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-zl- ~J~-~tr- ~ The Twentymile sandstone lies approximate]y 200 feet above the Middle sandstone, 370 feet below the "P" coal seam, and 220 feet below the "R" coal seam, the lowest coal seam to be mined at the Trapper Mine. The sandstone underlies much of the permit area of the Eagle Mines and forms broad outcrop areas near the central portions of the permit areas of the Eagle and Trapper Mines along the valley walls of the Williams Fork and Yampa Rivers. Pumping tests performed for the Trapper Mine, by Utah International Inc., on the Twentymile sandstone yielded values for transmissivity of 77 to 85 gpd/ft2. Utah International Inc. postulates that these values are very low, given the yield of the Twentymile sandstone near the axis of the Big Bottom Synciine. In the Big Bottom Basin Utah International, Inc. obtained yields of 500 gpm and they postulated transmissivity values of 5,000 gpd/ft and permeability values of 50 gpd/ft2. Both Utah International, Inc, and Empire Energy Corporation have water supply wells completed in the Twentymile sandstone; the Trapper Mine office facility well and the Eagle No. 9 Mine well. The Trapper Mine well (GD-1) produces 75 gpm. The Eagle No. 9 well produces 9.6 gpm. Other wells are completed in this sandstone and used for domestic supplies in the general area. The White sandstones are a series of three massive and cross-bedded sandstone aquifers. Each sandstone is separated from the adjacent sandstone by a thin series of shales and thin coals, which act as aquicludes and aquitards. The lowest sandstone, the first White sandstone, is about 150 feet thick in the general area. This sandstone aquifer is located an average of 130 feet above the Eagle No. 9 Mine and 20 to 50 feet above the uppermost coal seam to be mined at the Trapper Mine. The northern limits of mining at the Trapper Mine will remove portions of the first White sandstone. The aquifer will be in direct hydrologic communication with reclaimed spoils at the Trapper Mine. Empire Energy Corporation has monitored water levels and prepared piezometric maps for the first White sandstone (Maps III-6b and 6c of the permit application). Three monitoring wells are currently being monitored; 81-03A, 81-04A and 81-19. The applicant has performed aquifer tests on the White sandstone at wells 81-04 and 81-]9. The values for permeability obtained were 0.6 gpd/ft2 and O.14 gpd/ft2, respectively, and an estimated storativity of 0.0015 from well 81-04. Geologic information submitted by Empire Energy states that the second and third White sandstones have lithologies and depositional histories equivalent to the first White sandstone. The company postulates from this that the aquifer characteristics of these sandstones are similar to the first White sandstone. Data from the Trapper Mine permit application shows limited ground water also occurs. within the discontinuous, lenticular sandstones associated with coal seams and the coal seams themselves within the Mesaverde Group. The permeabilities of these water-bearing units are quite low, generally an order of magnitude less than the fractured sandstone aquifers. The "F" and "P" seam coals have low permeabilities, except where the seams have been fractured by natural and induced stress applied to the coal seams. Utah International, Inc. has conducted aquifer tests on coals and interburden strata in the Upper Williams fork Formation. Transmissivity values ranged from 174 to 2,760 gpd/ft. korizontal permeability values ranged from 10 to 50 gpd/ft2 and storativity values ranged from 0.00032 to 0.0083.