AN ASSESSMENT OF COAL RESOURCES AVAILABLE FOR DEVELOPMENT
CENTRAL APPALACHIAN REGION
M. Devereux Carter and Nancy K. Gardner
U.S. Geological Survey Open-File Report 89-362
Chapter 5 - RESULTS
Results of the coal availability investigations for the four study areas are summarized in Table 2 and Figures 3-14. Individual coal bed statistics are depicted in the twelve tables of the Appendix. Much more detail is presented in the individual reports cited for each of the study areas.
Table 2 shows the calculated coal-resource tonnages by study area for original coal, coal mined and lost-in-mining, remaining coal, coal restricted due to land-use and technologic restrictions, and available coal resources. Figures 3 and 4 show the same information by percentages. A total of one billion tons of coal is estimated to be unavailable due to landuse and technologic restrictions in the four areas studied. Of the original resources in the four areas, only 61 percent are estimated to be available for mining under current conditions. The range in the amounts of available resources is surprisingly small - 58 percent in the Vansant quadrangle to 64 percent in the Sylvester quadrangle. Figures 3 and 4 show that the coal mined and lost-in-mining ranges from 6 percent in the Sylvester quadrangle to 14 percent in the Vansant quadrangle, an 11 percent average. The land-use restrictions exhibit the greatest variability - less than 1 percent in the Vansant quadrangle to 17 percent (largely a forest preserve) in the Noble quadrangle, a 3 percent average. Technologic restrictions range from a minimum of 11 percent in the Noble quadrangle to 28 percent in the Sylvester quadrangle, a 25 percent average. In the four quadrangles, land use accounts for only 11 percent of the restrictions, while technologic factors average 89 percent; however, in more populated areas of the Centra.1 Appalachian Region, this relationship could be altered in favor of land-use restrictions.
Figure 5 depicts summary statistics for both surface and deep minable coal in the four study areas combined. Of the original coal resources, 3 percent has been removed by surface methods and 8 percent has been mined and lost-in-mining by underground methods; land use restricts 2 percent of the surface and 1 percent of the deep coal; and technologic considerations restrict less than 2 percent of the surface coal but 23 percent of the deep coal. In the four study areas, the deep coal beds are more affected by restrictions than are the surface minable coal beds. The remaining surface resource is reduced by 16 percent, while resources of the remaining deep minable coal beds are decreased by 27 percent. One-third of the available coal is minable by surface methods and two-thirds by underground methods.
Figures 6 through 9 depict the original, remaining, and available surface and deep resources by coal bed. The beds are arranged in stratigraphic sequence from left to right representing coal beds from top (youngest) to bottom (oldest). The surface minable coal dominates the upper part of the section while the largest underground resources are in the middle to lower parts of the section. Larger amounts of coal appear to be restricted in the middle and lower coal beds. In fact, in the Vansant quadrangle, four of the lower five coal beds appear to be totally eliminated from future mining due to technologic restrictions.
5.1 Land-use Restrictions
Figure 10 depicts the combined land-use restrictions that were identified and applied to the remaining coal resources of each of the four quadrangles. The variation is quite striking, especially between the Noble quadrangle in Kentucky and the Vansant quadrangle in Virginia. The largest restricted areas in the Noble quadrangle are portions of a 15,000-acre forest preserve that was deeded to the University of Kentucky in the early part of the century with provision that the preserve never be mined. In the Vansant quadrangle, power lines, pipelines, and highways were considered locally not to cause serious enough constraints to surface or deep raining to be applied within this study area.
Figures 11 and 12 illustrate the individual land-use restrictions of the four study areas as a whole and by quadrangle. To keep the following percentages in perspective, note that land-use restrictions represent only 11 percent of all restrictions in the study areas. The largest single land-use restriction of the four areas is the forest preserve in the Noble quadrangle, accounting for just over two-thirds of the land-use restrictions (69 percent); while streams are 11 percent; towns, 9 percent; power lines and pipelines, each 4 percent; oil and gas wells, 2 percent; and cemeteries, 1 percent. Land-use restrictions are highly variable between the study areas: in the Noble quadrangle, the forest preserve accounts for almost 98 percent of
the total; in the Vansant quadrangle, towns predominate with 88 percent; in the Sylvester quadrangle, towns and streams are nearly equal with 41 and 40 percent, respectively; in the Matewan quadrangle, the land-use restrictions are fairly evenly divided amongst streams at 38 percent, power lines 25 percent, and pipelines 20 percent. Oil and gas wells and cemeteries consistently comprise a small fraction of the land-use restrictions, ranging from 0 to 9 percent. Because of the steep dopes of the four study areas in the Central Appalachian Region, most population centers axe concentrated in the valleys and, consequently, are below the outcrops of most of the major minable coal beds. The few coal beds affected by towns are those lower in the stratigraphic sequence.
