1M 127 /*f.6V. @UUr$. SuA4>W t- ^ Availability of the Colchester Coal for Mining in Northern and Western Illinois Christopher P. Korose, Scott D. Elrick, and Russell J. Jacobson 4 %v \ ^rff^f -^***^^t > '" jSk i i^*^ ' w L. 4^a aBfc^E^^^^^B ^nt' . ■ ' i^, iBkr^^3^BMb^9' Illinois Minerals 127 2003 Rod R. Blagojevich, Governor Department of Natural Resources Brent Manning, Director ILLINOIS STATE GEOLOGICAL SURVEY William W.Shilts, Chief -rfl w Equal opportunity to participate in programs of the Illinois Department of Natural Resources (IDNR) and those funded by the U.S. Fish and Wildlife Service and other agencies is avail- able to all individuals regardless of race, sex, national origin, disability, age, religion, or other non-merit factors. If you believe you have been discriminated against, contact the funding source's civil rights office and/or the Equal Employment Opportunity Officer, IDNR, One Natural Resources Way, Springfield, IL 62702-1271; 217/785-0067; TTY 217/782-9175. This information may be provided in an alternative format if required. Contact the IDNR Clearinghouse at 217/782-7498. Cover photo: Bucket wheel excavator removing overburden from the Colchester Coal, Freeman United Coal Co. Industry Mine, McDonough County, Illinois, 1989. Editorial Board Jonathan H. Goodwin, Chair Michael L. Barnhardt David R. Larson B. Brandon Curry John H. McBride Anne L. Erdmann Donald G. Mikulic William R. Roy ILLINOIS E^SSGS DEPARTMENT OF ^^^^ F RESOURCES Illinois State Geological Survey Printed by authority of the State of Illinois PRT3291907 0.5M-2/03 ©Printed on recycled and recyclable paper stock. Availability of the Colchester Coal for Mining in Northern and Western Illinois Christopher P. Korose, Scott D. Elrick, and Russell J. Jacobson Illinois Minerals 1 27 2003 Rod R. Blagojevich, Governor Department of Natural Resources Brent Manning, Director ILLINOIS STATE GEOLOGICAL SURVEY William W.Shilts, Chief Natural Resources Building 615 E. Peabody Drive Champaign, Illinois 61821-6964 Home page: http://www.isgs.uiuc.edu/ Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/availabilityofco127koro Acknowledgments We are especially appreciative to the following mining experts who gave us information on cri- teria that limit the availability of coal: Manny Efframian, Tom McCarthy, David Johnson, George Martin, James Niemeyer, and Monna Nemecek of AMAX Coal Company; Greg Bieri and Philip Deaton of Arch Minerals; Dan Pilcher of Arclar Coal Company; Philip Ames, Bruce Dausman, Christopher Engleman, and Christopher Padavic of Black Beauty Coal Company; Brent Dodrill, James Hinz, Edward Settle, and Randy Stockdale of Consolidation Coal Company; S.N. Ghose, Dana Meyers, Marvin Thompson, and John Williams of Cyprus-AMAX Coal Company; Michael Caldwell, Neil Merryfield, and Roger Nance of Freeman United Coal Mining Company; Dan Ganey and Thomas Denton of Kerr-McGee Coal Company; Alan Kern, Michael Meighan, and John Popp of MAPCO Coal Inc.; James Grimm of Midstate Coal Company; Jeffrey Padgett of Monterey Coal Company; Eric Quam of Old Ben Coal Company; Michael Anderson, Vick Daiber, Marc Silverman, and Grady White of Peabody Coal Company; Robert Gullic and Walter Lucus of Sahara Coal Company; Steve Short and Dennis Oliver of Sugar Camp Coal Company; Guy Hunt of Turris Coal Company; Douglas Dwosh, Kenneth Ginard, and David Thomas of Weir International Min- ing Consultants; Daniel Barkley, Dean Spindler, and Scott Fowler of the Illinois Office of Mines and Minerals; and Robert Bauer of the Illinois State Geological Survey. This project was supported by the U.S. Geological Survey, Department of the Interior, under the following agreements: 14-08-000T-A0773, 14-08-0001-A0841, 1434-92-A0940, 1434-93-AI137, 14-94-A1266, 1434-95-A01346, 1434-HQ96AG-01460, 1434-HQ97AG-01759, 1434-98HQAG- 2015, 1434-99HQAG-0081, 1434-00HQAG-0165, and 01 ERAG0042. We especially thank Harold J. Gluskoter and M. Devereux Carter of the U.S. Geological Survey and Heinz Damberger and Colin Treworgy for their guidance and support. This study utilized a number of databases compiled over many years by Coal Section staff members. Valerie Straayer assisted with data compilation and processing. Alan Myers, Melisa Borino, and Cheri Chenoweth updated the mined areas, and Melisa Borino digitized the Francis Creek Shale thickness map. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. This manu- script is published with the understanding that the U.S. Government is authorized to reproduce and distribute reprints for governmental use. Contents Acknowledgments ii Executive Summary 1 Introduction 2 Coal Resource Classification System 2 Sources of Data, Limitations, and Mapping Procedure 2 Geology and Mining 2 Colchester Coal 3 Floor and Roof Stratigraphy 4 Coal Quality 9 Quadrangle Studies 12 Technological and Land-Use Factors that Affect the Availability of Coal for Mining 12 Available Resources 15 Conclusions 17 References 17 Appendixes 1 Remaining Colchester Coal resources and availability by county 20 2 Source maps for Colchester Coal resources 21 Tables 1 Availability of the Colchester Coal for mining in Illinois 1 2 Resources of the Colchester Coal in individual quadrangles studied 12 3 Criteria used in this study to define resources available for surface mining 12 4 Criteria used in this study to define resources available for underground mining 14 5 Availability of the Colchester Coal for mining, by thickness category 14 Figures 1 Extent of the Pennsylvanian System in the Illinois Basin 3 2 North-south cross section of the Pennsylvanian System in Illinois 3 3 General stratigraphic position of the Colchester Coal 4 4 Thickness of the Colchester Coal 5 5 Depth of the Colchester Coal 6 6 Selected structural features in northern Illinois 7 7 Generalized stratigraphic section from the Colchester Coal underclay to the Houchin Creek Coal 8 8 Regional thickness of the Francis Creek Shale 9 9 Chlorine content of the Herrin Coal 11 10 Quadrangle study areas used to identify criteria for coal available for mining 13 11 Availability of the Colchester Coal for mining in Illinois 15 12 Availability of the Colchester Coal for surface mining 15 13 Areas of the Colchester Coal available for surface mining 16 14 Restrictions to the Colchester Coal for underground mining 17 Executive Summary The Colchester Coal, as mapped in this study, makes up about 9% (19 bil- lion tons) of Illinois' original resourc- es. This coal bed is present throughout the Illinois Basin coalfield, but is typically thinner than the more exten- sively mined Herrin Coal, Springfield Coal and the other coals described in earlier reports in this series (Treworgy et aJ. 1999a, 2000; Korose et al. 2002). Thus, resources have been mapped only in northern and western Illinois where the Colchester is thickest. This coal was mined extensively in north- ern Illinois during the nineteenth and early to middle twentieth centuries. The degree to which the remaining Colchester Coal resources are utilized in the future depends on the avail- ability of deposits that can be mined economically and competitively with other coals and alternative fuels. This report identifies those resources that have the most economically favorable geologic and land-use characteristics for mining and alerts mining compa- nies to geologic conditions that have a potentially negative impact on mining costs. Of the 19 billion tons of original Colchester resources, approximately 1 billion tons are available for mining (table 1). "Available" means that the surface land-use and geologic condi- tions related to mining the deposit (e.g., thickness, depth, in-place ton- nage, and stability of bedrock over- burden) are comparable with those of other coals currently being