abandoned pits may be found today where large bodies of it were left. Within the past three years, this material has been found to be of exceptional interest and value because of the extraordinarily high content of alumina. 1 The Physical Properties and the Methods of Testing the Clays The methods of testing employed were, with few exceptions, those rec- ommended tentatively by the American Ceramic Society’s Committee on Standards in its report of 1918. iBuehler, H. A., Biennial Report of the State Geologist of Missouri, p. 18, 1919. zw 20 ILLINOIS FIRE CLAYS ^ a Purplish to Red Iron Oxide : : Horizon : v! Sand 40 30 20 10 0 40 Scale In feet N :?~~r Scale in feet Fig. 47. Diagrammatic sketches of the “K” pit of the Illinois Kaolin Company. Above : North-south profile section. Below : Sketch of the north face. 44 ILLINOIS FIRE CLAYS evident, but Indian red hematite predominates. At each contact zone there is a layer of iron oxides, generally impure from admixtures of sand and clay, though several large hand specimens of pure hematite were broken from these seams. Beyond the contact this iron band grades from hematite through limonite into red, purple, and mottled clay. Concretions of iron oxide may be found 20 feet or more from the contact. Along this zone of iron, more commonly on the side of the clay, are numerous lenses, pellets, and plate-like stringers of clay with perfect slicken- sided surfaces and coatings of felty flakes of white mica. Such smoothed zones may be seen out six feet or more from the contact, separated not Fig. 48. View of the southwest wall of the “K” pit of the Illinois Kaolin Company. uncommonly by thin sheetings of sand. Lines of weakness extend far beyond these smoothed pellets, as shown in some places by checks in the clay, and in others only upon the weathering of the clay after exposure. Such lines are roughly parallel to the line of contact between the sand and clay. A few larger spalls of clay are caught and completely surrounded by the sand. Rarely is a large quantity of sand included within the clay, but if so included, it is drawn out into a thin flattened stringer bounded on each side by slickensided clay pellets. These zones have so conspicuous a color when freshly exposed that they stand out and can be traced by the eye from the far side of the pit. The purple iron zone is reported to have been lower in the direction of the UNION COUNTY 45 limestone wall at the south and to have everywhere been underlain by sand. This relation of sand to clay, due to a doming of the sand up into and through the clay may explain many of the irregularities found in the clay of the district. Later drilling is reported to have revealed another body of clay with almost vertical walls northwest of the present pit, presumably adjoining the sand dome on the northwest. Pyrite occurs at certain levels near one edge and a few thin lenses of lignite were found. Details of the working of this pit and the surrounding property are given by St. Clair in State Geological Survey Bulletin 36 and will be repeated here only briefly. The clay is dug by steam shovel, hauled by small steam engine to a large shed east of the mouth of the pit, cleaned by hand, graded, and stored or loaded directly onto the Mobile and Ohio Railroad switch. Large quantities of clay have been dug and one wall now shows an exposure of 20 feet of variegated, purple and white clay above 35 feet of white and bluish white, highly plastic clay. The greatest overburden is 40 feet with an average of 15 feet or perhaps more. The southwest wall of the “K” pit is cliff of limestone (fig. 48), and the relation of the clay to this wall suggests that it was deposited in depres- sions bordered at least partly by the limestone. Two other pits designated as the “G” and the “F,” are located on this same property, north and west of the present “K” pit. PITS OF THE FRENCH CLAY BLENDING COMPANY The pit of the French Clay Blending Company in the NW. sec. 35, T. 11 S., R. 2 W., was not in operation when visited. Judging from former records and from the fact that clay outcrops in a gully not far from the pits, the workings probably represent one of the largest remaining clay deposits of the area. One exposure of bed rock just southeast of the former pit is an unfossiliferous limestone with chert, which dips 14° NE. and strikes N. 28° W. This clay was mined by shafts and connecting drifts, and by open pits. No sample was obtained. GOODMAN PIT Location and Method of Working The pit owned and operated by Dr. Goodman of Cobden is located in the NW. %. sec. 2, T. 12 S., R. 2W. (fig. 49). The clay is obtained from shafts 14 by 14 feet, that are tightly cribbed, sheeted, and intercrossed with strong log braces set in about three feet from each side. When one shaft reaches the bottom of the clay it is abandoned and partly filled with the overburden from the next shaft which is dug so that it adjoins the old one 46 ILLINOIS FIRE CLAYS by half the length of one of its sides. This method recovers all the clay with a minimum working of overburden. Stripping and digging from an open pit would reduce the cost of pro- duction. Prospecting by drill and pits would outline the shape of the deposit and the quantity available, and thus indicate the development justified. Geology The log of the working shaft, which was down about 100 feet when visited March, 1918, is as follows: Fig. 49. View of Dr. Goodman’s mine in the NW. M sec. 2, T. 12 S., R. 2 W. Log of the Goodman shaft in the NW.% sec. 2, T.12S., R.2W . Thickness Depth Feet Feet Description of strata Loess 10 10 Gravel 1 11 Sand 2 13 Clay fPink clay (Sample No. 27) 27 40 •j White and pink (Sample No. 28) 30 70 (^White clay (to bottom of pit) (Sample No. 25) 30—}— 100 Sand, orange UNION COUNTY 47 The pink clay is reported to have an approximately uniform thickness over the deposit so far as worked. The white clay is increasing in quantity and quality as the pits are driven farther south in the ridge, for accompany- ing the rise in the upper surface is a lowering of the base. The results of tests made on samples No. 27, No. 28, and No. 25 are given on pages 53-56. One small pocket of lignite has been found in the white clay and five or six perfectly smoothed and polished pebbles have been taken from the lower levels. The top of the clay rises south under the ridge and the relation to the sand at the base suggests irregularities similar to those in the Illinois Kaolin Company’s pit. A sketch made at the mouth of the shaft (fig. 50) shows the relation of this thickening to the overlying sand and gravel. In addition to the samples noted above, a sample of the “Chocolate” (sample No. 30) clay which is found associated with the white clay was taken, and the results of tests made on it are given on pages 56 and 57. 48 ILLINOIS FIRE CLAYS MINES OF FREDERICK E. BAUSCH LOCATION AND METHOD OF WORKING The present Bausch workings include three pits. No. 1 mine, located near the center of sec. 35, T. 11 S., R. 2 W., is reported to have reached a depth of 55 to 60 feet. Tunnels driven from shafts at various levels total 500 feet. The overburden of ten feet has two feet of gravel at the base. The clay is underlain by white sand. Both pyrite and lignite are present commonly occurring together. Pink clay is wanting in this deposit. At mine No. 2 in the NE. cor. of SW. Yl sec. 35, T. 11 S., R. 2 W., the section is given as follows : Section measured at Bausch Mine No. 2 in sec. 35, T. 11 S., R. 2 W. Thickness Feet 3. Soil 15 2. Sand, reddish, coarse, gravelly (vertical seam) 40 1. Clay, one side of shaft pink, other side, white 25 Mine No. 3 is located in the SE. )4 sec. 27, T. 11 S., R. 2 W., near the center of the east line of the section, about one mile from the loading stage at Kaolin. The mining is by shaft and tunnels, and the clay is said to be drifting down following the quicksand below. At the present working it is 30 feet thick, with an overburden of about 18Y feet. The clay is assorted and trimmed by hand. Three grades of clay are made: namely, A1 or No. 3 (sample No. 121), Blue No. 2 (sample No. 122), and No. 1 (sample No. 9) ; tests were made on these samples with the results given on pages 57 to 59. Geology This pit is located between upthrown Mississippian limestone at the east and the Devonian highlands at the west. The limestone outcrops in a scarp less than 200 yards east of the pit, dips 20° E., and strikes N. 15° W. Drillings by the Illinois Kaolin Company south of this pit near the NE. cor. sec. 34 show only black pyritic Devonian shale. The clay is evidently in an isolated depression. ELMER GANT MINE The Gant clay mine is located in the SE. % SE. % sec. 2, T. 12 S., R. 2 W., about \y 2 miles by wagon road from the Mobile and Ohio Railroad switch at Kaolin. The clay is mined from a shaft 14 by 14 feet with “lead tunnels.” It is drawn out by horse and bucket and the better grades are assorted and trimmed by hand. Three grades are made, pink and white mottled, No. 3 (sample No. 29) ; white, No. 2 (sample No. 23) ; and the bluish white, No. 1 (sample No. 26) ; tests of these samples are reported on pages 59 to 61. UNION COUNTY 49 The overburden of loess and gravel is from 6 to 12 feet thick. Several test pits have been dug and borings have been made ; one is reported to have gone 73 feet in clay. The present workings are 35 feet deep. But very small amounts of lignite have been found associated with the clay and no pyrite is reported. This clay is obtained from a hollow on the west side of a loess-covered ridge. On the opposite side, beds of crystalline Mississippian limestone are found in place and loose slabs extend up to a level which is not far below the top of the clay. T. P. SIFFORD PIT A pit opened by T. P. Sifford is located on the Mary A. Walker farm in the SW. Y\ sec. 1, T. 12 S., R. 2W. The overburden does not exceed 15 feet. The present shaft, a double hoist, 15 by 10 feet, has been dug 62 feet deep into 50 feet of clay. A boring, it is said, penetrated 72 feet of clay. White clay is reported to be above and pink below. In one side of the pit a streak of lignite was associated with concretions of pyrite and marcasite. This pit is little more than a quarter of a mile east of the Gant pit and is separated from it by a high loess-covered ridge and the crystalline limestone mentioned above. A pit 35 feet deep, dug 100 feet south of the shaft, penetrated nothing but orange sand, below the gravel, indicating a condition similar to that found in the Illinois Kaolin Company’s pit. No clay has been shipped from this pit. MADDOX AND NIXON PIT The Maddox and Nixon clay mine is located in the NE. J4 sec. 10, T. 12 S., R 2 W., less than half a mile west of the loading switch on the Mobile and Ohio Railroad. Six 14- by 14-foot cribs have been mined from clay reported to be from 12 to 35 feet thick. The top of the clay rises and the base lowers as the pits are driven farther back into the ridge. Three grades of clay have been obtained: No. 1, blue clay (sample No. 11); No. 2, white clay (sample No. 16) ; and No. 3, pink and white mottled clay. The best grade comes from the lower parts of the pits. Results of tests made on samples No. 11 and No. 16 are given on pages 61 and 62. The overburden is about 12 feet thick. White sand underlies the clay. SMALLER PITS Much prospecting done outside of the main clay area, has discovered a few small lenses of clay. Wm. Ferril dug a small amount of sandy clay from pits in the NE. ^4 sec. 3, T. 12 S., R. 2 W. Much sand and gravel accompanies this clay and the quantity is probably small. Samples No. 18 and No. 22 were taken from this property, and reports on their testing are given on pages 62 and 63. The latter is Ferrill’s best or “Blue” clay. 50 ILLINOIS FIRE CLAYS Fig. 51. Map of the Mountain Glen area. The lands known to include deposits of having proven or probable commercial value are indicated by shading The following list contains the names of the owners of the several pits or mines shown on the above map : 1. Frederick E. Bausch (Mine No. 3.) 2. French Clay Blending Company 3. Frederick E. Bausch (Mine No. 2) 4. Illinois Kaolin Company (3 pits) 5. Frederick E. Bausch (Mine No. 1) 6. Dr. Goodman 7. Elmer Gant 8. Maddox and Nixon UNION COUNTY 51 Another pit has been opened in the NE. sec. 17. T. 11 S., R. 2 W., where the clay is sandy and mixed with red surface clay at the top. No clay has been shipped. This is at an elevation of about 625 feet above sea level. Much other prospecting has been done, and it is hardly likely that there are many deposits of the high grade clay that are not now known. Figure 51 is a map of the Mountain Glen area on which the lands known to include deposits of clay having proven or probable commercial value, are indicated by shading. COMPARISON WITH THE CLAYS NEAR MAYFIELD, KENTUCKY Pink and white clay reported to be 30 feet thick is dug on the D. M. Chapman farm 2^2 miles west of Hickory, Kentucky. The pink clay is mostly at the top and there is some coloring from lignite. Similar clay is also dug 3 miles west of Hickory, where the average thickness is about 16 feet. These clays are in the lower part of the Wilcox group. In color, texture, and physical properties these clays resemble the Union County clays of Illinois. The presence of lignite and the lack of stratification is common to both. COMPARISON WITH THE CLAYS OF LUTESVILLE, MISSOURI In texture and color the clays of Union County, Illinois, are similar to the kaolin of the Lutesville district, Missouri. Those clays, however, are thought to occupy the same position as the bed rock from which they were derived and are a residual product from the decay of a sedimentary rock, presumably a cherty limestone interbedded with thinner beds of siliceous strata. This decay seems to have been localized along fault planes. In the Bausch mine, two miles west of Glen Allen, a sandstone bed is now repre- sented by three feet of quartzite 30 feet below the top of the shaft. This is interbedded with white kaolin above and below. Traces of former bedding planes are evident in the walls of the mine and irregular seams of chert parallel the bedding and sets of fracture lines. Large numbers of chal- cedonic nodules suggest considerable solution, concentration, and redeposition of silica, though part of the siliceous material is still distributed as stringers and beds of granular white “tripoli.” In some of the concretionary masses such silica has served as the nucleus of deposition and is now enclosed in a coating of hard, banded chalcedony. The clay varies from white through grayish- white to reddish pink. The presence of lignite and an occasional pebble in the Illinois clays is proof of reworking, transportation, and redeposition, or, in other words, of a sedimentary clay in contrast to the similar clay in Missouri which is still residual. 52 ILLINOIS FIRE CLAYS RESULTS OF TESTS UNION COUNTY, MOUNTAIN GLEN AREA Samples F, G, and K 3 (Illinois Kaolin Company; SW. J /4 sec. 35, T. 11 S., R. 2 W.) Three samples of clays received from the Illinois Kaolin Company prior to the visit of members of the Survey were tested with the results as shown under the headings F, G, and K 3 . (F) (G) (K 3 ) Water of plasticity 37.4 41.4 Shrinkage water 18.9 24.0 Pore water 18.5 17.4 Modulus of rupture . .Ibs. per sq. in. 142.5 145 195.6 With 50% standard sand — Modulus of rupture.. . .lbs. per sq. in. 259.5 163.7 202.8 Slaking test 21 21^2 Screen test : — (Sample F) Mesh Residue Character of residue Per cent 20 13 Silica and particles of coal 40 10 Quartz particles, some colored with iron 60 47 Quartz particles, round- ed, colored with iron 80 13 Clear quartz particles 120 3.14 White and brown quartz particles 200 1.4 White quartz particles (Sample G) 120 37 200 22 Drying shrinkage : — Linear ; wet length Linear ; dry length Volume Burning test : — (Sample F) Burning Cone Porosity Color shrinkage Percent Percent 2 19.9 9.2 5 6.6 Cream 11.0 9 3.2 Gray exterior ; bluestoned 11.5 12 3.96 Tan exterior; bluestoned 10.8- 13j/ 2 3.68 10.6 15 4.2 Tan exterior; bluestoned 11.0 White quartz particles Quartz sand -Per cent- (F) (G) (K 3 ) 5.26 5.27 10.0 5.68 5.68 11 28 29 40.2 Remarks Hackly fracture UNION COUNTY 53 (Sample G) 2 25.1 White ... 5.9 5 18 Cream white ... 8.4] 9 7.55 Cream ... 9.2 1 12 2.81 9 4 ( 13 2.57 ... 11.41 15 3.26 Tan exterior ; bluestoned. . . . ... 11.1 Hackly fracture Hackly fracture ; vein- ing of fine cracks in the surface (Sample K 3 ) 04 34 Cream white ... 4.3" I 02 33 Cream white ... 4.8 ! 2 20 Cream white i >- Hackly fracture 5 21 Cream white ... 9.0 9 7 Cream white ... 12.0J 13 3 Gray white ; bluestoned Fine-meshed surface cracks 14 3 Tan exterior ; bluestoned. . . . ... 13.0 (F) (G) (K 3 ) Fusion test Cone 29/30 Cone 32 Summary Samples F, G, and K 3 are all similar in appearance, excepting for the slight differences in color. In plasticity and working properties there is little difference. They are all similar in having a higher strength when mixed with standard sand than when tested as pure clay. The bonding strengths of K 3 and F are medium. G is low. The amount of residue left on the various sizes of screen mesh is exceedingly small. The drying shrinkage of K 3 is medium high while that of F and G is medium low. The burning shrinkages at cone 9 are high for all three samples. The sample F is well vitrified at cone 9, while the other samples are slightly less so at the same temperature. These are refractory clays, which do not overburn at cone 15. These clays belong to a class which has been found very useful for admixture with others in the production of close burning refractory bodies ; also of bodies not of refractory nature but of close texture or having a high content of non-plastic material which must be well bonded together. Sample No. 27 (Goodman pit ; NW. *4 sec. 2, T. 12 S., R. 2 W.) This is a soft pinkish-colored clay, varying somewhat in shade and showing an occasional yellowish streak. The working properties of the plastic mass are good. It flows through a die satisfactorily when in a stiff condition. Water of plasticity per cent 36.4 Shrinkage water per cent 8.2 Pore water per cent 28.2 Modulus of rupture lbs. per sq. in. 265 With 50% standard sand — Modulus of rupture lbs. per sq. in. 120.9 Slaking test, average min. 20 54 ILLINOIS FIRE CLAYS Screen test : — Mesh Residue Character of Per cent residue 120 015 Fine sand 150 57 Sand 200 63 Sand Drying shrinkage : — Linear; wet length Linear; dry length Volume Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 2 23 Pink 9.57 5 14 Pink 10.85 9 2.6 Light tan ; bluestoned 12.0 12 1.6 Light tan exterior; heavily blue- stoned 13 7 Light tan exterior ; heavily blue- stoned 9.27 15 6.24 Dark buff ; bluestoned 10.4 Fusion test: — It deforms at 29/30 cone. Per cent .. 6.7 . . 7.38 .. 29.4 Remarks Hackly fracture Hackly fracture Fine mesh of cracks Summary The strength of the unburned clay is medium. The bonding strength is medium low. The percentage of residues left on the screens is slight. The drying shrinkage is medium. The total shrinkage at cone 9 is medium high. Vitrification is complete at cone 12. The apparent overburning at cone 13^4 may be due to the development of small cracks in the test piece during the firing since there is no further increase in the porosity at cone 15. It is a refractory clay. This clay is adapted for use in the manufacture of refractories, especially those which burn densely. This clay burns to a very dark color for a fire clay. Sample No. 28 (Goodman pit; NW. % sec. 2, T. 12 S., R. 2 W.) This is a soft clay varying in color from cream to red. The plastic mass is readily molded. It flows poorly through the die. Water of plasticity per cent 38.3 Shrinkage water per cent 18.7 Pore water per cent 19.5 Modulus of rupture lbs. per sq. in. 192.7 With 50% standard sand — Modulus of rupture lbs. per sq. in. 151.8 Slaking test, average min. 10.5 Drying shrinkage : — Per cent Linear ; wet length 7.45 Linear; dry length 8 Volume 30.9 UNION COUNTY 55 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 01 30 Pinkish white 7.42 3 16 Light cream 11.1 4 10.1 Light cream 11.7 6 7 Cream 12.0 Hackly fracture 9 3.0 Cream ; bluestoned 12.9] 12 2.5 Gray; bluestoned 13.5} Vitreous ; hackly 13 3.4 Cream ; bluestoned 13.6) fracture 15 4.7 Tan exterior ; bluestoned. . 13.4 Hackly fracture. Fine veining of cracks throughout test piece Soluble salts : — Pieces burned at the low cones show strongly characteristic yellowish surface coating after soaking in water. Fusion test : — It deforms at cones 32/33. Summary This clay has a medium low strength in the unburned condition. Its bonding strength is low. The absence of residues on the screens indicates a very fine-grained material. The drying shrinkage is medium. The total shrinkage at cone 9 is high. Vitrification is nearly complete at cone 12. The clay is highly refractory and is espe- cially adapted to the manufacture of such wares, especially those which should burn dense at a low temperature. Sample No. 25 (Goodman pit; NW. % sec. 2, T. 12 S., R. 2 W.) This is a white clay which shows a few reddish stains on the faces of fractures. Its working properties in the plastic condition are good. When the clay is in a stiff con- sistency it flows satisfactorily through a die. Water of plasticity per cent 39.5 Shrinkage water per cent 19.4 Pore water per cent 20 Modulus of rupture lbs. per sq. in. 131.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 141.4 Slaking test, average min. 12 Drying shrinkage : — Per cent Linear ; wet length 8.3 Linear; dry length 9.1 Volume 32 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 23.7 Cream .... 8.45 5 20 Cream . . . . 9.15] 9 3.6 Gray ; bluestoned .... 10.9 12 0.7 Gray ; bluestoned .... 11.9 Hackly fracture 1314 0.9 .... 12.5 15 3.0 Gray exterior ; bluestoned.. .... 11.8 Fusion test: — It deforms at cone 32. 56 ILLINOIS FIRE CLAYS Summary The strength of the unburned clay is medium low. Its bonding strength is medium low. Practically no residues are retained on the screens. The drying shrink- age is medium. The total burning shrinkage at cone 9 is high. Vitrification is com- plete at cone 12. Overburning seems to be indicated at cone 15. It is quite possible that this appearance is due to the peculiar cracking of the piece rather than a real vesicular structure. It is a refractory clay. It is suggested that it will find important uses in the manufacture of refractories, especially those requiring a dense structure. Sample No. 30 (Goodman pit; NW. ^ sec. 2, T. 12 S., R. 2 W.) This is a soft clay of a cream color, shading into reddish. Its working prop- erties in the plastic condition are good. It flows satisfactorily through a die when it has a stiff consistency. Water of plasticity per cent 44.2 Shrinkage water per cent 21.4 Pore water per cent 22.8 Modulus of rupture lbs. per sq. in. 345 With 50% standard sand — Modulus of rupture lbs. per sq. in. 229.4 Slaking test . . Screen test : — Mesh 13 Residue Per cent . 1.46 . 0.39 . 0.24 Character of residue Cream-colored sand Cream-colored sand Very fine sand 120 150 200 Drying shrinkage : — Per cent Linear ; wet length 7.5 Linear ; dry length 8.25 Volume 34.6 Burning test Cone 2 Porosity Color Per cent 9% 7 C rpam Burning shrinkage Per cent 12.3 Remarks 5 1.3 Gray 13.7'| 9 3.7 13.01 Hackly vitreous frac- 12 3.2 Tan exterior ; bluestoned interior 13.2 f ture 13 0.1 12.4 1 15 53 Buff ; bluestoned . 