HUMOIS GEOLOGICAL SURVEY LIBRARY STATE OF ILLINOIS WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION VERA M. BINKS, Director LIGHT- BURNING CLAY RESOURCES IN LA SALLE COUNTY. ILLINOIS Walter E. Parham DIVISION OF THE ILLINOIS STATE GEOLOGICAL SURVEY JOHN C. FRYE, Chief URBANA CIRCULAR 277 1959 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/lightburningclay277parh LIGHT- BURNING CLAY RESOURCES IN LA SALLE COUNTY, ILLINOIS Walter E. Parham ABSTRACT For this study of the nature and possible uses for the light- burning clay deposits of LaSalle County, Illinois, about 50 samples of the underclay below the No. 2 Coal were collected and tested. Laboratory tests were run to determine the drying and firing shrinkage, water of plasticity, fired color, refractoriness, and bond- ing properties of the clay. The thickness of the clay, its overbur- den, and types of associated sediments were recorded from field observations and, at some places, from water well drillers' logs. The most favorable areas for prospecting for light-burning clay are found along the top of the river bluffs on the south side of the Illinois River between the towns of LaSalle and Ottawa, and in the valley flats east of Ottawa along the north side of the river. Most of the shallow light-burning clay deposits observed in out- crop have been exhausted or are now being quarried, but explora- tory drilling may locate other deposits at depths shallow enough. to be worked commercially. INTRODUCTION LaSalle County in north-central Illinois, about 80 miles southwest of Chi- cago, is divided into a north and south section by the westward flowing Illinois River. Near Streator, LaSalle, and Ottawa, local clay resources provide a source of income for many people. Many of the older clay pits have been worked out and a number of new pits have been dug. This report on the clay resources of the coun- ty may serve as a guide for those interested in locating and exploiting new clay deposits. The major part of LaSalle County is covered by Pleistocene glacial deposits (Cady, 1919; Willman and Payne, 1942), but outcrops of the older rocks are found generally along the Illinois, Vermilion, and Fox Rivers. Some of these outcrops include exposures of clay below the No. 2 Coal, Pennsylvanian in age, which rests on the older Ordovician rocks (fig. 1). The normal sequence of rocks encountered in outcrop and drill holes throughout this area is shown in a generalized form in figure 2. In LaSalle County the bedrock strata have been folded into an anticline that trends north-northwest to south-southeast across the county and is known as the LaSalle Anticline (fig. 1). The beds on its east side slope gently toward the east but those on the west side dip steeply westward. [3] ILLINOIS STATE GEOLOGICAL SURVEY KEY f;.. . J Pennsylvonian rocks Axis of LaSalle Anticline Fig. 1 . - Generalized block diagram of the bedrock in LaSalle County. The clays underlying the No. 2 Coal have been used widely in the brick and structural clay products industries in LaSalle County. Various deposits have been found to be satisfactory for use in face brick, stoneware, terra cotta, sewer pipe, and refractory and bonding clays. Probably the majority of the county is underlain by similar deposits, but the only exposures are along the Illinois River between Ottawa and LaSalle, and at a few other localities near the mouths of the Vermilion and Fox Rivers (fig. 3). A more complete account of the geology of this region is given in reports by Cady (1919) and Willman and Payne (1942). Additional data on ceramic tests of the light-burning clays of LaSalle County are given in reports by Willman and Payne (1942) and Parmelee and Schroyer (1921). LIGHT-BURNING CLAY RESOURCES Pleistocene Pennsylvanian &=-^^ & ////r 1E3. PennsylvanianP*— <*P- Ordovician Till, 10 to 90 feet thick, buff to yellow-brown, contains many rock fragments. Shale, Francis Creek, to 20 feet, dark gray, contains ironstone nodules. Coal (No. 2), to A\ feet, generally l\ feet. Underclay, 1 to 3 feet, dark gray in top few inches, lighter in bottom portion, fine- grained . Clay-like band, green, to 10 inches, shows some bedding, commonly 8 inches thick, if present. Underclay, up to 15 feet thick, light gray, fine-grained, generally sandy near base, Sandstone, St. Peter, light colored to white, composed of rounded quartz grains. Fig. 2. - Generalized geologic column. REPORTS OF TESTS This report includes locations of existing clay deposits, their thickness, overburden, type of underlying sediment, and the results of tests on the physical properties of the clay. The test results include the drying and firing shrinkage of the clay, water