mined in the state. "Technological" factors (e.g., coal too thin to mine economically, and size of the in-place reserve block) are the major restrictions to mining and restrict 86% (16.1 billion tons) of the resources. "Land-use" factors (e.g., towns and highways) restrict 7% (1.4 billion tons) of the resources, and mining has depleted 2% of the original resources. The Colchester Coal has the fourth- largest resources (19 billion tons) of all coal seams in the state, but only 5% Table 1 Availability of the Colchester Coal for mining in Illinois, in bil- lions of tons. Total Potential mining method' Surface Underground Colchester Coal Original 19.0 10.7 13.4 Mined 0.5 (2) 2 0.3 (2) 0.2 (2) Remaining 18.5 (98) 10.4 (98) 13.2 (98) Available 1 (5) 1 (10) Available with conditions Technological restrictions 16.1 (86) 7.9 (73) 12.4 (92) Land-use restrictions 1.4 (7) 1.5 (15) 0.8 (6) ' Surface and underground resources do not add to the total because coal that lies between 75 and 200 feet deep is included in both categories. Values are rounded to the nearest 0.1 billion tons. See appendix 1 for information tabu- lated by county. The term "original resources" refers to the amount of coal originally in the ground prior to any mining. In this report, the ISGS defines surface minable coal as all coal in the ground that is 18 or more inches thick and lying less than 200 feet deep, whereas underground minable coal is all coal 28 or more inches thick and lying 75 or more feet deep. 2 Numbers in parentheses are percent of original resources. (1 billion tons) is available for min- ing. The vast majority of the coal is too thin to mine economically using underground methods in the cur- rent mining environment. Thus, all of the available Colchester resources are available for mining by surface methods only. Whether or not the resources of this coal are ultimately mined depends on a variety of other factors that are beyond the scope of this study to as- sess, including the willingness of local landowners to lease the coal, demand for a particular quality of coal, accessi- bility of transportation infrastructure, proximity of the deposit to markets, and cost and availability of compet- ing fuels. To avoid high mining costs resulting from unfavorable geologic conditions, companies could gener- ally avoid areas of thick drift and thin bedrock cover, areas with potentially weak or water-bearing sandstone in the immediate mine roof, large areas of excessive partings in the coal, and faulted areas. Areas with low-cost, surface-minable resources are limited and will likely support only small, short-term operations. This report is the fourth in a series to explain the availability of coal in Illinois for future mining. Previous re- ports assessing the availability of the Springfield and Herrin Coals contain important background information explaining the criteria used in this report to identify available coal (Tre- worgy et al. 1999a, 2000; Korose et al. 2002). These statewide assessments of coal resources are based on earlier publications that reported the avail- ability of coal in 21 study areas. The study areas were 7.5-minute quadran- gles representative of mining condi- tions in various parts of the state. Coal resources and the related geology were mapped in these study areas, and the factors that restricted the availability of coal in the quadrangles were identified through interviews with more than 40 mining engineers, geologists, and other mining special- ists representing 17 mining compa- nies, consulting firms, and govern- ment agencies experienced in mining Illinois coals. The major restrictions identified in these individual study areas were used for the statewide as- sessments of the availability of coals lor mining. Illinois State Geological Survey linois Minerals 1 27 Introduction This report is the fourth in a series to assess the availability of coal resources for future mining in Illinois. The read- er is referred to reports by Treworgy et al. (1999a, 2000) for background details and the general criteria used to define resources available for mining. Coal Resource Classification System The Illinois State Geological Survey (ISGS) follows the terms and defini- tions of the U.S. Geological Survey (USGS) coal resource classification system (Wood et al. 1983). With minor modifications to suit local conditions, these definitions provide a standard- ized basis for compilations and com- parisons of nationwide coal resources and reserves. The term "original resources" refers to the amount of coal originally in the ground prior to any mining. In this report, the ISGS defines "surface min- able coal" as all coal in the ground that is 18 or more inches thick and lying less than 200 feet deep; "underground minable coal" is all coal 28 or more inches thick and lying 75 or more feet deep. Coal that is 28 or more inches thick and lying from 75 to 200 feet in depth is considered in calculations as both surface minable and under- ground minable. In recent years, the USGS has pro- moted the idea of further defining the characteristics of resources by dividing remaining resources into two categories: "restricted" and "avail- able" (Eggleston et al. 1990). Restricted resources are those that have some economic factor that makes it unlikely they will be mined in the foreseeable future. The terms "technological" and "land use" are used to distinguish between basic differences in these economic restrictions. Land-use re- strictions include manmade or natural features that are illegal or impractical to disturb by mining. Technologi- cal restrictions include geologic or mining-related factors that negatively impact the economics or safety of mining. Resources in the available category are not necessarily economi- cally minable at the present time, but are expected to have mining condi- tions comparable with those currently being mined. Determining the actual cost and profitability of these depos- its requires further engineering and market assessments and site-specific studies. This study follows the USGS example of dividing resources into available or restricted categories. The ISGS also uses an additional category, "available with potential restrictions," which designates resources that are not restricted by the land-use or techno- logical restrictions but that have some known special condition that makes them less favorable for mining. Close proximity to rapidly developing urban areas, the presence of a relatively high density of oil wells or test holes, and potentially unstable roof conditions are examples of potential restrictions that have resulted in resources being placed in this category. In this study, therefore, remaining resources are the sum of resources restricted by land use factors, resources restricted by technological factors, resources avail- able with potential restrictions, and available resources. The USGS classification system uses the terms "measured," "indicated," and "inferred" to indicate the reli- ability of resource estimates based on the type and density of data (Wood et al. 1983). The ISGS uses similar categories, which in previous reports have been called Class la, Class lb, and Class Ha (Treworgy et al. 1997b). Because these earlier ISGS categories are essentially equivalent to the USGS categories, the USGS terminology defined by Wood et al. (1983) is used in this report. Collectively, the resources in these three categories are termed "identified resources" to distinguish them from resources based on less reliable estimates. Sources of Data, Limitations, and Mapping Procedure The maps that accompany this report were largely compiled from previously published maps, which are listed in appendix 2. These maps were com- piled digitally, and