11.4 Hackly vitreous frac- ture. Surface cov- ered with mesh due to cracks Soluble salts: — Piece burned at cone 2 after soaking in water shows greenish-yellow surface coating. Possibly vanadium salts. Fusion test : — It fused at cone 32. Summary The strength of the unburned clay is medium. Its bonding strength is medium. The percentage of residues is slight. The drying shrinkage is medium. The total UNION COUNTY 57 shrinkage at cone 9 is high. Practically complete vitrification is reached at cone 5 and overburning is slight if any at cone 15. Suggested uses : Refractories, particularly crucibles and glass pots, etc. ; archi- tectural terra cotta, sanitary ware, stoneware. Sample No. 121 (Frederick E. Bausch mines; near Mountain Glen) This is a soft white clay. When tempered with water, it becomes very plastic and inclined to be sticky. It flows very poorly through the die. Water of plasticity per cent 37.1 Shrinkage water per cent 20.9 Pore water per cent 16.2 Modulus of rupture lbs. per sq. in. 191 With 50% standard sand — Modulus of rupture lbs. per sq. in. 123.3 Slaking test, average Screen test : — Mesh , min. 22 -}- 60 80 120 200 Drying shrinkage : — Per cent Linear ; wet length 7.4 Residue Per cent . Trace . Trace . .09 . .24 Character of residue Sand Fine white sand White sand and mica Linear ; dry length Volume Burning test: — 8.2 33.5 Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 18.3 Cream white .... 8.3 Hackly fracture 5H 13.0 Cream white .... 8.8^ 9 1.68 Gray ; bluestoned .... 9.6 12 1.40 Gray; bluestoned .... 10.3 Hackly vitreous frac- 1 3X 2.0 Gray ; bluestoned .... 9.8 ture 15 2.5 Gray exterior; bluestoned.. .... 9.3 J Fusion test: — It deforms at cone 30. Summary The clay has a medium low strength and medium low bonding strength. The amount of screen residues is negligible. The drying shrinkage is medium. The total shrinkage at cone 9 is high. Vitrification is practically complete at cone 9 and the clay is not overburned at cone 15. The clay is refractory. This is the type of clay which is useful in the manufacture of dense burning refractories. Sample No. 122 (Frederick E. Bausch mines ; near Mountain Glen) This is a soft white clay which becomes very plastic when tempered with water. It is also somewhat sticky. It flows badly when forced ..through a die. 58 ILLINOIS FIRE CLAYS Water of plasticity Shrinkage water Pore water Modulus of rupture With 50% standard sand — Modulus of rupture Slaking test, average Screen test : — Mesh 120 200 per cent 37.9 per cent 20.6 per cent 17.3 lbs. per sq. in. 177.0 lbs. per sq. in. 136.5 min. 29-f- Residue Character of Per cent residue .25 White sand .10 White sand Drying shrinkage : — Per cent Linear ; wet length 7.4 Linear ; dry length 7.8 Volume 35 Burning Cone test : — Porosity Color Burning shrinkage Remarks Per cent Per cent 2 20.0 Cream white 8.0 3 13.3 Cream white Cracked along lines of differential flow 6 10.0 Darker cream white. . 'i 9 1.3 Gray ; bluestoned . . , 12 2.8 Gray , 9.7 ► Hackly fracture m 2.4 Gray 10.4 15 3.3 Gray to tan exterior ; bluestoned 10.2 Fusion test: — Down at cone 32. Not vesicular. Summary The strength of this clay with and without the addition of standard sand is medium low. It has a very fine texture, leaving hardly more than a trace of residue upon the screens. The drying shrinkage is medium and the total shrinkage at cone 9 is high. Vitrification is practically complete at cone 9 and the slight increases in porosity at the higher cones is apparently due to the formation of fine cracks which permeate the mass, rather than due to overburning. It is a refractory clay. Suggested Uses : This clay belongs to the type of refractory clays which is of importance in the preparation of refractory wares having a dense structure. It is also similar to the architectural terra cotta and stoneware clays, although it is doubtful that it could be used alone to advantage for the latter purpose. Sample No. 9 (Frederick E. Bausch mines; near Mountain Glen) This is a soft clay of a pink color with streaks of brownish yellow and red. Its working property is fair, and it is rather sticky. Its conduct when flowing through a die is fair. Water of plasticity per cent 32.7 Shrinkage water per cent 23.5 Pore water per cent 9.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 104.4 Slaking test, average min. 19 Fusion test: — It deforms at cone 31. UNION COUNTY 59 Summary This clay is slightly more refractory than Nos. 121 and 122 but similar to them in its properties in both the unburned and the burned condition. Sample No. 29 (Elmer Gant mine; SE. *4 SE *4 sec. 2, T. 12 S., R. 2 W.) This is a soft white clay, marked by a few yellow and a few black veins. Some of the pieces are of a pronounced yellowish color. Its working properties in the plastic condition are good except that it is somewhat sticky. Its conduct when flow- ing through a die is fair. Water of plasticity per cent 35.8 Shrinkage water per cent 18.7 Pore water per cent 17.1 With 50% standard sand — Modulus of rupture lbs. per sq. in. 286.12 Slaking test, average min. 16 Screen test: — Mesh Residue Character of Per cent residue 120 0.45 White sand 200 0.23 White sand Drying shrinkage : — Linear ; dry length Linear ; wet length Volume Burning Cone test : — Porosity Color Burning shrinkage j Per cent 20.4 Light cream Per cei .... 7.4] it 2^ 11.3 Light cream ... 9.6 3 10.6 Light cream . . . . 9.6 6 2.3 Cream . ... 10.0 8H 2.0 Cream; slightly bluestoned. 1 1 1 r 9 2.1 Cream; slightly bluestoned. . 12 1.9 Cream ; bluestoned . ... 11.0 13 2.2 Cream ; bluestoned .... 11.0 15 3.0 Tan exterior ; bluestoned . . . . . . 9.6 Fusion test : — It deforms between cones 32 and 33. Per cent .. 6.2 . . 5.75 .. 30.4 Remarks Hackly fracture Summary This clay has medium strength. The percentage of residue is slight. The dry- ing shrinkage is medium. The total shrinkage at cone 12 is medium high. Vitrifica- tion is nearly complete at cone 6. Suggested uses are refractories, especially for crucibles and other dense wares, architectural terra cotta, stoneware, sanitary ware. Sample No. 23 (Elmer Gant mine; SE. % SE. *4 sec. 2, T. 12 S., R.2W.) This is a white soft clay which has some veins of red through it. Its working properties in the plastic condition are good. It flows fairly well through a die. Water of plasticity per cent 35.8 Shrinkage water per cent 19.2 Pore water . . . . per cent 16 6 60 ILLINOIS FIRE CLAYS Modulus of rupture With 50% standard sand — Modulus of rupture Slaking test, average Screen test : — Mesh 20 40 60 120 200 Drying shrinkage : — Residue Per cent . Trace . Trace . Trace . 0.2 . 0.43 .lbs. per sq. in. 311.2 lbs. per sq. in. 302.3 min. 23 Character of residue White sand White sand Per cent Linear ; dry length 7.7 Linear; wet length 7.1 Volume 32.5 Burning test: — Burning Cone Porosity Per cent Color shrinkage Per cent Remarks 2 12.1 Cream white .. 10.0 3 4.8 Cream white . . 9.0 6 2.6 Cream ; bluestoned .. 9.5 Hackly vitreous frac- ture 9 2.4 Cream ; bluestoned .. 10.0 Vitreous fracture 12 2.9 Bluestoned .. 10.0 Vitreous fracture 13 1.1 Light tan exterior ; bluestoned Vitreous fracture 15 2.0 Tan exterior; bluestoned .. 10.0 Fine closed cracks on the surface Fusion test: — It deformed at cone 32. Summary The strength of the unburned clay is medium. Its bonding strength is medium. The percentage of screen residues is slight. The drying shrinkage is medium. The total shrinkage at cone 9 is high. Vitrification is complete at cone 13. It is a re- fractory clay. It is suggested that it will be found of use in the manufacture of re- fractories requiring a densely burned body at a low temperature, such as crucibles. Sample No. 26 (Elmer Gant mine; SE. ^ SE. % sec. 2, T. 12 S., R. 2 W.) This is a soft white clay which may be brought to a good plastic condition with the development of some stickiness. It flows through a die satisfactorily when it is in a stiff condition. Water of plasticity per cent 41.5 Shrinkage water per cent 25 Pore water per cent 16.5 Modulus of rupture lbs. per sq. in. 259.0 With 50% standard sand — Modulus of rupture lbs. per sq. in. 137.5 Slaking test, average min. 34 Drying shrinkage : — Per cent Linear ; dry length 8.4 Linear ; wet length 7.64 UNION COUNTY 61 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 16 10.2 5 1.4 Gray white 10.7] | 9 1.8 Stoneware gray . . 11.3 | 12 2.8 Light tan exterior ; heavily blue- K Hackly, vitreous frac- stoned 11.0 ture 13 3.27 10.0 15 3.0 Gray exterior ; bluestoned 9.1 Hackly fracture Fusion test : — It deformed at cone 33. Summary The strength of the unburned clay in the dry condition is medium. The bonding strength is medium low. It leaves no residues on the screens. The drying shrinkage is medium. The total shrinkage at cone 9 is high. Vitrification is practically com- plete at cone 5. It is highly refractory clay. It is suggested that it will find use in the manufacture of refractories, especially those having a dense body. Sample No. 11 (Aladdox and Nixon mine ; NE. 14 sec. 10, T. 12 S., R. 2 W.) This is a plastic clay of a white color, through a die quite satisfactorily. Water of plasticity Shrinkage water Pore water Modulus of rupture Slaking test, average Screen test : — Mesh 40 60 80 120 200 Drying shrinkage, linear; dry length Burning test : — It has good working properties and flows per cent 32.9 per cent 23.5 per cent 9.3 lbs. per sq. in. 43.4 (?) min. 6 Residue Character of Per cent residue None . 0.03 White sand . 0.03 White sand . 0.8 White sand, some mica . 2.1 White sand, some mica Burning Cone Porosity Color shrinkage Total shrinkage Per cent Per cent Per cent 02 39.6 Light cream 3.8 8.3 1 38.4 Light cream 4.5 9.0 3 31.1 Light cream 7.4 11.9 5 28.8 Dark cream 9.0 13.5 7 15.6 Dark cream 9.9 14.4 9 12.9 Light brown 11.2 15.7 13 6.9 Light brown . ... Fusion test: — It deforms at cone 33. 62 ILLINOIS FIKE CLAYS Summary The percentage of screen residues is slight. The drying shrinkage is medium low. The total shrinkage at cone 9 is high. Vitrification is incomplete even at cone 13. It is a highly refractory clay. It is suggested that it will find use in the manu- facture of refractories of a high grade. Sample No. 16 (Maddox and Nixon mine; NE. % sec. 10, T. 12 S., R. 2 W.) This is a soft clay of nearly white color. Its working property is good. Its con- duct when flowing through a die is satisfactory. Water of plasticity . Shrinkage water . . . . Pore water Modulus of rupture. Slaking test, average Screen test : — Mesh Residue Character of Per cent residue 60 . . . 0.05 White mica and white sand 80 . . . 0.22 White mica and white sand 120 . . . 5.3 White sand 200 . . . 5.4 White sand Drying shrinkage, linear ; dry length Volume Burning test: — Burning Cone Porosity Color shrinkage Total shrinkage Per cent Per cent Per cent 02 35.7 Light cream . . . ... 2.1 6.4 1 35.2 Light cream . . . ... 2.1 6.4 3 32.2 Light cream . . . ... 3.3 ^Conchoidal ) Fracture 5 20.4 Light cream . . . .... 7.4 11.7 7 19.6 Light cream . . . ... 8.0 12.3 9 17.8 Light cream . . . ... 9.2 13.5 13 13.0 Dark gray . . . ... 9.7 14.0 Fusion test: — It fused at cones 30/31 Summary The strength of this clay is low. The percentage of screen residues is con- siderable. Its dryin g shrinkage is low. The total shrinkage at cone 9 is medium high. It is not completely vitrified even at cone 13. This is a refractory clay and it will be found useful in the manufacture of refractories. Sample No. 18 (Wm. Ferril pit; NE. % sec. 3, T. 12 S., R.2W.) This is a soft white clay with occasional yellow discolorations. Its working property is good. It flows satisfactorily through ; a die. Water of plasticity . Shrinkage water . . . UNION COUNTY 63 Pore water per cent 24.6 Modulus of rupture: — The test pieces prepared for the determination of its strength proved to be too weak to be tested. Slaking test, average min. 6 Screen test : — Mesh Residue Character of Per cent residue 20 None 40 Trace 60 04 Fine white sand 80 0.2 Fine white sand 120 0.7 Fine white sand 200 0.9 Fine white sand Drying shrinkage, linear per cent 3.1 Volume per cent 12.5 Burning Cone test : — Porosity Color Burning shrinkage Total shrinkage Remarks 02 Per cent 40.9 White Per cent 1.9 Per cent 5.0 3 38.6 White 5.6 8.7 5 36.3 White 6.2 9.3 9 29.1 White 9.0 12.1 13 0.05 White Contains very Fusion test: — It deforms at cone 33/34. fine reddish specks Summary The strength of the clay is very low. The percentage of screen residues is slight. Its drying shrinkage is medium low. The total shrinkage at cone 9 is medium. Vitrification is incomplete even at cone 13. It is a highly refractory clay. It is sug- gested that this clay will prove to be of value when used with stronger clays in the manufacture of high grade refractories. Sample No. 22 (Wm. Ferril pit; N.E. *4 sec. 3, T. 12 S., R. 2 W.) This is a moderately hard clay of a light gray color. It has good working properties in the plastic condition and flows satisfactorily through a die. Since only a small sample was secured for the preliminary test and subsequent attempts to obtain more material were unsuccessful because the face of the pit was inaccessible, complete test could not be made. The fairly long period required for slaking may indicate a clay of high bonding strength. The fusion test is very satisfactory. Suggested uses : This clay will be of value in the manufacture of refractories and possibly of particular interest to manufacturers of crucibles. Slaking test, average Fusion test : — It fuses at cone 32. min. 42 64 ILLINOIS FIRE CLAYS MASSAC COUNTY PADUCAH POTTERY COMPANY’S PIT The Paducah Pottery Company has a clay pit on the east side of the Chicago, Burlington and Quincy Railroad half a mile north of Choat, in the NE. cor. sec. 17, T. 15 S., R. 4 E. The clay body is lens-shaped and the accompanying sketch (fig. 52) shows the relation to the sandstone and gravel above and the sandstone below. The grayish- white laminated clay is 14 feet 4 inches thick, and 2 feet 10 inches of reddish brown clay above are discarded with the overburden. The clay is loaded at Choat and shipped to the plant at Paducah. No tests have been made to determine the extent of the clay. 1 0 8 6 4 2 o 10 Scale In feet Fig. 52. Sketch showing the clay body and its relations to the surrounding strata at the Paducah Pottery Company’s clay pit north of Choat. A Soil. B Loess. C Chert pebbles, red clay, and quartz gravels. D Sandstone, cemented by iron. E White clay, laminated with thin sheets of fine micaceous sand. Shipments vary somewhat as the clay is needed at the pottery, but averaged in the spring of 1918 from one to two cars per week. CLAYS FROM THE VICINITY OF ROUND KNOB No clay is dug near Round Knob at the present time, though formerly clay was shipped to potteries at Metropolis and Paducah, and there is an abandoned pit a quarter mile south of Round Knob, in the SW. sec. 1, T. 15 S., R. 4 E. When operated this pit furnished three grades of clay, MASSAC COUNTY 65 white, blue, and gray, and had a working face of 8 to 10 feet. 1 Another pit nearby had 7 feet of clay. The overburden varied in thickness up to a maximum of 18 feet. Clay could still be obtained by removing a heavy overburden. A sample was taken from the road gutter a half mile west of Round Knob, in the N. y 2 SW. sec. 8, T. 15 S., R. 4 E., where the section is as follows : 4. 3 . 2 . 1 . Section half a mile west of Round Knob Gravel, rises with the hill Clay, red Clay, white and pink, sandy, laminated ; pie No. 46) Sand, red and white Thickness Feet 2 to 6 4 stains of iron oxide (sam- ey 2 \y 2 A report of the tests made on sample No. 46 is given on pages 65 and 66. CLAY FROM THE OBERMARK PROPERTY A well is reported to have penetrated 30 feet of clay on the C. G. F. Obermark farm in sec. 36, T. 14 S., R. 5 E. A thin sandy horizon lies about 4 feet below the surface and streaks of iron at other horizons. The clay is blue-gray, sandy, and of fair plasticity. The sample (Sample No. 47) was taken by boring in a creek bed. Ten acres or more of this clay is available under an overburden of not more than 6 feet. Similar clay has also been dug in sec. 6, T. 15 S., R. 5 E. A sample (Sample No. 48) was taken from clay exposed along the road between secs. 8 and 9, T. 15 S., R. 6 E. This is an ash-colored, sandy, lam- inated clay, interbedded with seams of limonite and probably not of com- mercial value. These two samples (No. 47 and No. 48) were tested with the results given on pages 66 and 67. RESULTS OF TESTS MASSAC COUNTY Sample No. 46 (N. K SW. 54 sec. 8, T. 15 S., R. 4 E.) This is a soft, very sandy clay, containing much mica. It is a cream color, mottled with brown and pink. When mixed with sufficient water, it develops a fair degree of plasticity and will flow through a die satisfactorily. Water of plasticity per cent 22.2 Shrinkage water per cent 11.6 Pore water per cent 10.6 Modulus of rupture lbs. per sq. in. 217.4 With 50% standard sand — Modulus of rupture lbs. per sq. in. 214.0 Slaking test, average min. 27 iPurdy, R. C., and DeWolf, F. W., Preliminary Investigations of Illinois Fire Clay : 111. State Geol. Survey Bull. 4, p. 149, 1907. See description of sample D28. 66 ILLINOIS FIRE CLAYS Screen test : — Mesh 20... 40.. . 60.. 80. . Residue Per cent 2.9 1.7 Character of Residue Pyrites, sandstone and mica Pyrites, sandstone and mica Mica and sand White sand 120... 36.2 White sand 150... 13.5 White sand 200... 5.9 White sand Drying shrinkage, linear Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 08 36.7 Light brownish red . . . . +0.5 06 35.4 Light brownish red .... +0.6 04 35 Light brownish red .... +0.8 02 36.8 Light brownish red . ... +0.6 The clay expands dur- 1 34.9 Light brownish red .... +0.8 ing burning 3 36.5 Light brownish red . ... +0.6 The burned pieces are 5 36 3 Darker brownish red very weak 7 35.3 Darker with iron specks... .... +1.0 9 36.0 Darker with iron specks... .... +0.7 11 35.5 Darker with iron specks... .... +0.9 Fusion test: — It deformed at cone 31. Summary This is a clay of medium strength, much higher than might be expected con- sidering its very sandy character. The bonding strength is medium. The percentages of screen residues are high. The drying shrinkage is low. Because of its sandy nature, the clay has a high and nearly constant porosity at all temperatures showing no sign of vitrification. This also explains the reason for the fact that it does not shrink but expands slightly at all temperatures. Suggested uses : The lack of strength of the unburned clay will restrict its usefulness to admixtures with other clays. Such sandy clays often have a distinct usefulness. Because of its high fusion test it should be of use in refractories. Sample No. 47 (C. G. F Obermark farm; sec. 36, T. 14 S., R. 5 E.) This is a dark colored, moderately hard clay. It has a medium plasticity when mixed with 28.5% water and in that condition shows rather poor flowing properties when squeezed through a die. Water of plasticity per cent 25.3 Shrinkage water per cent 16.0 Pore water per cent 9.3 Modulus of rupture lbs. per sq. in. 365.8 Slaking test, average min. 10 Drying shrinkage, linear per cent 6.8 PULASKI COUNTY 67 Burning test : — Burning Total Cone Porosity Color shrinkage shrinkage Per cent Per cent Per cent 02 20.6 Dark cream . . . 3.2 10.0 1 20.9 Dark cream . . 3.2 10.0 3 19.6 Cream 3.2 10.0 7 13.9 Gray 3.4 10.2 9 7.6 Gray 4.4 11.2 10 9.5 Gray Fusion test: — Completely deformed and vesicular at cone 27. Remarks Conchoidal fracture No evidence of over- burning Summary This clay has a medium strength and medium drying shrinkage. The burning shrinkage at cone 9 is low. It is an open burning clay, which is incompletely vitrified at cone 10. The clay is not refractory. Suggested uses : Face brick, stoneware, architectural terra cotta, sanitary ware. Sample No. 48 (Secs. 8 and 9, T. 15 S., R. 6 E.) This is a gray colored clay, mottled with brown. It contains much mica. Slaking test, average min. 12.5 Fusion test: — No deformation at cone 27. Summary Insufficient material was received for complete test. However, it was found to be a refractory clay. The mode of occurrence with seams of limonite will prevent its use unless some method of purification is employed. PULASKI COUNTY CLAYS FROM THE VICINITY OF GRAND CHAIN Clay was formerly dug for pottery near Grand Chain Landing and re- cently prospect pits have been opened at several places. On the O. C. Field property pits have been dug in lenses of clay in the N.E % sec. 9, T. 15 S., R. 2 E., where sample No. 38, tests of which are re- ported on pages 68 and 69, was taken. Both the bottom and the top are irregular, the top rising backward into the hill. A thickness of 20 feet of “black fat” clay has been exposed and is said to be underlain by blue and pink clay. The overburden of 3 feet of iron-cemented sand and gravel capped by loess thickens back over the ridge to a maximum of 15 feet. Clay has also been worked just above water level in Ohio River. J. W. Joynt of Tamms, Illinois, has done considerable prospecting both by boring and pits in east half of sec. 4 and west half of sec. 3, T. 15 S., R. 2 E. The clay is irregular and lenticular, ranging up to 12 feet as a maxi- mum thickness. It is underlain by sand and overlain by gravel and loess. At pits in the N. y 2 SE. % sec. 4 the overburden will average 14 to 15 feet. This clay is white and resembles the clay from Mountain Glen. Clay from 68 ILLINOIS FIRE CLAYS the J. B. Hays farm in the SW. 34 sec. 3 was of a chocolate color and con- tained lignite. The sample No. 37 was taken from a bin which contained clay from several test pits. Results of tests made are reported on pages 69 and 70. A sample of white to gray plastic clay was taken from the road ditch two miles east of Grand Chain, where clay was in the gutter. The sample was obtained by boring. The section is as follows : Section 2 miles east of Grand Chain Thickness Ft. In. 4. Loess 16 to 32 ... 3. Gravel and red clay 4 6 2. Clay, red 1± 1. Clay, white to gray, plastic; exposed in road gutter 21 4 Sample No. 45 resampled as No. 1678 represents the upper portion. Sample No. 44 resampled as No. 1691 is from the lower portion of the deposit. Results of tests made on these two samples are presented on pages 70 to 72. The top surface of the clay probably rises in the hill and if so the overburden would be less than given in the section. Other slopes show sand and impure clay at this horizon, proving that the clay is lenticular just as it is at other localities. CLAY FROM CALEDONIA A sample, No. 17, was taken from the dark gray clay exposed along the river bank at Caledonia (nearest railroad station, Olmsted). This comes from a 25-foot exposure and is a weathered product of the “soapstone” of Midway age. The lower 14 feet of a section exposed in the river bluffs on the Barber farm, 2^4 miles above Caledonia, in sec. 13, T. 15 S., R. 1 E., is of a gray, micaceous, thinly bedded clay. This contains some lignite and pyrite concre- tions and is said to extend down to low water level 20 feet below the bottom of the measured section. The overburden would be very thick, but hydraulic stripping would be possible at this place. Sample No. 37a (see page 73 for results of tests) is from this horizon. A very plastic white clay is exposed about 200 yards down stream at or near the water level. The exposure is small and the quantity uncertain. RESULTS OF TESTS PULASKI COUNTY Sample No. 38 (O. C. Field pit ; NE. y A sec. 9, T. 15 S., R. 2 E.) This is a soft shaly material of a brownish color. It has good plasticity and flows smoothly through the die when a suitable amount of water is added. PULASKI COUNTY 69 Water of plasticity . Shrinkage water . . . Pore water Modulus of rupture Slaking test Screen test : — per cent 38.6 per cent 24.6 per cent 14.0 lbs. per sq. in. 164.8 min. 50 Mesh Residue Character of Per cent Residue 20 0.27 Rock particles 40 0.25 Rock particles and sand 80 0.16 Rock particles and sand 120. 