of plasticity, fired colors, refractoriness, bonding properties, and possible uses. This type of information should aid in determining the most favorable loca- tions for prospecting for clay of a desirable nature. At a few places a single under- clay outcrop was divided into two or three samples from the top of the outcrop to the bottom to facilitate study of any vertical changes in its behavior. The top sample was given the letter "A, " the next lower sample "B, " and so forth. (Samples 1486, 1492, 1496, and 1499.) All other clay outcrops were sampled as single units. Extrusion and Firing of Test Bars Each sample of clay was dried and crushed to approximately i-inch in diam- eter or smaller. The sample was then mixed with enough water to develop plasticity and extruded into three individual test bars, each with the dimensions of 1 by 1 by 6 inches. The bars were air dried for at least two days, then measured to determine the percentage of drying shrinkage of the clay. The first brick was fired at 1832°F, the second at 201 2 °F, and the third at 2200 °F. After each firing, the bars were measured to determine the percentage of firing shrinkage. LIGHT-BURNING CLAY RESOURCES 7 The water of plasticity was determined for each sample at the time the test bars were extruded. Water of plasticity is that amount of water that must be added to a clay sample in order to develop plasticity. In general, it can be said that the greater the water of plasticity, the greater the shrinkage during drying and firing of a given clay. Samples 1504 and 1508 were not fired at 2200° F because at lower temper- atures they had indicated they would be unable to withstand higher firing temper- atures. Sample 1508 had already started to bloat, and sample 1504 had developed a glassy surface and a deep brick-red color. Color of Fired Test Bars Most of the clay samples for this study were taken from outcrops, and it is probable that weathering had altered the burning color of the clay. For a better in- dication of true burning color, it would be necessary to obtain unweathered samples of the clay from drill holes near the area in question. Our experience in the past has shown that a weathered light-burning clay usually burns darker than unweathered clay from the same deposit. High-Temperature Properties By testing the refractoriness of each sample, it was found that ten samples from LaSalle County withstood temperatures of cone 28 and above. Refractories are classified in the following manner (American Society of Testing Materials, 1958): High heat duty PCE (Pyrometric Cone Equivalent) of 31 or 32 Medium heat duty PCE of at least 29 The following uses have been suggested for these refractory clays (Coxey, 1950): High heat duty clays are often used for open hearth checkers in steel plants, linings and checkers in hot- blast stoves, cupola linings, rotary cement and lime kiln linings, shaft lime kiln linings, and high-temperature boiler settings. Intermediate heat duty clays have been used for cupola linings, lime kilns, heating furnaces, back-up courses of furnace walls, and as linings in ladles in iron and steel foundries. Although the lower limit in PCE for medium heat duty clays is 29, some of the LaSalle County clays ranged from 28 to 29 and are included in this clas- sification. Bonding Tests Because underclays are sometimes used as bonding clay for foundry sands, bonding tests were run on all but the extremely sandy samples. The clays were first ground in a disc grinder. A 2000-gram mixture of 92 percent bonding sand and 8 percent clay was made and mixed dry for two minutes in a sand muller. Water was then added to the mixture in the muller and three minutes of wet mixing fol- lowed. The wet mixtures were placed in sealed jars and allowed to set overnight in order to give the water sufficient time to mix thoroughly with the clay. Mixtures were made with varying amounts of water, 30 ml, 35 ml, and 45 ml. For some sam- ples of the stronger bonding clays, additional mixtures with 55 ml of water were made. The tests were run in a manner described in the Foundry Sand Handbook (American Foundrymen* s Society, 1952). A few of the samples were too sandy for the bonding test described above. These were tested in their natural state to determine whether they could be used for natural molding sand. ILLINOIS STATE GEOLOGICAL SURVEY RESULTS OF TESTS Sample 1485 C NE{ SW| sec. 8, T. 32 N. , R. 2 E. Glacial drift and soil 10' Thickness of clay 0-17 ■ Underclay (sample 1485) 0-17' Extrusion properties Fair Sandstone Water of plasticity 15.0% % Linear drying shrinkage 4.0 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.0 3.0 4.0 Total linear shrinkage 