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- ~_j ~. -20- ~ ~ ~ ~ 11',,-~ In the Round Bottom Synclinal Basin, ground water flow directions in rock aquifers have not been determined. The Division postulates, based on the geologic structure, that ground water flows west and north downdip to the axis of the Round Bottom Syncline in the vicinity of the 2 West area of the Eagle No.S Mine. Ground water flows in the Round Bottom Syncline in the vicinity of the proposed Sugarloaf Mine are to the east, toward the axis of the Round Bottom syncline. Faults within the general area may provide a vehicle for ground water communication between overlying and underlying aquifers; between aquifers and underground mine workings or open pits; and between aquifers and the overlying surface stream/alluvial systems. The faulting produces increased fracturing within and between aquifers (secondary porosity). These more porous fault zones with their higher permeabilities can control both vertical and horizontal movement of ground water between and within aquifers. In areas where hydrostatic heads are higher in the underlying aquifers than the overlying surface elevation or the hydrostatic heads in overlying aquifers, the vertical movement of water through the fault system would be either upward and discharge to the surface/alluvial systems, or upward and recharge overlying aquifers. The Tow Creek sandstone is confined by the underlying Mancos Shale and the thick Middle shale of the Iles Formation. Little information is available on the Tow Creek sandstone in. the general area of the Eagle No. 5 and No. 9, the Trapper, and the proposed Sugarloaf Mines. However, these mines will not impact the quantity or quality of waters in this sandstone, since there is sufficient stratigraphic separation between the mining operations and the Tow Creek, and since the Tow Creek is exposed outside of the permit areas of the mines (located in the Big and Round Bottom Synclinal Basins). The Trout Creek sandstone subcrops beneath the stream/alluvial systems of the Williams Fork and Yampa Rivers and outcrops along the valley walls of the rivers, and at the edges of the synclinal basins. The Trout Creek sandstone is confined by the underlying shales of the Iles shale and the overlying interbedded and lenticular shales, sandy shales, coals and sandstones. The Eagle No. 5 Mine is separated from the Trout Creek sandstone by 320 to 360 feet of interburden. Empire Energy Corporation has drilled three water supply wells in the Trout Creek sandstone, two at the No. 5 mine and one at Okie Park. Well yields from this aquifer are highly variable and range from 10 gpm to 100 gpm. The Trout Creek is an important regional sandstone aquifer used primarily for industrial and domestic uses. The Middle sandstone lies 61 to 267 feet above the "F" coal seam. It is recharged along the valley walls of the Williams Fork and Yampa Rivers and along ridges in the general area. Th'e Middle sandstone is recharged by and discharges to the stream/alluvial systems of the rivers. This sandstone aquifer is artesian downdip of its outcrops and subcrops. No water supply wells are completed in this aquifer in the general area. Empire Energy Corporation has installed three monitoring wells in the Middle sandstone; TR-4, TR-7a, and 81-01. These wells are monitored for ground water levels and water quality. The applicant's aquifer tests of this sandstone yielded low transmissivity values (0.7 gpd/ft) and low storativity values (0.00045 and 0.0015, page III-46j.