ILLINOIS GEOLOGICAL SURVEY LIBRARY *>""*. HARRISON STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION BUFF-BURNING CLAY RESOURCES OF WESTERN ILLINOIS W. Arthur White ILLINOIS STATE GEOLOGICAL SURVEY John C. Frye, Chief URBANA CIRCULAR 353 1963 BUFF-BURNING CLAY RESOURCES OF WESTERN ILLINOIS W. Arthur White ABSTRACT One hundred ten samples from clays occurring in the Spoon and Abbott Formations in Adams, Brown, Fulton, Han- cock, Henderson, McDonough, Schuyler, and Warren Coun- ties, Illinois, were tested to determine their potential uses. Bonding and ceramic properties were determined. The clays may be used for one or more of the following: drain tile, fil- lers, flower pots, flue liners, pottery, refractories, sewer pipe, stoneware, structural clay products, terra cotta, terra sigillata, and bonding clays for molding sands. INTRODUCTION This report on the buff-burning clay resources of western Illinois (Adams, Brown, Fulton, Hancock, Henderson, McDonough, Schuyler, and Warren Counties) is another in a series of guides to locating and developing new clay deposits that may be used in the manufacture of drain tile, flower pots, flue liners, pottery, re- fractories, sewer pipe, stoneware, structural clay products, terra cotta, and terra sigillata, and may be used as fillers and bonding clays. Previous reports (fig. 1) on buff-burning clay resources have been published for extreme southern Illinois, including Union, Alexander, Pulaski, Massac, Pope, Johnson, and Hardin Coun- ties (Lamar, 1948); LaSalle County (Parham, 1959); Knox County (Parham, 1960); Rock Island, Mercer, and Henry Counties (Parham, 1961); and southwestern and southern Illinois, including Pike, Scott, Greene, Calhoun, Jersey, Madison, St. Clair, Monroe, Randolph, Jackson, Williamson, Saline, and Gallatin Counties (Parham and White, 1963). Since most of these counties are covered by glacial deposits, exposures of the Pennsylvanian rocks are limited mainly to stream cuts, roadcuts, and mines. Many of the samples in this report were taken from beds of clay of the type that normally occur directly beneath coals. These beds of gray, fine-grained, nonlaminated 1 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 353 BUFF-BURNING CLAY RESOURCES 3 clay are called underclay and range in thickness from a few inches to about 20 feet. The remaining samples were taken from shales. Stratigraphic Occurrence of Clay and Shale Classification of the Pennsylvanian strata of the area of this report is in- dicated in figure 2 (modified from Kosanke et al., 19 60). Only those members that will aid in locating the samples stratigraphically are listed. Other reports of de- tailed geology of the area listed in the references are Parmelee and Schroyer, 1922; Savage, 1922; Nebel, 1919; Wanless, 1957; and Kosanke etal. , 1960. Through most of this area, the Pennsylvanian rocks have a gentle regional dip to the east. The Abbott and Spoon Formations (fig. 3) thicken with the addition of new members from west to east. In Adams, Brown, and Hancock Counties, the thickness of the Spoon and Abbott Formations ranges from a few feet to as much as 20 feet. Whereas in Fulton County the two formations may be 100 or more feet thick. The shales, limestones, sandstones, and coals are better developed in the eastern part of the area. The clays that have most generally been used in this area occur stratigraphi- cally between the Seahorne Limestone and the Bernadotte Sandstone. These clays have been referred to as "stoneware clays. " The clays in the Abbott and Spoon Formations are buff -burning and in the western part of the area some of the shales are also buff -burning. As is shown by the test data in table 1, the several stratigraphic units have consistent physical properties that influence their ceramic utilization. From the Abbott Formation, 8 samples were analyzed in a region from Fulton to Brown Coun- ties. The fired color of the samples from the Abbott ranged from gray to tan but were predominently buff; linear shrinkage was generally medium. In general, the clays and shales of the Abbott Formation are suitable for the manufacture of drain tile, fillers, flower pots, flue liners, pottery, low heat duty refractories, sewer pipe, stoneware, structural clay products, and terra cotta. It is reasonable to ex- pect that prospecting in the area of outcrop of this formation will yield commercial deposits that fall within the indicated range of properties. From the Spoon Formation, 90 samples were analyzed in a region from Warren and Fulton Counties to Adams and Brown Counties. The fired color of the samples from