6.0 7.0 8.0 Fired color Cream Cream Gray Surface texture of fired test bar: Shows irregular edges. Spotted and pock-marked by pyrite at 2200° F PCE: <28 Overburden: 10"; sediment above: till; sediment below: sandstone. Bonding properties: 4.75 (GCS psi); 1.0% (Optimum H„0). Possible uses; structural clay products, drain tile, flower pots. Sample 1486 NW| NE{ SWi sec. 8, T. 32 N., R. 2 E. Glacial drift and soil 20'+ Calcareous nodules 2" Underclay (sample 1486-A) 3^' Pyrite band 1 " Underclay (sample 1486-B) 3^' Firing temperature 1832°F % Linear firing shrinkage 3 . Total linear shrinkage 8.5 Fired color Cream Surface texture of fired test bar: Normal Thickness of clays 7' Extrusion properties Good Water of pla sticity 14.0% % Linear drying shrinkage 5.5 2012°F 4.0 9.5 Gray-brown 2200°F 3.0 8.5 Gray PCE: <28 Overburden: 20'; sediment above: till; sediment below: sandstone. Bonding properties: 6.75 (GCS psi); 1.9% (Optimum H 2 0). Possible uses: Structural clay products, stoneware, pottery, drain tile. Comment : Sample 1486 is a composite of samples 1486-A and 1486-B. LIGHT-BURNING CLAY RESOURCES Sample 1486-A Thickness of clay 3 1 ' Extrusion properties Good Water of plasticity 15% % Linear drying shrinkage 5 . Firing temperature 1832°F 2012T 2200°F % Linear firing shrinkage 2.5 4.0 5.5 Total linear shrinkage 7.5 9.0 10.5 Fired color Cream Cream Gray Surface texture of fired test bar: Blistery surface at 2200°F PCE: <28 Overburden: 20' Bonding properties: 6.90 (GCS psi); 1.8% (Optimum H 2 O) . Possible uses: Structural clay products, stoneware, pottery, drain tile, flower pots. Comment: Sample from top 3|" of underclay. Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Sample 1486-B Thickness of clay Extrusion properties Water of plasticity % Linear drying shrinkage 3 1 ' Fair 14, 5.0 1832°F 2012°F 2.5 5.0 7.5 10.0 Cream Gray-brown 2200°F 0.5 5.5 Gray Shows irregular edges. Spotted and pock-marked by pyrite at 1832°, 2012°, and 2200°F PCE: <28 Overburden: 2 3' 9" Bonding properties: 6.60 (GCS psi); 2.0% (Optimum H 2 0). Possible uses: Structural clay products, drain tile, flower pots. Comment: Sample from bottom 3|' of underclay. 10 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1487 NW{NE{SW| sec. 8, T. 32 N., R. 2 E. Till Underclay, pocket (sample 1487) Sandstone 20' Thickness of clay Small pocket Extrusion properties Fair Water of pla sticity 13.0% % Linear drying shrinkage 4.0 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 1.0 3.5 2.5 Total linear shrinkage 5.0 7.5 6.5 Fired color Cream Cream Gray Surface texture of fired test bar: Shows irregular edges PCE: <28 Overburden: 20'; sediment above: till; sediment below: sandstone. Bonding properties: 3.90 (GCS psi); 1.4% (Optimum H 2 0). Possible uses: Structural clay products, drain tile, flower pots. Comment: Sample from small pocket of clay. NWi sw| NE| Sample 1488 sec. 5, T. 32 N., R. 2 E. Glacial drift and soil No. 2 Coal Underclay (sample 1488) Dolomite 40' -60' 3' 17' Thickness of clay Extrusion properties Water of plasticity % Linear drying shrinkage 17' Good 11.0% 4.0 Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 1832°F 2.0 6.0 Pink 2012°F 4.5 8.5 Salmon 2200°F 6.5 10.5 Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 40' -60'; sediment above: coal, 3'; sediment below: dolomite. Bonding properties: 7.70 (GCS psi); 1.8% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flower pots. LIGHT-BURNING CLAY RESOURCES 11 Sample 1490 SW£ NW{ NW| sec. 32, T. 33 N., R. 2 E. Glacial drift, soil 10' -20' No. 2 Coal Underclay, contains much pyrite (sample 1490) Sandstone 3'-5' Thickness of clay 3' -5' Extrusion properties Good Water of plasticity 15.0% % Linear drying shrinkage 5.0 Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 1832°F 4.5 9.5 Salmon 2012°F 4.5 9.0 Tan 2200°F 5.0 10.0 Gray-brown Surface texture of fired test bar: Spotted and pock-marked by pyrite at all firing temperatures PCE: <28 Overburden: 10'- 20 '; sediment above: coal, 3|'-4|'; sediment below: sandstone. Bonding properties: 7.10 (GCS psi); 1.6% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, drain tiles, flower pots. Sample 1491 NW{ NW{ SEi sec. 21, T. 33 N., R. 2 E, Glacial drift, soil 5' Shale 12' No. 2 Coal 3' Underclay, dark (sample 1491 -A) 10" Underclay, light (sample 1491-B) 2' 1" Green clay-like band 6" -10" Underclay (sample 1491-D) 15' Limestone nodules Thickness of clays 18' Extrusion properties Good Water of plasticity 13.0% % Linear drying shrinkage 4.5 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.5 4.0 4.0 Total linear shrinkage 7.0 8.5 8.5 Fired color Cream Cream Buff Surface texture of fired test bar: Pock-marked and spotted