1.69 Rock particles and sand 200 1.52 Rock particles and sand Drying shrinkage : — Per cent Linear ; wet length 7.25 Linear ; dry length 7.8 Burning test: — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 33.4 White 1.8 02 2 5 9 13 14 24.7 18.1 16.5 14.0 3.7 2.8 Cream 3.4 Cream 6.0 Cream 5,6 Cream 6.0 Stoneware gray 7.0 Dark buff exterior, bluestoned.. 6.2 Hackly fracture Hackly fracture Hackly fracture, vitre- ous Smooth fracture Appears to be over- burned Fusion test: — It deforms at cone 30. Summary The dry clay has medium low strength. The amount of residues left on the screens is low. The drying shrinkage is medium. The total shrinkage at cone 9 is medium high. Vitrification is practically complete at cone 13. It is a refractory clay and therefore suitable for use in the manufacture of such wares. The light color of the burned clay and its other properties make it available for architectural terra cotta, stoneware, and sanitary ware. Sample No. 37 (Secs. 3 and 4. T. 15 S., R. 2 E.) This is a soft clay containing a few nodules of carbonaceous matter. It is of a light gray color. It flows through a die fairly satisfactorily. Water of plasticity per cent 30 Shrinkage water per cent 21.6 Pore water per cent 8.4 Modulus of rupture lbs. per sq. in. 487.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 249.7 Slaking test, average min. 7 70 ILLINOIS FIRE CLAYS Screen test : — Mesh Residue Character of Per cent Residue 20 Trace 40 Trace 60 Trace 80 T race 120 02 Quartz and mica par- ticles 200 07 Quartz and mica par- ticles Drying shrinkage : — Per cent Linear ; wet length 6.6 Linear ; dry length 7.1 Burning test : — Cone Porosity Per cent 2 15.9 Color Cream Burning shrinkage Per cent 4.95 Remarks 5 9.6 Darker cream 5.7 9 1.7 Gray 10.1? Conchoidal vitreous fracture 12 .57 5.6 Conchoidal vitreous fracture uy 2 18 Tan exterior ; bluestoned interior 4.34 Fusion test : — It deformed at cone 28. Summary The strength of the unburned clay is medium high. Its bonding strength is medium. There is only a trace of residues on the screens. The drying shrinkage is medium. The total shrinkage at cone 9 is high. Vitrification is practically com- plete at cone 9. The sample is apparently overburned at cone 13J-4 although it is thought this appearance may be due to the peculiar shattering of the clay during the firing. It is a refractory clay. Suggested uses : For refractories, particularly those of a dense character such as crucibles ; also architectural terra cotta, stoneware, and sanitary ware. Sample No. 45 (resampled as No. 1678) (2 miles east of Grand Chain) This clay was bored for samples and later resampled as No. 1678. This record applies to sample No. 1678. It is a clay of medium hardness and a red color. It develops a good plasticity when worked with the addition of a sufficient amount of water. When the plastic clay is squeezed through a die it flows fairly well. Water of plasticity per cent 29.2 Shrinkage water per cent 15.3 Pore water per cent 13.4 Modulus of rupture lbs. per sq. in. 526.6 With 50% standard sand — Modulus of rupture lbs. per sq. in. 299.5 Slaking test hours 2j/> PULASKI COUNTY 71 Screen test : — Mesh Residue Character of Per cent residue 20 1.0 Brown sandstone 40 Mica and white sand 60 Mica and white sand 80 Mica and white sand 120 30.2 Brown and white sand 150 9.4 Brown and white sand 200 2.0 Brown and white sand Drying shrinkage, linear Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 08 36.8 Reddish brown 0.6 06 35.0 Reddish brown 1.1 04 34.9 Reddish brown 2.0 02 35.0 Reddish brown 9 2 1 33.8 Reddish brown 2.5 3 33.5 Reddish brown 2.4 5 34.3 Brown and black 2.2 7 32.7 Brown and black 2.2 9 34.0 Black 1.9 The burned pieces are weak. Fusion test : — No. 45 deforms at cone 30. No. 1678 deforms at cone 28. Summary This clay has a medium high strength tested alone and a medium bonding strength. This is particularly interesting because the screen test shows the presence of a high content of fine grained sand which does not impair its working properties. The dry- ing shrinkage is medium. It shows a very open burning body at all temperatures with low burning shrinkages. The fusion test indicates a refractory clay. Such open burning refractory clays having good plasticity and strength are of value used alone or in mixtures in the manufacture of refractory wares. Sample No. 44 [resampled as No. 1691] (2 miles east of Grand Chain) This is a soft clay of a gray color. It develops a fair degree of plasticity. Water of plasticity per cent 33.8 Shrinkage water per cent 21.4 Pore water per cent 12.4 Modulus of rupture lbs. per sq. in. 465.6 With 50% standard sand — Modulus of rupture lbs. per sq. in. 325.6 Slaking test min. 32 Screen test : — Mesh Residue Character of Per cent Residue Trace Trace Mica Trace 20 40 60 72 ILLINOIS FIRE CLAYS 80 Trace 120 1.32 Mica and sand 150 5.47 Mica and sand 200 4.80 Mica and sand Drying shrinkage : — Per cent Linear ; wet length 6.8 Linear ; dry length 7.0 Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 08 31.0 Light gray 1.45 06 27.6 Light gray 2.24 04 23.2 Cream 3.81 02 22.2 Cream 3.6 1 17.2 Cream 4.1 3 17.4 Cream 4.6 5 11.5 Grayish 4.9 7 12.3 Grayish 5.1 9 10.4 Grayish 5.3 11 10.9 Grayish 5.0 Fusion test: — It deforms at cone 29. Summary This clay has a medium high bonding strength. The drying shrinkage is medium. It does not reach a low porosity within the temperature range employed — up to cone 11. The shrinkage at cone 9 is medium. It is a refractory clay, but not of high grade. In addition to its use in refractories, it is of the type used for stoneware, architectural terra cotta, and sanitary ware. Sample No. 17 (River bank at Caledonia) This is a clay of rather hard and shaly character which seems to contain a considerable quantity of mica. The clay is of a brownish color marked with yellow specks. It has rather a poor degree of plasticity and does not flow satisfactorily through a die. Water of plasticity per cent 80.9 Shrinkage water per cent 28.1 Pore water per cent 52.8 Modulus of rupture lbs. per sq. in. 180.9 Slaking test, average min. 4 Screen test : — Mesh Residue Character of Per cent residue 10 0.25 Particles of clay 14 2.2 Particles of clay 20 8.8 Particles of clay 35 19.5 Sand and clay 48 6.3 Clay and flakes of mica 65 4.3 Clay and flakes of mica 100 5.0 Clay and flakes of mica 150 4.0 Clay and flakes of mica 200 4.1 Clay and flakes of mica PULASKI COUNTY 73 Drying shrinkage, linear per cent 5.0 Volume per cent 25 Burning test : — Cone Porosity Per cent 38.6 38.2 38.8 38.6 34.6 34.0 02 1 3 5 7 9 13 14.8 Color Remarks Light brown Poorly oxidized Light brown Light brown Darker brown Darker brown Black Appears to show vitri- fication Black Overburned Fusion test : — It melts to a glass below cone 26. Summary The strength of the clay is medium low. The percentage of screen residue is high. Its drying shrinkage is medium low. It appears to be overburned at cone 13 even though its porosity is still quite high. The exceptionally high contents of water of plasticity and pore water indicates a very high colloidal content. Because of this the clay gives erratic results in the strength tests. This deposit has proved to be a good grade of fuller’s earth and a plant is in operation preparing it for the market. Sample No. 37 a (Barber farm ; sec. 13, T. 15 S., R. 1 E.) This is a light gray soft clay which contains many mica particles. The plastic mass is readily molded into shape and it flows well through a die. Water of plasticity per cent 27.9 Shrinkage water per cent 14.9 Pore water per cent 13.0 Modulus of rupture lbs. per sq. in. 240.7 With 50% standard sand — Modulus of rupture lbs. per sq. in. 238.7 Slaking test, average min. 15 Drying shrinkage : — Per cent Linear ; wet length 3.2 Linear ; dry length 3.4 Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 2 28.80 Cream 2.6 5 27.00 Cream 2.2 9 3.7 Light gray 6.1 12 7.2 Light gray 5.0 13^ 13.0 2.4 Fusion test: — Complete fusion at cone 25. 74 ILLINOIS FIRE CLAYS Summary This clay has medium strength. Its drying shrinkage is medium low. It devel- ops a high degree of vitrification between cones 5 and 9 with a medium burning shrinkage. It overburns at cone 12 and is non-refractory since it fuses at cone 25. The clay ought to find use for manufactures of stoneware, architectural terra cotta, sanitary ware and similar wares. ALEXANDER COUNTY CLAYS FROM THE AETNA POWDER COMPANY’S LAND Bedded clays are exposed at several places on the land of the Aetna Powder Company. High on the ridge at the first separator house, at least 9 feet of gray laminated clay has been exposed in the excavation for the foundation. The clay is light drab to gray in color and interstratified with distinct beds of mica and fine sand. The section is as follows : Section at first separator house of Aetna Powder Company at Fayville Thickness Feet 3. Loess, with soil at top 20 2. Gravel 1 to 2 1. Clay laminated (Sample No. 41) ; small crystals of gypsum 9 The clay could not be worked while this part of the plant is in operation. Results of tests of sample No. 41, which was taken from the upper 5 feet, are given below. In the hollow behind the old powder plant, clay is exposed at several places. The section varies from place to place, but the following is repre- sentative : 7. 6 . 5. 4. 3. 2 . 1 . Section behind old powder plant at Fayville Soil Loess Clay and sand, ash colored Sand, buff, but loosely cemented Conglomerate layers, cemented by iron ; pebbles up to 3 inches Clay, lignitic Clay, sandy, micaceous ; very pure in places (Sample No. 42) . . Thickness Ft. In. 1 3 . 10 + .. 4 5 6 1 6 3 4 Most of this clay has 20 feet or more of overburden. Results of the tests on Sample No. 42 are given below. RESULTS OF TESTS ALEXANDER COUNTY Sample No. 41 (Aetna Powder Company, at Fayville) This is a micaceous clay of a gray color streaked with brown. It is moderately hard. When plastic, it is rather sticky. Water of plasticity Per cent 32.3 Shrinkage water P* r cent 21.9 ALEXANDER COUNTY 75 Pore water Slaking test, average Drying shrinkage, linear Burning test : — Burning Total Cone Porosity Color shrinkage shrinkage Remarks Per cent Per cent Per cent 02 18.9 Cream .... 3.9 12.5 Shrinkage determined on very small piece 13 8.4 Gray 3.9 12.5 Vitreous ; conchoidal fracture ; not over- burned ; shrinkage determined on very small piece Fusion test : — Y deformed at cone 25. The cone appears to have developed a decided vesicular structure. Summary A very plastic and rather sticky clay, which has a medium drying shrinkage. It has a medium porosity at cone 02 and is still quite porous at cone 13 with a medium high shrinkage. Its fusion point is about cone 25, which places it amongst the non- refractory clays. The incomplete tests indicate a clay which may be suited for stoneware, sanitary ware, or similar wares. Sample No. 42 (Aetna Powder Company at Fayville) The clay is a uniform light gray in color. It is rather hard. When tempered with water it has a fair degree of plasticity and flows through a die satisfactorily. Water of plasticity per cent 29.1 Shrinkage water per cent 15.4 Pore water per cent 13.6 Modulus of rupture lbs. per sq. in. 283.1 Slaking test, average min. 10 Drying shrinkage, linear 7.5 Burning test : — Total Cone Porosity Color shrinkage Remarks Per cent Per cent 02 12.8 Cream 13.7 Hackly fracture, vitre- ous 5 1.3 Gray 16.0 9 0.0 Gray 17.5 13 0.0 17.5 Fusion test : — Cone down at cone 25. No vesicular structure seems to have been de- veloped in the cone. Summary The clay has a medium strength. Its linear shrinkage is medium. The total shrinkage at cone 9 is high. Practically complete vitrification is reached at cone 5 and there are no signs of overburning at 'Cone 13. It is a non-refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, and face- brick 76 ILLINOIS FIRE CLAYS CLAYS OF PENNSYLVANIAN AGE Field and Laboratory Notes on Pennsylvanian Clays Field notes by C. R. Schroyer Tests by C. W. Parmelee MONROE COUNTY Clay outcrops in St. Clair County along a small creek that flows south- west in the SW. yf\ sec. 22, T. 1 S., R. 10 W. The clay is at the base of the Pennsylvanian system, specifically at the Cheltenham horizon. At the outcrop it is mottled yellow and white, plastic, and comparatively free from sand. Borings show that the yellow color is restricted to the upper part where there is an overburden of gravel and glacial drift. Section of clay 1 mile south of Columbia Thickness Ft. In. 5. Overburden, clay and gravel 0 to 20 .. 4. Clay, yellow and white (by boring) 10 8 3. Clay, white, exposed in bank of creek 2 2. Clay; boring in bed of creek (Sample No. 61) 3 6 1. Limestone, Mississippian The slope above the creek has slumped and it is uncertain if this thick- ness of 16 feet 2 inches represents the maximum thickness of the clay, which is exposed for 320 feet along the stream. A well 28 feet in depth ended in loose sand less than a quarter of a mile east of the outcrop. Other wells which should have reached the clay if it were a persistent bed, have not revealed it elsewhere. The quantity of this clay, though apparently small, is probably sufficient so that development for use as a blend with other clays might be considered. It is at the horizon of the Cheltenham clay of the St. Louis district. Sample No. 62 was taken from a boring which penetrated the entire thickness. RESULTS OF TESTS MONROE COUNTY Sample No. 61 (1 mile south of Columbia) This is a medium hard, grayish-colored clay, mottled with dark brown. It has a medium hardness. When tempered with water it becomes very plastic. Water of plasticity per cent 33.5 Shrinkage water per cent 20.5 Pore water per cent 13 Modulus of rupture, average lbs. per sq. in. 567 minimum lbs. per sq. in. 420 maximum lbs. per sq. in. 773 With 50% standard sand — Modulus of rupture lbs. per sq. in. 372.7 Slaking test, average min. 16 Drying shrinkage, linear per cent 8.4 PENNSYLVANIAN CLAYS 77 Screen test : — Mesh 20 Residue Per cent T race Character of residue 35. . Trace 60.. 0.32 Colored sand 120... 0.3 Colored sand 200.. Colored sand Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 1.5 Tan 7.6 Hackly, vitreous 2 0.6 Tan 7.4 Hackly, vitreous 5 1.6 Tan 6.9 Vitrified, hackly 9 6.1 Tan 6.3 Overburned 13 7.0 Dark tan Overburned Fusion test : — Complete fusion before cone 26. Summary This clay has an exceptionally good strength when tested alone, but only medium when mixed with standard sand. It is very free from all particles coarser than 200 mesh. The drying shrinkage is medium. It develops a high degree of vitrification at an exceptionally low temperature and overburns at cone 5. It is completely fused before cone 26 is reached and therefore is a non-refractory clay. This clay will probably be most useful for the manufacture of brick and blocks, etc., for building purposes, and possibly pavers. Sample No. 62 (1 mile south of Columbia) The sample borings are a gray color, mottled with yellow, a suitable quantity of water, the clay becomes very plastic. Water of plasticity Shrinkage water Pore water Slaking test, average Drying shrinkage, linear Burning test : — When mixed per cent per cent per cent min. per cent with 38.9 22.9 15.9 8 8.5 Cone Porosity Color Burning shrinkage Total shrinkage Remarks 02 Per cent 1.5 Terra cotta . . . . Per cent .... 3.7 Per cent 11.2 Vitrified 1 1.8 Light brown . . . . . . . 4.0 12.5 Vitrified 5 0.7 Reddish brown . Vitrified conchoidal 9 5.0 Reddish brown . 6.5 fracture Overburned 13 8.5 Reddish brown . Vesicular 1J O.U I\CUUIMI Fusion test : — Completely fused at cone 27, vesicular. Summary This is a non-refractory clay which vitrifies at a very low temperature and over- burns between cones 5 and 9. Its drying shrinkage is medium. Burning shrinkage at cone 1 is high. It is suited for use in the manufacture of building brick and common wares. 78 ILLINOIS FIRE CLAYS MADISON COUNTY “The outcrop of the fire clay in Madison County extends from a point on the county line north of Godfrey southerly and easterly to East Alton. South of East Alton it is cut ofif by the alluvium of the Mississippi River bottom. Fire clay is found, however, two miles east of Collinsville at Cantine at a depth of 270 feet, and it seems probable in view of the extent of the fire clay into the St. Louis district, that it may be found underlying the entire county.” 1 This clay is used for sewer pipe by the East Alton Stoneware Pipe Company at their plant \ l / 2 miles northeast of East Alton. Section of the Stoneware Pipe Company’s shaft at East Alton in the NE. % sec. 15, T. 5 N., R. 9 IV. 7. 6 . 5. 4. 3. 2. 1 . Shale, light colored ; flint concretions and nodules of calcareous ironstone Shale, black; “slate” of miners Coal (No. 2) Clay, “little vein” Limestone; hard, flinty, brecciated beds Green shale — 3 in. Dark shale — 2 in. Fireclay Coal — 1 in. Light colored fireclay — 3 ft. (Sample No. 59) Dark clay, colored by carbon — 11 ft. (Sample No. 60) Sandstone, brown, below Thickness Ft. In. 50 1 6 2 3 4 7 14 6 Only the upper 2 y 2 to 3 feet of the dark clay and the 3 feet of light clay are used for sewer pipes. The lower beds run high in sulphur and contain large amounts of pyrite. These lower beds are variable in thickness and in places missing, so that the total thickness is not over six feet. At the old mines in the NW. sec. 15 the thickness is reported to have been about seven feet. RESULTS OF TESTS MADISON COUNTY Sample No. 59 (Stoneware Pipe Company’s shaft; NE. % sec. 15, T. 5 N., R. 9 W.) A very hard, dark gray colored clay which develops a good plasticity although a little sticky. It flows satisfactorily through a die when rather soft. Water of plasticity per cent 36.2 Shrinkage water per cent 24.0 iLines, Edwin H., The Pennsylvanian fire clays of Illinois : 111. State Geol. Survey Bull. 30, p. 66, 1917. MADISON COUNTY 79 Pore water Modulus of rupture With 50% standard sand — Modulus of rupture Slaking test Screen test : — Mesh Residue Per Cent 40 17 60 4.57 80 1.05 120 6.76 150 1.4 200 1.44 Drying shrinkage : — Linear ; wet length Linear ; dry length Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 2 3.4 Grayish white 6.3 5 2.4 6.6 9 5.4 Tan exterior 5.7 12 14.2 Red tan exterior, bluestoned in- terior 3.4 13 11.9 2.3 15 10.0 Buff bluestoned 2.9 Oxidation conduct: — Very difficult to oxidize. Fusion test : — Down at cone 28. per cent 12.2 lbs. per sq. in. 589.0 lbs. per sq. in. 169.8 hours 6 Character of residue Pyrites Pyrites, hard particles of clay and fine sand Pyrites, fine sand, and clay Pyrites, sand, and clay Pyrites, mica, fine sand, mostly clay Mica, fine sand and clay Per cent . 9.72 . 10.5 Remarks Black core Black core Large iron slag spots Summary A clay which has medium high strength when tested without admixture of sand but shows a medium low bonding power. It contains a notable amount of mineral particles which are retained upon the screens. The presence of pyrite amongst these explains the slag spots formed at high temperatures as well as the pitted and vesicular appearance of the fusion test. Undoubtedly this clay can be greatly improved by washing. The drying shrinkage is medium high and the burning shrinkage at cone 9 is medium high. Its low porosity at cone 2 is unusual. The overburning which de- velops between cones 9 and 12 is undoubtedly due to the high carbon and sulphur content. It is a difficult clay to oxidize. It is thought that the purification of this clay by washing will greatly improve its properties and extend its usefulness ; otherwise, it will be very difficult to use because of its high carbon-sulphur content and consequent slow oxidation. 80 ILLINOIS FIRE CLAYS Sample No. 60 (Stoneware Pipe Company’s shaft; N.E . x /^ sec. 15, T. 5 N., R. 9 W.) The sample is a dark brown clay, having a flinty hardness. Its plasticity is good although it is slightly sticky. When it has rather a soft consistency, it flows well through a die. Water of plasticity per cent 3.3.05 Shrinkage water per cent 23.05 Pore water per cent 10.0 Modulus of rupture lbs. per sq. in. 427 With 50% standard sand — Modulus of rupture lbs. per sq. in. 164.5 Slaking test . . Screen test : — hours Mesh Residue Character of Per cent residue 60 Particles of sand 80 100 0.16 Fine sand 150 0.17 Fine sand and organic matter 200 0.15 Fine sand and organic matter Drying shrinkage Pet cent Linear ; wet length 8.72 Linear ; dry length Burning test: — Cone 2 5 9 12 13 9.3 Burning Total Porosity Per cent Color shrinkage Per cent shrinkage Per cent Remarks 2.45 Red 7.28 15.5 Vitreous 1.5 Grayish 7.3 Black core 0.7 Gray exterior 7.4 Black core 2.6 Tan exterior ; bluestoned . . 7.8 3.8 >t : — Cone 31 — bloated. 