necessary adjust- ments were made where two or more maps bordered or overlapped one another. Past ISGS studies describe in detail the process of constructing digital coal resource base maps from original paper sources, the result- ing necessary adjustments made to certain map areas, and coal tonnage calculations (Treworgy et al. 1997b, Treworgy and Bargh 1982). The source maps have varying degrees of completeness and accuracy, are designed for a regional assessment, and have a resolution of 1:500,000. Features or details of features smaller than about one-half mile across may not be accurately portrayed or may be omitted altogether. Source data for the maps was obtained from a variety of public and private sources: drilling logs, core descriptions, and geophysi- cal logs obtained from companies and descriptions of mine and outcrop exposures made by ISGS geologists. For this study, resources of the Col- chester Coal were revised or newly mapped in Bureau, Fulton, Henry, Knox, Morgan, Peoria, and Stark Counties utilizing newly available data. Minor corrections and revisions were made to maps from other coun- ties. New mapping was prioritized in areas where the coal was thought to be of mineable thickness and where the density of available coal test data was the greatest. Previous mapping of Colchester Coal resources was concentrated in northern and western Illinois; elsewhere, the coal is likely too thin to be of economic interest and is beyond the scope of this study to assess. Mined areas were updated to April 1, 2002, by using maps obtained from coal companies. Geology and Mining The coal-bearing rocks of Illinois were deposited during the Pennsyl- vanian Period approximately 290 to 323 million years ago (Geological Society of America 1999). The strata of the Pennsylvanian System underlie about two-thirds of the state. Only the northern fourth of Illinois and narrow belts along the Mississippi, Ohio, and Illinois Rivers have no Pennsylva- nian rocks. The coal-bearing strata of Illinois extend into southwestern Indiana and western Kentucky as a single continuous coalfield known as linois Minerals 1 27 linois State Geological Survey 50 50 Miles Extent of Pennsylvanian System Figure 1 Extent of the Pennsylvanian System in the Illinois Basin (modified from Treworgy et al. 2000). the Illinois Basin or Eastern Interior Coal Field (fig. 1). Within the Pennsylvanian strata, coal seams of Illinois and the midconti- nent are present as part of cyclic rock sequences called cyclothems, in which a succession of sandstone, shale, lime- stone, and coal units mark the shifting ancient shoreline environment during a complete cycle of marine invasion and retreat (Udden 1912, Wanless and Weller 1932). The seams are not evenly distributed through the approximately 3,000-foot-thick section of coal-bear- ing rocks in Illinois, and most occur in the middle of the Pennsylvanian section. These Pennsylvanian coals are continuous over large areas and generally crop out along the margins of the basin (fig. 2), although the thickness of any particular seam may be quite variable. In excess of 20 coal seams have been mined commercially in Illinois, but fewer than 10 are important in terms of past and present production. Included in figure 3 and in order of geologic age these major seams in Illinois are the Danville (youngest), Herrin, Springfield, Colchester, Seely- ville, Dekoven, and Davis Coals. Some of the coals in the Illinois Basin can be correlated across state boundaries. Colchester Coal The 19 billion tons of Colchester Coal resources are the fourth-largest in the state and constitute about 9% of the state's total original coal resources. The Colchester Coal Member of the Carbondale For- mation (Hopkins and Simon 1975; fig. 3) is found near the base of the Car- bondale throughout southern Illinois, where the base of the formation is de- fined by the Davis Coal; the Colchester remains the base of the Carbondale in northern and western Illinois where the Davis is absent or not identified (Jacobson et al. 1985). The Colchester Coal is a normal, bright-banded coal present throughout the Illinois Basin coalfield. The coal and its overlying black shale, the Mecca Quarry Shale, are key marker beds that have been traced throughout the basin using core data and wireline logs. Over most of the basin the Colchester is generally thin, ranging from less than one inch tol8 inches thick in southern, central, and eastern Illinois, and resources have not been mapped in these areas. The coal is typically thicker through- out most of northern and western Illinois, where the coal is 2 to 3.5 feet thick (locally 4 feet) and has been ex- tensively mined (fig. 4). The coal crops out along the margins'of the Illinois Basin and reaches a maximum depth in southeastern Illinois of about 1,500 feet (fig. 5). Jacobson (1985) noted that, over much of northern Illinois, thickness patterns of the Colchester showed a strong relationship to geologic structures of the La Salle Anticlinorium, where in the synclinal troughs the Colchester reaches its greatest thickness (up to 3 to 4 feet), and on the anticlinal crests it thins to as little as 1 to 2 feet. Peppers and Pfefferkorn (1970) also found significant variation in the flora of the Colchester Coal on top of these anticlinal crests (northwest Ancona Anticline, formerly the Ancona and Garfield Domes, fig. 6). Peppers and Pfefferkorn (1970) concluded that the variation represented drier conditions because of the higher topographic elevation of this structural feature and N III I Well locations II I I I I I II II I S I I I 500 ~ -500 o CO > ^ -1,000 -1,500 -2,000 Quaternary System ) Pennsylvanian System Figure 2 North-south cross section of the Pennsylvanian System in Illinois (from Treworgy et al. 2000). linois State Geological Survey linois Minerals 1 27 CD o CC "O c o _Q CO O Danville Jamestown Herrin Springfield Houchin Creek Colchester Seelyville/gU° veri Figure 3 General stratigraphic posi- tion of the Colchester Coal. Coals are shown in order of geologic age (young- est seam at top). Formal nomenclature is from Jacobson et al. (1985). its effect on the paleoenvironment of the local Colchester swamp. Their findings demonstrate that these struc- tures were developing during peat formation and that the deeper, wetter synclinal troughs accumulated more peat than the higher, dryer anticlinal crests. The name Colchester was first used by Worthen (1868) for the exposures of the coal near Colchester, McDonough County. The type section for the Colchester was designated by Wanless (1956) in Sec. 12.T5N, R4W. Over the years, several local names were ap- plied by miners and coal companies to this seam including the La Salle No. 2 Coal or the "Third Vein" in northern Il- linois. The Colchester Coal is perhaps the most widespread minable seam in North America and is correlated with the Croweburg Coal of Missouri and Kansas, the Schultztown of west- ern Kentucky, the Broken Arrow (or Croweburg) of Oklahoma, the White- breast of Iowa, the Colchester Coal Member (Ilia) of Indiana, the Lower Kittanning Coal of Ohio, the Princess No. 6 of eastern Kentucky, and the No. 6 Block of West Virginia (Willman et al. 1975, Peppers 1996). At one time, the Colchester Coal was the principal seam mined in Illinois, but current production of Colchester Coal has dropped to almost nothing. The first major coal industry in Il- linois centered on the Colchester in the northern part of the state, where the transportation costs were lower because of the coal's close proximity to the Chicago market. Low trans- portation costs were the main factor in development of this coal resource. Early operations in the Colchester existed in shallow underground mines in Grundy, Kankakee, and