GENERAL43393 - Laserfiche WebLink

Home Browse Search

-2L- Some recharye to the Rollins sandstone and other waterdeariny sandstones may come indirectly from the percolation of snow~nelt and precipitation dowmvard through faults and fractures and other shallow yround water systems. Shallow groundwater occurs in the thin soil mantel, burned coal outcrops, colluvial and alluvial deposits. Urill holes which penetrated the Rollins sandstones near the Urchard Valley f4ine were initially dry, but after allowing these holes to recover several days some accwnulated up to 3U0 gallons of water in the casing. However, this amount of water is insufficient to provide a tlesirable well yield. This indicates that recharye along outcrops and subcr•ops above the level of the North Fork is insufficient to sustain yround water wells developed in thz Rollins. The only domestic use of tnz 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 fur domestic use (Prince and Nrnow, 1974). Preliminary aquifer tests were performed by Hnacunda Minerals Company on the Barren rnember of the hlesaverdz Formation in September, 1975. Tne preliminary transmissivity obtained for this member was calculated to ue 2.4b y/d/ft. Nlso, Nnaconda Pinerals Company performed a preliminary aquifer test on a fractured aria in the "F" seam which yielded a transmissivity of 1ti.68 g/d/f t. Nnother "F" seam well completed in an unfractured area in the coal wain was dry. These aquifer tests indicate that the "F" wain and the lenticular sandstones of the Barren member ara poor aquifers at best, as yround water flow is mainly concentrated in fractured rock. Uoservations made underground by the staff of the uivision at the Blue Ribbon, Hawk's Nest, Mt. Gunnison and Somerset P1ines also indicate that the coal seams in the region are poor aquifers with very low iransmissivities. The "6-2", "E" and "F" seams were observed to weep sliylitly 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 wzep for short periods of time following mining and eventually dry up. The Hawk's iVest Mine workings in the "E" seam are dry even though these workings are within 6UU feet of the North Fork, are bzlow the level of the North Fork, and are parallel to the North Fork. These in-mine obervations indicate that the "B-2", "E" and "F" coal seams and their roof strata are not significant regional aquifers. Observations of mining within the "C" seam at the Bear No. 1 and No. 2 mines and of rnininy within the "U" seam at the Urchard Valley Mine indicate that the "C" and "D" seams and their asociated 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.