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-19- indicates that the Sudduth coal is a poor aquifer, except in areas of faulting where there is an increased secondary permeability. The Sudduth coal seam is the only rock strata within the lower Coalmont Formation with a large enough areal extent to be considered a regional aquifer. Flow within this aquifer is controlled by the dip of the coal bed. Regional flow within the coal is downoip to the axis of the Bourg Syncline and the Johnny Moore Syncline, and then down the plunge of the synclinal axes. The coal seam is overlain and underlain by confining siltstone and shale strata ~~~hich act as aquitards and aquicludes. The confining layers restrict the coal recharge zone to a narrow outcrop and subcrop band and also produces the artesian conditions observed in monitoring wells. No permitted water wells are completed within the Sudduth coal seam. The lower Coalmont Formation whim overlies the Sudduth coal consists of interbedded and lenticular calcareous sandstones and siltstones. Ground water within this stratwn is localized in the lenticular sandstones. The siltstones which intertongue with the lenticular sandstones act as aquitards which restrict the vertical and horizontal movement of ground water to and from these sandstones. Wyoming Fuel has conducted both laboratory permeability tests on core samples and slug aquifer tests on monitoring holes completed in the lower Coal Formation. The laboratory tests indicate that both the sandstones and siltstones have very low permeabilities, 0.05 and U. 02 millidarcies, respectively. Slug tests conducted by Wyoming Fuel at well sites 16 and 5C yielded higher permeabilities, 1.U9 millidarcies, or 0.02 gpd /f t2 for 16 and O.UI gpd/ft2 for 5C. The higner permeabilities measured in the aquifer tests were attributed to the higher secondary (fracture) porosities within the bore hole. Higher permeabilities were measured for this strata in pumping tests conducted by Kerr Coal Company and the U.S.G.S. (0.37 to 7.5 gpd/ft , respectively). Kerr also noted that fractures greatly increase the aquifer's permeability and that the sandstones, in the absence of fractures, have low permeabilities. The only permitted water well in the area is completed in a 26 foot lenticular sandstone of the Coalmont Formation. This water well is located in section 35, T9N, R78W and is owned by the Kerr Coal Company. This sandstone tapped by the Kerr well is stratiyraphically higher than the strata which will be disturbed during mining at the Kerr, Wyoming Fuel, and Bourg mines. The Upland Terrace deposits which unconformably overly the Pierre shale and the Coalmont Formation have sufficient permeability to store and transmit water. Ground water in this aquifer is under unconfined water table conditions. Recharge to this aquifer is primarily through infiltration during snowmelt and during sporadic precipitation events. Ground water within these deposits flows down along the contact between the permeable terrace deposits and the bedrock. Springs and seeps develop where this contact has been exposed by headward eroding streams. Une such spring has been identified in an area adjacent to the Wyominy Fuel mine on a small tributary of the North Fork of Bolton Draw. This spring feeds a small pond used for stock and wildlife watering. No wells are located within the Upland Terrace Deposits.