Laserfiche WebLink
2.04.7 Hydrology Description <br />The areas of the colluvial- alluvial sediments in Hubbard Creek and Terror <br />Creek lie above the coal seam to be mined. Protection of these sediments is <br />provided by limited extraction zones under the Creeks and assuring the <br />projected extent of subsidence is 100 -feet from the centerline of the Creeks. <br />The colluvial- alluvial sediment in the West Fork of Terror Creek will be mined <br />under. WWE conducted an analysis of potential subsidence impacts on the <br />West Fork of Terror Creek aquatic life and water supply due to potential <br />mining of the LBA tract (WWE, 2013). The analysis concluded there would <br />not be any significant impact on the creek. The report is located in Volume <br />1116, Tab 23. <br />Mesaverde Formation - Perched Groundwater <br />All of the mines in the region report a similar experience as that observed at <br />the Bowie No. 2 Mine. The Mesaverde formation does not contain extensive <br />aquifers. Typically, the formation is dry or the rock units are of such low <br />permeability they yield insufficient water for sustained use. Even the <br />extensive Rollins Sandstone, the recognized aquifer in the region, is highly <br />cemented and a low producer. <br />Groundwater occurrences within the Mesaverde Formation have been <br />interpreted from monitoring holes and logs run during the exploration drilling <br />process (refer to Geology Map 07). From the monitoring holes, water quality <br />samples were obtained and static water levels or potentiometric elevation <br />data were noted. The data shows there is also groundwater in the coal <br />seams. In addition, file research was done on the logs of the exploration drill <br />holes to detect static water levels noted during drilling or logging. From the <br />available information east of Terror Creek, two saturated horizons within the <br />Mesaverde Formation, above the Rollins Sandstone, were interpreted. Both <br />are characterized as locally discontinuous saturated strata occurring as <br />perched horizons. One is stratigraphically between the Rollins Sandstone <br />member and the "C" coal seam, typically 200 ft. below the "D" coal seam <br />(refer to the potentiometric surface presented on Map 11, Lower Perched <br />Water Zone). The other, is located above the "D" coal seam (refer to the <br />potentiometric surface presented on Map 10 Upper Perched Water Zone). <br />The "D" coal seam is located 400 feet above the Rollins Sandstone and is <br />separated from the Rollins Sandstone by sandstones, siltstones, clays, and <br />PR -14 2.04-38- 06/14 <br />