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-zz- Description of the Hydrologic Environment - Ground water Regime (Cont'd) Some recharge to this continuous unit may come directly from the percolation of snowmelt and precipitation downward through faults and fractures. Grill holes which penetrated the Rollins sandstone near the Orchard Valley Mine were initially dry, but after allowing these holes to recover they accumulated water, sometimes as much as 300 gallons. However, this amount of water is insufficient to provide a desirable well yield. This indicates that recharge along outcrops and subcrops above the level of the North Fork is insufficient to sustain ground water wells developed in the Rollins. The only domestic use of the water from the Rollins sandstone is from wells along the North Fork near the Hawk's Nest mines. The water quality elsewhere is considered too saline for domestic use (Price and Arnow, 1974). Preliminary aquifer tests were performed by RRCO on the Barren member of the Mesa- verde Formation in September, 1975. The preliminary transmissivity obtained for this member was calculated to be 2.46 g/d/ft. Also, ARCO performed a preliminary aquifer test on a fractures area in the "F" seam which yielded a transmissivity of 16.68 g/d/f t. Another "F" seam well completed in an unfractures area in the coal seam was dry. These aquifer tests indicate that the "F" seam and the lenticular sandstones of the Barren member are poor aquifers at best, as ground water flow is concentrated in fractured rock. Observations made underground by the staff of the Division at the Blue Ribbon, Hawk's Nest, Mt. Gunnison and Sommerset mines also indicate that the coal seams in the region are poor aquifers with very low trans- missivities. The "B-2", "E" and "F" seams were observed to weep slightly at fresh cut faces, while mine entry walls a short distance from the face were dry. The sandstone and siltstone roof strata in the Blue Ribbon, Hawk's Nest and Somerset mines also weep for short periods of time following mining and eventually dry up. The Hawk's Nest Mine workings in the "E" seam are dry even though these workings are within 600 feet of the North Fork, are beloro the level of the North Fork, and are parallel to the North Fork. These in-mine observations indicate that the "B-2", "E" and "F" coal seams and their roof strata are not significant regional aquifers. Observation made of mining within the "C" seam at the Bear No. 1 and No. 2 mines and of mining within the "D" seam at the Orchard Valley Mine indicate that the "C" and "D" seams and their associated roof strata also are not significant regional aquifers. If the coals and their roof strata were aquifers, these strata would have continued to weep throughout the life of these mines. Some fractures and faults transect the Mesaverde Formation and extend vertically to the surface. These Faults and fractures produce narrow bands of secondary porosity within the rock strata. Due to the low permeability of the rock strata within the Mesaverde Formation, these faults and fractures provide the primary path through which water flows both vertically between rock strata and horizontally within rock strata. When faults and fractures are encountered within the mines in the North Fork region, they generally produce mine inflows. The flow characteristics of each mine inflow associated with faults and fractures depend upon the lateral extent and the proximity of the fault or fracture to a stream valley. All inflows from these sources are characterized by an initial surge of water which then either decrease, or ceases completely with time. Since most stream channels in the North Fork drainage basin are developed in zones of weak fractured rock associated with fracturing and faulting (Dunrud, 1976), mine inflows from fractures and faults below these streams mimic the temporal flow characteristics of the overlying streams. In the Nawk's Nest Mine, an inflow was encountered under the ephemeral drainage of