Will Coun- ties; in small mines near the coal's outcrop along the Illinois River in LaSalle County; and in deeper mines west of the LaSalle Anticlinorium (fig. 6; Nelson 1995) in LaSalle, Bureau, and Putnam Counties. This area, referred to as the "Longwall District," is the oldest mining district in Illinois. Three shaft mines opened in LaSalle County in 1856, and mining commenced at Wilmington in 1866. By 1880, LaSalle County ranked second in total coal output and Will County ranked third (Andros 1915). Longwall mining (described and illustrated in detail by Andros 1914, 1915) permitted the operators to recover a much larger percentage of coal resources than their room-and-pillar competitors in south- ern Illinois. Higher recovery partially offset the productivity losses inherent in mining thin coal seams such as the Colchester. However, production in the Colchester appears to have peaked in northern Illinois around 1900 and had begun a serious decline by 1915 (Cady 1915). At that time, local indus- tries using the coal for fuel included brick and ceramic manufacturers, glass makers, cement plants, rolling mills, and zinc smelters (Cady 1915, Stull and Hursh 1917). In many cases, the raw materials for these operations came from the same mines or pits as the coal, or the sources were lo- cated closely to the coal mines. These uses of coal have since been mostly replaced by petroleum and natural gas or the industries themselves have gone away. Since the 1920s, surface mining of the Colchester Coal in Illinois has proven to be more economical than underground mining, and, during the late 1920s through the 1960s, several large-scale surface mines operated in Grundy, Kankakee, and Will Coun- ties. In addition, some mining of the Colchester (mostly in smaller sur- face mines) has occurred in western Illinois in Adams, Brown, Hancock, McDonough, and Schuyler Counties. With general reductions in shipping costs over the years, the mining of thicker and shallower coal seams in southern Illinois gradually took pre- cedence over the Colchester. Innova- tions such as unit trains and modern earth-moving equipment now allow power plants in Illinois to buy cleaner- burning Wyoming coal more cheaply than some Illinois coals. Social and cultural changes have also weighed heavily in the decline of Col- chester Coal mining and of the Illinois coal industry as a whole. Changing public attitudes have led to increas- ingly more stringent safety, health, and reclamation laws and increas- ing restrictions on where coal can be mined. One result of such restric- tions is an industry-wide trend that has seen the decline of smaller-scale, local-owner mining in the state; only the large mining companies are able to afford compliance with these laws. Surface mining the Colchester Coal, which tends to occur in small reserve blocks, was unattractive to the larger mining companies, but was a good source of livelihood for the small- and medium-sized coal producers of the twentieth century. At the time of this report, only one surface mine near the Schuyler/McDonough county line is actively mining the Colchester Coal in Illinois. Floor and Roof Stratigraphy The Colchester Coal is underlain by a well- developed underclay — a paleosol, which is an ancient soil that devel- oped prior to peat accumulation. This underclay is a claystone to sandy-clay- stone that, in many places along the Illinois River near LaSalle, was mined extensively for brick manufacturing. At least two underground mines in LaSalle County have reported "floor heave," or the squeezing of the linois Minerals 1 27 linois State Geological Survey Coal thickness (inches) Less than 28 28 to 42 42 to 66 Insufficient thickness data for resource calculation Mined-out areas; Colchester Coal Colchester Coal eroded A 30 Miles Figure 4 Thickness of the Colchester Coal. Illinois State Geological Survey linois Minerals I 27 5 STARK PUTNAM > MARSHALL * , PEORIA 1 'TAZEWELL **4»jj*- DEWITT LOGAN PIATT MACON MOULTRIE JCHRIST1AN SHELBY MONTGOMERY CUMBERLAND u FAYETTE EFRNGHAM JASPER CRAWFORD 1 . RICHLAND LAWRENCE 1 ENCE J s / S HAMILTON WHITE > SALINE GALLATIN JOHNSON POPE HARDIN Coal depth (feet) Less than 200 200 to 500 500 to 1 ,000 Greater than 1,000 Mined-out areas; Colchester Coal Colchester Coal eroded A 50 Miles Figure 5 Depth of the Colchester Coal. linois Minerals 1 27 linois State Geological Survey .' WHITESIDE LEE DEKALB HENRY C3? BUREAU KENDALL KNOX STARK Toulon f~\ Domes MARSHALL PEORIA MENARD LOGAN Structural features Extent of Colchester Coal Figure 6 Selected structural features in northern Illinois (modified from Nelson 1995). A 25 Miles Illinois State Geological Survey linois Minerals l 27 underclay into the mine from under- neath coal support pillars, especially where the claystone was thick or con- tained less sand (unpublished mine notes, ISGS Coal Section). Weakening of the nearby roof and /or constricted mine openings can potentially result from such adverse mine floor condi- tions. Directly overlying the Colchester Coal in many parts of western and north- ern Illinois is the Francis Creek Shale Member of the Carbondale Formation (fig. 7; Hopkins and Simon 1975), a medium gray, silty shale that locally exceeds 80 feet thick in the northeast- ern part of the Illinois Basin coalfield. The Francis Creek forms a large clastic wedge that extends across the north- ern part of the coalfield and thins out to the west and south in the western part of the basin (fig. 8; Smith 1970). It is best known for the famous Mazon Creek sideritic concretions found in parts of Kankakee, Will, and Grundy Counties in the northeastern part of the basin and also in western Illinois in Fulton County. These concretions have yielded a fossil fauna and flora (including many soft-bodied organ- isms that are rarely preserved and known nowhere else, such as the Illi- nois State Fossil, the "Tully Monster") that give clues to the depositional environments of the Francis Creek and hence some understanding of the distribution of lower-sulfur values in some of the Colchester Coal beneath the Francis Creek roof (Coal Quality section). In northeastern Illinois, where the Francis Creek reaches its maximum thickness, the unit is much more silty and sandy and consists largely of siltstone and sandstone. Toward the south and west, the Francis Creek becomes less silty and sandy as it thins. However, in parts of Fulton County, the amount of sandstone and siltstone increases locally and reaches a maximum thickness of 18 feet along a 1-mile-wide, north-south outcrop belt where the Francis Creek grades upward into or is locally eroded by the sandstone deposits. Locally, in northeastern Livingston and southeastern Grundy Counties, the channel-fill Cardiff Coal is found Houchin Creek Coal Survant (Lowell) Coal Oak Grove Limestone Mecca Quarry Shale -Francis Creek Shale Cardiff Coal Colchester Coal xxxxxxxxxxx Figure 7 Generalized stratigraphic section from the Colchester Coal under- clay to the Houchin Creek Coal (modified from Jacobson 1985). and mined a short distance above the Colchester (Cady 1915). The coal is recognized in this area only and is present in localized, linear deposits, often occurring as multiple benches of coal up to 12 feet thick, separated by gray shale. Although it has been both underground and surface mined, the resources of Cardiff Coal are small, and detailed drilling would be required to identify any additional deposits. The Cardiff Coal may overlie the Colchester directly or be separated from it by up to 10 feet of unnamed gray shale that is lithologically similar to the Francis Creek Shale (Jacobson 1985). ISGS geologists who visited under- ground mines in LaSalle County reported "rolls," or local irregularities, in