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~~ <br />Orchard Valley Mine were initially dry, but after allowing these holes <br />to recover some water accumulated, up to 300 gallons, in the casing. <br />However, this amount of water is insufficient to provide a desirable <br />well yield. This indicates that recharge along outcrops and subcrops <br />above the level of the North Fork is insufficient to sustain ground <br />water wells developed in the Rollins. The only domestic use of the <br />water from the Rollins sandstone is from wells along the North Fork near <br />the Hawk's Nest Mines. The water quality elsewhere is considered too <br />saline for domestic use (Prince and Arrow, 1974). <br />Preliminary aquifer tests were performed by WECC on the Barren member of <br />the Mesa Verde Formation in September, 1975. The preliminary <br />transmissivity obtained for this member was calculated to be 2.46 <br />g/d/ft. Also, WECC performed a preliminary aquifer test on a fractured <br />area in the "F" seam which yielded a transmissivity of 16.68 g/d/ft. <br />Another "F" seam well completed in an unfractured area in the coal seam <br />was dry. These aquifer tests indicate that the "F" seam and the <br />lenticular sandstones of the Barren member are poor aquifers at best, as <br />ground water flow is mainly concentrated in fractured rock. <br />Mine inflow studies submitted by the mines and visual observations by <br />Randal Price at the Somerset Mine, Orchard Valley Mine and Mt. Gunnison <br />Mine in 1985 and 1986 indicate that the coal seams in the North Fork <br />Valley are poor aquifers at best. Generally, mine inflows were observed <br />to occur in areas of shallow overburden and under stream valleys. <br />Some fractures and faults transect the Mesa Verde Formation and extend <br />vertically to the surface. These faults and fractures produce narrow <br />bands of secondary permeability within the rock strata. Due to the low <br />permeability of the rock strata within the Mesa Verde Formation, these <br />faults and fractures provide the primary path through which water flows <br />both vertically between rock strata and horizontally within rock strata. <br />When faults and fractures are encountered within the mines in the North <br />Fork region, they generally produce mine inflows. The flow <br />characteristics of each mine inflow associated with faults and fractures <br />depend upon the lateral extent and the proximity of the fault or <br />fracture to a stream valley. All inflows from these sources are <br />characterized by an initial surge of water which then either decreases, <br />or ceases completely with time. <br />Since most stream channels in the North Fork drainage basin are <br />developed in zones of weak fractured rock associated with fracturing and <br />faulting (Dunrud, 1976), mine inflows from fractures and faults below <br />these streams mimic the temporal flow characteristics of the overlying <br />streams. In the Hawk's Nest Mine, an inflow was encountered under the <br />ephemeral drainage of Hawk's Nest Creek. The rates of inflow beneath <br />this drainage fluctuate seasonally with a slight lag time in response to <br />the flows in the overlying stream. In the Somerset Mine, inflows <br />beneath Hubbard Creek are continuous and may reflect the perennial <br />nature of this stream. <br />37 <br />