by pyrite at 2200°F PCE: <28 Overburden: 20'; sediment above: coal, 3'; sediment below: calcareous (?). Bonding properties: - (GCS psi); - (Optimum H 2 0) . Possible uses: Bonding clay, structural clay products, drain tile, flowerpots. Comment : Sample 1491 is a composite of samples 1491-A, 1491-B, and 1491-D, 12 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1491-A Thickness of clay 10" Extrusion properties Good Water of plasticity 12.0% % Linear drying shrinkage 5.0 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.5 4.0 3.5 Total linear shrinkage 7.5 9.0 8.5 Fired color Cream Cream Gray Surface texture of fired test bar; Spotted and pock-marked by pyrite at all firing temperatures PCE: <28 Overburden: 20' Bonding properties: 7.05 (GCS psi); 1.9% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, drain tile, flower pots, Comment: Sample from top 10" of underclay below coal. Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Sample 1491-B Thickness of clay Extrusion properties Water of plasticity 2'1 " Good 12.0% % Linear drying shrinkage 5.0 1832°F 2.5 7.5 Cream 2012°F 3.5 8.5 Cream 2200°F 3.5 8.5 Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 20'10" Bonding properties: 7.00 (GCS psi); 2.0% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flower pots. Comment: Sample from bottom 25" of underclay below coal. LIGHT-BURNING CLAY RESOURCES 13 Sample 1491-D Thickness of clay 15' Extrusion properties Good Water of plasticity 9.5% % Linear drying shrinkage 4.0 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.0 4.5 4.5 Total linear shrinkage 6.0 8.5 8.5 Fired color Cream Cream Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: <20' Bonding properties: 6.00 (GCS psi); 1.6% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flowerpots. Comment: 15' of underclay below green, clay-like band. Sampl e 1492 SW± NI ' 4 SWi sec. 21, T. 33 N., R. 2 E. Glacial drift, soil 10 '-20' Thickr less of clays 11'4"+ No. 2 Coal 2±' Extrusion properties Goqd Underclay (sample 1492-A) 3'4" Water of plasticity 17.0% Green, clay-like band 10" % Linear drying shrinkage 5.5 Underclay (sample 1492-B) 8'+ (Base covered) Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 3.0 5.0 6.0 Total linear shrinkage 8.5 10.5 11.5 Fired color Salmon Tan Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 10' -20'; sediment above: coal, 2^'; sediment below: ? Bonding properties: - (GCS psi); - (Optimum H^O). Possible uses: Bonding clay, structural clay products, pottery. Comment : Sample 1492 is a composite of samples 1492-A and 1492-B, 14 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1492-A Thickness of clay 3'4" Extrusion properties Good Water of pla sticity 13.0% % Linear drying shrinkage 7.5 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 1.0 3.0 4.5 Total linear shrinkage 8.5 10.5 12.0 Fired color Pink Salmon Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 10' -20' Bonding properties: 8.90 (GCS psi); 2.1% (Optimum H 2 0) . Possible uses: Bonding clay, structural clay products, pottery. Comment: 40" of underclay below coal. Sample 1492-B Thickness of clay 8'+ Extrusion properties Good Water of plasticity 13.0% % Linear drying shrinkage 5.5 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.0 4.0 5.0 Total linear shrinkage 7.5 9.5 10.5 Fired color Cream Buff Gray -buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 10' - 20' Bonding properties: 7.93 (GCS psi); 1.8% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, pottery, stoneware, drain tile, flower pots. Comment: 8' of underclay below green, clay-like band. LIGHT-BURNING CLAY RESOURCES 15 NE| NE| SE{ Glacial drift, soil No. 2 Coal Underclay (sample 1493) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage- Fired color 15'+ 2' 6' Sample 1493 sec. 21, T. 33 N. , R. 2 E. Thickness of clay- Extrusion properties Water of plasticity % Linear drying shrinkage 6' Fair 19.0% 5.0 1832°F 3.0 8.0 Pink 2012°F 6.5 11.5 Pink 2200°F 4.5 9.5 Tan Surface texture of fired test bar: Shows irregular edges PCE: 28 Overburden: 17'; sediment above: coal, 2'; sediment below: sandstone. Bonding properties: 9.30 (GCS psi); 3.4% (Optimum H 2 0). Possible uses: Refractories, bonding clay, structural clay products, drain tile, flue liners, flower pots. Sample 1494 NW| NE{ SW! sec. 22, T. 33 N. , R. 2 E. Glacial drift, soil Covered Underclay (sample 1494) Sandstone, 10 '-15' 5'± 6'(?) Thickness of clay 6'(?) Extrusion properties Good Water of pla sticity 18.0% % Linear drying shrinkage 6.0 Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 1832°F 2.5 8.5 Orange 2012°F 4.5 10.5 Tan 2200°F 4.5 10.5 Brown Surface texture of fired test bar: Normal PCE: <28 Overburden: 15' -20'; sediment above: coal (stripped); sediment below: sandstone, Bonding properties: 8.05 (GCS psi); 2.5% (Optimum H 2 0). Possible uses: Bonding clay, stoneware, structural clay products, pottery, drain tile, flowerpots. 