the Colchester Coal roof contact with the Francis Creek Shale. In these areas, the coal thinned under a locally thicker shale roof, which made min- ing more difficult. The Oglesby Mine (in LaSalle County) also noted "bad roof" conditions where the Francis Creek was "filled with slickensided slip planes." These horizontal slip fea- tures along the Francis Creek bedding planes caused the roof to "fall in rather irregular masses" (unpublished mine notes, ISGS Coal Section), which likely resulted in dangerous mining condi- tions that required additional roof control. The Mecca Quarry Shale Member of the Carbondale Formation (Hopkins and Simon 1975) overlies the Francis Creek Shale and rests directly on the Colchester Coal where the Francis Creek is absent. It is a hard, fissile, black shale that locally reaches 4 feet in thickness but generally ranges from 1 to 2 feet thick. The shale contains a marine fauna dominated by floating and bottom-dwelling forms. Large limestone concretions and small phosphatic lenses and nodules are locally abundant in the shale. The Mecca Quarry is a unit even more widespread than the Colchester, being present throughout most of the basin and into adjacent states. The Mecca Quarry is an important stratigraphic marker because of its distinctive low- resistivity signature on electric logs and very high gamma-ray log readings. The Oak Grove Limestone, which overlies the Mecca Quarry Shale, var- ies from a horizon of large septarian concretions or multiple thin limestone nodules to a more-or-less continuous single bed of argillaceous limestone (or calcareous shale, in some areas). Illinois Minerals 1 27 Illinois State Geological Survey Francis Creek Shale thickness (feet): Less than 20 20 to 40 40 to 60 60 to 80 Greater than 80 Francis Creek Shale not present or not mapped Colchester Coal eroded A 30 Miles Figure 8 Regional thickness of the Francis Creek Shale (from Smith 1970). Over much of northern and western Illinois (Hopkins and Simon 1975), the Oak Grove is made up of a persistent succession of thin but paleontologi- cally and lithologically distinct lime- stone beds, many of which are only a few inches thick and are interbedded with dark gray to black shale. The Oak Grove Limestone interval typically does not exceed 15 feet and it, like the Mecca Quarry Shale, disappears in areas where the Francis Creek exceeds 40 feet in thickness. Limestone units are much less abundant in southern Illinois within the Oak Grove interval. Coal Quality The quality of coal was not considered as a factor in determining its availabil- ity. Although coal quality is an ex- tremely important factor in individual sales contracts and the magnitude of demand for a particular coal, avail- ability for mining of a specific resource cannot be ruled out based strictly on quality. Coal washing, blending with other seams, and other techniques can be used to mitigate some undesir- able quality characteristics of coals. Because most Illinois coal resources have a relatively high-sulfur con- tent, the demand for these resources is currently limited. However, the market for high-sulfur coal, although less than in the past, is expected to continue and may increase as power plants with new emission control technologies come into production. Illinois Basin coals, including the Col- chester, are high-volatile, bituminous coals that range in rank from rank A in the southeastern corner of the state to rank C in the northwestern two-thirds of the state (Treworgy et al. 1997b). linois State Geological Survey linois Minerals 1 27 For these coal ranks and over the same area, respectively, heat content ranges from more than 25 million BTU per ton to less than 20 million BTU per ton (as received). The Colchester Coal resources identified in this report are rank C. The sulfur contents of several Illinois coal seams, including the Colchester, are closely related to the depositional history of the coals and the roof strata (Gluskoter and Simon 1968, Treworgy and Jacobson 1986). In areas where the peat swamp was inundated with marine waters, the sulfur content of the coal is commonly in the range of 3 to 5% (as-received basis, equivalent to 2.5 to 5 pounds of sulfur per mil- lion BTU). In these areas, the coal is overlain by marine rocks including black shale and limestone. In areas where the peat was buried by a thick (more than 20 feet) layer of estuarine or deltaic clastic sediments in fresh or brackish water before or shortly after the swamp was inundated by marine waters, the sulfur content of the coal is generally less than 2.0% and may be as low as 0.5%. Hence, depositional conditions asso- ciated with low-sulfur Colchester Coal are tied to the distribution of the Fran- cis Creek clastic wedge. Low-sulfur Colchester Coal was reported by Glus- koter and Simon (1968) from mines in the area of northeastern Illinois where thick (20 to 80 feet) Francis Creek deposits composed largely of siltstone and sandstone are found (parts of Will and Grundy Counties, fig. 8). However, high-sulfur coal also was found in other mines in the general area. Else- where throughout the distribution of the Francis Creek, one mine in Wood- ford County had reportedly low-sulfur values. At the Banner Mine in Peoria and Fulton Counties, Hopkins and Nance (1970) reported that the pyritic sulfur of the Colchester decreases as the Francis Creek thickens, but the content of the organic sulfur (which is difficult to remove by conventional coal-preparation techniques) remains constant. As already stated, Illinois coals over- lain by thick, apparently non-marine shales such as the Francis Creek are, in many cases, lower in sulfur over much of their distribution, especially where the gray shales are over 20 feet thick. The Francis Creek seems generally to fit this pattern, but the variability in northeastern Illinois is puzzling. The Francis Creek seems to have prograd- ed mostly from the northeast over the coal swamp, with possibly a second progradation into western Illinois from the north, into the Fulton and Peoria County area, where it merges with the larger area from the northeast (Wright 1965; Shabica 1970; Jacobson, unpublished field studies). Peat in the northeastern part of the Francis Creek coverage area (fig. 8) may have been covered early by the thick sandstone, siltstone, and shale of the Francis Creek, which protected the peat while it was still under fresh to brackish conditions. In western Illinois (the southwestern extent of the Francis Creek), the peat may have been largely contaminated by sulfur-bearing saline marine waters before the Francis Creek was deposited. The complexity in sulfur values in the northeastern part of the coal- field may possibly be related to two main factors. First, the lower sulfur values in this region of thick Francis Creek are found in a transitional area between marine and non-marine deltaic conditions. The fossil fau- nas and floras found in the sideritic concretions support the interpreta- tions of a transitional zone as some of the fossil assemblages found are distinctly marine in origin and others are non-marine. Thus, it is likely that, during the time the Francis Creek was being deposited, marine conditions prevailed locally, which could have contaminated the peat with additional sulfur (Treworgy and facobson 1986). A second factor in the local occur- rences of the higher sulfur values may have to do with the lithology of the Francis Creek. Throughout the basin, where similar gray shales have been observed (Energy Shale over the Herrin Coal and the Dykersburg Shale over the Springfield Coal), localized, predominately sandstone areas occur above the coal as deltaic or crevasse splay channel sandstones, and the coal beneath these channels