the Spoon Formation ranged from gray to red but were predominently buff. Linear shrinkage was generally medium, and the P.C.E. ranged from below 20 to 30+. In general, the clays and shales of the Spoon Formation are suitable for the manufacture of drain tile, fillers, flower pots, flue liners, pottery, low and medium heat duty refractories, sewer pipe, stoneware, structural clay products, terra cotta, and terra sigillata. Commercial deposits that fall within this range of properties can probably be found by prospecting in the area of outcrop of this formation. Nine samples from McDonough and Schuyler Counties are listed as either Abbott or Spoon Formation. The fired color of these samples ranged from white to salmon but were predominently buff; linear shrinkage was generally medium. In general, the clays are suitable for drain tile, fillers, flower pots, flue liners, pottery, low heat duty refractories, sewer pipe, stoneware, structural clay products, terra cotta, and terra sigillata. The Carbondale clays and shales are all red-burning and can be used in the manufacture of drain tile, flower pots, pottery, sewer pipe, and structural clay products. ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 353 System Group Formation Member Pleistocene Series Mattoon McLeansboro Bond Modesto Pleasantview Sandstone Carbondale Purington Shale Francis Creek Shale Colchester (No. 2) Coal Browning Sandstone Abingdon Coal Isabel Sandstone Kewanee Greenbush Coal Wiley Coal Pennsylvanian Spoon Seahorne Limestone DeLong Coal Brush Coal Hermon Coal Seville Limestone Rock Island (No. l)Coal Bernadotte Sandstone Pope Creek Coal McCormick Abbott Tarter Coal Manley Coal Babylon Sandstone Mississippian Fig. 2 - Modified stratigraphic section. BUFF-BURNING CLAY RESOURCES Fig. 3 - Geologic map of area studied and sample locations (after Geologic Map of Illinois, 1945). 6 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 353 MINERALOGY The mineralogy was determined by x-ray, differential thermal analysis, and microscope techniques, and by megascopic observation. The clay minerals are illite, kaolinite, chlorite, and mixed-layer. The important nonclay minerals are chiefly quartz and minor amounts of pyrite, siderite, calcite, and gypsum. The quartz and pyrite occur in various concentrations in all the clays. Siderite, calcite, and gypsum occur in some of the deposits and only in small percentages. Gypsum usually occurs on, or near, the surface of the weathered clay. During weathering of pyrite in the clays, iron sulfate and sulfuric acid are formed. The sulfuric acid, in turn, may react with any calcite present, or with the calcium on the exchange positions of the clay minerals to form gypsum. The clays and shales in the western part of the area tend to be higher in kaolinite, to be more refractory, and to burn to lighter colors than the same clays and shales in the eastern part of the area. Many of the shales that tend to burn buff in Adams and Brown Counties tend to burn red in Fulton County. REPORT OF TESTS Information on the formation, drying, and firing of the test bars, on high- temperature properties, and on bonding tests is given in this report. It also con- tains information on the sample locations, thickness of overburden, type of under- lying and overlying sediments, and results of tests for the physical properties (table 1). Test Bar Formation and Firing The clay was ground and water was added. The mix was worked by hand to form a plastic mass. It then was stored in a humid box overnight or until it could be used. Each sample was molded into three bars, 1" x 1" x 3" or 1" x l" x 6", the size depending on quantity of sample. Some of the bars were dried slowly under moist cloths, some in air, and some in ovens at 230 °F (110°C). Defects were then recorded. Drying shrinkages were calculated from measurements of the bars be- fore and after drying. One of the test bars of each sample was fired to 1832 °F (1000°C), and another to 2012°F (1100°C). From these two firings, it was decided whether the third bar should be fired to 1922°F (1050°C) or 2200°F (1205°C). After each firing, the test bars were measured to determine the percentage of firing shrinkage and total shrinkage. High -Temperature Properties The refractoriness of the clay materials of Illinois tends to be controlled by the quantity of kaolinite in relation to the other minerals— the more kaolinite, the more refractory the clay material. Large quantities of quartz may increase or decrease the refractoriness of the clay material. The particle size of the quartz also may influence the refractoriness— the