5.2 Technologic Restrictions
Figures 13 and 14 present the individual technologic restrictions of the four study areas combined and by quadrangle. By far the largest single technologic restriction, nearly 74 percent, is the minimum minable thickness of the coal. Coal beds occurring too close above or below one another is second at almost 19 percent. Deep-mine barrier pillars and previous deep mining in coal beds too close above or below one another each account for 21 percent of the restrictions. Geologic factors account for 2 percent of the technologic restrictions, while oil and gas wells and overburden together total less than 1 percent.
Coal considered too thin for mining is consistently the largest restrictive factor in each of the four quadrangles, ranging from 52 percent in the Matewan quadrangle to over 99 percent in the Noble quadrangle. The location of another thicker coal bed above or below within an unsafe distance may, or may not, be a significant factor in restricting the development of the remaining coal resource. This factor ranges from no reduction at all in the Noble quadrangle to 6 percent in the Sylvester quadrangle, 22 percent in the Vansant quadrangle, and 36 percent in the Matewan quadrangle. In the areas where appreciable underground mining has occurred, deep-mine barrier pillars and mines too close above or below potentially minable beds each restrict from 1 to 9 percent of the coal. Oil and gas wells are present in all four areas, but, as a constraint to mining, never exceed 1 percent.
Thickness of overburden is barely a factor in restricting coal development in the four quadrangles. In the Noble quadrangle, none of the coal beds are deeper than 1,000 feet below the surface. Forty-three percent of the coal beds in the Vansant quadrangle are deeper than 1,000 feet, but this is not considered a constraint to mining in this area. In fact, over two-thirds of the coal mined in the Vansant quadrangle has come from depths greater than 1,000 feet below the surface, all from the Pocahontas No. 3 coal bed. In the steep terrain of the Sylvester quadrangle where about 6 percent of the coal is at depths greater than 1,000 feet, underground mining by drifting in from the outcrop reaches great depths in relatively short distances which is not restrictive to mining, just more expensive. In the Matewan quadrangle, there is a small amount of coal deeper than 1,000 feet; however, coal considered unlikely to be mined for reasons of depth totals less than 1 percent of the technologic restrictions within the quadrangle.
Geologic factors such as poor roof and floor conditions, washouts, displacement faults, colluvium, and inferior coal quality probably represent a significant constraint to mining. Unfortunately, there is too little information available in the four study areas to confirm this supposition. Only in the Sylvester quadrangle is there enough information to allow 1) the mapping of several areas where coal has been washed out (eroded away before or soon after burial), and 2) some statistical analysis of possible restrictions on two coal beds because of organic constituents (inertinite) that would inhibit complete and rapid burning in power-generation boilers. From only those few data points, it was determined that these two adverse geologic factors represent about 5 percent of the technologic restrictions in the Sylvester study area.
5.3 Other Restrictions
Other major land-use restrictions looked for but not found in the four study areas were National and State forests, parks, and monuments, as well as protected species habitats. Major potential technologic restrictions that do not occur in the four study areas are coal beds that dip too steeply or are highly faulted.
There are a number of other potential restrictions to mining that more not applied in these four studies. These include such economic considerations as the cost of mining, availability of transportation, proximity to markets, subdivision of surface and mineral ownership, and size of a logical mining unit. In addition, recovery factors were not applied. The impact of such restrictions was beyond the scope of these studies, but they would certainly further reduce the amount of coal available for development.
5.4 Compliance Coal
Noncompliance with new source performance standards (NSPS) for sulfur dioxide emission, currently not to exceed 1.2 pounds of S02 per million btu input (Office of the Federal Register, 1988) is not a restriction to mining. However, compliance is certainly a factor in determining the marketability of coal and, consequently, the availability of compliance coal was evaluated in all four study areas. Matewan is the only quadrangle with enough control points to map the sulfur content in terms of S02 generation. In this study area, for the 90 percent of the coal beds with available data, only 44 percent of the resource in these beds meets NSPS SO2 compliance levels. A statistical analysis of potential S02 generation was performed on coal beds with sufficient data in the other three quadrangles. In the Sylvester quadrangle, the results, while quite variable, indicate that the majority of the remaining resources could be expected to meet current compliance standards. In the Vansant quadrangle, with analyses on only seven coal beds, 43 percent of those resources could be considered compliance. For the Noble quadrangle, there are not enough data points to indicate more than that the coals vary in quality and that both compliance and noncompliance coal exist in the area. However, a report by Cobb and others in 1982 revealed that in eastern Kentucky approximately 43 percent of the coal beds meet compliance standards. Although the data axe insufficient, one could generalize that approximately one-half of the available coal in the four study areas could be expected to meet current new-source S02 performance standards.
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