Item Number: OFS01-01
Map Scale: 1:1,000,000

ABSTRACT: This study assesses the coal resources of the Danville and Springfield Coal Members (Dugger and Petersburg Formations, respectively) in Indiana and provides new estimates of the tonnage of coal in the following categories as of January 1, 2000: original resources in place, resources remaining after mining, identified resources, demonstrated reserve base, accessible reserve base, and estimated recoverable reserves. In addition, the sulfur, heat, and ash content of the Danville and Springfield Coals were mapped in order to allocate indicated reserves, demonstrated reserve base, accessible reserve base, and estimated recoverable reserves according to specified categories of sulfur, heat, and ash content. The resources and reserves categories are defined based upon criteria for minimum coal thickness, overburden thickness, and reliability category. Three reliability categories are used to express the relative degree of geologic assurance or reliability of the resource estimate based upon the density of coal thickness data points that are used to derive the resource estimate. The reliability categories are: measured (0-0.5 miles from the data point), indicated (0.5-2.0 miles), and inferred (2.0-4.0 miles). The geologic and land use factors which limit the mining of the Danville and Springfield Coal were identified through interviews with geologists and mining engineers from companies mining these coals in Indiana and Illinois. These factors were mapped and then applied to the tonnage of demonstrated reserve base in order to calculate the tonnage of accessible reserve base. Recovery-rate factors for surface and underground mining (80% and 50%, respectively) were estimated using proprietary mine recovery rate data from mines operating in the Danville and Springfield Coals during the 1980s and 1990s. Estimated recoverable reserves were calculated by multiplying the accessible reserve base by these recovery-rate factors. The tonnage of original identified resources of Danville and Springfield Coal in Indiana is calculated to be 18.8 billion short tons (tonnage by coal bed is also provided in this report). Of the 18.8 billion short tons, 1.8 billion short tons have been removed by mining or lost in the mining process, thus leaving 17.0 billion short tons of remaining Danville and Springfield resources. Of the remaining resources, 16.4 billion short tons are demonstrated reserve base. Technological and land use restrictions remove 9.2 billion short tons of demonstrated reserve base from potential mining, thus leaving 7.2 billion short tons (38.2% of the original resources or 42.3% of the remaining resources) of accessible reserve base. Of the 7.2 billion short tons of accessible reserve base, 0.9 billion short tons (4.7% of the original resources or 12.3% of the total accessible reserve base) are estimated to be recoverable by surface mining, while 3.1 billion short tons (16.4% of the original resources or 43% of the total accessible reserve base) are estimated to be recoverable by underground mining.

Conolly, C. L., Rupp, J. A. 2001, Coal reserve assessment and database development of the Danville and Springfield Coal Members in Indiana: final report: Indiana Geological Survey Open-File Study 01-01, 52 p., 19 fig.

Notes: Publications in the Indiana Geological Survey Open-File series have been inconsistently named using a variety of series titles including "Open-File Report," "Open-File Map," and "Open-File Study." Prior to 1994, a publication in this series was generally referred to as an "Open-File Report" (but not always). To help reduce confusion created by these inconsistencies, the IGS now refers to every publication in the Open-File series as an "Open-File Study." To be entirely correct in writing a bibliographic reference for a publication, one should use the series name and number that appears on the publication itself.

Also contains a CD with ArcInfo coverages and associated metadata and Access database of resource information.

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Keywords: coal, database, energy resources, Danville Coal Member, Springfield Coal Member, Dugger Formation, Petersburg Formation, sulfur, ash, heat, reserves, Pennsylvanian, Carbondale Group

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