has significantly higher sulfur values. This phenomenon is probably related to the porosity of the coarser elastics such as these sandstones, which were likely porous enough to let sulfate- bearing waters percolate downward to the peat, even though the mostly non-marine clastic deposits (gray shales) protected the majority of the peat from the next marine transgres- sion in the area. Both factors likely relate to the varia- tion of sulfur values for the Colchester Coal in the northeastern part of the basin, but relationships between the factors are not possible to determine given the current data. There is no detailed information on sandstone distribution or the actual detailed paleoenvironments indicated by the concretion faunas for a given area of Francis Creek, or how this information might relate to the few known low- sulfur occurrences. Thus, any occur- rences of lower-sulfur areas are likely to have poorly definable boundaries associated with the paleoenviron- ments and variable lithologies of the delta lobe represented by the Francis Creek deposits. Detailed exploration is needed to delineate these deposits. Chlorine content of Illinois coals is loosely correlated to depth. For the Herrin Coal, chlorine increases from less than 0.1% (as received) at shallow depths along the margins of the basin to greater than 0.4% in the central part of the basin (fig. 9; Chou 1991). Few analyses for chlorine are available for the Colchester Coal. Because chlo- rine is thought to be related to basin fluids, not coal genesis, throughout the basin, the Colchester should have slightly higher chlorine levels than the Herrin Coal does. Yet, based on this projection, chlorine content should be similar to those of other coals com- monly used in current Illinois markets, as most of the remaining Colchester resources in northern and western Illinois are located along the margins of the Illinois Basin. Although chlo- rine content in British coals has been correlated with corrosion and fouling of high-temperature boilers, no stud- ies have found such a correlation for chlorine in Illinois coals (Monroe and Clarkson 1994; Chou et al. 1998, 1999). 10 Illinois Minerals 1 27 Illinois State Geological Survey HENRY BUREAU LA SALLE GRUNDY PUTNAM STARK MARSHALL KANKAKEE WARREN FULTON HANCOCK MCDONOUGH LIVINGSTON PEORIA WOODFORD MC LEAN TAZEWELL MASON LOGAN VERMILION CHAMPAIGN DEWITT PIATT EDGAR \ UNION JOHNSON POPE HARDIN Chlorine (percent) Less than 0.1 0.1 to 0.2 0.2 to 0.3 0.3 to 0.4 Greater than 0.4 Herrin Coal eroded A 50 Miles Figure 9 Chlorine content of the Herrin Coal (modified from Chou 1991; linois State Geological Survey linois Minerals 127 II Quadrangle Studies The criteria defining available coal resources were developed through a series of 21 assessments of 7.5-min- ute quadrangles (fig. 10; Jacobson et al. 1996; Treworgy 1999; Treworgy et al. 1994, 1995,1996a, 1996b, 1997a, 1998, 1999b; Treworgy and North 1999). These assessments included interviews with more than 40 mining engineers, geologists, and other min- ing specialists representing 17 mining companies, consulting firms, and government agencies actively involved in the Illinois coal industry Additional background of this program and a detailed description of the framework for the investigations in Illinois are provided in previous reports (e.g., Treworgy et al. 1994, 1999a, 2000). Of the 21 areas studied, 3 quadrangles in northwestern Illinois included some resources of the Colchester Coal (fig. 10; table 2; Treworgy et al. 1997a). The total for Colchester Coal resources in these quadrangles was 187 million tons or about 1% of the original Col- chester resources in the state. Avail- ability of the coal in the 3 quadrangles ranged from to 34% and averaged 26% when tonnages were factored in. None of the coal was thick enough to be available by underground mining methods. Stripping ratio accounted for the majority of the technological restrictions to surface mining of the Colchester Coal. Technological and Land- Use Factors that Affect the Availability of Coal for Mining A detailed description of the criteria used in this study to define available and restricted resources and their ef- fect on mining was given in previous reports (Treworgy et al. 1999a, 2000). These criteria are a composite set of rules developed based on interviews with mining companies, observations of mining practice, and the assess- ments of the 21 quadrangles. In tables 3 and 4, the criteria are orga- nized according to the relevant mining methods (surface or underground mining) currently practiced in Illinois. Table 2 Resources of the Colchester Coal in individual quadrangles studied, in millons of tons. Mined Remaining Available Restrictions Quadrangle Original Technological Land use Augusta 75 Kewanee North 23 Roodhouse East 89 Total 187 1 (2) 1 1(<1) 74 (98) 23 (100) 89 (100) 186 (99) 19 (24) 30 (34) 49 (26) 48 (64) 22 (94) 47 (53) 117 (62) 7 (10) 1 (6) 12 (13) 20 (11) ' Numbers in parentheses are percent of original resources. Table 3 Criteria 1 used in this study to define resources available for surface mining. Technological restrictions Minimum seam thickness 18 inches Maximum depth 200 feet Maximum unconsolidated overburden 60 feet Stripping ratio 2 Maximum 25:1 Maximum average 20:1 Minimum size of mine reserve (clean coal) Cumulative tonnage needed to support a mine and preparation plant 10 million tons Individual block size (thousands of tons) Less than 50 feet of overburden 150 More than 50 feet of overburden 500 Land-use restrictions (width of unminable coal around feature) Cemeteries not used State parks and preserves 100 feet Railroads 100 feet Federal and state highways 100 feet Other paved roads not used Major airports 100 feet High-voltage transmission towers not used Pipelines 100 feet Underground mines 200 feet Towns 0.5 miles Available with potential restrictions Potential land-use conflicts land-use patterns are incom- patible with mining 3 ' See previous investigations in this series for a detailed explanation of differences in crite- ria (Treworgy et al. 1999a, 2000). 2 Cubic yards of overburden/per ton of raw coal; volumes and weights not adjusted for swell factors or cleaning losses. 3 No available coal resulted within the identified areas. Because surface mining can be used to mine coal lying as deep as 200 feet and underground mining can be used to extract coal lying as shal- low as about 75 feet (if there is suf- ficient bedrock), resources that are 75 to 200 feet deep were evaluated for their availability for both surface and underground mining. This study does not consider the avail- ability of coal that could be mined using an auger or highwall miner. Such tech- niques, which allow additional tonnages of coal to be recovered from the final cut of a surface mine, have been used on a limited basis in Illinois. In many cases, such coal is minable by underground methods. Except for seam thickness, 12 linois Minerals 1 27 linois State Geological Survey Kewanee North |~~| JPrinceville J Peoria West Tallula £ ^Middleton Villa Grove D _jNokomis Atwater Extent of Pennsylvanian strata County boundary I I Quadrangle study areas (areas with Colchester Coal resources in bold) Extent of the Colchester Coal Snyder/ West Union Vincennes Mt. Carmel Shawneetown Figure 10 Quadrangle study areas used to identify criteria for coal available for mining. i* -*► Illinois State Geological Survey linois Minerals I 27 13 Table 4 Criteria 1 used in this study to define resources available for underground mining. Technological restrictions Minimum seam thickness Minimum bedrock cover Minimum ratio of bedrock to unconsolidated overburden Minimum interburden between minable seams Minimum size of mining block (clean coal) Faults (width of zone of no mining) Cottage Grove Fault System Master fault Subsidiary faults Rend Lake Fault System Centralia Fault Wabash Valley Fault System Land-use restrictions (width of unminable coal around feature) Surface and underground mines Towns Subdivisions Churches and schools Cemeteries High-voltage transmission towers Interstate highways Major airports Dams Closely spaced oil wells 2 Available with potential restrictions Closely spaced oil wells 2 Potential land-use conflicts Bedrock cover 42 inches 75 feet 1:1 40 feet 40 million tons 500 to 1000 feet 100 feet 200 feet 300 feet 800 feet 200 feet Ofeet not used not used not used not used 100 feet 100 feet 100 feet fewer than 7 wells per 40 acres 4 to 7 wells per 40 acres land-use patterns are incompatible with mining 3 greater than minimum but less than 100 feet 1 See previous investigations in this series for a detailed explanation of differences in criteria (Treworgy et al. 1999a, 2000). 