6.1 Overburned Summary This clay is similar in some respects to sample No. 59. Its bonding strength is medium low although the pure clay has a considerably higher modulus of rupture. It contains very little material too coarse to pass a 200-mesh sieve. The drying shrinkage is medium high. The burning conduct is of particular interest because of the low porosity reached at a low cone (2) and maintained over a wide range of temperature. There are some slight indications of overburning above cone 12. The presence of a black core at cones 5 and 9 indicates that care will be required in oxidizing this clay during burning. Suggested uses : Its property of burning dense at a low temperature and main- taining a wide vitrification range ought to make it desirable for vitrified or close bodies. It may possibly serve for pavers although the poor oxidation conduct may prevent this. It is being used for sewer pipe and probably would serve for conduits. The color of the burned clay is not satisfactory for stoneware. It may possibly be used for architectural terra cotta. CALHOUN COUNTY 81 CALHOUN COUNTY Formerly a plant at Golden Eagle manufactured fire brick from the clay lying directly below the No. 2 coal. The mines are in bad condition (fig. 53) and no measurement of the clay could be made. Five feet of the upper part of the seam was mined. At the bottom of this level are nodular limestone boulders full of pyrite crystals. Smaller boulders were found scattered through the clay. The sample No. 58 was taken from a pile of clay which had been dug several years previous. However this clay was still unslacked and appeared fresh and in good condition. Fig. 53. Abandoned fire clay pit at Golden Eagle. The area underlain by this clay is small, but with the present equipment might again justify operation. Directly above the clay is a two-foot coal bed which is mined with it. Transportation is entirely by water. RESULTS OF TESTS CALHOUN COUNTY Sample No. 58 (Abandoned plant at Golden Eagle) This is a very hard grayish colored clay which contains much finely divided pyrite. Upon the addition of a suitable amount of water it develops a good but sticky degree of plasticity. It slakes very slowly. Water of plasticity per cent 34.4 Shrinkage water per cent 25.5 Pore water per cent 18.9 Modulus of rupture lbs. per sq. in. 165.7 With 50% standard sand — Modulus of rupture lbs. per sq. in. 124.6 Slaking test hours 5 y 2 82 ILLINOIS FIRE CLAYS Screen test : — Mesh Residue Character of Per cent residue 120 50 Pyrites, fine sand and particles of sand 150 09 Mica and sand 200 12 Pyrites, sand, clay and organic material Drying shrinkage : — Per cent Linear; wet length 10.05 Linear; dry length 11.6 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 10.0 6.1 5 5.2 Tan 6.0 Small black core 9 7.0 Buff 4.3 Black core, fine iron 12 5.0 Buff exterior ; bluestoned. . , 5.0 spots 13 7.0 2.6 Flashed 15 5.5 Buff; bluestoned 2.8 Overburned Fusion test: — Cone Ys deformed at cone 26. The cone has a vesicular structure. Summary This clay has a medium low strength and a medium low bonding strength. The drying shrinkage is medium high. The effect of the small residue of finely divided pyrite becomes evident at the higher temperatures, especially in the fusion test. Washing the clay for some products will correct this. The poor oxidation conduct should be noted. The clay is on the border line between a non-refractory and a refractory material. The test piece has the appearance of having been overfired at cone 15. Suggested uses : Architectural terra cotta, face brick. GREENE COUNTY At White Hall, Greene County, fireclay has long been dug for use in the manufacture oPsewer pipe, and stoneware and refractory clay has been shipped widely from the pits at Drake. Two miles southeast of Hillview in the S. sec. 34, T. 12 N., R. 13 W., a small amount of clay has been recovered from above the Mississippian limestone. This is probably a residual clay from the decay of the limestone and if so, does not properly belong in the Pennsylvanian system. The clay has a greenish or bluish white color when wet, but whitens upon drying. The exposed part contains abundant cherty and calcareous nodules, and gritty calcareous sand. The thickness may locally be as much as 10 feet but the distribution is irregular and pockety, conforming as it does into the irregular surface of the underlying weathered limestone. GREENE COUNTY 83 Section of the small opening in S.]/2sec.34, T.12N., R.13W. Thickness Feet 4. Loess and soil 10 =*= 3. Gravel 2 2. Clay, blue, containing calcareous sand and small gravel ; traces of pink (Sample No. 57) 3 1. Limestone, residual, decomposed, and cherty; covered at base but underlain by bedded limestone further down the ravine 12 The extent of this clay is uncertain, but it has been found in nearby wells to the west. A few carloads have been dug from the slope above the limestone one mile west of this outcrop where a boring is said to have pene- trated 9 feet of clay. The results of the tests made on sample No. 57 are given on pages 84 and 85. The overburden would range from 15 to 35 feet, depending upon how far the working penetrated the divides. Washing would be necessary to make this clay suitable for use as a refractory. The results of the tests made on sample No. 55 which is from the E. N. Ford farm near Hillview, are given on pages 85 and 86. Clay has not been shipped from Drake for over two years. Previous to that time it had been shipped more widely than any other in Illinois. The greatest thickness of clay ever dug was 26 feet. A well penetrated 8 feet of clay below this. As both the top and bottom are irregular, the thickness is variable and becomes as little as 5 feet. An eighth of a mile south of the station it is 20 feet thick. The overburden varies from 10 to 40 feet, a thickness that makes the working of the old pit unprofitable. The clay has an Indian red color locally, especially near the top of the west pit, which renders the clay useless for refractory purposes. Clay is also reported from north of the railroad at Drake, where a well section was given as follows: Log of well north of Drake Description of strata “Earth” Not described Sandstone Clay Limestone Thickness Depth Ft. Ft. ... 12 12 ... 8 20 ... 7 27 ... 15 42 Sample No. 136, sent in by Mr. A. M. Cain, was taken from a shallow pit north of the railroad. Sample No. 54 was taken from the lower clay; sample No. 56 from the upper clay, 34 mile south of Drake. Sample No. 53 from the farm of C. T. Hicks, 34 mile south of Drake. The results of tests on these samples are given on pages 86 to 90. 84 ILLINOIS FIKE CLAYS Section of clay pits east of White Hall Thickness Ft. In. 6. Soil and yellow underlying hardpan 3 5. Clay, yellow, and till 16 4. Shale and clay, sandy; stringers of gravel 17 5 3. Clay, buff and white (Sample No. 49) 3 5 2. Clay, bluish with scattered purplish red and dark stains (Sample No. 52) 7 6 1. Partly covered to deepest part of pit; clay not now worked 3 6 The clay above as well as that below is used entirely for sewer pipe and stoneware by the White Hall Sewer Pipe and Stoneware Company at their plant in White Hall. Results of tests on samples No. 49 and No. 52 are given on pages 90 to 92. 6 . 5. 4. 3. 2 . 1 . Section 2 x / 2 miles northeast of White Hall Drift Shale, local Coal (No. 2) Clay, yellow, sandy Clay, white and buff (Sample No. 51) Clay, bluish ; iron concretions in places ; used for sewer pipes (Sample No. 50) Thickness Ft. In. 12 1 10 2 6 4 6 17 6 The results of tests made on samples No. 51 and No. 50 are given on pages 92 to 94. Lines 1 says of this area: “It is reported * * * that good deposits extending another mile east are available when the present pits are worked out. The dip of the rocks here is easterly, and nothing is known of the clay after it gets below drainage, but it is possible that shafts would reach the clay over a large area.” RESULTS OF TESTS GREENE COUNTY Sample No. 57 (S. sec. 34, T. 12 N., R. 13 W.) The sample is a gray colored clay stained with yellow and containing a few black spots. When tempered with water it is very plastic. Water of plasticity per cent 25.9 Shrinkage water per cent 14.9 Pore water per cent 11.0 Modulus of rupture lbs. per sq. in. 565. 5 With 50% standard sand — Modulus of rupture lbs. per sq. in. 370 Slaking test, average min. 9 Drying shrinkage, linear per cent 7.0 Volume per cent 27.6 iLines, Edwin H., Pennsylvanian fire clays of Illinois: 111. State Geol. Survej’ Bull. 30, p. 67, 1914. GREENE COUNTY 85 Burning test : — Cone 02 Porosity Per cent 12.9 Color Gray Burning shrinkage Per cent 12.5 Remarks 1 18.9 Cream 11.1 3 1.5 Dark gray 12.5 Vitreous conchoidal 5 0.3 Dark gray 13.1 fracture 7 0.4 Dark gray 12.5 Glassy fracture 9 0.6 Dark gray 12.1 Glassy fracture 13 0.6 Dark gray 11.7 Glassy fracture Small particles of some more fusible mineral are scattered through the mass. Note: — Grayish color of cone 3 et seq. may be due to reduction. Fusion Test : — Fused completely at cone 26. Summary The strength of the unburned clay is medium high and the bonding strength is medium. The drying shrinkage is medium and at cone 9, the total shrinkage is medium. The test pieces were virtually non-porous at cone 3 and showed no signs of overburning at cone 13, indicating a very long range of vitrification. It is not a refractory clay. Suggested uses: The very satisfactory strength tests together with the early vitrification and long heat range suggest a clay useful for stoneware, architectural terra cotta, sewer pipe, and paving brick. The rapid rate of vitrification between cones 1 and 3 may prove to limit its usefulness. Sample No. 55 (E. N. Ford farm, near Hillview) This clay is colored brown mottled with gray. It contains numerous lumps of limestone varying in size from a small grain to a hazel nut. The clay tempered with water has good plasticity but is slightly sticky if too wet. Its conduct when squeezed through a die is fair. Water of plasticity per cent 39.5 Shrinkage water per cent 25.4 Pore water per cent 14.1 Modulus of rupture lbs. per sq. in. 172.5 With 50% standard sand — Modulus of rupture lbs. per sq. in. 145.17 Slaking test, average min. 55 Screen test : — Mesh Residue Character of Per cent residue 40 25 Light colored particles, few sand grains 60 97 Light colored particles, few sand grains 80 23 More fine sand 120 42 Light particles and fine sand 150 18 Light and colored 200 07 Fine sand, mica, light and hard particles 86 ILLINOIS FIRE CLAYS Drying shrinkage : — Per cent Linear ; wet length 6.05 Linear ; dry length 7.52 Volume 25.0 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 2.19 Very light tan 9.58 5 0.5 Very light tan 9.58 9 3.3 Gray 9.78 Vitreous fracture 12 4.62 Gray with iron spots 8.4 Small light red iron spots slagged in the piece 13 9 0 6.3 Fusion test : — Deforms at cone 29. Summary This is a clay of a medium low strength and medium low bonding strength. It has only a slight amount of screen residues coarser than a 200 mesh. The drying shrinkage is medium. It is practically non-absorbent at cone 2 and overburns be- tween cones 5 and 9. The shrinkage at cone 9 is high. Although the test cone did not deform until cone 29 was reached, yet there were numerous slag spots indicating advanced stages of fusion in local areas. Suggested uses: Face brick, sewer pipe (?), paving brick (?), architectural terra cotta, sanitary ware. Sample No. 136 (A. M. Cain; near Drake) This sample is a sandy, hard clay of a light gray color, mottled with brown. It has a medium plasticity and is inclined to be sticky. When forced through a die it flows satisfactorily. Water of plasticity per cent 25.6 Shrinkage water per cent 14.9 Pore water per cent 10.7 Modulus of rupture lbs. per sq. in. 586 With 50% standard sand — Modulus of rupture lbs. per sq. in. 376 Slaking test, average min. 28 Screen test : — Mesh Residue Character of Per cent residue 20 5.31 Quartz particles 40 39 Quartz particles 60 1.67 Quartz particles 80 55 Quartz particles, white and brown 120 3.76 Quartz particles 200 2.96 Quartz particles, most- ly brown GREENE COUNTY 87 Drying shrinkage : — Per cent Linear ; dry length 9.5 Linear; wet length 10.7 Volume 28.8 Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 04 24.7 Salmon -|-0.65 02 25 Red brown -|-0.8 2 23.7 Red brown 0.2 5 23 Red brown 1.4 9 20 Chocolate 1.5 13 21 Chocolate 3.1 Fusion test: — Completely deformed at cone 25. Summary This clay has a medium high strength, tested alone, but its bonding strength is medium. It contains a considerable amount of quartz sand. The drying shrinkage is medium high. The total shrinkage at cone 9 is medium. The burning shrinkages at all temperatures are low. In fact, there is a slight swelling at temperatures up to cone 1. The clay is open burning since its porosities are high at cones 5 and above. It is non-refractory. It is suited best for brick and similar products having a dark color and high porosity. Sample No. 54 mile south of Drake) This is a soft clay of a light gray color mottled strongly with darker gray and occasional brown spots. After the addition of a suitable amount of water it de- velops good plastic properties and flows fairly well through a die. Water of plasticity per cent 24.5 Shrinkage water per cent 11.7 Pore water per cent 12.8 Modulus of rupture lbs. per sq. in. 250 With 50% standard sand — Modulus of rupture lbs. per sq. in. 220 Screen test: — Mesh Residue Character of residue Per cent 20 0.13 Roots and rock parti- cles 40 0.03 Roots and rock parti- cles 60 015 Quartz sand 80 0.03 Quartz sand 120 0.54 Quartz sand, and mica 200 »• 4.2 Quartz sand, and mica 88 ILLINOIS FIRE CLAYS Drying shrinkage : — Linear ; dry length Linear ; wet length Volume Burning test : — Burning Cone Porosity Color shrinkage Percent Percent 02 22 White 1 22 White 3 21 Light cream 2.8 5 20 Light cream 3.5 6 19 Light cream 3.9 8 16 Dark cream 4.1 12 7.6 Cream, bluestoned slightly 5.7 13 4.0 Light tan exterior, bluestoned... 5.8 15 4.0 Tan exterior, bluestoned 6.9 Fusion test: — Deforms at cone 29. Per cent .. 5.7 .. 5.4 . . 24.1 Remarks Earthy fracture, vana- dium? stain Earthy fracture, vana- dium? stain, slight iron stain Earthy fracture, vana- dium? stain, slight iron stain Summary This is a clay having medium bonding strength. The drying shrinkage is me- dium. It contains very little material coarser than a 200 mesh. The burning shrink- age at cone 8 is medium. Samples burned up to and including cone 8 have quite a high porosity. This decreases rapidly between cones 8 and 12. It is a refractory clay. Possible uses : Architectural terra cotta, sanitary ware, stoneware, face brick, as a bond clay in refractories. Sample No. 56 04 south of Drake) A medium soft clay colored light gray, with brown stains and containing a few- black nodules. When tempered with water it is very plastic and flows well through a die. Water of plasticity per Shrinkage water per Pore water Modulus of rupture lbs. With 50% standard sand — Modulus of rupture lbs. Slaking test, average min. Screen test : — Mesh Residue Per cent 20 0.3 21.2 10.1 11.1 462 231.8 14 Character of residue 40 . Rootlets and rock par- ticles 0.12 Rootlets and quartz grains GREENE COUNTY 89 60 0.33 80 0.08 120 3.42 200 Drying shrinkage : — 8.59 Linear; dry length Linear; wet length Volume Burning test: — Cone Porosity Per cent 1 23 2 20 3 21.4 6 19 Color Cream Cream Light cream Light cream Burning shrinkage Per cent . . 2.2 ... 2.5 , . . 3.4 . . . 3.3 9 15 12 7 13 4 Cream 3.5 Dark cream 4.4 Light tan exterior ; bluestoned . . 4.5 15 5 Light tan ; bluestoned Fusion test; — Cone 28. Rootlets and white quartz grains White sand and mica with some organic matter White sand Per cent .. 4.9 .. 4.7 . . 19.5 Remarks Earthy fracture Earthy fracture Earthy fracture, slight veining of iron stain Earthy fracture Earthy fracture Very minute glassy spots on and in the piece Summary The strength of the dry clay is medium high. Its bonding strength is medium. The amount of residues on the screens is small. The drying shrinkage is medium low and the total shrinkage at cone 9 is medium. It is a refractory clay. Suggested uses : Architectural terra cotta, stoneware, sanitary ware, face brick, refractory wares. Sample No. 53 (C. T. Hicks; y$ mile south of Drake) This is a hard clay of a light gray color mottled with brown and darker gray color. When tempered with water it develops a good degree of plasticity and may be made to flow satisfactorily through a die. Water of plasticity per cent 17.2 Shrinkage water per cent 8.74 Pore water per cent 8.51 Modulus of rupture *. lbs. per sq. in. 120.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 103.1 Screen test: — Mesh Residue Character of residue Per cent 20 0.3 Quartz grains, rock grains and roots 90 ILLINOIS FIRE CLAYS 40. 60. 80. 120 . 200 . .09 Quartz grains, rock grains and roots 1.0 White sand with dark- er particles 0.4 White sand with dark- er particles 3.8 White sand with dark- er particles 4.6 White sand with dark- er particles Drying shrinkage Per cent .. 4.0 .. 3.8 Linear; dry length Linear; wet length Volume 17.1 Burning test : — Cone Porosity Color Burning shrinkage Remarks 02 Per cent 26 White Per cent 2.4 Earthy fracture 3 23 Very light cream 3.6 Earthy fracture shows 6 22 Very light cream 4.4 vanadium (?) stain Earthly fracture. Iron 8 19 Very light cream 4.6 spots, very small 9 18.2 Very light cream 4.9 12 13.0 Very light cream 6.2 13 7.6 Very light cream .... 6.2 Iron spots, very small 15 7.0 Bluestoned ; tan exterior. . . 7.5 and not conspicuous Fusion test : — Deforms at cone 30. Summary This clay has a medium low strength and a medium low bonding strength. The amount of the residues left upon the screens is moderate. The drying shrinkage is low. Shrinkage at cone 8 is medium. Vitrification proceeds slowly until cone 13 is reached. It is a refractory clay. Suggested uses : Face brick, architectural terra cotta, sanitary ware, and refrac- tories. Sample No. 49 (Clay pit east of White Hall) This is a light gray colored clay with brown stains which is moderately hard. Good plasticity is developed upon the addition of water, and in this condition it flows readily through a die. Water of plasticity per cent 24.3 Shrinkage water per cent 11.2 Pore water per cent 13.1 Modulus of rupture lbs. per sq. in. 369.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 189.5 Slaking test, average min. 23 GREENE COUNTY 91 Screen test : — Mesh Residue Character of residue Per cent 20 0.46 Colored sand 40 0.37 Colored sand 60 1.94 Colored sand 80 0.54 Colored sand 120 0.13 Colored sand 200 Trace Colored sand Drying shrinkage : — Per cent Linear ; wet length 4.75 Linear ; dry length 4.98 Volume 21.2 Burning test: — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 22.8 Cream 7.2 3 18.4 Light cream .... 7.2 Smooth fracture ; very fine iron speck 6 16.5 Cream .... 7.2 Smooth fracture ; very fine iron speck 8 12.9 Cream .... 5.8 9 9.6 Cream 5.6 Smooth fracture, very fine iron speck 12 0.5 Gray interior; light tan exterior 7.0 13 1.01 .... 6.5 15 8.8 Bluestoned ; buff exterior. . . 6.0 Very small iron spots Fusion test: — It fused at cone 30. Summary The clay has a medium strength and medium low bonding strength. The amount of screen residues is slight. The drying shrinkage is medium low and the burning shrinkage at cone 9 is medium. The clay vitrifies to a porosity of less than one per- cent between cones 9 and 12. Overburning appears at about cone 15. Suggested uses : Stoneware, architectural terra cotta, face brick, sanitary ware, refractories. Sample No. 52 (Clay pit east of White Hall) This is a hard dark gray colored clay mottled with yellowish brown. When ground and tempered with water it develops a good plasticity and flows readily through a die. Water of plasticity per cent 23.0 Shrinkage water per cent 9.9 Pore water per cent 13.1 Modulus of rupture lbs. per sq. in. 380.2 With 50% standard sand — Modulus of rupture lbs. per sq. in. 243.9 Slaking test, average min. 10 Screen test : — 92 ILLINOIS FIRE CLAYS Mesh Residue Character of residue Per cent 20 Trace 35 0.12 Particles of shale, coal and sand 48 0.10 Particles of shale, coal and sand 65 0.15 Particles of shale, coal and sand 100 2.0 Particles of shale, coal and sand with much mica 150 3.8 Particles of shale, coal and sand with much mica 200 8.1 Particles of shale, coal and sand with much mica Drying shrinkage : — Per cent Linear ; dry length 5.0 Volume 18.5 Burning test : — Cone Porosity Per cent Color 02 21.6 Light tan 1 15.7 Light tan 3 10.6 Tan 5 7.2 Gray 1 . . . 8 2.5 Gray 1 . . 13 1.6 Gray . . . . Fusion test: — Fused completely at cone 26. Total shrinkage Per cent . 9.1 Remarks . 10.4 . 10.1 . . 10.4 Semi vitreous fracture . 11.3 Vitreous luster .. 11.0 Vitreous luster, con- choidal fracture Summary The clay has a medium strength and a medium bonding strength. The screen residues are considerable. The drying shrinkage is medium low. The total shrink- age at cone 8 is medium. The clay is well vitrified at cone 8 and is not overburned at cone 13. It is non-refractory. Suggested uses : Stoneware, sanitary ware, architectural terra cotta, face brick. Sample No. 51 (2*2 miles northeast of White Hall) This is a rather hard clay of a dark brown color and good plasticity. Its con- duct when squeezed through a die is fair. Water of plasticity per cent 24.0 Shrinkage water per cent 14.1 iGrayish color may be due to reduction. GREENE COUNTY 93 Pore water Modulus of rupture With 50% standard sand — Modulus of rupture Slaking test, average Screen test : — Mesh 20 60 80 120 200 Residue Per cent . Trace . Trace . Trace . 0.18 . 1.4 per cent 9.9 .lbs. per sq. in. 446.8 .lbs. per sq. in. 199 min. 1 1 Character of residue Colored sand White sand and mica Drying shrinkage : — Per cent Linear; dry length 6.4 Linear ; wet length 6 0 Volume 27.8 Burning test : — Cone Porosity Per cent 02 19. Color White Burning shrinkage Per cent 4.8 Remarks 3 16.2 Light cream 5.3 Smooth, fine grain fracture 6 13.5 Light cream 5.3 Smooth fracture, near- ly vitreous sy 2 9.8 Cream 5.8 Smooth fracture, near- ly vitreous 9 9.5 Cream 6.1 Smooth fracture, near- ly vitreous 12 1.1 Stoneware gray, uniform... 7.6 Smooth fracture 13 0.5 Stoneware gray, uniform... 7.6 Smooth fracture Soluble salts : — Pieces burned at cone 02 give a strong yellow surface discoloration after being soaked in water. Fusion test: — Deforms at cone 31. Summary The strength of the raw clay is medium high. The bonding strength is medium low. The percentage of screen residues is slight. The drying shrinkage is medium. The total shrinkage at cone 9 is medium. Clay is well vitrified at cone 12. It is a refractory clay. Suggested uses : Refractories, stoneware, architectural terra cotta, sanitary ware, face brick. Sample No. 50 (2^4 miles northeast of White Hall) This clay is of a dark gray color with some portions brown and other reddish. It is quite hard but a good plasticity is developed when it is mixed with water and properly worked. Its conduct when flowing through a die is fair. Water of plasticity per cent 22.4 Shrinkage water per cent 10 6 Pore water per cent 11.8 94 ILLINOIS FIRE CLAYS Modulus of rupture lbs. per sq. in. 20 7 With 50% standard sand — Modulus of rupture lbs. per sq. in. 275.5 Slaking test, average min. 11 Screen test : — Mesh Residue Character of residue Per cent 40... Quartz particles 60... Quartz particles 80... 120... Mica and quartz sand 200... 4.7 Mica and quartz sand Drying sh rinkage : — Per cent Linear; dry length 5.9 Volume 21.8 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 28.6 Light tan, pinkish 0.13 02 25.1 Cream, pinkish 1.5 2 20.6 Light tan 3.1 Very fine iron spots 5 20.1 Tan 3.3 9 13.1 Stoneware gray 4.6 Smooth fracture 13 10.8 Stoneware gray 4.5 Fusion test: — It fused completely at cone 26. Summary The strength of the dry clay is medium. The bonding strength is medium. The quantity of screen residue is small. The shrinkage at cone 9 is medium. It is a non-refractory clay. Suggested uses : It is reported as being used for sewer pipe. It appears adapted for stoneware, architectural terra cotta, sanitary ware, and face brick. SCOTT COUNTY The clay at Alsey underlies 5 feet of cherty limestone, above which there are 28 to 34 inches of coal. Between these is a 2- to 3-foot thickness of dark, shaly clay. Only the upper part of the lower clay is dug, as the lower beds contain much pyrite. Almost the entire output of the plant had come to be fire brick when it closed in February, 1918, though formerly only building brick was made. Production ran about 20,000 bricks per day but enlargement of the plant insures a possibility of double that quantity. The United States Bureau of Standards reports above the signature of A. V. Bleininger, “In the fusion test, conducted in an electric furnace, the softening point of the fire brick was found to correspond to cone 31 or approximately 3083 degrees F. From this it appears that the fire clay may be considered of No. 1 grade.” SCOTT COUNTY 95 Sample No. 71 was taken from the stock pile of the clay used for fire brick and No. 70 from the clay which overlies the limestone. Results of tests are given on pages 96 and 97. The Cheltenham clay is exposed in the bluff of Mauvais Terre Creek half a mile west of Exeter. The section varies in short distances, and the clay is stained yellow by iron along seams where water circulates. Gypsum crystals may be seen on the weathered surface. This clay was used several years ago by potteries at Exeter and Merritt. Section along Mauvais Terre Creek half a mile west of Exeter Thickness Ft. In. 8. Limestone; weathers to rounded boulders, some of large size. Hard; fossiliferous 3 10 7. Clay, yellow and impure 2 10 6. Clay, dark blue 3 10 5. Clay, drab yellow irony seams, gypsum crystals ; the lower 4 feet sandy and not included in sample ; probably high in sulphur and iron 12 6 4. Clay, somewhat colored by carbon 8 3. Coal and coaly shale 1 0 to 6 2. Conglomerate, sandy; pebbles up to the size of a walnut 2 0 to 6 1. Limestone, Mississippian ; cuts out both conglomerate and coal nearby Sample No. 65, reported on pages 97 and 98, includes No. 6 and part of 5 of the section. Section at small coal opening on Mauvais Terre Creek about 4 l /2 miles downstream from Exeter Thickness Ft. In. 8. Clay shale 4 7. ‘‘Slate” or carbonaceous shale 2 6. Coal (No. 2) 2 8 5. Covered 5 4 4. Limestone, nodular; same as number 8 of previous section 4 6 3. Clay, impure, stained yellow 3 6 2. Limestone, regular bedded, with shale partings 8 8 1. Clay unmeasured At outcrops two miles northeast of Alsey numerous gypsum crystals appear on the surface of four feet of clay just below the limestone. 