16 ILLINOIS STATE GEOLOGICAL SURVEY NE| SW± SE± Samp] sec. Le 1495 22, T. 33 N., R. 2 E. Glacial drift, soil No. 2 Coal Underclay (sample Sandstone 1495) 30'- -35 1 5 i t Thickness of clay Extrusion properties Water of plasticity % Linear drying shrinkage 5' Good 16.0% 5.5 Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 1832°F 1.5 7.0 Salmon 2012°F 3.5 9.0 Salmon 2200°F 4.0 9.5 Brown Surface texture of fired test bar: Normal PCE: <28 Overburden: 30' -35'; sediment above: coal, 1'; sediment below: sandstone. Bonding properties: 6.00 (GCS psi); 1.7% (Optimum H2O) . Possible uses: Stoneware, structural clay products, pottery, drain tile. Sample 1496-A SE| NE± NEi sec. 27, T. 33 N., R. 2 E. Glacial drift, soil No. 2 Coal Underclay (sample 1496-A) Green, clay-like band Underclay, sandy (sample 1496-C) (Base covered) Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Normal PCE: <28 Overburden: 23'; sediment above: coal, 3'. Bonding properties: 8.08 (GCS psi); 1.5% (Optimum H z O). Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flower pots. Comment: 2' of underclay above green, clay-like band. 20'+ 3' 2' 10" ) 4'+ Thickness of clay 2' Extrusion properties Good Water of plasticity 16.5% % Linear drying shrinkage 6.0 1832°F 2.0 8.0 Cream 2012°F 2200"F 3.5 5.0 9.5 11.0 Cream Buff LIGHT-BURNING CLAY RESOURCES 17 Sample 1496-C Thickness of clay 4'+ Extrusion properties Good Water of pla sticity 17.0% % Linear drying shrinkage 5.5 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.0 3.5 5.0 Total linear shrinkage 7.5 9.0 10.5 Fired color Salmon Salmon Buff Surface texture of fired test bar: Normal . PCE: <28 Overburden: 25' 10" Bonding properties: 7.50 (GCS psi); 2.0% (Optimum H2O) . Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flowerpots. Comments: 4' of underclay below green, clay-like band. Sample 1497 NE} NW{ NE± sec. 26, T. 33 N., R. 2 E. Glacial drift, soil No. 2 Coal Underclay, sandy (sample Sandstone 5 Thi 1497) '-10' n (?) 9' Thickness of clay Extrusion properties Water of plasticity % Linear drying shri 9' Fair 14.0% nkage 3.0 Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 1832°F 2.0 5.0 Pink 2012°F 4.0 7.0 Pink 2200°F 6.5 9.5 Buff Surface texture of fired test bar: Shows irregular edges . PCE: 31-32 Overburden: 5' -10'; sediment above: coal (thin); sediment below: sandstone. Bonding properties: 6.90 (GCS psi); 2.0% (Optimum H 2 0) . Possible uses: High heat duty refractories, structural clay products, stoneware, pottery, flue liners, drain tile, flower pots. Comment: Possibly a cavity filling. 18 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1498 NE{ SW{ NW| sec. 25, T. 33 N., R. 2 E. Glacial drift, soil No. 2 Coal Underclay (sample 1498) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 20' Thickness of clay 6' -8' stripped Extrusion properties Good 6' -8' % Linear drying shrinkage 4.0 1832°F 1.0 5.0 Pink 2012°F 2.5 6.5 Pink 2200°F 4.5 8.5 Buff Surface texture of fired test bar: Normal PCE: 28-29 Overburden: 20'; sediment above: coal mined out; sediment below: sandstone Bonding properties: 5.70 (GCS psi): 0.8% (Optimum H 2 0). Possible uses: Medium heat duty refractories, structural clay products, flue liners, pottery, drain tile, flower pots. Sample 1499-A SE| NW|SE| sec. 25, T. 33 N., R. 2 E. Glacial drift, soil No. 2 Coal Underclay (sample 1499-A) Green, clay-like band Underclay (Seen at water level) Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar; Normal PCE: <28 Overburden: 5' -20'+; sediment above: coal, 2\ l ; sediment below: sandstone. Bonding properties: 7.90 (GCS psi); 1.8% (Optimum H z O). Possible uses: Bonding clay, structural clay products, stoneware, pottery, drain tile, flowerpots. Comment: 4' of underclay above green, clay-like band. '-20'+ 4' 8" ? Thickness of clay 4' Extrusion properties Good Water of pla sticity 14.0% % Linear drying shrinkage 4.0 1832°F 3.5 7.5 Cream 2012°F 2200°F 4.5 4.5 8.5 8.5 Cream Buff LIGHT-BURNING CLAY RESOURCES 19 Sample 1500 NW± SEi NE} sec. 30, T. 33 N., R. 3 E, Glacial drift, soil 60" -70' No. 2 Coal mined out Underclay (sample 1500) 5'-6 Sandstone 1 Thickness of clay 5'-6' t Extrusion properties Fair >' Water of plasticity 12.5% % Linear drying shrinkage 2.0 1832°F 2012°F 2200°F 2.5 4.5 8.5 4.5 6.5 10.5 Cream Cream Cream Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Shows irregular edges PCE: 28 - 29 Overburden: 60' -70'; sediment above: coal mined out; sediment below: