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APPENDIX A AREAS OF RELATIVE SIMILARITIES OF RECOVERABLE RESERVES 65
1. PENNSYLVANIA- WEST VIRGINIA A high proportion of total remaining underground reserves (see Table 1) in Pennsylvania and northern West Virginia is in the Pittsburgh bed despite its extensive past exploitation and depletion. These remaining reserves consequently occur under relatively deep cover and access is generally more difficult. Reserves in the other beds also are generally behind extensive areas of past depletion and tend to be thinner and less well defined. Remaining reserves in southern West Virginia occur in a much larger number of coal beds than in Pennsylvania and northern West Virginia, but the best of these teds also have undergone extensive depletion and are more difficult to reach. The prevailingly steep ridge-and-valley topography of southern West Virginia serves to separate regaining reserves that outcrop above drainage levels into areas of highly variable shapes and extents. Where they occur below drainage, the remaining reserves may be more extensive but also more difficult to reach and the high ridges create substantial depths of cover. The remaining surface-minable reserves in the two states are widely scattered geographically and generally exist as narrow strips of numerous outcropping beds that can only be recovered along steep ridge-side slopes. This results in individual mines of limited size with high rates of annual depletion. The amount of coal production from surface vines in Pennsylvania increased sharply between 1969 and 1974, with production from underground mines having decreased accordingly. Production from surface mines in Vest Virginia has been relatively constant during the same period while that from underground mines has decreased steadily. 2. KENTUCKY (Eastern), MARYLAND, VIRGINIA Remaining coal reserves in eastern Kentucky and Virginia are similar to those in southern West Virginia (Area 1). There are numerous beds in eastern Kentucky and Virginia, the best of which have undergone substantial depletion. The topography is characterized by steep ridge-and-valley slopes except in the northern portions of the eastern Kentucky coal-bearing area where the bed occurrences are comparatively inferior to those in the more iirportant portions to the south. 66
Remaining coal reserves in Maryland are very limited, and this state is placed in Area 2 largely for convenience. Aside from any reserves left in the greatly depleted Pittsburgh bed (usually over 8 feet in thickness), reserves in the other beds are prevailingly thin, averaging less than 36 inches. Maryland coal, present in ony two counties, occurs in the form of a basin with beds outcropping around the margins of the basin and becoming quite deep in the interior, flatter portions of the overall structure. Production from surface mines has increased sharply in all three states during the past six years while underground production has remained approximately the same in eastern Kentucky but has decreased markedly in Maryland and Virginia. 3. TENNESSEE, ALABAMA The percentages of depletion are higher in Tennessee and Alabama than in any other states (58.8 and 56. H percent, respectively). Remaining reserves are distributed among numerous coal beds, many of which are notably thinner than elsewhere in the overall Apalachian area. The coal beds in northern Tennessee are sinilar to those in the southwestern portions of eastern Kentucky in that they lack continuity and are irregular in minatle extent. The reserves in southern Tennessee and Alabama partially occur in fields where the beds dip steeply froir their outcrops and partially where they are relatively flat. Production from both surface and underground mines has remained relatively constant in both states during the past six years. Recent exploration indicates that relatively large amounts of surface-minable lignite exist in south- central Alabama (south of the bituminous coal fields) and possibly extend northwest into Mississippi. There are no statewide estimates available of the total of such reserves. iÂ». OHIO The Pittsburgh coal bed of western Pennsylvania and northern Nest Virginia (Area 1) also extends into eastern Ohio but has likewise been extensively depleted, while the percent depletion is notably lower (22.4 percent) than in the other eastern states (Areas 1, 2, 3) and the remaining reserves are relatively large, they occur primarily in up to eight beds that are either thinner and deeper or generally poorer quality and mining characteristics than those beds now being mined. While production from surface mines increased sharply until 1971, it has decreased somewhat during the past three 67
years. Underground production remained relatively constant until 1970 but also has declined during the past four years. 5. ILLINOIS, INDIANA, KENTUCKY (Western) The coal fields of Illinois, Indiana, and western Kentucky are essentially in a broad, shallow basin and are characterized by the general occurrence of froir one to three principal beds with relatively favorable mining conditions and extending persistently within very large areas. There are also other beds in various portions of the basin, but these are less extensive or thin. While the principal beds have been widely mined, generally parallel with their perimeters of occurrence, there remain large amounts of reserves where thicknesses, quality, and mining characteristics are not notably different froir areas where mining has been or is being conducted. Depletion in the three states ranges from 13.1 to 22.2 percent. While production from surface mines has decreased somewhat in Illinois in the past six years and increased irregularly in Indiana and western Kentucky during the same period, it seems likely that this method of mining has reached a general plateau and that chances for iraterial increases are slight. Insofar as surface mining of the principal beds is concerned, remaining surface-minable reserves are probably only those generally in areas of presently active surface operations. Production from underground mines has remained relatively constant in Illinois and western Kentucky for a number of years but has virtually ceased in Indiana (146,000 tons in 1974). 6. IOWA, KANSAS, MISSOURI The coal reserves of Iowa, Kansas, and Missouri are prevailingly thin except in scattered and relatively local areas in Iowa. There has been virtually no underground production from the thin beds, but production from Iowa has remained relatively constant although low. Production froir surface mines in all three states has been relatively constant during the past six years but also has been comparatively low. Since coal production commenced and peaked at approximately the same time in all three states, the unusually low percentage of depletion in Missouri (7.7 percent) suggests that the estimated remaining recoverable reserves of over 3 billion tons underground and 1 billion tons surface-minable either may be overstated or much of the reserve reported may actually not be recoverable under present conditions of mining. 7. ARKANSAS, OKLAHOMA The estimated recoverable coal reserves in Arkansas and Oklahoma are minor in amount. The percentages of depletion 68