1 If conditions here are similar to those at Alsey, the fire clay might be expected to be of better quality east of the outcrop where it would lie at a greater depth. The record of the city well at Jacksonville, Morgan County, shows five feet of fire clay below a coal at a depth of 148 feet. Near Franklin six feet of fire clay is reported at a depth of 347 feet. lOp. cit., p. 68. 96 ILLINOIS FIRE CLAYS RESULTS OF TESTS SCOTT COUNTY Sample No. 71 (Abandoned plant at Alsey) The sample is a hard material of a dark gray color. When tempered with water it becomes very plastic. Its conduct in flowing through a die is fair. Water of plasticity per cent 21.8 Shrinkage water per cent 10.9 Pore water per cent 10.9 Modulus of rupture lbs. per sq. in. 328 With 50% standard sand — Modulus of rupture lbs. per sq. in. 144 Slaking test, average min. 10 Screen test : — Mesh Residue Per cent 20 0.6 40 0.13 60 0.11 80 0.14 120 Trace 200 Trace Drying shrinkage : — Linear ; dry length Linear ; wet length Volume Burning test : — Total Cone Porosity Color shrinkage Per cent Per cent 02 16 Cream 7.1 3 15 Light cream 5.3 5 14 Light cream 6.0 6 12.7 Light cream 6.0 8 11.2 Light cream 9 10 Cream 6.6 12 — Bluestoned ; light buff outside. . . 9 13 1.0 Bluestoned 15 3.4 Buff exterior ; bluestoned (black) 8.9 Fusion test: — It deforms between cones 30 and 31. Per cent .. 5.9 .. 5.6 .. 21.4 Remarks Vanadium stain (?) Vanadium stain (?) Contains fine black specks Summary The clay has a medium strength and a medium low bonding strength. The amount of screen residues is slight. Drying shrinkage is medium and total shrinkage at cone 9 is medium high. It is practically non-porous at cone 13 and apparently shows slight overburning at cone 15. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, face brick, sanitary ware, refractories. SCOTT COUNTY 97 Sample No. 70 (Abandoned plant at Alsey) This is a grayish colored clay of medium hardness. It is very plastic when tempered with water. Water of plasticity per cent 41.8 Shrinkage water per cent 31.4 Pore water per cent 10.4 Modulus of rupture lbs. per sq. in. 609 With 50% standard sand — Modulus of rupture lbs. per sq. in. 302.8 Slaking test, average min. 7 Drying shrinkage, linear per cent 12.5 Screen test : — Mesh Residue Character of residue Per cent 10... Hard lumps of black shale 14... Trace Hard lumps of black shale 20... 0.85 ] | 35... 6.8 | 48... 7.4 65... 7.4 l Hard lumps of black shale with particles- of 100... 5.1 150... 8.1 200... 8.5 Burning te t — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 20 Yellow cream 2.9 Hackly fracture 02 18 Dark cream . 4.7 Hackly fracture 2 7.5 Buff cream . . 6.2 Hackly fracture 5 3.5 Buff cream . . 5.9 Hackly fracture 9 2.5 Gray ; bluestoned . . 6.8 Hackly fracture 13 10 Light tan ; bluestoned. . . 5.6 Black core 14 9 21.5 Bloated Fusion test: — It fuses at cone 26. Vesicular structure. Summary The clay has a medium high strength and medium bonding strength. The dry- ing shrinkage is high. The total shrinkage at cone 9 is high. It is fairly well vitrified at cone 2 and is overburned at cone 13. The oxidation rate is slow. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, face brick. Sample No. 65 (Bluff of Mauvais Terre Creek mile west of Exeter) This is a brownish colored shaly clay. It becomes very plastic when tempered with water. It flows satisfactorily through a die. 98 ILLINOIS FIRE CLAYS Water of plasticity . . Shrinkage water Pore water Modulus of rupture . , Slaking test, average Screen test : — Mesh per cent 22.0 per cent 9.9 per cent 12.0 , lbs. per sq. in. 240.8 min. 6 20 40 60 80 120 200 Drying shrinkage : — Linear ; dry length Linear ; wet length Volume Burning test: — Residue Per cent . 0.22 "] . 0.40 . 0.77 . 0.64 . 2.9 . 2.3 Character of residue Colored sand Per cent . . 4.9 . . 4.7 .. 18.7 Cone Porosity Color Burning shrinkage Remarks 02 Per cent 24 Pinkish cream Per cent 3.1 1 24 Pinkish cream 3.1 3 22 Medium cream 3.8 Fine iron specks, earthy 5 21 Medium cream 4.0 fracture 6 21 Medium cream 4.2 Fine iron specks ; earthy 9 17 Light tan 4.3 fracture Numerous fine iron 12 9 Darker tan 6.2 specks Numerous fine iron 13 3.5 Rlnestoned 6.6 specks 15 3.3 Buff exterior ; bluestoned (black) 6.7 Iron spots Fusion test: — It deforms between cones 26 and 27. Summary This clay has a medium strength and a medium low drying shrinkage. The total shrinkage at cone 9 is medium. It is well vitrified at cone 13 and not over- burned at cone 15. It is a non-refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, for which uses it should be washed, face brick. PIKE COUNTY Clay outcrops in the west bluff of Illinois River at Bedford. The rela- tion to the Mississippian limestone at the north suggests faulting. Twenty- seven feet of clay are exposed above and 16 or more feet below. This thick- ness makes the deposit of special interest. PIKE COUNTY 99 Section of the river bluff at Bedford Thickness Ft. In. 7. Loess and loose limestone blocks to top of mound 50 6. Covered, cherty fragments over slope 10 5. Clay, bluish gray; partly covered yellow iron stains in lower part (Sample No. 67) 27 4. Covered interval 11 6 3. Partly covered, probably clay 9 2. Clay, blue (Sample No. 69) 16 6 1. Partly covered to water level in Illinois River; loose blocks indi- cate Mississippian limestone in the lower part of this interval. . . 20 Clay has been dug in small amounts about 2 miles north of Pittsfield and used as a blend for surface clay in making building brick and drain tile and possibly also for pottery. This deposit (sample No. 66, p. 101) is reported to vary from 6 to 13 feet in thickness. It is of a bluish white color where exposed and has an overburden of drift and loess up to 20 feet in thickness. Boring has shown that the clay extends back under the bluff over an area of several acres and the topography suggests that extensive areas are underlain by clay both to the south and east. RESULTS OF TESTS — PIKE COUNTY Sample No. 67 (West bluff of Illinois River at Bedford) This is a gray colored, soft clay which develops a good plasticity. Water of plasticity per cent 26.5 Shrinkage water per cent 12.5 Pore water per cent 14.0 Modulus of rupture lbs. per sq. in. 303.8 With 50% standard sand — Modulus of rupture lbs. per sq. in. 248.7 Slaking test, average min. 15 Screen test : — Mesh 40 60 80 120 200 Drying shrinkage : — Linear; dry length Linear; wet length Volume Residue Character of Per cent residue . . . 0.12 Quartz sand, and pyrite . . . 0.4 Quartz sand, and pyrite . . . Trace . . . 0.3 Sand and some pyrite . . . 0.3 Sand and some pyrite Per cent 6.4 6.0 23.9 100 ILLINOIS FIRE CLAYS Burning test : — Burning Cone Porosity Color shrinkage Per cent Per cent 04 25.4 Terra cotta 2.1 02 16.6 Light red brown 4.8 2 6.7 Brown 7.4 5 2 Brown-red 5.6 9 2.7 Brown-red Fusion test : — It fused to glass at cone 25. Remarks Hackly fracture Vitreous, appears to be overburned Overburned badly Summary The clay has a medium strength and a medium bonding strength. The drying shrinkage is medium. The total shrinkage at cone 5 is medium low. At cone 9 the sample is overburned. It is a non-refractory clay. Suggested uses: Face brick, sewer pipe, hollow block, paving brick (?). Sample No. 69 (West bluff of Illinois River at Bedford) This is a clay of a uniform gray color, containing some shaly particles. It is very plastic when tempered with water. The flowing conduct of the clay when forced through a die is satisfactory. Water of plasticity per cent 24.7 Shrinkage water per cent 13.5 Pore water per cent 11.2 Modulus of rupture lbs. per sq. in. 498.3 With 50% standard sand — Modulus of rupture lbs. per sq. in. 242.0 Slaking test, average min. 14 Screen test : — Mesh Residue Per cent 20 None 40 Trace 60 0.3 80 Trace 120 0.2 200 0.2 Drying shrinkage : — Per cent Linear ; dry length 6.6 Volume 26 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 26.5 Terra cotta 4.8 Hackly fracture 02 14.4 Terra cotta 4.9 Hackly fracture 2 1.8 Reddish brown 7.6 Hackly fracture 5 24 Reddish brown Overburned 9 19.9 Red-brown Swelled PIKE COUNTY 101 Fusion test : — Bloated and fell over before cone 8 in a Fletcher furnace. Summary This clay has a medium high strength, a medium bonding strength, and a me- dium drying shrinkage. The total shrinkage at cone 2 is medium ; vitrification pro- ceeds rapidly and is practically complete at cone 2. It is overburned at cone 5. Suggested uses : Common brick, drain tile. Sample No. 66 (2 miles north of Pittsfield) This is a soft clay, colored yellow to dark brown. A fair degree of plasticity may be developed. Water of plasticity Shrinkage water Pore water Modulus of rupture Slaking test, average Screen test : — Mesh Residue Per cent 20 0.08 per cent 27 per cent 13.5 per cent 13.5 . .lbs. per sq. in. 414.5 min. 11 Character of residue 40. 60. 80. 120 . 200 . Trace Trace Trace 0.79 1.32 Rock particles and or- ganic matter White sand and root- lets White sand and root- lets Drying shrinkage : — Linear ; dry length Volume Burning test Per cent .. 8.2 .. 24.5 Cone 02 2 3 Porosity Per cent 17 14 12 Color Burning shrinkage Per cent Cream 4.9 Cream 5.1 Medium cream 5.8 Medium cream 6.2 Remarks 1.2 Stoneware gray 6.3 Smooth fracture; fine iron specks (?); none on another trial piece Smooth fracture; fine iron specks (?); none on another trial piece Somewhat conchoidal fracture Vitreous 102 ILLINOIS FIRE CLAYS 12 1.0 Gray white 5.0 Fine veining of iron stain ; good color 13 1.6 Gray white 4.5 15 3.8 Gray white 4.5 Fine iron spots Fusion test: — It deformed at cone 29. Summary The sample is a clay of medium high strength which has a medium drying shrinkage. The total shrinkage at cone 9 is medium high. Vitrification is practi- cally complete between cones 6 and 9. There are some indications of overburning at cone 15. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, a plastic bond for refractories. ADAMS COUNTY Toward the west the basal clays of the Pennsylvanian contain more gypsum, and are generally streaked by yellowish and buff iron markings. In a road cut 2^4 miles north and one mile west of Camp Point, 8}4 feet of distinctly bedded clay are exposed. The upper 2*4 feet are tough, ash colored clay, containing much gypsum sand and small gypsum crystals, and colored by streakings of iron. An overburden of from 5 to 15 feet of gravel and clayey till with locally thin sandstone layers immediately above the clay, forms the covering. BROWN COUNTY On Crooked Creek in the vicinity of Ripley, clay has been dug for stone- ware. The old pits one mile south of Ripley are almost obliterated by sur- face wash and caving. Since the clay directly underlies the drift it does not promise to be of refractory value. SCHUYLER COUNTY At a small mill and kilns at Frederick, drain tile is manufactured from a mixture of surface clay and bedded Coal Measures clay. Section of the clay pit at Frederick Thickness Ft. In. 5. Loess 9 4. “Potter’s clay” 8 3. Coal (“peacock vein”) 3 3 2. Clay, drab and sandy; plant remains and yellow iron stains 10 1. Shale, blue MC DONOUGH COUNTY “The line of outcrop of the clay in McDonough County extends along the bluffs and ravines of the east fork of Crooked Creek from Bardolph to the county line on the north side and Tennessee on the south side, whence it extends southeast toward Schuyler County.” 1 Clay is being dug about !Op. cit., p. 70. MC DONOUGH COUNTY 103 Colchester and from a pit about 3 miles northeast of Macomb. At the open pit of the Macomb Sewer Pipe Works about 3 miles north- east of Macomb the clay is stripped, loaded by steam shovel, and hauled over a standard gauge track to the plant at Macomb. Samples No. 73a, No. 73b, and No. 73c are respectively from the top, middle and bottom of a boring on the Company’s property. Results of tests are given on pages 105 and 106. A section of the face of the pit is as follows : 6. 5. 4. 3. 2 . 1 . Section of the face of the pit of the Macomb Sewer Pipe Works, 3 miles northeast of Macomb Thickness Feet Loess, drift, and soil 20 to 25 Sandstone, hard, and chert 6 Coal traces Clay, used for sewer pipe 10 Pebbles and iron concretions in layer Shale, dark blue 10-}- The Colchester Brick and Tile Company uses the clay from this horizon at its plant near Colchester in the manufacture of refractory brick, tile, and silo blocks. The clay is dug from an open pit in the side of a hollow (fig. 54) and hauled by wagon to the mill. Section of Colchester Brick and Tile Company’s pit, half a mile north of Colchester Thickness Ft. In. 7. Shale, sandy 20 6. Shale, dark, and coal 2 5. Fireclay, poor grade 3 4. Shale, dark 6 3. Fireclay, stained yellow by iron (Sample No. 75a) 6 2. Shale 7 1. Fireclay (Sample No. 75b) 10 Sample No. 75a is from No. 3, and sample No. 75b from No. 1 of the above section. Results of tests are given on pages 106 to 108. Most of the clay obtained about Colchester is taken from mines west of town. The clay taken from the shaft of the Gates Fireclay Company is used for making flue linings among other clay products. Log of shaft at the Gates Fireclay Company’s mine, near Colchester Thickness Depth Description of strata Feet Feet Soil and glacial clay 24 24 “Soapstone,” compact shale 26 50 Coal (No. 2) 2'A 52^ Fireclay, used in the manufacture of flue linings, etc., “upper vein” (Sample No. 88, see pages 108-109) 55d 58 104 ILLINOIS FIRE CLAYS Log of Gates Fireclay Company’s mine shaft — Continued Limestone, scattered boulders "Hard rock,” probably sandstone 6 64 Clay, "middle vein” 8 72 Sandstone 5 77 Shale 8 85 The firm of Baird Brothers is operating a mine one mile northwest of Colchester in a 7- to 8-foot bed of clay that lies below the “middle vein” of the Gates shaft. On the Valentine farm three drift tunnels have been opened into a 7- to 8-foot bed of clay, and about 150 tons are taken out Fig. 54. View of the Colchester Brick and Tile Company’s pit half a mile north of Col- chester showing No. 2 coal near the top and stoneware clay at the base. per day. One hundred and twenty acres of the adjoining Forncuff farm are underlain by the lower and upper clay. The middle clay contains so many boulders that it cannot be worked profitably. The clay is hauled by steam locomotive over a tram to tipple at the Chicago, Burlington and Quincy Railroad at Colchester. Sample No. 74 (p. 109) is from south mine, and sample No. 78 (p. 110) from the north mine on the Valentine farm. Sample No. 75 (p. Ill) was taken from a carload of clay as it came from the Meyers mine, west of the Baird mines. Two other mines were being operated in June, 1918; one 3 miles west of town in the same bed as are the above mines, another 2 y 2 miles west where the No. 2 coal and the underlying clay are both recovered. MC DONOUGH COUNTY 105 RESULTS OF TESTS MCDONOUGH COUNTY Sample No. 73-a (Macomb Sewer Pipe Works ; 3 miles northeast of Macomb) The sample is a gray shaly material, containing many mica flakes. It becomes very plastic when worked with water. Water of plasticity per cent 28.3 Shrinkage water per cent 12.9 Pore water per cent 15.4 Modulus of rupture lbs. per sq. in. 352.2 Slaking test, average min. 13 Drying shrinkage : — Per cent Linear ; dry length 6.5 Volume 22.9 Eurning test :— Total Cone Porosity Color shrinkage Per cent Per cent 1 16 Cream 10.6 5 10 Cream 12.4 9 4.8 Light gray 13.1 15 2.1 Light gray 10.0 Fusion test: — Cone slightly deformed at cone 26. Vesicular at cone 27. Summary The clay has a medium strength. The drying shrinkage is medium and the total shrinkage at cone 9 is medium high. It has a low porosity at cone 9 and has only a slight porosity at cone 15. It is non-refractory. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, face brick. Sample No. 73-b (Macomb Sewer Pipe Works ; 3 miles northeast of Macomb) This is a rather hard clay, varying in color from a light to a dark gray. When tempered with water it becomes very plastic and flows satisfactorily through a die. Water of plasticity per cent 24.9 Shrinkage water per cent 11.9 Pore water per cent 13.0 Modulus of rupture lbs. per sq. in. 356.5 Slaking test, average min. 9 Drying shrinkage : — Pet cent Linear 6.2 Volume 21.8 Burning test: — Cone Porosity Color Total shrinkage Remarks 1 Per cent 10.9 Light brown Per cent 13.7 Poorly oxidized 5 5.1 Brown 14.0 9 0.4 Dark brown 12.5 15 0.0 Dark gray 11.2 Overburned, beginning to bloat 106 ILLINOIS FIRE CLAYS Fusion test: — At cone 26 the cone was deformed half way and showed many bubbles on the surface. Summary The strength is medium. The drying shrinkage is medium. Burning shrinkage at cone 9 is medium. It burns to a dense body at cone 5 and is practically non- porous at cone 9. At cone 15, signs of overburning appear. It is non-refractory. Suggested uses : Sewer pipe, face brick, possibly paving brick. Sample No. 73-c (Macomb Sewer Pipe Works ; 3 miles northeast of Macomb) This is a hard dark gray-colored clay which develops a very good plasticity. Water of plasticity . Shrinkage water . . . Pore water Modulus of rupture Slaking test, average Drying shrinkage : — Per cent Linear 7.0 Volume 16.8 Burning test : — Total Cone Porosity Color shrinkage Remarks Per cent Per cent 1 11.2 Cream 12.5 5 4.0 Cream 14.4 Conchoidal vitreous fracture 9 0.2 Gray 14.4 Conchoidal vitreous fracture 15 0.8 Gray 11.2 Conchoidal vitreous fracture Fusion test : — Y deformed at cone 27. Vesicular. Summary The clay has a medium strength. The drying shrinkage is medium and the total shrinkage at cone 9 is medium high. It attains a low porosity at cone 5 and is completely vitrified between that and cone 9. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, face brick, sanitary ware, and some types of refractories. Sample No. 75-a (Colchester Brick and Tile Company’s pit; mile north of Colchester) This is a clay which is not of a uniform color, varying from gray to yellowish brown. The gray portions are harder than the yellow. Tempered with water, it develops a medium plasticity. When squeezed through a die, it flows rather badly. Water of plasticity per cent 25 Shrinkage water per cent 7.6 Pore water per cent 17.3 Modulus of rupture lbs. per sq. in. 269.6 With 50% standard sand — Modulus of rupture lbs. per sq. in. 192 Slaking test, average min. 4 MC DONOUGH COUNTY 107 Screen test : — Mesh 40 60 80 120 Residue Character of Per cent residue 0.2 White and colored sand 1.4 White and colored sand 0.3 White and colored sand 3.3 White and colored sand and mica 200 3.7 White and colored sand and mica Drying shrinkage : — Pet cent Linear ; dry length 4.7 Linear ; wet length 4.5 Volume 11.2 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Light red 1.0 Light red 1.7 Dark tan 4.4 Brown 8.2 04 02 5 9 13 Porosity Per cent 33 30 23.3 13.5 16.9 Hackly fracture Hackly fracture Overburned Fusion test- — It fused completely at cone 26. Summary The clay has a medium strength, a medium low bonding strength, a medium low drying shrinkage, and a medium high total shrinkage at cone 9. Minimum porosity — 13.5% — is attained at cone 9 and overburning appears at cone 13. It is a non-refractory clay. Suggested uses : Brick, tile. Sample No. 75-b (Colchester Brick and Tile Company’s pit; y 2 mile north of Colchester) This is a hard gray-colored clay, having an irregular fracture. When tempered with water, it develops a good plasticity and flows well through a die. Water of plasticity per cent 20.0 Shrinkage water per cent 8.6 Pore water per cent 11.4 Modulus of rupture lbs. per sq. in. 263 With 50% standard sand — Modulus of rupture lbs. per sq. in. 199.6 Slaking test, average min. 8 Screen test : — Mesh Residue Character of residue Per cent 20 0.3 Rock particles 40 0.9 Rock particles and quartz sand 60 2.1 Rock particles and quartz sand 80 0.3 Rock particles and quartz sand 120 1.4 Quartz sand and mica 200 2.2 Quartz sand and mica Drying shrinkage : — Linear Volume Burning test : — Cone Porosity Per cent 04 30 Color White Burning shrinkage Per cent 0.1 Per cent 4.8 Remarks 02 28 Cream 0.5 2 25.5 Cream 1.7 Hackly fracture 5 25.0 Cream 2.0 Hackly fracture 9 17.4 Gray white 3.0 A very few fine iron spots 13 6.3 Stoneware gray 5.2 Many slagged iron spots 14 68 Ruff 2.7 Fusion test : — Completely deformed at cone 26. Not fused as much as 75-a. Summary The strength of the clay is medium. Its bonding strength is medium. The drying shrinkage is medium low and total shrinkage at cone 9 is medium. The porosity is low at cone 14 but vitrification is incomplete. It is a non-refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, face brick. Sample No. 88 (Gates Fireclay Company’s mine, near Colchester) This is a dark colored, very hard clay, which becomes very plastic when tem- pered with water. Water of plasticity per cent 27.7 Shrinkage water per cent 11.7 Pore water per cent 15.9 Modulus of rupture lbs. per sq. in. 496 With 50% standard sand — Modulus of rupture lbs. per sq. in. 243 Slaking test, average min. 14 Screen test : — Mesh 20 40 60 80 120 200 Residue Character of Per cent residue . None . Traces 0.29 Dark red grains . 0.2 . 2.8 . 1.0 Drying shrinkage : — Per cent Linear ; dry length 7.2 Linear ; wet length 6.7 Volume 28 MC DONOUGH COUNTY 109 Burning test : — Burning Cone Porosity Per cent Color shrinkage Per cent Remarks 01 0.8 Tan .... 7.7 Vitreous fracture 2 0.6 Darker tan . . . . 7.6 Vitreous fracture 3 0.5 Grayish tan .... 7.3 Vitreous fracture 4 0.7 Grayish tan . . . . 6.9 Vitreous fracture 6 0.8 Dark gray ... 6.9 Vitreous fracture 9 2.6 Stoneware gray . . . . 7.3 Numerous fine iron spots ; vitreous frac- ture 12 4.4 Bluestoned, surface flashed. . . . . 4.0 Numerous fine iron spots ; vitreous frac- ture 13 2.2 Buff exterior . . . . 