sandstone. Bonding properties: 7.60 (GCS psi); 1.6% (Optimum H2O). Possible uses: Medium heat duty refractories, bonding clay, structural clay prod- ucts, flue liners, drain tile. Sample 1502 NE| SW| NW! sec. 30, T. 33 N., R. 3 E. Glacial drift, soil 20' No. 2 Coal Underclay (sample 1502) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Shows irregular edges PCE: 31 Overburden: 20 '-30'; sediment above: coal, 2'; sediment below: sandstone. Bonding properties: 8.30 (GCS psi); 2.0% (Optimum H 2 0) . Possible uses: High heat duty refractories, bonding clay, structural clay prod- ucts, flue liners, drain tile, flower pots. 30' 2' 5' Thickness of clay 5' Extrusion properties Fair Water of plasticity 15.0% % Linear drying shrinkage 3.0 1832°F 3.0 6.0 Pink 2012°F 4.5 7.5 Pink 2200°F 8.5 11.5 Tan 20 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1503 C S| NE| sec. 29, T. 33 N. , R. 3 E. Glacial drift, soil No. 2 Coal (?) Underclay (sample 1503) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage- Fired color Surface texture of fired test bar: Shows irregular edges 80' - 100" Thickness of clay covered Extrusion properties 7' Water of plasticity % Linear drying shri 1832°F 2012°F : 1.0 3.0 4.0 6.0 Pink Pink 7' Fair 13.0% e 3.0 2200°F 5,5 8.5 Cream sandstone. PCE: 29 Overburden: 80' -100'; sediment above: coal (?); sediment below: Bonding properties: 7.70 (GCS psi); 4.3% (Optimum H2O). Possible uses: Medium heat duty refractories, bonding clay, structural clay products, flue liners, drain tile, flower pots. Sample 1504 SE|NEiSE| sec. 21, T. 33 N. oai mm mi.1-1.. R. 3 E. Glacial drift, soil so'-ioo 1 Thickness of clay 2'+ No. 2 Coal (mined out) Extrusion properties Good Underclay (sample 1504) 2' exposed Water of plasticity 15.5% (Base covered) % Linear drying shrinkage 5.5 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage 2.5 5.5 not fired Total linear shrinkage 8.0 11.0 - Fired color Brick red Brick red - Surface texture of fired test bar: Normal PCE: <28 Overburden: 80'-100'; sediment above: coal mined out; sediment below; limestone (?) Bonding properties: 4.35 (GCS psi); 1.4% (Optimum H2OJ. Possible uses: Structural clay products, drain tile, flowerpots. LIGHT-BURNING CLAY RESOURCES 21 Sample 1505 SW{ NW| NW{ sec. 28, T. 33N., R. 3 E. Glacial drift, soil 60'-65' Thickness of clay 5'± No. 2 Coal 2^' Extrusion properties Good Underclay (sample 1505) 5'± Water of plasticity 14.0% % Linear drying shrinkage 4.5 Firing temperature 1832°F 2012"F 2200°F % Linear firing shrinkage 2.5 4.5 5.0 Total linear shrinkage 7.0 9.0 9.5 Fired color Light salmon Salmon Buff Surface texture of fired test bar: Normal PCE: <28 Overburden: 60' -65'; sediment above: coal, 2\ x ; sediment below: ? Bonding properties: 7.56 (GCS psi); 1.5% (Optimum H2O) . Possible uses: Bonding clay, structural clay products, stoneware, drain tile, flower pots. Sample 1506 C W£ NW{ sec. 22, T. 33 N. , R. 3 E. Glacial drift, soil No. 2 Coal Underclay (sample 1506) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Shows irregular edges . PCE: 30 Overburden: 40' -50'; sediment above: coal, 2' (mostly mined out); sediment below: sandstone. Bonding properties: 6.90 (GCS psi); 2.2% (Optimum H 2 0). Possible uses: Medium heat duty refractories, structural clay products, flue liners, drain tile, flower pots. 40'-50' 2'+ 7'-8' Thickness of clay 7'-8' Extrusion properties Fair Water of pla sticity 14.0% % Linear drying shrinkage 3.0 1832°F 2.0 5.0 Pink 2012°F 4.0 7.0 Pink 2200°F 6.5 9.5 Cream 22 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1507 SEA Nw} NWi sec. 6, T. 34 N., R. 5 E. Glacial drift, soil Shale No. 2 Coal Underclay (sample 1507) 50' -60' 2' 0"-i" i'-l*' Thickness of clay l'-l£' Extrusion properties Poor Water of plasticity 11.5% % Linear drying shrinkage 3.0 Firing temperature' % Linear firing shrinkage Total linear shrinkage Fired color 1832 8 F +0.5 2.5 Pink 2012°F 0.0 3.0 Pink 2200°F 0.5 3.5 Tan Surface texture of fired test bar: Rounded edges and crumbly PCE: <28 Overburden: 50' -60'; sediment above: coal, 0- 1 "; sediment below: sandstone. Bonding properties: too sandy (GCS psi); - (Optimum H 2 O) . Possible uses: Natural molding sand. Sample 1508 SWiSE A NEi sec. 1, T. 34 N., R. 4 E. Glacial drift, soil Coal Underclay (sample 1508) 40'-45' 2" 8"- 10" Coal \ " Underclay, very sandy 1 ' — 2 ' Firing temperature 1832 °F % Linear firing shrinkage 5 . Total linear shrinkage 11.0 Fired color Brick red Surface texture of fired test bar: Normal Thickness of clay 8" -10" Extrusion properties Good Water of plasticity 20 . 