2 Two categories of resources in areas of closely spaced oil wells are used in this study. 3 Resources initially in this category were ultimately restricted by insufficient size of the re- serve block. Table 5 Availability of the Colchester Coal for mining, by thickness category, in billions of tons. 18 to 28 inches 28 to 42 inches 42 to 66 inches >66 i nches Total Original 4.3 13.4 1.3 19.0 Mined <0.1 (<1) 1 0.4 (4) <0.1 (1) 0.5 (2) Remaining 4.3 (100) 13.0 (96) 1.2 (99) 18.5 (98) Available 0.3 (8) 0.6 (4) 0.1 (7) 1.0 (5) Available with conditions Technological restrictions 3.4 (79) 11.7 (87) 1.0 (78) 16.1 (86) Land-use restrictions 0.6 (13) 0.7 (5) 0.1 (14) 1.4 (7) 1 Numbers in parentheses are percent of original resources. 14 Illinois Minerals 1 27 Illinois State Geological Survey Mined or lost 0.5 bt 2%- Land-use restrictions 1 .4 bt 7% Available 1 bt 5% Block size <1% Thick unconsolidated overburden 4% Mined or lost 2% Other land-use restrictions 4% 1 Technological restrictions ] Land-use restrictions Figure 1 1 Availability of the Colchester Coal for mining in Illinois (bt = billion tons). Figure 12 Availability of the Colchester Coal for surface mining (based on 10.7 billion tons). most of the factors that restrict under- ground mining also restrict auger or highwall mining. The amount of ad- ditional tonnage that is recoverable by these methods is likely not significant. All technological or land-use fac- tors that restrict mining are based on economic and social considerations, and most are not absolute restrictions on mining. Companies can choose to mine underground in areas of severe roof or floor conditions or thin seams if they are willing to bear the higher operating costs, interruptions and delays in production, and lower em- ployee morale that result from operat- ing in these conditions. It is possible, for example, to mine through or under most roads or under small towns if a company is willing to invest the time and expense necessary to gain ap- proval from the appropriate governing units or individual landowners and to mitigate damage. The maximum strip- ping ratio is an economic limit, and areas of coal with high stripping ratios may be more economical to mine by underground methods or may remain unmined until the market price for coal increases relative to production costs. Similarly, previous economic and social conditions, at times, have enabled companies to mine in areas where factors are now restrictive. The current highly competitive price environment in the coal industry is expected to prevail in the Illinois Basin indefinitely. This situation makes it uneconomical to produce coal that is more expensive to mine.Therefore, the criteria used to determine available coal for this report are likely to cover mining conditions for the foreseeable future. Available Resources One billion tons (5%) of the origi- nal resources of Colchester Coal are available for mining (fig. 11). Of these available resources, about 600 million tons are 28 to 42 inches thick, and 100 million tons are 42 to 66 inches thick (table 5). All of the available Colches- ter resources are available for mining by surface methods only. Technologi- cal factors restrict 86% of the original coal resources (16.1 billion tons), land use restricts 7% (1.4 billion tons), and 2% (0.5 billion tons)of the original Colchester resources have been previ- ously mined. About 10.7 billion tons of the original Colchester Coal resources lie at depths shallow enough to be considered for surface mining (less than 200 feet deep). Of these, 1 billion tons (about 10%) are available for surface mining (fig. 12). Technological factors restrict 73% (7.9 billion tons) of the surface minable resources, and the majority of these are restricted by unfavorable stripping ratio (69% of resources). Un- favorable drift thickness restricts 4% of the resources, and size or geometry of the mining block restricts less than 1%. Land use restricts surface mining of 15% (1.5 billion tons) of the resources; 1 1% is restricted by towns. Areas of Colchester Coal available for surface mining occur throughout several counties in north-central and western Illinois. These areas consist mainly of smaller blocks that parallel the crop of the coal (figure 13). About 13.4 billion tons of the origi- nal Colchester Coal resources lie at depths greater than 75 feet and are potentially minable by underground methods. The majority of these resources are less than 42 inches thick (the minimum thickness for underground-available coal), and, of the coal resources thicker than 42 inches, no resources are available for underground mining. Small areas of available coal resulted after our initial classifications; however, these areas consisted of tonnage blocks less than the minimum required to meet the mine reserve and were thus consid- ered restricted. Technological factors restrict 92% (12.4 billion tons) of the potentially underground minable resources, land use restricts 6%, and 2% of the resources have been previously mined linois State Geological Survey linois Minerals 1 27 15 3 HENRY BUREAU LASALLE 10 Miles _ r ^^ *>•£' ,-r- = L B GRUNDY WILL '-rV [ PUTNAM BROWN MORGAN Colchester Coal Available Restricted or mined out Colchester Coal eroded Figure 13 Areas of the Colchester Coal available for surface mining. 16 linois Minerals 1 27 Illinois State Geological Survey Land-use restrictions 6% Block size 4% Mined or lost 2% ] Technological restrictions Figure 14 Restrictions to the Colchester Coal for under- ground mining (based on 13.4 billion tons). (fig. 14). The major technical restric- tions are coal less than 42 inches thick (64%) and thin bedrock or thick unconsolidated overburden (24%). Mining reserve blocks of insufficient size restrict almost 4% of the resourc- es. Areas of Colchester Coal evaluated for underground mining generally correspond to the resources indicated in figure 4 (thickness of the Colchester Coal), except for shallow coal lying less than 75 feet deep. Conclusions The Colchester Coal represents 19 billion tons (9%) of the state's origi- nal coal resources, and 1 billion tons of this coal are available for mining. "Available" means that the land-use and physical characteristics of the de- posit (e.g., thickness, depth, in-place tonnage, and stability of bedrock over- burden) are comparable with the con- ditions under which these and other coals are currently being mined in the state. All 1 billion tons of the available Colchester resources are available by surface mining methods only. Technological factors cause the most significant restrictions to the avail- ability of the Colchester Coal. For underground mining, these factors include thickness of the coal seam, undesirable overburden characteris- tics, and insufficient size of