2.6 Many fine iron spots ; blue core Fusion test: — Partly deformed at cone 27. Summary The strength of the unburned clay is medium and its bonding strength is medium. The amount of residue on the sieve is low. The drying shrinkage is medium and the total shrinkage when burned at cone 9 is medium high. It is practically non- porous at cone 01 which is an unusually low temperature and shows distinct over- burning at cone 13. The sample burned at that temperature appears to be reduced. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, refractories (particularly when good bonding properties are required), sanitary ware, face brick. Sample No. 74 (Valentine farm, south mine; near Colchester) This is a dark gray colored clay which becomes very plastic upon the addition of water. Water of plasticity per cent 22.0 Shrinkage water per cent 8.0 Pore water per cent 14.0 Modulus of rupture lbs. per sq. in. 221.8 With 50% standard sand — Modulus of rupture lbs. per sq. in. 214.9 Screen test : — The sample would not slake satisfactorily for this test. Slaking test, average min. 8 Drying shrinkage : — Per cent Linear ; dry length 4.8 Linear ; wet length 4.6 Volume 15.0 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 1 21 Cream 2.2 2 20 Cream 2.3 110 ILLINOIS FIRE CLAYS 3 20 Cream .. 2.3 Fine iron speck 6 17.9 Slightly darker .. 3.2 Fine iron speck 9 13.4 Cream . . 3.5 Fine iron speck 12 9.0 Cream . . 4.0 Numerous quartz grains ; fine iron spots 13 4.1 Buff . . 4.4 Iron spots, small ; slagged 15 3.9 Bluestoned ; buff exterior . . . .. 4.3 Slagged iron spots Fusion test: — Cone half way down at cone 26. Summary The clay has a medium strength and medium bonding strength. Drying shrink- age is medium low and total shrinkage at cone 9 is medium. It is non-refractory. Weathering or aging will improve its working properties. Suggested uses : Face brick, stoneware, and terra cotta. But its slow slaking character as noted under the screen test may limit its usefulness for the latter pur- poses. Sample No. 78 (Valentine farm, north mine ; near Colchester) This is a hard dark gray colored clay which may be brought to a very plastic condition. Its conduct when flowing through a die is very good. Water of plasticity per cent 19. Shrinkage water per cent 9.4 Pore water per cent 9.6 Modulus of rupture lbs. per sq. in. 325.8 With 50% standard sand — Modulus of rupture lbs. per sq. in. 209.4 Slaking test, average min. 7 Screen test : — Character of residue Mesh Residue Per cent 20 0.8 Hard 40 0.7 Hard 60 0.7 Hard 80 0.22 Hard 120 0.75 Hard 200 0.7 Hard Per cent . . 4.1 Drying shrinkage : — Linear ; dry length Linear; wet length 4.0 Volume 16.9 Burning test Cone Porosity Color Burning shrinkage Remarks 01 Per cent 23 Cream white Per cent 2.8 Granular fracture 1 23 Cream white 2.6 Granular fracture 3 20 Cream white 3.3 Granular fracture 6 18 Cream white 4.0 Granular fracture 8 18 Cream Granular fracture 9 14.9 MC Cream DONOUGH COUNTY 4.0 111 12 9.0 Dark cream or light tan 5.2 Earthy fracture. Nu- merous fine iron specks. Also quartz grains. 15 6.5 Buff exterior; bluestoned 7.2 Numerous iron spots. Slagged. Fusion test No deformation at cone 25. It deforms at cone 29. Summary The strength of the unburned clay is medium. Its bonding strength is medium. The drying shrinkage is medium low. The total shrinkage at cone 9 is medium. A low porosity is not reached until cone 15. It is a refractory clay. Suggested uses : Architectural terra cotta, stoneware, sanitary ware, refractories, and face brick. Sample No. 75 (Meyers mine; near Colchester) This is a very hard dark gray clay which slakes very slowly. However, when properly worked with sufficient water, it develops a fair degree of plasticity and may be forced through a die satisfactorily. Water of plasticity per cent 20.7 Shrinkage water per cent 9.1 Pore water per cent 11.6 Modulus of rupture lbs. per sq. in. 295.6 Slaking test, average min. 8 Drying shrinkage : — Per cent Linear ; dry length 4.9 Linear; wet length 4.7 Volume 17.6 Burning test : — Cone 02 Porosity Per cent 20 Color Cream Burning shrinkage Per cent 2.8 Remarks 2 17.3 Cream 4.7 5 13.8 Cream 8.3 9 6.8 Cream 11.0 Fine iron spots 12 2.5 Gray white 11.5 Fine iron spots 13 1.5 Grayish white 10.5 Numerous iron spots, small 15 4.0 Grayish white Numerous iron spots ; slagged Fusion test: — No deformation at cone 30. No vesicular structure. Note: — The iron (?) spots are so black as to suggest the presence of manganese. Its unusual appearance may be due to reduction. The effect at higher cones is very unique and interesting. The clay has shrinkage at Summary a medium strength. The drying shrinkage is medium low. Total cone 9 is medium high. Minimum porosity. Complete vitrification is 112 ILLINOIS FIRE CLAYS reached at cone 13. At cone 15 the slight increase in porosity may indicate incipient overburning. It is a refractory clay. Suggested uses : The appearance of numerous fine slagged spots at the high temperatures raises a question as to the desirability of this as a material for re- fractories. Its slow slaking character lessens its value in some degree for stoneware and architectural terra cotta. However, weathering or aging will correct these difficulties. FULTON COUNTY A sample of clay (No. 84) from about a mile northwest of Avon was taken at the Avon Milling and Manufacturing Company’s plant at Avon. The clay had been dug from the bed of Swan Creek and is used for refrac- tory linings about the boiler. RESULTS OF TESTS FULTON COUNTY Sample No. 84 (Avon Milling and Manufacturing Company, at Avon) The clay is a dark gray color with darker patches due to the presence of car- bonaceous matter. Its plasticity is only fair and its conduct in flowing through a die is fair. Water of plasticity per cent 21.5 Shrinkage water per cent 9.0 Pore water . . . . : per cent 12.4 Modulus of rupture lbs. per sq. in. 214 Slaking test, average min. A l / 2 Screen test : — Mesh Residue Character of Per cent residue 40 0.5 Sand and coal 60 3.2 Sand and coal 80 0.4 Sand and coal 120 2.3 Sand and coal 200 11.6 White sand, mica, and coal Drying shrinkage : — Per cent Linear ; wet length 3.7 Linear ; dry length 3.8 Volume . . . Burning test: — Cone 2 3 6 9 13 15 Porosity Per cent 26 26 25 20 11.6 16.6 Burning Color shrinkage Per cent Light tan 1.8 Light tan 1.9 Light tan 2.6 Light tan 3.7 Buff 5.5 Buff 5.8 Remarks Granular fracture Granular fracture Granular fracture Granular fracture Fine iron ( ?) spots Fine iron (?) spots Fusion test : — The cone fused to a glass at cone 28. FULTON AND MERCER COUNTIES 113 Summary The strength of the clay is medium. There is a considerable amount of residue left on the screens. The drying shrinkage is medium low, and when burned at cone 9, the total shrinkage is medium low. Vitrification is incomplete at cone 13 and it is overburned at cone 15. It is a non-refractory clay. Suggested uses: Architectural terra cotta, face brick. It appears to be rather short for stoneware. MERCER COUNTY The Northwestern Clay Manufacturing Company formerly recovered small amounts of clay with the No. 1 coal at their pits near Griffin. A sample was taken from clay which had been drawn from below the No. 1 coal at that time. The shale, till, and overlying soil are used for sewer pipe. Section of the Northwestern Clay Manufacturing Company's pit at Griffin Thickness Ft. In. 6 Soil and yellow clay 10 5. Shale (Sample No. 86) 25 to 30 4. Limestone 2 3. “Potter’s clay,” thin horizon unmeasured 2. Coal (No. 1) 2 5 1. Clay (Sample No. 85) 6 RESULTS OF TESTS MERCER COUNTY Sample No. 86 (Northwestern Clay Manufacturing Company’s pit, at Griffin) The material is a hard grayish-colored, shaly clay, streaked with brown and black. The plasticity is fair. Water of plasticity per cent 29.5 Shrinkage water per cent 21.9 Pore water per cent 7.6 Modulus of rupture lbs. per sq. in. 190.2 Slaking test, average min. 6 Screen test : — Mesh Residue Character of Per cent residue 10 2.2' 14 1.7 20 2.4 35 3.2 ► Particles of shale, grains 48 0.6 of coal 65 0.4 100 1.1 150 1.0 Shale with mica 200 1.5 Shale with mica Drying shrinkage : — Linear ; dry length Linear ; wet length Per cent . . 3.62 .. 3.5 114 ILLINOIS FIRE CLAYS Burning test : — Cone Porosity Color Burning shrinkage Remarks Per cent Per cent 02 18.4 Dark red 5.0 Hackly fracture 5 14.5 Dark red 8.5 9 0.5 Dark red 9.4 Vitreous fracture 12 Bloated Fusion test : — It fused completely at cone 27. Summary The drying shrinkage is medium low. The strength is medium low. The total shrinkage at cone 9 is medium high. The shale reaches a minimum porosity at or before cone 9 and overburns beyond that point. Suggested uses : Sewer pipe, brick, tile, etc. Sample No. 85 (Northwestern Clay Manufacturing Company’s pit, at Griffin) The sample is a soft clay of a gray color with darker mottling. Its plasticity is very good when tempered with water. Water of plasticity per cent 28.8 Shrinkage water per cent 11.9 Pore water per cent 17.0 Modulus of rupture lbs. per sq. in. 386.7 Slaking test, average min. A l /i Screen test : — Mesh Residue Character of Per cent residue 10 7.0' 14 6.5 20 8.9 35 13.8- Particles of coal and 48 3.7 shale 65 5.4 100 3.9 150 2.4' Particles of coal and 200 2.6 - shale, with flakes of mica Drying shrinkage, linear per cent 6.5 Volume per cent 21 Burning test : — Total Cone Porosity Color shrinkage Remarks Per cent Per cent 02 14.4 Cream 13.4 1 6.7 Cream 14.6 3 0.5 Gray 15.9 5 0.8 Dark gray 16.2 7 1.2 Dark gray 13.6 13 1.4 1.6 Dark gray Dark gray 11.1 7.5 Vitrified Bluestoned Bluestoned ; vesicular Bluestoned ; vesicular Bluestoned ; vesicular slightly slightly slightly Fusion test : — Completely deformed at cone 26. Vesicular. ROCK ISLAND COUNTY 115 Summary The strength of the clay is medium. The quantity of screen residues is high. The drying shrinkage is medium. The total shrinkage at cone 5 is medium high. Complete vitrification is attained at a very low cone and the incipient overburning which seems to appear at cone 9 does not become serious even at cone 16. The appearance of the pieces suggests reducing conditions during the burn. The appear- ance of a whitewash on the pieces burned at cone 7 or lower should be noted. It is non-refractory. Possible uses : Architectural terra cotta, paving brick, stoneware, sanitary ware, sewerpipe, conduits. ROCK ISLAND COUNTY A sample was taken from the clay above No. 1 coal at Sears (sample No. 83). The clay below that coal was covered by water when visited. A second sample was taken from white clay lying directly below the No. 1 coal (sample No. 81) ; ordinarily a 5-foot sandstone commonly separates this clay and the coal but here it is missing. The clay 1 is full of pyrite concretions which weather to limonite at the surface. The plant which formerly operated here is now idle and the pits are in bad condition. Results of tests on samples No. 83 and No. 81 are given on pages 115 and 116. A large part of the upper 40 feet of the overburden which is a fine loess of pure quartz sand is now used for moulding sand. The value of the overburden in this case would materially reduce the cost of obtaining the clay if it were to be worked from an open cut. The maximum over- burden would be nearly 60 feet. At Carbon Cliff the fine clay (Cheltenham) varies from 10 to 25 feet in thickness, being replaced where the lesser thickness is found by as much as 10 feet of black shale which apparently wedges out laterally into the clay. The clay shows iron stains and traces of red. At its base there is a layer of nodular impure limestone boulders and limonite concretions. The over- burden of 18 to 25 feet could be removed most economically, it is believed, by a steam shovel. Sample No. 79 was taken from the west bank and sample No. 80 from the working face in the east pit. Results of tests are on page 117. RESULTS OF TESTS ROCK ISLAND COUNTY Sample No. 83 (Clay above No. 1 coal at Sears) This is a medium hard clay which is colored gray, heavily mottled with brown. The plasticity is very good when it is tempered with water and it flows satisfactorily through a die. Water of plasticity per cent 28.7 Shrinkage water Per cent 16.4 Pore water per cent 12.2 lAccording to Lines, Op. cit., this clay was formerly used for sewer pipe. 116 ILLINOIS FIRE CLAYS Modulus of rupture, maximum lbs. per sq. in. 768 minimum lbs. per sq. in. 664 With 50% standard sand — Modulus of rupture lbs. per sq. in. 329 Slaking test, average min. 11 x / 2 Drying shrinkage : — Per cent Linear ; dry length 7.5 Linear ; wet length 7.0 Volume 31.2 Burning test: — Cone Porosity Color Burning shrinkage Remarks Per cent Per cent 04 28.0 Pinkish red 1.0 02 15.0 Pinkish tan 5.1 Hackly fracture 2 1.1 6.7 Hackly fracture 5 2.2 Dark tan 6.8 Glossy fracture 9 1.6 Dark tan 6.5 Smooth vitreous frac- ture 13 12.0 Gray 4.5 Overburned Fusion test: — It entirely fused at cone 27. Summary The strength of the clay is medium high and its bonding strength is medium. The drying shrinkage is medium. The total shrinkage at cone 9 is medium. Vitrifi- cation proceeds very rapidly between cones 02 and 2, at which temperature it is practically complete. It is overburned between cones 9 and 13. It is non-refractory. Suggested uses : Face brick, paving brick, sewer pipe, drain tile. The color of the burned material is rather dark for stoneware or terra cotta. Sample No. 81 (Clay below No. 1 coal at Sears) This is a soft gray colored clay, streaked with brown and containing a few black spots. It contains much mica. Water of plasticity per cent 22.6 Shrinkage water per cent 9.8 Pore water per cent 12.7 Slaking test, average min. 8 Drying shrinkage : — Per cent Linear 5.2 Volume 17.8 Burning test: — Total Remarks Total Cone Porosity Color shrinkage Per cent Per cent 1 13.7 Brown 8.7 5 6.1 Dark brown 11.8 9 2.4 Dark brown 11.2 15 Bloated badly Fusion test: — Completely fused at cone 26 to brown glass showing a partly vesicular structure. Summary The drying shrinkage is medium low and vitrification is practically complete at cone 9. It is overburned between that cone and cone 15. It is non-refractory. Suggested uses : Brick, tile. ROCK ISLAND COUNTY 117 Sample No. 79 (West bank at Carbon Cliff) This is a soft clay having a dark gray color with some brown streaks. When tempered with water it becomes very plastic. It flows fairly well through a die. Water of plasticity Shrinkage water Pore water Modulus of rupture With 50% standard sand — Modulus of rupture. . . . Slaking test, average Screen test : — Mesh 20 Residue Per cent Character of residue 40 60 80 120 200 ... 1.8 Sand and mica Drying shrinkage : — Per cent Linear ; dry length 6.6 Linear; wet length 6.2 Volume Burning test: — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 32 Cream ... 0.0 02 32 Cream . . . 1.0 Hackly fracture 2 28 Cream . . . 1.5 Hackly fracture 5 28 Cream . . . 2.0 Hackly fracture 9 23 Cream . . . 3.1 Hackly fracture 13 18 Cream . . . 3.6 Granular fracture 14 6 Brown exterior; bluestoned. . . . 2.8 Fusion test : — It fuses entirely at cone 26. No vesicular structure. Summary The clay has a medium strength and a medium low bonding strength. The drying shrinkage is medium and the total shrinkage at cone 9 is medium. The clay is very open burning until cone 14 is reached. It is non-refractory. Suggested uses : Architectural terra cotta, stoneware, sanitary ware, and face brick. Sample No. 80 (East pit at Carbon Cliff) This is a clay of a medium degree of hardness, colored gray with a darker mottling. It develops a good degree of plasticity when tempered with water and flows satisfactorily through a die. 118 ILLINOIS FIRE CLAYS Water of plasticity Shrinkage water Pore water Modulus of rupture Slaking test, average Drying shrinkage, linear Volume Per cent 20.5 per cent 9.2 per cent 11.3 lbs. per sq. in. 445.4 min. 10^2 per cent 6.2 per cent 17.7 Burning test: — Total Cone Porosity Color shrinkage Remarks Per cent Per cent 02 20.7 Cream 7.2 1 19.7 Cream 7.5 3 16.4 Cream 8.1 Hackly fracture 5 13.4 Gray 8.6 Hackly fracture 8 10.4 Gray 10.0 9 7.2 Gray 9.8 Vitrified ; hackly frac- ture 13 7.5 Gray 9.7 Conchoidal fracture Fusion test: — Test pieces are % deformed at cone 26 and slightly vesicular. Summary The clay has a medium high strength and medium shrinkage at cone 9. The total shrinkage is medium. Vitrification is still incomplete at cone 13. The clay borders on the refractory type. Suggested uses : Stoneware, architectural terra cotta, refractories, face brick. LA SALLE COUNTY At the pits of the Utica Firebrick and Clay Company two miles south of Utica the section is variable, but a somewhat generalized section of the east pit (fig. 55) is as follows: Sections of the east pits of the Utica Firebrick and Clay Company 2 miles south of Utica Thickness Ft. In. 6. Overburden, glacial drift and soil 12 5. Coal (No. 1) 1 6 4. Clay, blue, “Joliet clay” (Sample No. 87, p. 125) ; the upper foot contains numerous pyrite concretions, and similar concretions are found in the lower Ibeds 3 6 3. Clay, green 8 2. Clay, gray, jointed (Sample No. 77, p. 126) ; used for fire brick; the upper 3 feet has a few small pyrite seams and concretions (av. 8 ft.) ; at one place 2 feet of the residual basal clay is lighter in color grading into a darker clay above 4 10 1. Sandstone, St. Peter; forms the “nigger heads” of the mines; the surface of the sandstone is very uneven and in one place rises so that the clay is only 1 Yi feet thick LA SALLE COUNTY 119 A second section of East pit of the Utica Firebrick and Clay Company Thickness Feet 3. Soil and drift 2 to 5 2. Clay, dark gray, with scattered pebbles and some conglomerate 10* 1. Conglomerate, highly weathered, heavy Sample No. 82 from the east pit was lost in transit, and H. E. Culver of the Survey staff visited the pit later with the intention of taking a sub- Fig. 55. View of the Utica Firebrick and Clay Company’s pit south of Utica; No. 2 coal overlies the clay. stitute sample. Being unable to find the exact location from which sample No. 82 had been taken, he measured the following section and took sample No. C 82 ; results of tests are given on pages 126 and 127. Section of West pit of the Utica Firebrick and Clay Company, near Utica 4. Overburden, soil and drift 2 to 5 3. Clay, gray, yellow when first exposed, very tough 2 to 3 2. Clay, darker yellow, “putty clay” (Sample No. 82) ; chert concre- tions and pyrite at base 5 to 6 1. Sandstone; very much hardened by iron at surface The clay is hauled by train from the pit to a tipple, dumped down onto a tram at river level, transferred across the Illinois River by barge and then taken by train to the plant at Utica. 120 ILLINOIS FIRE CLAYS About 20 acres has been tested by drilling beyond the borders of the present pits. The plant can produce from 12,000 to 20,000 fire brick per day and about 30 tons of ground fireclay is shipped every month as well as crude clay in varying amounts up to 1000 tons. Small lots of the yellow “putty” clay have been shipped for ochre but most of it is used as furnace lining. A boring between the two pits has shown that the “putty” clay overlies the better grade blue clay. M. J. Gorman and Company are operating an open pit in sec. 21, T. 22 N., R. 1 E. The clay is hauled \ l / 2 miles by team and wagon to Utica. The average production is about 10,000 tons per year, including both “putty” and blue clay. Section of M. J. Gorman and Company's pit V/ 2 miles south of Utica 9. 8. 7. 6 . 5. 4. 3. 2. 1 . Soil Soil and drift Coal (No. 2), absent over parts of the clay Clay, yellow and blue, very plastic, scattered gypsum crystals ; clay” (Sample No. 97, pp. 127-128) Clay, green Clay, blue (Sample No. 100, pp. 128-129) Pyrite, large boulders, usually with calcareous centers Clay, blue Sandstone, probably St. Peter Thickness Ft. In. 1 6 3 “putty 4 6 9 5 Sample No. 98 was taken from the side of a gully a few rods up-stream from the mouth of the clay pit. It lies, however, below the mouth of the pit in altitude. This is not worked, and the sample was taken from a 2' x 4' x 3" cut on the sloping surface of the clay bank which lies beneath soil and above sandstone which is probably St. Peter, but may be the lower sandstone of the Pennsylvanian. See page 129 for results of tests. More than seventy acres of clay have been proved by boring. The Company is contemplating tractor and trailer haulage over the 1 V 2 miles of paved road to the railroad at Utica. The Illinois Clay Products Company are producing 250 to 300 tons of ground fireclay per day, from their mine at Deer Park. Only the upper 6 or 7 feet is mined at the present time, as it is found impracticable to mine a greater thickness. LA SALLE COUNTY 121 Section of Illinois Clay Products Company's mine at Deer Park Thickness Ft. In. 10. Overburden, of glacial till and soil unmeasured 9. “Soapstone,” compact, sandy clay shale 15 ± 8. Coal (No. 2); forms roof of mine 3 6 7. Clay (Sample No. 93, p. 130) ; only thej upper 6 to 7 feet mined at present; erratic lenses of sandrock at the bottom of the present workings; pyrite nodules about 3 feet from the top of the clay, also large pisolitic boulders ; in part of mine, clay rests on St. Peter sandstone and possibly in other part on “Trenton” lime- stone 13 Outside the mouth of the mine lower beds are exposed as follows : 6. Sandstone, thin layer 3 5. Clay, coal and coaly shale (No. 1 [?]) 6 4. Fireclay, very fine textured, plastic, and light in color (Sample No. 96, p. 131) 4 3. Fireclay, sandy 2 2. Pyrite bed, less than 2 1. Limestone, Trenton The clay is hauled by train and electric motor to the mill and after grinding is carried by cable train across the Big Vermilion River to the Rock Island Railroad. At Lowell the clay below the No. 2 coal has been used in a small way for pottery at the Lowell Stoneware Company’s plant. Section of the Lowell Stoneware Company’s pit at Lowell Thickness Feet 4. Overburden, drift and soil 1 to 12 3. Coal (No. 2) ZV 2 2. Clay (Sample No. 90, p. 132), dark gray to light drab “W” clay; the upper three feet contains much pyrite at the base of which there are locally traces of green coloring 12 to 25 1. Limestone, Trenton Preliminary drilling is said to have proved that the clay underlies at least 200 acres. A great part of this is overlain by an overburden of less than 15 feet and could easily be removed by steam shovel. Near the river bank small quantities of clay have been dug from directly beneath 1 to 7 feet of soil and drift overburden. The clay here is distinctly bedded and of a gray color with an occasional yellow pocket. It is sold as the “R” clay (sample No. 89, p. 132). The Pennsylvanian rocks are missing on the east flank of the La Salle anticline at Utica. The bluffs of Illinois Valley are largely St. Peter sand- stone from Utica to Twin Bluffs on the south side of Illinois River. At Twin Bluffs the National Fireproofing Company is working clay in open cut from directly above the St. Peter sandstone, and about a mile to the east the 122 ILLINOIS FIRE CLAYS Herrick Clay Manufacturing Company is tunneling the clay (sample No. 95, p. 133) from the same horizon. A section of the face of the former pit is given here: Section of National Fireproofing Company’s pit at Twin Bluffs 5. 4. 3. 