0% % Linear drying shrinkage 6.0 2012°F 2.5 8.5 Brick red 2200°F not fired PCE: <28 Overburden: 40' -45'; sediment above: coal, 2"; sediment below: coal 1 /' . Bonding properties: 8.90 (GCS psi); 2.1% (Optimum H 2 0). Possible uses: Bonding clay, structural clay products, drain tile. LIGHT-BURNING CLAY RESOURCES Sample 1509 NW{NW{SW{ sec. 13, T. 33N., R. 2 E. 23 20'- 25' Thickness of clay l|'-2' 2'+ Extrusion properties Would not extrude, too sandy l£ '- 2 ' Water of plasticity % Linear drying shrinkage Glacial drift, soil No. 2 Coal Underclay, sandy, coal streaks (sample 1509) Sandstone Firing temperature 1832°F 2012T 2200°F % Linear firing shrinkage - Total linear shrinkage - Fired color - Surface texture of fired test bar: No test bar PCE: <28 Overburden: 20' -25'; sediment above: coal, 2'+; sediment below: sandstone. Bonding properties: too sandy (GCS psi); - (Optimum H2O). Possible uses: Natural molding sand. Sample 1510 W|NW± SE| sec. 13, T. 33 N., R. 2 E. Glacial drift, soil 20' No. 2 Coal stripped Underclay, purple, sandy (sample 1510) 1»2" Sandstone Firing temperature 1832 °G % Linear firing shrinkage +1.0 Total linear shrinkage 1.0 Fired color Tan Thickness of clay 1 ' 2 " Extrusion properties Too sandy to hold Water of plasticity % Linear drying shrinkage 2012°F +1.0 1.0 Tan sharp edges 8.0% 2.0 2200°F 0.0 2.0 Buff Surface texture of fired test bar: Rounded edges and crumbly PCE: 28 - 29 Overburden: 20'; sediment above: coal (stripped); sediment below: sandstone. Bonding properties: too sandy (GCS psi); - (Optimum H2O). Possible uses: Medium heat duty refractories (?), natural molding sand. 24 ILLINOIS STATE GEOLOGICAL SURVEY Sample 1511 NWi NW} SEi sec. 18, T. 33 N., R. 3 E. Glacial drift, soil No. 2 Coal Underclay, sandy (sample 1511) 10' Thickness of clay 2.\ x 2-*-' Extrusion properties Too sandy to hold ) 2£' sharp edges Water of pla sticity 9 . 0% % Linear drying shrinkage 1.0 1832°F 2012 8 F 2200°F 0.0 1.0 1.0 1.0 2.0 2.0 Brick red Brick red Brick red Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Rounded edges and crumbly PCE: <28 Overburden: 10'; sediment above: coal, 2\ u , sediment below: sandstone. Bonding properties: too sandy (GCS psi); - (Optimum H 2 0). Possible uses: Natural molding sand. Sample 1512 NE| NE| NE| sec. 17, T. 33 N., R. 3 E. Glacial drift, soil No. 2 Coal Underclay (sample 1512) Sandstone 20'-25' stripped 6' Thickness ot clay Extrusion properties ] Water of plasticity 11 % Linear drying shrinkage 6' Fair .0% 2.0 1832°F 0.0 2.0 Gray 2012°F 2.0 4.0 Gray 2200°F 3.5 5.5 Gray Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color Surface texture of fired test bar: Shows irregular edges PCE: 28 - 29 Overburden: 20' -25'; sediment above: coal (stripped); sediment below: sandstone. Bonding properties: 3.50 (GCS dsI); 1.3% (Optimum H^O). Possible uses: Medium heat duty refractories, structural clay products, flue liners, drain tile, flower pots. LIGHT-BURNING CLAY RESOURCES 25 Sample 1513 SW{ SW± SEA S ec. 18, T. 33 N., R. 3 E. Glacial drift, soil No. 2 Coal Underclay (sample 1513) Sandstone Firing temperature % Linear firing shrinkage Total linear shrinkage Fired color 10'-15' 2 1 ' Thickness of clay li'-6' Extrusion properties Too sandy to hold sharp edges Water of pla sticity 10.0% % Linear drying shrinkage 2 . 1832°F 0.0 2.0 Pink 2012°F 1.0 3.0 Cream 2200°F 2.0 4.0 Cream Surface texture of fired test bar: Rounded edges and crumbly PCE: 31-32 Overburden: 10'- 15'; sediment above: coal, 2\ } ; sediment below: sandstone. Bonding properties: too sandy (GCS psi); - (Optimum H2O). Possible uses: High heat duty refractories (?); natural molding sand. Sample 1514 SE^NWi SWj sec. 9, T. 33 N., R. 3 E. Thickness of clay No. 2 Coal 2' Extrusion properties Too sandy to hold Underclay, sandy (sample 1514) 5' sharp edges Sandstone Water of pla sticity 8 . 5% % Linear drying shrinkage 2.0 Firing temperature 1832°F 2012°F 2200°F % Linear firing shrinkage +1.0 0.0 0.0 Total linear shrinkage 1.0 2.0 2.0 Fired color Tan Tan Tan Surface texture of fired test bar: Rounded edges and crumbly PCE: <28 Overburden: 20' -30'; sediment above: coal, 2'; sediment below: Bonding properties: too sandy (GCS psi); - (Optimum H2O). Possible uses: Natural molding sand. sandstone. 26 ILLINOIS STATE GEOLOGICAL SURVEY RECOMMENDATIONS The clay deposits thin north and northeast of the Illinois River. As shown in figure 1, the beds on the west side of the LaSalle Anticline dip more steeply than do the beds on the east side. The gentle dip east of the anticline makes the east slope a more favorable area for exploitation of the clay deposits. The north-south canyons of Starved Rock State Park cut through the clay and underlying rock along the Illinois River between Ottawa and LaSalle, exposing the clay along the tops of most of the canyons. Along the southern boundary of the park the best exposures with the thinnest overburden lie along the small streams. Listed below are a few points to keep in mind when looking for these clay deposits in LaSalle County. 