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M. Devereux Carter and Nancy K. Gardner

U.S. Geological Survey Open-File Report 89-362

Chapter 2 - METHODS

To assess the available coal resources of the entire Central Appalachian Region by studying the region in the detail necessary to produce meaningful results would be a monumental task. To do this in a timely and cost-effective manner requires that areas of manageable size and significance be identified to serve as models to ultimately allow extrapolation of results into the areas between models and to the regions beyond. The 7.5-minute quadrangle was selected as the ideal study scale -Or several important reasons: 1) a 1:24,000-scale map has proven optimal for general purpose geologic and resource mapping in the United States; 2) because of its widespread utility, base maps, geologic maps, and digital elevation models (DEM's) commonly are available at this scale; 3) focusing on a selected group of these relatively small areas, 50 to 65 square miles, allows consideration of the effects of a large number of restrictions that would be difficult and prohibitively expensive to accomplish on an entire coal region or even a coal field basis.

Computer techniques were a critical component in handling the multitude of parameters considered, overlain, combined, and calculated. The USGS provided the NCRDS with its stratigraphic and geochemical data bases, GIS capabilities, and programs to manipulate data and calculate available coal resources according to the classification system of the USGS (Wood and others, 1983). The computer also permitted relatively quick and easy updates as restrictions were added or modified and new estimates generated.

State geological agency personnel met with local coal industry engineers, geologists, and mine operators, as well as State and Federal regulatory personnel, who were familiar with local mining practices and with regulations as they applied to these practices, to determine the specific constraints applicable within their specific study areas. State personnel were responsible for all collection, evaluation, and correlation of coal data; encoding of stratigraphic data and digitizing of line data; and editing and validation of data in the system. State personnel also performed all computer manipulation (gridding, contouring, combining, resource calculation, and tabulation) in three of the four study areas. The USGS primarily developed the methodology and coordinated the program to ensure the maintenance of standards and consistency. The USGS also provided data entry and storage, as well as interactive access to the data bases and software necessary to utilize the data and calculate available resources. The USGS further provided computer training and assistance to State personnel throughout the project. Research is continuing into the appropriate methodology for extrapolating the results obtained from each study area to the larger coal area it represents and ultimately to the entire region.

Buffer zones in which raining is not permitted were drawn around many of the surficial and underground features to be included as a part of the areas restricted from mining. Areas adjacent to surficial features that are restricted from mining, e.g., 100-ft buffer zones around power lines and pipelines, were digitized by the State agency personnel. Unminable buffer zones surrounding oil and gas wells and cemeteries were generated by NCRDS GIS graphics programs. NCRDS personnel accessed the USGS Information Systems Division's ARC/INFO GIS to delineate unminable buffer zones around active or abandoned underground mines, which were then returned to NCRDS programs for further GIS processing.

Prior to the initiation of the cooperative program, a pilot study (fig. 1) was performed to develop the methodology and to test the applicability of NCRDS software to the program requirements. In fact, the methodologies were modified and NCRDS subroutines were enhanced as the project progressed. For the pilot study, all data were provided by the Kentucky Geological Survey, and all computer data manipulation and resource calculation and tabulation were performed by the USGS. The methodology developed during the pilot study and the summary results of that study are documented in Eggleston and others (in preparation). The methodology established in the pilot study provided the framework for the additional three study areas described herein.

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