2 1 . Thickness Ft. In. Overburden, drift unmeasured Shale (“Soapstone”) 8 Coal (No. 2) 1 11 Shale, black 6 Clay (Sample No. 94, p. 134) ; lighter in color and more sandy toward the bottom 7 At the Herrick mine the clay is 8 feet thick and because of the east- ward dip the overlying shale has increased to more than 30 feet. At the National Fireproofing pit the drift overburden and the shale are used for drain tile and building blocks. The coal above the clay is also recovered. At both plants the clays are ground and shipped. The output from the National Fireproofing plant is approximately 800 tons per week and a similar or somewhat lesser quantity is shipped from the Herrick mine. At Ottawa the Fox and Illinois rivers have cut through the Pennsyl- vanian and are now flowing on St. Peter sandstone. About 2 miles east of that city basal Pennsylvanian clay is dug from two open pits ; that of the Chicago Retort and Firebrick Company and that of the National Fire- proofing Company. 10 . 9. 8 . 7. 6 . 5. 4. 3. 2 . 1 . Section of the National Fireproofing Company’s “Pioneer’’ pit 2 miles east of Ottawa Thickness Ft. In. Soil Shale (“soapstone”) 16 Coal 2 Fireclay, dark 1 Fireclay, lighter gray (Sample No. 91, p. 135) ; lenses of large rounded pisolitic boulders which contain large amounts of pyrite 8 Clay, green, in lenses, local Sandstone, hard, brown 1 to 4 Clay, very light in color (Sample No. 92, p. 136) 5 to 9 Clay, sandy 1 Sandstone, St. Peter 6 2 2 The clay is dug by steam shovel and hauled by electric tram to the plant at Ottawa. The output is about 5000 tons of manufactured ware per month, chiefly hollow ware and fire brick, and 1000 tons of ground fireclay. LA SALLE COUNTY 123 Section of the Chicago Retort and Firebrick Company’s pit northeast of Ottazva Thickness Ft. In. 8. Soil 1 7. Shale, blue, weathers light; “soapstone” . .. 17 6. Shale, darker ; colored by carbon 2 5. Coal 2 4. Gypsum, persistent layer 1 3. Clay, colored by carbon 2 2. Fireclay (Sample No. 101, p. 136) ; traces of green in lower beds where clay becomes lighter in color ; large rounded sandy pyritic boulders in bottom of pit ; smaller pyrite concretions scattered in the clay 4 to 8 1. Sandstone, St. Peter This section differs little from the preceding one, except that instead of the lower clay it has the green clay resting directly upon the St. Peter sandstone. A large area of this clay has been removed, but the Company reports holdings of 300 acres of tested reserve clay land east and north of the present pit. No use is made of the overburden which is removed by steam shovel and tram. Three grades of clay are used: (1) Raw clay from this pit; (2) raw clay blended with Missouri flint clay; and (3) raw clay blended with a mix- ture of raw and calcined Missouri flint clay. About half a mile southeast of Dayton, clay is mined from a tunnel driven in the side of a deep ravine. Section at Dayton Clay Works half a mile south of Dayton Thickness Feet 6. Loam, drift, and soil 6 5. Shale, more compact toward the base 32 4. Shale, dark blue 1 3. Coal (No. 2) 2. Clay, sandy, pyritic gray (Sample No. 99, p. 138) 4^2 to 5^2 1. Sandstone Sample No. 102 (p. 138) was from an outcrop of the gray fireclay above. The clay is ground and loaded by elevated conveyor onto a switch of the Chicago, Burlington and Quincy Railroad about 100 yards east of' the plant. The Chicago Firebrick Company is reopening the entries of the old Spicer Coal Company’s mine 2 miles* east of Marseilles with the intention of obtaining the clay which here is at a depth of about 90 feet. The clay is worked from a new face at the outer margin of the former mine by the room and pillar system. 124 ILLINOIS FIRE CLAYS Section of Chicago Firebrick Company's shaft 2 miles east of Marseilles Thickness Feet Shaft from top of coal to surface 90 =*= 4. Coal (No. 2) zy 2 3. Fireclay, drab, comparatively free from pyrite but colored by carbon. .Z l / 2 to 6 2. Clay, green ; rich in pyrite y 2 to 3 1. Fireclay; pyrite in small crystals to bottom of present workings; a maximum of 12 feet of this lower clay has been penetrated; at the shaft the St. Peter sandstone is 8 feet 4 inches below the bot- tom of the coal 5 The clay is shipped as ground clay. Sample No. 129 was taken from the working face omitting the green clay. (See page 140). South and east from Utica, or away from the crest of the La Salle anticline, the base of the Pennsylvanian beds lowers and in only a few places have mine shafts penetrated to the level of the clay. Two miles south of Streator, the shaft of the Streator Clay Manufac- turing Company penetrates the No. 2 coal, but the underlying clay is not of as good a quality as that farther north. Section of Streator Clay Manufacturing Company’s shaft 2 miles south of Streator Thickness Ft. In. Shaft 230 4. Coal (No. 2) 2 6 3. Fireclay, gray and blue (Sample No. 130-a, p. 140) l 1 /3to4 2. Clay, sandy, “sandrock” 3 to 5 1. Clay, greenish gray; “Intermediate clay” (Sample No. 130-b, p. 140) 2 6 Bottom not reached. At Kangley the Spring Lake Coal Company is mining the No. 2 coal. Clay brought out in lifts from digging sumps was sampled from the dump. Results of tests on the sample (No. 131) are given in page 140. Section of the Spring Lake Coal Company’s shaft at Kangley 4 miles northwest of Streator Thickness Feet Shaft * 200 2. Coal (No. 2) 3 1. Clay (Sample No. 131) ; bluish and greenish gray with small gypsum crystals and an occasional iron stain 5 Bottom not reached. I A SALLE COUNTY 125 RESULTS OF TESTS LA SALLE COUNTY Sample No. 87 (East pit of the Utica Firebrick and Clay Company ; 2 miles south of Utica) This clay is of medium hardness. It is of a dark gray or slate color speckled with a few black spots. The plasticity is very high when it is tempered with water, and its conduct when flowing through a die is good. Water of plasticity per cent 25.6 Shrinkage water per cent 17.0 Pore water ,p e r cent 8.6 Modulus of rupture lbs. per sq. in. 497.6 With 50% standard sand — Modulus of rupture lbs. per sq. in. 290.3 nun. 10.5 Slaking test, average Screen test : — Mesh 20 None 40 60 80 120 200 Drying shrinkage : — Linear; wet length 8.5 Volume 34.5 Burning test : — Color Cream, nearly white 3.1 Light cream 4.2 White exterior Cream 5.1 Residue Per cent Character of residue . . T race . 0.4 Fine white sand . 0.2 Fine white sand . 0.7 Fine white sand . 0.9 Fine white sand Per cent 9.3 Cone Porosity Per cent 02 17.0 2 12.3 4 10.7 8 8.4 9 8.2 12 4.7 14 5.0 Cream 5.1 Burning shrinkage Per cent . . 3.1 Remarks .. 4.2 Fine iron spot Fine iron spot .. 5.1 Numerous fine spots iron .. 5.1 Numerous fine spots iron .. 5.8 Numerous fine spots iron .. 5.6 Numerous fine iron spots, slagged Oxidation conduct : — Appears to be very slow. Fusion test: — Deforms at cone 28. Summary The strength of the raw clay is medium high and its bonding strength is high. The amount of residue on the sieves is slight. The drying shrinkage is medium and the total shrinkage at cone 9 is medium high. Vitrification is incomplete at cone 14. Oxidation appears to have been very slow. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, face brick, refractories. 126 ILLINOIS FIRE CLAYS Sample No. 77 (East pit of the Utica Firebrick and Clay Company; 2 miles south of Utica) This is a very hard dark gray colored clay. When powdered and tempered with water, it develops a fair degree of plasticity and will flow through a die satisfactorily. Water of plasticity per cent 19.8 Shrinkage water per cent 9.3 Pore water per cent 10.5 Modulus of rupture lbs. per sq. in. 320 With 50% standard sand — Modulus of rupture lbs. per sq. in. 261 Slaking tests, average min. 9 Screen test : — Mesh Residue Character of Per cent residue oi] 0.2 1.0 1.8 | 1.21 Quartz and pyrite 20 40 60 120 200 Drying shrinkage : — Per cent Linear ; dry length 7.5 Linear ; wet length 7.0 Volume 19.2 Drying conduct : — Efflorescence, i. e., “whitewash,” appears at the corners of the sample. Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 14.4 Cream 4.4 Granular fracture 3 11.0 Cream 4.8 Granular fracture 6 vn 00 Darker cream 5.4 Granular fracture 8 5.1 Grayish 5.5 Granular fracture 9 4.4 Grayish 5.1 12 6.0 Bluestoned 4.3 1254 Tan, light bluestoned 15 5.0 Buff exterior ; bluestoned, black 3.6 Some iron spots Fusion test: — Cone Y deformed at cone 28. Vesicular structure. Summary The clay has a medium strength and a medium bonding strength. The drying shrinkage is medium and at cone 9 the total shrinkage is medium high. The clay attains a fairly low degree of porosity at cone 6 and is not overburned at cone 15. It is a refractory clay. Suggested uses : Stoneware, architectural terra cotta, sanitary ware, refractories, face brick. Sample No. C82 (West pit of the Utica Firebrick and Clay Company, near Utica) This sample was a mixture of a light colored material, which was very hard, and a soft yellow mass. When tempered with water it developed a very good plas- ticity and could be squeezed through a die satisfactorily. I A SALLE COUNTY 127 Water of plasticity per cent 32 Shrinkage water per cent 16.9 Pore water per cent 15.1 Modulus of rupture lbs. per sq. in. 484.8 With 50% standard sand — Modulus of rupture lbs. per sq. in. 185.2 Slaking test, average min. 9 Screen test : — Mesh Residue Character of residue Per cent 10 7.8 Sand, colored rock fragments 14 3.5 Sand, colored rock fragments 20 3.5 Sand, colored rock fragments 35 1.3 Sand, colored rock fragments, and coal 48 Sand, colored rock fragments, and coal 65 1.0 Sand, colored rock fragments, and coal 100 T race 150 Trace 200 Drying shrinkage : — Per cent Linear 6.8 Burning test : — Total Cone Porosity Per cent Color shrinkage Per cent Remarks 02 33.7 Reddish cream 1.8 1 3.9 Dark grav 12.7 Very brittle 3 2.2 Dark gray 13.6 Very brittle 5 1.0 Dark brown 12.5 Bloated. Sample heated above this cone was melted. Fusion test: — Complete fusion at cone 26. Cone shows vesicular structure, but not very decided. Summary The strength of the clay is medium high. Its bonding strength is medium low. The drying shrinkage is medium. Total shrinkage at cone 5 is medium high. It appears bloated as though overburned at cone 5. The clay is non-refractory. Suggested uses : Common brick and tile. Sample No. 97 (M. J. Gorman and Company’s pit; 1^ miles south of Utica) The following tests relate to the sample collected by Mr. Culver. The material is of a medium hard shaly nature. With it is mixed a softer por- tion. The color is dark gray and brown. A good plasticity may be developed. When forced through a die, the clay flows rather badly. Water of plasticity per cent 35.6 Shrinkage water per cent 22.9 Pore water per cent 12.5 Modulus of rupture lbs. per sq. in. 565 With 50% standard sand — Modulus of rupture lbs. per sq. in. 201 Slaking test, average min. 60 128 ILLINOIS FIRE CLAYS Screen test: — Mesh 20 40 60 80 120 150 200 Drying shrinkage : — Linear ; dry length Linear : wet length Drying conduct : — Shows tendency to warp. Burning test : — Cone Porosity Color Per cent 08 30 Salmon 06 27 Buff 04 24 Cream 02 23 Buff 1 22 Buff 2 16 Stoneware 4 9.5 Gray 7 5.6 Gray 9 6.5 Gray 10 4.4 Gray with brown specks Fusion test: — It fused at cone 28. Residue Per cent . 0.3 17.3 17.6 6.0 . 0.8 1.8 , 4.0 Per cent .. 10.5 .. 9 Burning shrinkage Per cent .. 1.6 .. 2.2 .. 3.1 .. 4.0 .. 4.6 .. 5.4 .. 5.7 .. 5.2 . . 5.5 .. 5.3 Summary The strength of the clay is medium high. Its bonding strength is medium. The total percentage of residue on the screens is high. The drying shrinkage is medium high at cone 9. The total shrinkage is high. The vitrification proceeds slowly and is incomplete at cone 10. It is a refractory clay. Suggested uses : Refractories, face brick. Sample No. 100 (M. J. Gorman and Company’s pit; \ l / 2 miles south of Utica) Resampled by Mr. Culver. The clay is a very hard gray colored material. Its conduct when forced through a die is good. Water of plasticity per cent 24.6 Shrinkage water per cent 13.8 Pore water per cent 10.8 Modulus of rupture lbs. per sq. in. 475 With 50% standard sand — Modulus of rupture lbs. per sq. in. 222 Slaking test, resample min. 40 LA SALLE COUNTY 129 Screen test : — Mesh Residue Character of Per cent residue 20 0.2 Fragments of rock and pyrites 40 0.06 Sand and pyrites 60 3.5 Sand, particles of clay and pyrites 80 2.1 120 14.1 Particles of clay 150 3.4 Particles of clay 200 6.5 Particles of clay The sample did not slake completely. Drying shrinkage: — Linear; wet length per cent 7.3 Burning test : — Burning- Cone 08 Porosity Per cent 24 Color Lisrht errav shrinkage Per cent 2.1 06 23 Buff and cream 2.5 04 20 Dark cream 3.3 02 18 Dark cream 4.0 1 16 Dark cream 4.4 3 12 Gray 5.0 5 8 Gray with iron speckles 5.5 7 6 5.5 9 6 5.5 11 7 Brown 5.7 Fusion test: — It deformed at cone 31. Summary The strength of the clay is medium high. Its bonding strength is medium. The amount of screen residues is high. The drying shrinkage is medium. The total shrinkage at cone 9 is medium high. Vitrification is incomplete at cone 11. It is a refractory clay. Suggested uses: Refractories, face brick. The slow slaking properties may limit its usefulness for terra cotta, stoneware, and sanitary ware. Sample No. 98 (Side of gully near M. J. Gorman and Company’s pit, near Utica) This report relates to sample obtained by Mr. Culver. This is a soft clay, yellow in color and marked with brown spots. When tem- pered with water, it has good plasticity. Water of plasticity per cent 28 Shrinkage water per cent 12.7 Pore water per cent 15.3 Modulus of rupture lbs. per sq. in. 246 With 50% standard sand — Modulus of rupture lbs. per sq. in. 149 Slaking test, average min. 65 130 ILLINOIS FIRE CLAYS Screen test : — Mesh Residue Per cent Character of residue 20 ... 42 Chert and sandstone fragments 40. . ., 1.0 60 2.8 80 5.3 White and yellow sand 120 2.2 White and yellow sand with some mica 150 2.00 White and yellow sand with some mica 200 4.8 White and yellow sand with some mica Drying shrinkage: — Linear; wet length per cent 6.2 Burning test: — Burning Cone Porosity Color shrinkage Per cent Per cent 08 36 Brownish red 1.7 06 34 Brownish red 2 ? 04 32 Brownish red 3.4 02 31 Brownish red 3.8 1 30 Brownish red 4.3 3 28 Chocolate 5.0 5 22 Bluish black 6.2 7 19 Bluish black 6.8 9 17 Bluish black 7.6 Fusion test: — It deforms at cone 29. Summary The clay has a medium strength, a medium low bonding strength, and a medium drying shrinkage. It contains a considerable percentage residue material too coarse to pass the screen test. The total shrinkage at cone 9 is medium high. The clay is quite open burning. The very dark color of the samples carried to cone 5 and beyond suggests the possibility of reduction during burning. It is refractory. Suggested uses : Face brick. The dark color of the burned clay and its burning conduct suggest the possibility of the iron content being abnormally high for a re- fractory material, even though the fusion test was satisfactory. Sample No. 93 (Illinois Clay Products Company’s mine at Deer Park) This is a dark gray colored clay which is a semi-flint in its character. It appears to contain a notable amount of pyrites. Water of plasticity Per cent 25 Shrinkage water per cent 15.9 Pore water per cent 9.1 Modulus of rupture lbs. per sq. in. 554.7 With 50% standard sand — Modulus of rupture lbs. per sq. in. 302.5 Slaking test, average min. \0 l /> Drying shrinkage : — Per cent Linear ; wet length 7.2 Linear ; dry length 7.8 Volume 32.6 LA SALLE COUNTY 131 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 2 72 Grayish white 6.0 Nearly vitreous 3 3.3 Gray 6.3 Nearly vitreous frac- ture 6 3.0 Gray 6.6 Nearly vitreous 8 2.2 Gray 5.5 Some fine iron spots 12 11.8? Bluestoned 2.6 13 7.3 Buff ; slagged spots ; blue core. 3.2 Buff exterior, blue core, numerous iron spots 15 4.6 Dark terra cotta flash outside ; gray inside 4.0 Large iron spots over- burned Fusion test : — It deformed at cone 29. Summary The strength of the clay is medium high and its bonding strength is medium. The drying shrinkage is medium. The total shrinkage at cone 8 is medium high. It is practically non-porous at cone 8 and is slightly overburned at cone 13. It is a refractory clay. Suggested uses : Refractories, especially those requiring a clay having a good strength and burning to a dense structure. Facebrick. Its slow slaking property when mixed with water is rather unfavorable for its use for stoneware and terra cotta. Sample No. 96 (Illinois Clay Products Company’s mine at Deer Park) The sample was a hard, dark gray colored material of medium plasticity. Water of plasticity 19 Shrinkage water 10 Pore water 0 Modulus of rupture 277 With 50% standard sand — Modulus of rupture . . 107.3 Slaking test, average Screen test: — Too hard t,o slake. 7 Drying shrinkage : — Per cent Linear ; dry length 5.8 Linear ; wet length 5.5 Volume 20.5 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 18 White 3.9 2 17 Light cream 3 14 Light cream 6 12 Light cream 9 7 Cream . . . . 4.4 Earthy fracture . . . . 6 Earthy fracture Granular .... 6.1 12 3.0 Bluestoned ; uniform gray. . .... 7 Earthy fracture 13 2.4 Bluestoned ; uniform gray . , . . . . 6.8 Earthy fracture 15 2.4 Bluestoned ; uniform gray . . . . . 7.0 132 ILLINOIS FIRE CLAYS Fusion test: — It fused about cone 31. Summary The strength of the clay is medium and its bonding strength is medium low. The drying shrinkage is medium. At cone 9 the total shrinkage is medium. Vitri- fication is nearly complete at cone 12 and there is no sign of overburning at cone 15. It is refractory. Suggested uses : Refractories and face brick. Its slow slaking is rather unsatis- factory for stoneware and architectural terra cotta. Sample No. 90 (Lowell Stoneware Company’s pit ; at Lowell) This is a hard dark colored, i. e., gray clay which becomes very plastic when tempered with water. Its conduct when flowing through a die is very good. Water of plasticity per cent 20.8 Shrinkage water per cent 8.5 Pore water per cent 12.2 Modulus of rupture lbs. per sq. in. 420 With 50% standard sand — Modulus of rupture lbs. per sq. in. 290 Slaking test, average min. 9 Screen test : — Clay was too hard to slake. Drying shrinkage : — Per cent Linear; dry length 6.8 Linear; wet length 6.2 Burning test: — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 18 White 4.1 3 14 Light cream . . 5.0 Earthy fracture 6 12 Light cream . . Earthy fracture 9 9.5 Cream 5.7 12 5.0 Darker cream 7.0 Granular but vitreous fracture 15 2.0 Tan exterior; bluestoned badly. 7.6 Fusion test : — Deformation at cone 30/31. Summary The strength of the clay is medium high and its bonding strength is medium. Because of its hardness, the clay could not be slaked properly for the screen tests. The drying shrinkage is medium. The total shrinkage at cone 9 is medium. Vitri- fication is practically complete at cone 15. It is a refractory clay. Suggested uses: Refractories, especially if good bonding power is desired. Its slow slaking property is a disadvantage for stoneware and architectural terra cotta, although otherwise it seems adapted to these uses. Sample No. 89 (Near river bank at Lowell) This report relates to a resampling of the deposit by Mr. Culver. This hard clay is of a gray color and it has a low degree of plasticity. The conduct of the plastic body when forced through a die is only fair. LA SALLE COUNTY 133 Water of plasticity per cent Shrinkage water per cent Pore water per cent Modulus of rupture lbs. per sq. in. With 50% standard sand — Modulus of rupture lbs. per sq. in. Slaking test, average min. Screen test : — 18 6.6 11.3 179 137.6 12 Mesh Residue Character of residue Per cent 20... 4.5 Particles of coal, rock and pyrites 40... 6.8 Particles of coal, rock and pyrites 60... 2.3 Particles of coal, rock and pyrites, some mica 80... 1.1 Particles of clay 120... 0.9 Particles of clay 150... 2.0 Particles of clay 200... 9.4 Particles of clay Drying shrinkage -Linear Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 08 30 White +.4 06 27 Cream ...+0.3 04 28 Cream ....- 0.1 02 1 3 5 7 9 11 28 27 25 19 19 17 12 Cream 0.26 Cream 0.3 Cream 1.0 Cream with black spots 2.5 Cream with black specks 2.2 Black specks 2.0 Black specks 2.5 Appears overburned Fusion test: — Fused completely at cone 26. Summary The strength of the unburned clay is medium low. Its bonding strength is medium low. The amount of residues on the sieves is high. The total shrinkage at cone 9 is medium low. The vitrification is still quite incomplete at cone 11, al- though it has the appearance of having been overburned. It is a non-refractory clay. Suggested uses : Stoneware, although the hardness and slow-slaking properties together with the low strength may be quite disadvantageous ; face-brick. Sample No. 95 (Herrick Clay Manufacturing Company; 1 mile east of Twin Bluffs) This sample appears to be a mixture of clay and quartzite lumps and grains. It is a grayish or dark color. Modulus of rupture lbs. per sq. in. 157 Slaking test, average min. 6 J 34 ILLINOIS FIRE CLAYS Screen test : — Mesh Residue Character of residue Per cent 20 3.5' 40 1.8 60 13.9 C Quartz sand and pyrites 120 23.3 200 2.6 Fusion test Deforms at cone 27. Summary The strength test is medium low. The percentage of residues on the screens is high. It is refractory. Sample No. 94 (National Fireproofing Company’s pit at Twin Bluffs) The sample is a dark gray, hard clay which contains some sandy material. When tempered with water a medium degree of plasticity may be developed. It does not flow readily through the die. Water of plasticity Shrinkage water Pore water Modulus of rupture Slaking test, average Screen test : — Sample does not slake. Drying shrinkage : — per cent 16.9 per cent 7.6 per cent 9.2 lbs. per sq. in. 140.6 min. 8^2 Linear : dry length Linear ; wet length Volume Burning test : — Per cent .. 4.0 .. 3.9 .. 15.9 Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 24.7 Gray 1 1 25.3 Grayish white . . ... 1.0 1 3 24.6 Cream ... 1.5 ! 5 21.9 Light brown . . . . T Specked with iron 7 22.1 Light brown . . . . . . . 2.0 9 22 Dark brown . . . 2.0 12 19 Terra cotta . . . 2.0 Color may be due to flashing 13 16 Red brown with black spots on interior . . . 3.0 15 11 Bluestoned, gray black . . . 5.0 Oxidation conduct : — Material seems to flash very readily. Fusion test: — It deforms at cone 31. Summary The strength of the clay is medium low. At cone 9 the total shrinkage is medium low. Its drying shrinkage is medium low. The clay is quite open burning, vitri- LA SALLE COUNTY 135 fication being incomplete at cone 15. It is a refractory clay. Suggested uses : The rather poor plasticity may render it difficult to form this clay readily; otherwise it is adapted to use for face brick. Although the fusion test indicates a material of refractory nature, yet the presence of numerous iron spots as indicated at the lower cones is not very satisfactory. Sample No. 91 (National Fireproofing Company’s pit; 2 miles east of Ottawa) This is a hard clay of a dark gray color which contains a notable amount of pyrites. It is fairly plastic. Water of plasticity per cent 17.3 Shrinkage water per cent 9.1 Pore water per cent 8.2 Modulus of rupture lbs. per sq. in. 309.5 With 50% standard sand — Modulus of rupture lbs. per sq. in. 236.7 Slaking test, average min. 9 Screen test : — ■ Mesh Residue Character of Per cent residue Trace 0.3 2.3 1.1 2.1 2.4 Pyrite and sand 20 40 60 80 120 200 Drying shrinkage : — Per cent Linear ; dry length 6.8 Linear; wet length 6.3 Volume 18.9 Burning test Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 24.8 White .... 2.6 Fine specks of iron oxide 02 22.4 White . . . . 