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The Wadge coal seam, in the area of the Foidel Creek Mine, is separated from the underlying Trout Creek sandstone by about 3J0 feet of interbedded sandstones, siltstones, shales and coals. The Wadge coal seam is separated from the overlying Twen[ymile sandstone by 700 feet of massive shale and interbedded sandstones, siltstones, shales and coals. Overburden depths in the current permit area range from 0 to 1,700 feet. The stratigraphy and geologic structure within the Twenrymile Park Synclinal Basin control the ground water Flow within the permit and adjacent areas. There are three reeional bedrock aquifers within the permit and adjacent areas of the Foidel Creek underground mine. These aquifers are the Trout Creek sandstone, the Twenrymile sandstone, and the Wadge coal-overburden zone. All three aquifers exhibit artesian conditions in central portions of Twenrymile Park Basin. The quality in all aquifers is moderately poor but is tolerable for use as a drinking supply. The geologic structure created by folding and faulting within the Twentmile Park Synclinal Basin affects [he direction of flow within the rock aquifers. In the permit and adjacent areas, the direction of ground water flow in the bedrock aquifers is down dip toward the center of the Twenrymile Park Basin. Faults in the area produce localized fracture zones within the rock strata. These zones of increased permeability, in turn, increase the potential for vertical and horizontal movement of ground water within the rock svata. However, experience to date in the Foidel Creek mine shows little to no inflow along the fault zones at the level of the Wadge coal seam. Some inflows were encountered in 9R, and 6R gateroad as they were developed into the Eastern Mining Disvict. These inflows appeazed to be localized, and tapered off over time. The Twenrymile sandstone is separated from the underlying Wadge coal-overburden aquifer by up to 700 feet of impermeable shale within the permit and adjacent areas. The underlying 700-foot shale and the overlying shales and siltstones of the upper Williams Fork Formation and the Lewis Shale Formations produce the confined artesian conditions within the Twenrymile sandstone aquifer. To the northeast, the Twenrymile sandstone recharges the alluvial aquifer and provides base flow to the tributaries of Trout Creek down gradient of the mine. Salts in the Twenrymile sandstone waters aze predominantly sodium bicazbonate and result in TDS levels of 150 mgll. This aquifer is occasionally used for domestic needs. The alluvia of Trout Creek and its tributazies are important sources of ground water. The alluvial bodies are used as water supplies, provide subirrigation to vegetation, and supply base flow to the sveams. The alluvial bodies are recharged by both the sveams and the bedrock aquifers. The mine is located in the upper reaches of the Yampa River Basin. The permit area and adjacent areas are drained by Foidel Creek, an intermittent sveam ,and Fish Creek and Middle Creek, both perennial streams. Fish Creek drains east into Trout Creek whereas Foidel Creek drains northeast to bfiddle Creek before Middle Creek joins Trout Creek. The quality of water in the Fish Creek and Foidel Creek drainages have been affected previously by surface mining upsveam and downsveam of the underground mine's existing surface facilities. Alluvial valley Floors are identified downstream of the mining area at the confluence of Foidel and Middle Creek, and on Trout Creek from its confluence with Middle Creek downsveam to the Yampa River. Permit Revision No. 3 declassified portions of Foidel and btiddle creeks previously classified as AVF's. Detailed discussion concerning alluvial valley Floors can be found in Section 8, part XVIII of this document as well as Exhibit 7j of the permit. The climate within the permit and adjacent areas is semi-arid with a mean annual precipitation of 14.6 inches. Approximately 45 percent of this precipitation occurs during the growing season of April though September. High temperatures generally range from 70-80°F in the summer months to below freezing in the winter months. Normally, a significant snowpack resides on the ground for 4-5 months during the winter. Two broadly classified soil complexes exist within the permit area. These are Typic Paleoborolls - Borollic Camborthids and Argic Cryoborolls- Cryic Paleoborolls. However, prior to mining, the Typic Paleoborolls - C:\J H B\G82056\RN03V2N03FIND.doc