1) The clay commonly is found where Pennsylvanian and Ordovician rocks are in contact. 2) The clay thins rapidly north of the Illinois River and has been entirely eroded in many parts of this area. 3) West of the LaSalle Anticline, the rocks dip steeply westward, making it impossible to strip the clay except along the narrow, spotty outcrop belt close to the axis of the anticline near the Vermilion River. (The depth to the clay at the Matthiessen and Hegeler Zinc Company, marked on figure 3, is about 500 feet.) 4) East of LaSalle and along the south side of the Illinois River, the clay is found along the top of the river bluff, but its gentle eastward dip brings it to river level at Ottawa. East of Ottawa it is found only in subsurface, and on the river's south side the overburden becomes so thick that stripping is difficult. Along the north side of the river in the valley flat, between Ottawa and Marseilles, the overburden is 20 to 40 feet thick. 5) South of the Illinois River, between LaSalle and Ottawa, and especially along the south edge of the Starved Rock State Park, the clay deposits are fairly shallow and generally are at least 5 to 7 feet thick, although in a few places the clay is as much as 15 feet thick. South of this area the clay is covered by thicker overburden. 6) Figure 1 shows a large area of contact between the Pennsylvanian and Ordovician rocks cutting across the LaSalle Anticline and Vermilion River south of the Illinois River. The depth to the clay in this area is approximately 250 feet. This east-west linear depression corresponds to the valley of an ancient river that flowed to the west and cut a valley in the rocks as it crossed the LaSalle Anticline. 7) In outcrops from which samples 1491, 1492, 1496, and 1499 were taken, a narrow, green, clay-like band separated the gray underclay into an upper and lower portion. The band also was found in an old abandoned pit at Ottawa where it was 2 inches to 3 inches thick. West of Ottawa it was not found on the north side of the Illinois River. When fired, this green, clay-like band bloats and burns a deep brown color; it is not refractory. This clay should not be mixed with the clay above or below during the mining process. It probably occurs in most of the area south of the Illinois River and also east of Ottawa. 8) Because the clay in most of this county was deposited on an uneven surface, there may be a great variation in the thickness of the clay within a given area. LIGHT-BURNING CLAY RESOURCES 27 For any operation involving a new clay deposit from this region, it is recom- mended that drill samples of the clay be obtained first because, as mentioned above, weathered clay outcrop samples can give misleading results as to the fired color and texture of the material. The bonding strength may be greater for a weathered sample than for the same clay in its unweathered state. The dashed line in figure 3 bounds an area in which the clay should have 100 feet of overburden or less. This is the area recommended for exploration by drilling. The subsurface data are sketchy throughout this region, yet the indica- tions are that, if the clay is present, this should be the most favorable area for prospecting. Much of the shallow clay in this vicinity has already been or is now being mined and, although there are still a few of these areas along the south boundary of Starved Rock State Park, it is fairly evident that these deposits are limited. Thus, it is probable that in the future the deeper clay deposits may take on greater economic importance. REFERENCES American Society of Testing Materials, 1958, Standard classification of fireclay refractory brick: ASTM, C27-58, Pt. 5, p. 277-279. American Foundrymen's Society, 1952, Foundry sand handbook: 6th edition, p. 17-28, 85-89, 93-95. Cady, Gilbert H., 1919, Geology and mineral resources of the Hennepin and LaSalle quadrangles: Illinois Geol. Survey Bull. 37. Coxey, J. R., 1950, Refractories: State College of Pennsylvania, School of Mineral Industries, p. 100-132. Parmelee, C. W., and Schroyer, C. R., 1921, Further investigations of Illinois fire-clays: Illinois Geol. Survey Bull . 38-D. Willman, H. B., and Payne, J. N., 1942, Geology and mineral resources of the Marseilles, Ottawa, and Streator quadrangles: Illinois Geol. Survey Bull. 66. Illinois State Geological Survey Circular 277 27 p., 3 figs., 1959 nnnnni CIRCULAR 277 ILLINOIS STATE GEOLOGICAL SURVEY URBANA ^"flt* 5 " 4