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The Sudduth seam is generally poorly fractured and contains <br />• only very minor amounts of water. Water, and the <br />piezometric head, observed in the coal in well lA are <br />believed to be derived directly from the overlying sand- <br />stone, The shale sequence underlying the coal is again <br />an aquitard which confines waters in the sandy strata <br />of the underlying Pierre Formation. <br />Available core and observations of the highwall of the <br />existing mine show the coal, overburden and underlying <br />sediments to be relatively poorly fractured. Fractures <br />that have developed in the sediment are often healed with <br />calcareous binders. However, at the point at which the <br />fault was encountered in the old pit, fracturing was <br />• sufficient to channel ground water flow. Nearly all of <br />the ground water entering the existing pit enters through <br />fractures associated with this fault. During the spring, <br />flows up to 20 gpm have been estimated to be entering the <br />mine through this fracture system. If faulting is similarly <br />encountered on the new lease tract, it is expected that <br />such fractures could also dominate ground water movement <br />in this area. <br />Piezometric Surfaces <br />Four wells were installed by Wyoming Fuel Co. for water <br />sampling and utilization as piezometers. Well 1 is 600 ft. <br />in depth and is perforated in the coal underburden of the <br />Pierre formation. Well 1-A is 360 ft. deep and is perforated <br />6 <br />