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unconfined conditions are encountered near the outcrops. The saturated aquifer thickness of these units ranges between four and 200 feet. The Wadge Coal aquifers appears to be largely confined, whereas the Wadge iJnderburden aquifer occurs under both confined and unconfined conditions. The Wolf Creel: Coal occurs under confined conditions, however the Wolf Creek Underburden is both~unsaturated and unco~ned. Movement of groundwater in bedrock aquifers is controlled by structural foldinf; and faulting and stratigraphy. Confined conditions occur at synclinal axes, and unconfined conditions occur near the outcrops. No significant faulting is known to occw• within the proposed permit area. Two recharge boundaries are known to exist in the permit area. ?,n erosional face along the northerly-plunging axis of the Fish Creek anticline provides a locali::ed recharge boundary for the Wadge Coal and Wadge Overburden. Additionally., the Wolf Creek Coal outcrop, parallel to the axis of the Fish Creek Anticline, is a recharge boundary for the Wolf Creek Coal. In general, the Williams Fork Formation, which includes the Twentynule Sand:~tone and the Middle Coal Group has yields of up to 100 gpm but the average yield is approximately 10 gpm. The underlying Trout Creek Sandstone has a yield of approximately 5 gp:m and occurs under confined conditions with an artesian head of 30 feet above the ground surface. Alluvial aquifers in the proposed permit area include the Sage Crc;ek alluvium, Armand Draw alluvium and Grassy Creek alluvium. The Sage Creek Alluvium has; a saturated thickness of between 7.5 and 56 feet. Armand Draw alluvium and Grassy Creek alluvium have saturated thicknesses of 12 and 11-28 feet, respectively. Groundwater occurs under unconfined conditions in the alluvial aquifers Movement of groundwater in the alluvial aquifers is controlled by thc; characte:risties of the stream drainages within which they occur, including the stream gradient as well as the width, thickness and hydraulic conductivity of the alluvial deposits. Recharge to alluvial aquifers occurs as infiltration from snowmelt and precipitation and as seepage losses from streams. Baseline groundwater quality studies for the Yoast mine included the alluvial aquifers, the Middle Coal Group, and the Trout Creek Sandstone. The following table summarizes baseline data for pH, SO4, and total dissolved solids (TDS) for the units mentioned above. Yoazt Min< 10 July 6, 1995