3.5 Fine specks of iron oxide 2 18.5 Grayish white . . . . 4.8 Granular 5 16.5 Grayish white . . . . 5.4 Granular 9 14.0 Grayish white . . . . 5.6 Numerous fine iron spots 13 7.9 Grayish white . . . . 7.0 14 6.3 Brown red ; bluestoned . . . . . 5.3 Iron ^pots, slagged 15 16.3 Brown red ; bluestoned . . . . . 4.8 Iron spots, slagged Fusion test: — Fused completely at cone 27. Summary The strength of the clay is medium and its bonding strength is medium. The percentage of residues left on the sieves is moderate. The drying shrinkage is medium and the total shrinkage at cone 9 is medium. Vitrification is incomplete at cone 14 and apparently the clay is overburned at cone 15. It is non-refractory. Suggested uses: Stoneware, architectural terra cotta and sanitary ware (the presence of pyrites may make this use impossible), face Ibrick. 136 ILLINOIS FIRE CLAYS Sample No. 92 (National Fireproofing Company’s pit; 2 miles east of Ottawa) This is a very hard clay of a light gray color. It flows readily through a die. Water of plasticity Shrinkage water Pore water Modulus of rupture Slaking test, average Drying shrinkage : — It has only a medium plasticity. per cent 17 Per cent 6.9 per cent 10.1 lbs. per sq. in. 201 min. 5 Per cent Linear ; dry length 4.7 Volume 14 Burning test: — Cone 01 Porosity Color Per cent 17.8 White Burning shrinkage Per cent 4.7 Remarks 2 17 Light cream 4.9 Earthy fracture 3 13 Light cream 6.0 Earthy fracture 6 12 Light cream 6.4 Earthy fracture 9 8 Light cream 6.2 Earthy fracture 12 4.7 Darker light buff 6.9 Very fine iron spots evenly distributed 15 6.1 Light buff ; bluestoned . . . 7.1 Fusion test: — It deformed at cone 29. Summary The strength of the clay is medium. Its drying shrinkage is medium low. The total shrinkage at cone 9 is medium. It still has an appreciable porosity at cone 12 and apparently is slightly overburned at cone 15. It is a refractory clay. Suggested uses : Refractories, stoneware, architectural terra cotta. Sample No. 101 (Chicago Retort and Firebrick Company’s pit, northeast of Ottawa) This is a dark gray colored, very hard clay, which develops a fair plasticity when tempered with water. It flows only fairly well through a die. Water of plasticity per cent 20.0 Shrinkage water per cent 11.5 Pore water per cent 8.5 Modulus of rupture, maximum lbs. per sq. in. 532 Modulus of rupture, average lbs. per sq. in. 335 With 50% standard sand — Modulus of rupture : — 14 of 20 pieces gave an average (not including values of 292.5 and 296.0) lbs. per sq. in. 177 Slaking test, average rnin. 7J4 Drying shrinkage : — Per cent Linear ; dry length 7.0 Linear; wet length 6.5 Volume 23.5 LA SALLE COUNTY 137 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 19 Cream . ... 3.6 2 17 Cream . . . . 4.0 Earthy fracture 4 Cream . . . . 4.4 Earthy fracture 6 15 Darker cream . . . . 4.2 Earthy fracture 9 13 Cream . . . . 4.4 Earthy fracture 12 11 Light terra cotta : flashed . . .... 4.1 Many fine iron spots 13 12 Light terra cotta; flashed.. . . . . 4.6 Many fine iron spots, slagged 15 13 Buff . . . . 5.3 Golden buff, numerous iron spots Fusion test It deforms at cone 29. Summary The tests of the clay showed it to have medium strength, but it should be noted that a single test piece gave a much higher value. The bonding test also gave two values, considerably higher than the average of a large number of pieces. The drying shrinkage is medium. The total shrinkage at cone 9 is medium. Vitrification is incom- plete at cone 12, at which temperature it is still quite open. Apparently slight over- burning occurs above this point. The clay is refractory. Suggested uses : Face brick, stoneware, architectural terra cotta, sanitary ware, refractories. Sample No. 99 (Dayton Clay Works ; Yz mile south of Dayton) The clay is of a dark gray color. It is quite sandy (see screen test), and the plasticity is low. It flows poorly through a die. Water of plasticity per cent 15.9 Shrinkage water per cent 5.1 Pore water per cent 10.8 Modulus of rupture lbs. per sq. in. 215 With 50% standard sand — Modulus of rupture lbs. per sq. in. Slaking test, resample min. Screen test : — Mesh Residue Per cent 20 4.9 107 22]/ 2 40. 60. 80. 120 . 200 . Character of residue Pyrites and carbona- ceous matter 0.3 Pyrites and quartz sand 5.8 White quartz sand 3.7 Quartz sand 8.4 Quartz sand 4.5 Darker colored sand Drying shrinkage : — Per cent Linear ; dry length 4.9 Linear ; wet length 4.7 Volume 9 138 JLUNOIS FIRE CLAYS Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 08 30 Light gray white 2.0 06 30 Light gray white 2.0 04 30 Light gray white 2.0 02 29 Light gray white 4.1 1 25 Light gray white 6.2 3 22 Licht orrav white 9.3 5 Light gray white; iron specks.. 8.3 6 23 Slightly darker 7 Slightly darker 6.2 9 19 Slightly darker 12 16 Terracotta; flashed Numerous iron spots 15 21 Terracotta; flashed Many large iron spots Fusion test: — It fused at cone 30. Summary The clay has a medium strength, and a medium low bonding strength. The amount of screen residues is high. The drying shrinkage is medium low. The mini- mum porosity was reached at cone 12 and it appeared to overburn at cone 15. fusion test indicates a refractory clay. Suggested uses : Face brick. Certain types of refractories. The Sample No. 102 (Resampled by H. E. Culver) (Dayton Clay Works ; y 2 mile south of Dayton) This is a hard clay which is dark gray, nearly black in color. When tempered with water, it becomes very plastic and flows through a die satisfactorily. Water of plasticity per cent 33 Shrinkage water per cent 12 Pore water per cent 21 Modulus of rupture lbs. per sq. in. 297 With 50% standard sand — Modulus of rupture lbs. per sq. in. 22 3 Slaking test, average min. 13 Screen test : — Mesh (Sample slaked badly.) 20 40 60 80 120 150 200 Residue Per cent . 0.8 . 0.3 . 1.9 . 0.4 . 1.0 . 0.6 . 0.9 Character of residue Sand Clay particles Drying shrinkage: — Linear; wet length per cent 6.0 I. A SALLE COUNTY 139 Burning test Burning Cone Porosity Color shrinkage Per cent Per cent 08 29 Salmon 3.0 06 23 Brownish red 4.4 04 15 Darker 6.3 02 12 Chocolate 7.6 1 7 Gray 9.2 3 1.2 Greenish black 9.4 5 Overburned Fusion test: — Completely fused at cone 27. Vesicular. Summary The clay has a medium strength and a medium bonding strength. It slakes rather poorly and leaves a moderate amount of residues upon the screens. The drying shrinkage is medium. The clay has a short heat range. It reaches a minimum porosity at cone 3 and is overburned at cone 5. It is non-refractory. Suggested uses : Brick and tile. Sample No. 129 (Resampled by Mr. Culver) (Chicago Firebrick Company’s shaft; 2 miles east of Marseilles) This clay has a dark gray color. It is very hard. When tempered with water, it has good plasticity. Its conduct when squeezed through a die is fair. Water of plasticity Shrinkage water Pore water Modulus of rupture, maximum Modulus of rupture, average With 50% standard sand — Modulus of rupture . . Slaking test, 2nd sample Screen test : — Mesh Residue Character of Per cent residue 20 . ... 1.2 Quartz, coal, pyrites 40 . . . . 0.4 60 0.8 80 . . . . 1.3 Particles of hard clay 120 . . . . 0.4 Particles of hard clay 150 . . . . 0.3 Particles of hard clay 200 .... 1.27 Particles of hard clay Drying shrinkage : — Per cent Linear ; dry length 12.5 Linear ; wet length 10.0 140 ILLINOIS FIKE CLAYS Burning test: — Cone Porosity Color Burning shrinkage 08 Per cent 22 Cream Per cent 1.5 06 20 Cream 2.1 04 13 Grayish 3.0 02 12 Grayish 4.0 1 7 Grayish 42 3 8 Grayish 4.4 4 Overburned Iron spots Fusion test: — It deforms at cone 27/28. Summary The strength of this clay as determined by taking the average of nineteen of twenty-one test pieces is medium high. It should be noted that the maximum strength test of 900 pounds per square inch was obtained with four test pieces. The bonding test was medium. The amount of residues left upon the screens was moderate. The drying shrinkage was medium high and the total shrinkage at cone 1 was high. The sample appeared to be overburned at cone 4. The fusion test indicates a refractory clay. Sample No. 130-a (Streator Clay Manufacturing Company’s shaft; 2 miles south of Streator) This is a dark colored, very hard clay, which contains much pyrite. Its slaking time averages 6 l /i minutes. It is completely fused at cone 25. Sample No. 130-b (Streator Clay Manufacturing Company’s shaft; 2 miles south of Streator) This is a dark colored, i. e., grayish, very hard clay. The average time of the slaking test was nineteen minutes. It is completely fused at cone 25. Sample No. 131 (Spring Lake Coal Company’s shaft at Kangley) This is a hard, greenish-gray colored clay, which is stained with iron oxide. It has a conchoidal fracture. When tempered with water, a medium plasticity may be developed. Its conduct when forced through a die is satisfactory. The occurrence of gypsum crystals in the clay was noted. Water of plasticity per cent 29.7 Shrinkage water per cent 13.3 Pore water per cent 16.4 Modulus of rupture lbs. per sq. in. 361.8 With 50% standard sand — Modulus of rupture lbs. per sq. in. 192.6 Slaking test, average min. 15 Drying shrinkage : — Per cent Linear 5.7 Volume 20.0 LA SALLE COUNTY 141 Screen test : — Mesh Residue Character of Per cent residue 10 0.9 ' 14 1.0 20 1.1 35 2.6 48 1.18 - Particles of shale, pyrite, 65 1.0 and coal 100 0.8 150 0.65 200 0.50 Burning test : — Cone Porosity Color Total shrinkage Remarks 04 Per cent 10.3 Terra cotta Per cent 13.9 Scummed by efflorescent salts 01 1.75 Terra cotta 15.3 Vitreous glassy fracture 3 0.9 Reddish brown . . . 15.3 Vitreous glassy fracture 5 4.8 Brown Overburned, bloated 7 11.8 Brown Overburned, bloated Soluble salts : — Salts appear on the pieces after burning. Fusion test*: — It fused at cone 25. Summary The strength of the clay is medium. Its bonding strength is medium low. The amount of coarse particles is moderate and the fractions are quite evenly distributed. The total shrinkage at cone 3 is high. The clay vitrifies rapidly at a low temperature and is overburned at cone 5, thus having a very limited heat range. It is non- refractory. Suggested uses : Common brick. GRUNDY COUNTY An exceptional thickness of clay is found in the depression formerly occupied by Goose Lake. Lenses of this clay are of a semi-flinty nature and thin layers of coal are interbedded with it. This coal varies in thick- ness, and at the west end will total 6 or 7 feet. The total thickness of the clay is reported to vary from 30 to 40 feet and the overburden over the 200 acre deposit ranges from practically nothing to 6 or 8 feet with an aver- age of about 3 feet. A drilling 30 feet deep did not reach the bottom of the clay. “Islands” of rock are found in the clay and suggest its accumula- tion in solution basins in the crystalline Richmond limestone which out- crops at the north ; at least these basins were in some way partly separated from the main “Coal Measures” sea at the south. Fig. 56 is a view of the clay pit at the west end of the Goose Lake area. A face exposed in the bank of a small test pit is as follows : 142 ILLINOIS FIRE CLAYS Fig. 56. View of the clay pit at the west end of the Goose Lake area in Grundy County. Section of upper part of Goose Lake clay Thickness Ft. In. 5. Peaty soil and peat 8 to 10 4. Sandstone, local thin lenses 0 to 3 3. Fireclay, flint or semi-flint, drab, stained by iron and showing colorings of carbon (Sample No. 133) 1 2. Shale, stained black by carbon 6 1. Clay, drab gray with yellow stains of iron oxide (Sample No. 134) 3 6 The upper “flint” or “semi-flint” is underlain by a thin coal which is in turn above a plastic clay of lower refractory value. An additional sample, known as No. X, which was obtained from a pit on the Anderson farm in Goose Lake Township, Grundy County, was col- lected and shipped to the Survey by D. C. Haeger. It is known as No. 1 fire clay, according to Mr. Haeger. The clay lies in a bed 5 feet in thick- ness and is covered by 20 to 24 feet of soft stone, 30 to 36 feet of sandstone, and 16 inches of black soil. Results of tests on sample No. X are given on page 144. RESULTS OF TESTS GRUNDY COUNTY Sample No. 133 (Clay pit at the west end of the Goose Lake area) This is a drab colored, flinty clay, stained with iron. When ground and tem- pered with water, it develops a medium plasticity. GRUNDY COUNTY 143 Water of plasticity Shrinkage water Pore water With 50% standard sand — Modulus of rupture Slaking test, average Screen test : — Mesh 40 60 80 120 200 Drying shrinkage : — Linear ; dry length Linear ; wet length Volume per cent 18.2 per cent 8.6 per cent 9.6 lbs. per sq. in. 59.6 min. 3 Residue Character of Per cent residue . 0.14' . 0.24 0.30 Particles of hard clay 0.64 and sand . 0.25 ► Per cent .. 3.6 . . 3.5 . . 16.6 Burning test : — Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 02 24 White . . . 2.8' 01 24.3 White . . . 3.3 3 22 White ... 4.2 6 21 White ... 4.3 Earthy fracture 9 17 Cream white . . . 5.0 12 12 Cream white ... 6.4 i Granular fracture; nu- 13 8 Cream white ... 7.2 1 1 merous flinty parti- 15 6 Buff; lightly bluestoned ... 8.3 1 \ cles and fine iron i stain Fusion test : — Deforms between cones 30 and 31. Summary The bonding strength of the clay is low. The drying shrinkage is medium low. The total shrinkage at cone 9 is medium. It has a low porosity at cone 15. It is a refractory clay. Suggested uses : Refractories. Sample No. 134 (Clay pit at west end of Goose Lake area) This is a clay of medium hardness, and gray colored but stained with yellow. Tempered with water, it has a medium degree of plasticity and shows a tendency to laminate when forced through a die. Water of plasticity per cent 31.8 Shrinkage water per cent 18.5 Pore water per cent 13.3 Modulus of rupture lbs. per sq. in. 442 With 50% standard sand — Modulus of rupture lbs. per sq. in. 194 Slaking test, average min. 14 144 ILLINOIS FIRE CLAYS Screen test : — Mesh 20 60 80 120 200 Drying shrinkage Linear; dry length 7.6 Linear; wet length 7.1 Burning test : — Residue Character of Per cent residue . 0.1 Sand . 0.7 Sand . 0.1 Sand . 0.9 Sand . 0.3 Sand Per cent Burning Cone Porosity Color shrinkage Remarks Per cent Per cent 04 30 Cream white 1.41 02 26 Cream white 3.0 1 2 17 Cream white 5-4 \ Earthy fracture 5 15 Cream white 6.0 9 11 Cream white 6.7] 13 4.1 Light gray 7.2 Vitreous ; not glassy 14 4.0 6.4 15 4.3 Light brown exterior ; bluestoned or light gray 6.3 Fusion test : — Deforms at cone 28. Summary The clay has a medium high strength and a medium low bonding strength. The drying shrinkage is medium. The amount of screen residues is low. At cone 9 the total shrinkage is medium high. It reaches a low degree of porosity at cone 13 and shows no sign of overburning at cone 15. It is a refractory clay. Suggested uses : Refractories, architectural terra cotta, stoneware, sanitary ware, face brick. Sample No. X (Anderson farm in Goose Lake township) This is a drab colored, flinty clay, which develops a medium plasticity when tem- pered with water — i. e., it is rather sandy or grainy. The plastic mass laminates badly when squeezed through a die. Water of plasticity per cent 26.6 Shrinkage water per cent 14.6 Pore water per cent 12.0 Modulus of rupture lbs. per sq. in. 317.4 With 50% standard sand — Modulus of rupture lbs. per sq. in. 202.3 Screen test : — Mesh Residue Character of Per cent residue 10 . 14. 20 . 35. 48. 65, 2.9 1.8 2.8 8.5 5.5 5.4 Fragments of coal and shale JOHNSON COUNTY 145 100 3.9 'j Fragments of coal and 150 2.7 j- shale, and some mica 200 3.0 J Drying shrinkage : — Per cent Linear 6.2 Volume 26 Burning Cone test : — Porosity Color Hardness Total shrinkage Remarks 04 Per cent 10.0 Gray Very hard . . . . Per cent 12 Granular fracture 01 6.9 Gray Very hard . . . 13 1 12.5 Gray Very hard . . . , 12 3 6.8 Gray Very hard 12.7 5 2.4 Gray Very hard . . . . 12.9 Slightly bluestoned 7 1.3 Gray Very hard 12.9 9 0.4 Gray Very hard . . . . 12.9 12 0.5 Gray Very hard . . . . 13.1 14 0.5 Gray Very hard . . . . 12.2 Some iron specks Fusion test: — It deforms at cone 28. Summary The clay has a medium strength and bonding strength. The air shrinkage and total shrinkage are medium. It is almost completely vitrified at cone 5 and shows no signs of overburning throughout the firing range. It is refractory. Suggested uses : Refractories, particularly those of a close texture. JOHNSON COUNTY About two miles southeast of Ozark station is a deposit of Pottsville oil shale or cannel coal which has been investigated by the Survey. Perhaps the best typical exposure of this deposit and the associated strata is that on the Stone land, a section of which is here given: Section of oil shale measured in a test pit on the Frank Stone land in the NW. % NW. y A sec . 35, T. 11 S., R. 4 E. Thickness Fi, In. 8. Soil, yellow 1 to 5 7. Shale, chocolate, siliceous 4 2 6. Mud, red, merely a streak 5. Oil shale 2 9 4. Coal, bituminous 154 3. Coal, cannel 4 2. Coal, bituminous, with peacock-colored blotches 2 1. “Fire clay,” white 5-4- . . In connection with the sampling of the oil shale a sample of the under- lying clay was taken and tested with the results that follow. 146 ILLINOIS FIRE CLAYS Sample No. C-18 — 1 (Sample taken from below the cannel coal near Ozark in sec. 35, T. 11 S., R. 4 E.) This sample is medium hard, gray colored clay ; mottled with brown, which latter color may be due to the presence of organic matter. It has rather poor plasticity. Water of plasticity . 22.09 Shrinkage water . . . 9.20 Pore water 12.89 Modulus of rupture 147.3 Slaking test, average 8 Drying shrinkage, linear 4.4 Burning test : — Total Cone Porosity Color shrinkage Remarks Per cent Per cent 04 18.7 Light tan 8.3 ] 01 16.4 Light tan 7.3 Earthy fracture 1 17.9 Gray 9 5 9.4 Dark gray 11.5 7 3.1 Dark gray 7 Shows signs of over- burning Fusion test: — It fuses at cone 16. Summary The clay has a medium low strength and a medium drying shrinkage. The burning shrinkage at cone 5 is medium high. It seems to be overburned at cone 7. The trial pieces have the appearance of having been subjected to reducing conditions at and above cone 5. The clay is non-refractory, in fact, it is very fusible. Suggested uses : Brick. Tabulation of Certain Physical Tests A knowledge of certain of the physical tests of a clay will enable the experienced person to determine very quickly whether it is likely to be of value for a specific purpose. Accordingly there are grouped in the following paragraphs classifications of the clays examined according to the results obtained in the more significant tests. A full explanation of the methods of testing and the interpretation has been given elsewhere. Slaking test : — The samples which required more than thirty minutes for slaking according to the standard test were: Nos. 22, 38, 44 (169) 55, 58. 59, 60, 97, 98, 100, 129, 136. Fusion test : — The samples which fused below cone 27 were: Nos. 17, 37-a, 41, 42, 47, 50, 52, 54, 55, 56, 57, 58, 61, 62, 67, 69, 70, 73-a, 74, 75-a, 75-b, 79, 80, 81, 82, 83, 84, 85, 86, 89, 91, 97, 102, 130-a, 131, 136. The samples which fused between cones 27 and 32 inclusive were : Nos. 9, 16, 22, 23, 25, 27, 28, 29, 30, 37, 38, 44, 45 (1678), 46, 48, 51, 53, 59, 60, 65, 66, 71, 73-b, 73-c, 75, 77, 78, 87, 88, 90, 92, 93, 94, 95, 96, 98, 99, 100, 101, 121, 122, 129, 133, 134, X. The samples which fused at cones 33 and above were: Nos. 11, 18, 26. TABULATION OF PHYSICAL TESTS 147 Porosities: — A grouping of the samples in accordance with their porosi- ties at various cones is given in the following table : 5% or less at or below cone 5 5% or less between cones 5 and 9 5% or less between cones 9 and 12 5% or less between cones 12 and 15 10% or more at cone 12 or above 23 F G 18 16 26 25 K 3 38 46 29 27 49 54 50 30 28 51 56 70 42 37 73-a 65 75-a 55 37-a 75 71 79 57 52 90 74 84 58 66 96 77 89 59 81 97 87 94 60 86 92 98* 61 121 99 62 122 134 101 67 69 73-b 73-c 82 83 85 88 93 102 131 ♦Probably. Strength tests : — The following are the transverse strength tests of the various clays reported in terms of the moduli of rupture in pounds per square inch. The symbol “p” is used to indicate results obtained in testing the clay only. The symbol “b” indicates the test of a mixture of equal parts of standard sand and clay; that is to say, the “bonding strength.” Sample Below 200 lbs. per sq. in. Between 200 and 400 lbs. per sq. in. Above 400 lbs. per sq. in. i P b P b P b 9 104.4 11 43.4 16 64.1 17 180.9 23 311.2 302.3 25 141.2 131.2 26 137.5 259 27 120.9 265 28 192 151.8 29 286.1 30 345 229 Sample 37 37-a 38 42 44 45 46 47 49 50 51 52 53 54 55 56 57 58 59 60 61 65 66 67 69 70 71 73-a 73-b 73-c 74 75 75-a 75-b 77 78 79 80 82 83 84 85 86 87 88 89 ILLINOIS FIRE CLAYS Below 200 lbs. per sq. in. Between 200 and 400 lbs. per sq. in. Above 400 lbs. . per sq. in. P b P b P b 249.7 487.2 240.7 238.7 164.8 283.1 325.6 465.6 299.5 526.6 217.4 214 365 8 189.5 369 2 207 275.5 199 446.8 380.2 243.9 120.2 103.1 250 250 172.5 145.1 231.8 462 370 565.5 165.7 124.6 169.8 589 164.5 427 372.7 567 240.8 414.5 303.8 248.7 242 498.3 302.8 609 144 328 352.2 356.5 339.3 221.8 214.9 295.6 192 269.6 ' 199.6 263 320 261 325.8 209.4 119.5 287.3 445.4 185.2 484.8 329 664 214 386.7 190.2 290.3 497.6 243 179 137.6 TABULATION OF PHYSICAL TESTS 149 Sample Below 200 lbs. per sq. in Between 200 and 400 lbs. per sq. in. Above 400 lbs. per sq. in. P b P b P b 90 290 420 91 309.5 236.7 92 201 93 94 302.5 554.7 140.6 96 107.3 277 97 201 565 98 149 246 99 107 215 100 222 475 101 177 532 102 297 223 121 191 123.3 122 177 136.5 129 247 795 131 192.6 361.8 133 59.6 134 194 442 SUMMARY Grouping of Clays According to Uses In the following summary the clays have been grouped according to uses to which they seem to be adapted. It is to be understood that the arrange- ment is based solely upon the data given, and not upon special tests. Refractory clays burning to a porosity of 5 per cent or less at cone temperatures not exceeding cone 9: Samples F, G, K 3 , Nos. 23, 25, 26, 27, 28, 29, 30, 37, 37a, 55, 59, 66, 73c, 88, 93, 121 , 122 . Refractory clays which have a porosity of more than 5 per cent below cone 9: Nos. 16, 18, 22,38, 44,45, 46, 49, 51, 53, 54, 56, 71, 75, 77, 78, 80, 87, 90, 92, 94, 96, 97, 98, 99, 100, 101, 129, 133, 134. Stoneware clays: Nos. 9, 23, 25, 26, 28, 29, 30, 37, 37a, 38, 41, 42, 44, 47, 49, 51, 52, 54, 56, 57, 65, 66, 70, 71, 73a, 73c, 74, 75, 75b, 77, 78, 79, 80, 85, 87, 88, 89, 90, 91, 92, 93, 96, 97, 100, 101, 121. 122, 134. Architectural terra cotta clays: Nos. 9, 23, 25, 26, 28, 29, 30, 37, 37a, 38, 41, 42, 44, 47, 49, 51, 52, 53 54, 55, 56, 57, 58, 60, 65, 66, 70, 71, 73a, 73c, 74, 75, 75b, 77, 78, 79, 80, 84, 85, 87, 88, 89, 90, 91, 92, 93, 96, 97, 100, 101, 121, 122, 134. Sewer pipe clays: Nos. 50, 57, 59, 60, 65, 67, 73b, 83, 86. Face brick clays: Nos. 42, 45, 47, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 61, 62, 65, 67, 70, 71, 73a, 73b, 73c, 74. 75b, 77, 78, 79, 80, 83, 84, 85, 86, 87, 88, 89, 91, 92, 93, 96, 97, 98, 99, 100, 101, 134. Common brick , tile, etc.: Nos. 61, 62, 69, 75a, 81, 82, 86, 102, 131, 136. Sanitary ware clays: Nos. 23, 25, 26, 28, 29, 30, 37, 37a, 38, 41, 42, 44, 47, 49, 51, 52, 53, 54, 55, 56, 57, 65, 66, 70, 71, 73a, 73c, 74, 75b, 77, 78, 79, 80, 85, 87, 88, 89, 90, 91, 92, 93, 96, 97, 98, 99, 100, 101, 134.