the reserve block. Although coal less than the minimum thickness identified in this report has been mined underground in recent years in the Appalachian region, those seams have certain quality characteristics that warrant a higher market price. The Colchester Coal is not known to have any quality characteristics that make it signifi- cantly more valuable than other coal resources. Thus, the availability of surface minable resources and under- ground minable resources in other, thicker coal seams makes the likeli- hood of underground mining of the Colchester Coal so remote that it is not considered available under current economic conditions. For surface mining, the major tech- nological restrictions to mining the Colchester Coal are stripping ratio and thickness of drift. These condi- tions make the cost of surface mining too high to compete successfully with underground mining of thicker seams or with surface-mined coal from western states in the current markets. To minimize the negative impacts of geologic conditions on surface mining costs, companies could avoid areas of thick drift and high stripping ratios. Land use, particularly close proximity to towns, is also a significant restric- tion to surface mining. In the reports in this series, the fac- tors that restrict mining are based on economic and social considerations and most are not absolute restric- tions on mining. Available resources are not necessarily economically minable at the present time, but the term available designates that these deposits are expected to have mining conditions comparable with those resources currently being mined in Illinois. Ultimately, the feasibility of surface mining the Colchester Coal is still dependent upon a variety of other factors that are beyond the scope of this study to assess, including the willingness of local landowners to lease the coal, demand for a particular quality of coal, accessibility of trans- portation infrastructure, proximity of the deposit to markets, and cost and availability of competing fuels. References Andros, S.O., 1914, Coal mining practice in District I (Longwall): Illinois State Geological Survey, Illinois Coal Min- ing Investigations, Bulletin 5, 42 p. Andros, S.O., 1915, Coal mining in Illinois: Illinois State Geological Survey, Illinois Coal Mining Investi- gations, Bulletin 13, 250 p. Cady, G.A., 1915, Coal resources of District I (Longwall): Illinois State Geological Survey, Illinois Coal Min- ing Investigations, Bulletin 10, 149 p. Cady, G.A., 1952, Minable coal reserves of Illinois: Illinois State Geological Survey, Bulletin 78, 138 p. 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North, 1999a, Availability of the Springfield coal for mining in Illinois: Illinois State Geological Survey, Illinois Minerals 118, 43 p. Treworgy. ( ■ ■< '<■, C.R Korose, and C.L. Wiscombe, 2000, Availability of the I lerrin Coal for mining in Illinois: Illinois State (ieological Survey, Il- linois Minerals 120, 54 p. Treworgy, C.G, J.L. McBeth, C.A. Chenoweth, GP. Korose, and D.E. North, 1998, Availability of coal resources for mining in Illinois, Albion South, Peoria West, Snyder- West Union, Springerton and Tallula Quadrangles, Clark, Edwards, Ham- ilton, Menard, Peoria, Sangamon and White Counties: Illinois State Geological Survey, Open File Series 1998-1, 92 p. Treworgy, C.G, E.I. Prussen, M.A. Jus- tice, C.A. Chenoweth, M.H. Bargh, R.J. Jacobson, and H.H. Damberger, 1997b, Illinois coal reserve assess- ment and database development: Final Report, Illinois State Geologi- cal Survey, Open File Series 1997-4, 105 p. Treworgy, C.G, and D.L. North, 1999, Availability of coal resources for mining in Illinois, Shawneetown Quadrangle, Gallatin County: Il- linois State Geological Survey, Open File Series 1999-7, 35 p. Treworgy, C.G, D.L. North, C.L. Conolly, and L. Furer, 1999b, Coal resources map and availability of coal for mining, Vincennes Quad- rangle, Lawrence County, Illinois and Knox County, Indiana: Illinois State Geological Survey, IGQ Vin- cennes-CR, 1:24,000. Udden, J. A., 1912, Geology and miner- al resources of the Peoria Quadran- gle, Illinois: United States (ieological Survey. Bulletin 506, 103 p. Wanless, H.R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey, Circular 217, 14 p. Wanless, H.R., and J.M. Weller, 1932, Correlation and extent of Pennsylva- nian cyclothems: Geological Society of America Bulletin, v. 43, no. 4, p. (1003-1016). Willman, H.B., E. Atherton, T.C. Bush- bach, C. Collinson, J.C. Frye, M.E. Hopkins, J.A. Lineback, and J.A. Simon, 1975, Handbook of Illinois stratigraphy: Illinois State Geologi- cal Survey, Bulletin 95, 261 p. Wood, G.W., Jr., T.M. Kehn, M.D. Carter, andW.C. Culbertson, 1983, Coal resource classification system of the U.S. Geological Survey: U.S. Geologi- cal Survey, Circular 891, 65 p. Worthen, A.H., 1868, Geology and paleontology: Geological Survey of Illinois, v. 3, 574 p. , Wright, C.R., 1965, Environmental mapping of the beds of the Liver- pool Cyclothem in the Illinois Basin and equivalent strata in the north- ern midcontinent region: Ph.D. the- sis, Urbana-Champaign, University of Illinois. linois State Geological Survey linois Minerals 1 27 19 Appendix 1 Remaining Colchester Coal resources and availability by county (millions of tons). Remaining Total available by County resources surface mining methods Adams 637 24 Bond 2 Brown 411 63 Bureau 777 Calhoun 12 4 Cass 232 1 Fulton 1,402 142 Greene 613 74 Grundy 820 60 Hancock 30 7 Henderson 53 1 Henry 624 53 Jersey 269 31 Kankakee 57 Knox 1,445 164 LaSalle 1,466 26 Livingston 1,521 McDonough 576 109 McLean 287 Macoupin 1,470 Madison 229 14 Marshall 494 Mercer 15 5 Montgomery 554 Morgan 797 13 Peoria 832 Pike 159 9 Putnam 377 Schuyler 606 123 Scott 255 12 Stark 423 Tazewell 214 Warren 347 90 Will 14 Woodford 517 Total 18,535 1,026 Values are rounded to the nearest 1 million tons. 20 Illinois Minerals 1 27 Illinois State Geological Survey Appendix 2 Source maps for Colchester Coal resources. Source Map Scale County (ISGS publications) year (x1000) Adams Reinertsen 1964 1964 125 Bond Cady 1952 1950 62.5 Brown Reinertsen 1964 1964 125 Bureau Cady 1952, Smith and Berg- gren 1963, Smith 1968, this study 1950 125 Calhoun Reinertsen 1964 1964 125 Cass Smith 1961 1961 125 Fulton Smith and Berggren 1963, this study 1963 125 Greene Smith 1961, Cady 1952 1950 125 Grundy Jacobson 1985 1985 62.5 Hancock Reinertsen 1964 1964 125 Henderson Reinertsen 1964 1964 125 Henry Smith and Berggren 1963, this study 1963 125 Jersey Cady 1952, Smith 1961 1950 125 Kankakee Cady 1952, Smith 1968 1950 125 Knox Cady 1952, Smith and Berg- gren 1963, this study 1950 125 La Salle Jacobson 1985 1985 1 62.5 Livingston Jacobson 1 985 1985 62.5 McDonough Reinertsen 1964 1964 125 McLean Cady 1 952 1950 62.5 Macoupin Cady 1952, Smith 1961 1950' 62.5 Madison Cady 1952, Smith 1961 1950 62.5 Marshall Cady 1952 1950 62.5 Mercer Reinertsen 1964, Searight and Smith 1969 1964 125 Montgomery Cady 1952 1950 62.5 Morgan Smith 1961, Cady 1952, this study 1950 125 Peoria Smith and Berggren 1963, Cady 1952, this study 1950 125 Pike Reinertsen 1964 1964 125 Putman Cady 1952 1950 62.5 Schuyler Reinertsen 1964 1964 125 Scott Smith 1961, Cady 1952 1961 125 Stark Smith and Berggren 1963, this study 1963 125 Tazewell Cady 1952, Smith and Berg- gren 1963 1950 125 Warren Smith and Berggren 1963 1963 125 Will Smith 1968 1968 125 Woodford Cady 1952 1950 62.5 1 Minor revisions made for this report. linois State Geological Survey linois Minerals I 27 21 pi * D CD C/3 a d 3 < O U 1/3 i—; djo "* qj a 3 CD tf o 13 d is 0) > en I Jatur GEO '3 PQ 0) 'l-H Q >> o CM CO 1 — 1 ^ u o -a co ^ H l-H 3 o j-J ° < -Q artment NOIS ST O t« CD 03 CD c 'c3 15 i-i 3 C/3 ex Dep ILLI — cd Z CD U