are moderately highâ21.3 percent and 27.4 percent, respectively. Feserves in the northern two-thirds of the Oklahoma coal-bearing area are similar to those in Kansas and Missouri. Remaining reserves in the southern one-third of Oklahoma occur in a broad west-east belt of undulating coal- bearing strata that also extends eastward into west-central Arkansas. Some of the coal beds in this belt are likewise thin, but there are a few beds with thicknesses of up to about 6 feet. The undulations are caused by geological forces that resulted in a more-or-less parallel series of folds at varying degrees of inclination, some of them quite steep. Such folding greatly increases the difficulties of mining. There has been very little underground mining in these two states in recent years while production from surface mines has remained about constant at comparatively low levels during the past six years. 8. COLORADO, UTAH Minor amounts of surface-minable reserves exist in Colorado and Utah, primarily in mountainous terrain. Reserves in Colorado occur mostly in the two northwestern counties in gently dipping shallow beds within limited areas. There may be additional surface-minable reserves in the comparatively shallow Denver basin in east-central Colorado, but these are inferior in quality and have not been estimated. Percent depletion is relatively low for both statesâ7.2 percent in Colorado and 14.0 percent in Utah. Estimated reserves are moderately large in both states, tut previous mining in the better beds generally took place at the most accessible locations. Future production consequently will have to come from deeper, thinner, or less readily accessible beds. There has been virtually no production froir surface mines in Utah while that in Colorado has slowly increased during the past six years. Production from underground mines in Colorado has remained about constant while that in Utah has increased somewhat during 1973 and 1974. Despite the handicaps described above, there has been a considerable amount of recent interest in acquisitions of both underground and surface-minable reserves in these two states, and plans for a number of new mines, primarily underground but some surface have been made. 9. WASHINGTON Recoverable underground reserves in Washington are irinor in amount while surface-minable reserves are limited to the one surface mine now active. Although over 4 million tons 69
were produced in 1918 (the year of peak production), underground production has declined to very limited amounts in recent years. The degrees of inclination in remaining coal beds range from moderate to almost perpendicular. 10. MONTANA, NORTH DAKOTA, SOUTH DAKOTA, WYOMING Estimates of recoverable amounts of both underground and surface-minable reserves are very large in Montana and Wyoming, while North Dakota contains only surface-minable reserves (its underground reserves are not now deemed suitable for future mining). Estimated surface-minable reserves in South Dakota are very limited and represent only a fringe of the much larger surface-minable areas of North Dakota. The four states are placed in one area of similarity since major portions of surface-minable areas are continuous and depletion is well below 2 percent. The major recoverable coal reserves are located in western North Dakota, eastern and southeastern Montana, and northeastern Wyoming. The surface-minable reserves and large portions of the underground reserves throughout this area tend to occur in beds that are much thicker than anywhere else in the contiguous US states. These beds averaging 20 feet but much thicker in many parts of Montana and Wyoming, are essentially flat and occur in moderate terrain, conditions that are highly conducive to large-scale surface mining. Production from underground mines in this area has been very limited during the past six years and has been confined largely to Wyoming. On the other hand, production from surface mines has increased ten-fold in Montana, by 50 percent in North Dakota, and almost four-fold in Wyoming during this same period. Advanced planning is now under way for a large number of new surface mines, and their development awaits only solution of restriction problems and, in some cases, completion of planned new transportation facilities. 11. ARIZONA, NEW MEXICO Estimates for underground reserves in Arizona are not available. Recoverable underground reserves in New Mexico primarily occur in the western and northeastern portions of the state where moderate amounts have been produced for many years. Intensive exploration in recent years has revealed the presence of large amounts of surface-minable reserves around the western and southern preimeters of the San Juan basin in northwestern New Mexico (probably somewhat greater than the 2.43 billion tons listed in Table 1). The surface-minable reserves of Arizona and New Mexico tend to occur either in zones of multiple individual beds 70
with irregular intervals between them or where two or more relatively thin coal-beds converge into a relatively thick single bed. Where sufficiently close together or sufficiently thick, the coal components in these areas can be recovered in single mining operations. The single active mine in Arizona, opened in 1970, produced over 6 million tons in 1974. Production from surface mines in New Mexico has increased markedly between 1969 and 1974, and one of the surface mines has been the largest individual mine in the United States during the past several years. Firm plans have been made for a number of new surface mines in New Mexico, and some of them await only completion of planned new transportation facilities. 12. TEXAS Although the presence of shallow lignite deposits in southeastern Texas (and northern Louisiana) has been long known, it was being mined at only two locations as recently as 1968. Since then, however, extensive exploration for surface-minable lignite has taken place. It appears probable that the total amount of recoverable reserves iray be perhaps as much as double the amount shown in Table 1 (1.29 billion tons). While frequently discontinuous, a number of areas have been found to contain beds from 6 to 15 feet in thickness. Other areas contain multiple beds from 3 to 5 feet thick that are sufficiently close together to be mined in a single operation. Several new large mines for Texas lignites are projected to be opened during the next several years. 13. ALASKA Recoverable coal reserves in Alaska are distributed in five or six separate areas of variable size, quality, and geological structure. The numerous coal beds vary widely in occurrence and thickness with some ranging up to 50 feet thick. The largest field is located in the northern roost portion of the state, but there has been considerable interest during the past several years in some of the southern fields from which production could be transported to comparatively ice-free ports for ocean shipirent. No planned major operations are now known for these areas. 71