larger the particle size, the more re- fractory the clay material. Large particles leave less surface area for reaction be- tween the clay particles and the quartz. However, a mixture of kaolinite and quartz will be less refractory than either one alone. BUFF-BURNING CLAY RESOURCES 7 On the basis of mineralogical data, samples with the largest amounts of kaolinite were selected for tests to determine their fusion temperatures (pyromet- ric cone equivalent, P.C.E.). A small sample cone made from each clay selected was placed in a gas-fired furnace with cones of P.C.E. 28, 29, 30, and 31. The samples were heated to their fusion points. If they fused below cone 28, cones 20 through 28 were used for some of the clays. If it was estimated from the min- eralogy that a clay would have a P.C.E. value of about 15, there is an X in the refractory column of table 1. Where the P.C.E. values are known, they are re- corded in table 1 . The American Society for Testing Materials has classified refractory clays according to their ability to withstand heat. The refractoriness of the clay is measured in pyrometric cone equivalents (P.C.E.). A cone of clay and standard cones are heated together and the fusion is compared. When the clay melts its refractoriness is recorded as, for example, P.C.E. 30, above 30, 30-31, or be- low 30. The classification is (American Society for Testing Materials, 1958): Super heat duty P.C.E. 33 minimum High heat duty P.C.E. 31 minimum Medium heat duty P.C.E. 29 minimum Low heat duty P.C.E. 15 minimum Bonding Tests Some underclays have been found to be satisfactory for use as bonding clays in foundry sand mixes. Mixtures of 92 percent sand and 8 percent clay were made and mixed with varying amounts of water. Bonding tests then were made according to the standards set forth in the "Foundry Sand Handbook" (Ameri- can Foundrymen's Society, 1952). The strengths for the various moisture contents are plotted against the moisture contents and a graph is constructed; then the maximum green compression strength (GCS) and optimum moisture are read from the graph and recorded in table 1 under bonding properties. DEPOSITS SAMPLED The descriptions of the deposits sampled (see appendix) are listed alpha- betically by county. The sample numbers, locations, stratigraphy, lithology, and thickness of lithological unit are given for each deposit. The deposits listed are selected from a much larger number of deposits that were sampled and tested. These deposits are representative of the clays of the area. Refractory and buff-burning clays are most likely to be found in the area where the Abbott and Spoon Formations crop out. They may also be found by pros- pecting near the edge of the Carbondale, where it overlies the Spoon and Abbott Formations and where both these formations are thin and not mapped as occurring between the Carbondale and Mississippian (fig. 2). Clay deposits of the Abbott and Spoon Formations are present under the Carbondale, and they may be found by prospecting near the basal boundary of the Carbondale. TABLE 1 - PLASTIC, FIRING, AND BONDING PROPERTIES m £ u & ^ Firing temp eratures in degrees Bon ding c 2 ° 3 mJ Lin ear firing Total linear prope rties Sample u 2 « c £ shr inkage (%) shrinkage (%) Fi red col >r GCS Opt.* & £ £ a 3* 1832° 2012° 2200° 1832° 2012° 2200° 1832° 2012° 2200° (psi) H 2 0(*> good 25 good 21 good 22 good 23 good 22 .8 7.3 2.1 4 .5 5.2 3.1 5 Adan 2 3.1 2 5.2 s County 9.4 11.5 10. 8.3 10.4 10. .9 6.3 0.0 4 .0 5.2 1.1 4 1 6.2 2 7.3 6.3 10.4 12. 6.3 9.4 12. Buff 14.0 Buff Buff Tan 8.3 2.1 4.2 1.1 10.4 5.2 3.1 6.3 8.3 8.3 11.5 13.5 Buff Buff 990-0 990P 990Q good 29.8 8.3 2 Brown C 1 5.5 5.5 10 4 13 8 13. good 24.4 5.2 3.1 6.3 5 2 8 3 11. good 22.8 4.2 24.5 6.3 1 31.9 6.3 3 4.1 5.2 4 2.0 4.2 7 1 7.2 2.0 9 2 8 3 8 4 13 3 9. 3 10. 5 8. 3.1 0.0 +1.0 5.2 8.3 8.3 990F 990G 9 1 8 13' 'E fair fair 16 20 4 3 8 4 1 2 1 1.0 4 6.2 8 2 3 3 5 1 4 2 10 2 7 4 12 3 5 990A 5'E good 20 3 5 2 2.1 4 2 5 2 7 3 9 4 990B 3' 6 ' good 22 4 2 1 3.1 5 2 5 2 7 3 9 4 990C 3' 23 6 4 2 1 4.1 6 2 5 2 8 3 10 990DD 5' good 22 5 2 1 2.1 4 2 6 3 7 3 9 4 9901 9' 25 3 5 2 5.2 7 3 5 2 10 4 12 5 990V 3' 2 1 fair 17 4 3 1 4.2 5 8 3 1 7 3 8 9 Fulton Count F72 7'E good 23 7 6.3 0.0 2.0 7.2 6.3 8 3 13.5 F13 18' good 36 2 7 3 5 2 9.4 12 5 16 7 me tf Buff Buff Buff luff Buff Buff Buff Buff Gray 6' good 26 13' 6" good 28 2' 6" good 23 3' good 31 .3 5.2 2.1 4.2 9.4 7 .4 5.2 2.1 5.2 8.3 7 3 9.4 14. 3 10.4 13. .3 7.3 2.1 6.2 6.2 9 4 13.5 13. .0 7.3 3.1 7.3 8.3 10 .0 6.3 2.0 5.2 7.2 8 4 14.6 15. 3 11.5 13. 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