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The recharge potential of the Coalmont formation on the <br />• lease tract is restricted by three parameters. First, <br />precipitation in the region is minimal, generally averaging <br />about 11 inches per year. Secondly, the proposed mine lies <br />on a moderate slope, up to 107. grade, on the side of the <br />anticline. This slope promotes runoff and reduces the <br />resident time of waters from major precipitation events <br />on the area of outcrop. Thirdly, only a small percentage <br />of the exposed outcrop is composed of sandstones with <br />adequate permeabilities to be receptive to significant <br />recharge. These sands are highly lenticular and are not <br />laterally continuous for significant distances. As <br />demonstrated on Plate ZI, many of these sands cannot be <br />readily correlated even over the span of the 90-acre tract. <br />The upper shale - siltstone - mudstone sequence acts as <br />an aquiclude on the lease tract. The sandy siltstone <br />sequence between the shale and the coal reacts as a sequence <br />of thin aquifers (the sandstone lens, separated by <br />thicker aquatards (the siltstones) which restrict vertical <br />water migration. Water in each sandstone will be under <br />an artesian head when encountered at depth. This head will <br />be proportional to the elevation of the recharge area for <br />that particular sand unit, its permeability, and the rate of <br />leakance out of the sand into the containing beds. <br />5 <br /> <br />