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§2,04 APPLICATION FOR PERPtIT FOR SURFACE OR UNDERGROUND MINING ACTIVITIES -- <br />MINIMUM REQUIREMENTS FOR INFORMATION ON ENVIRONMENTAL RESOURCES. <br />2,04.7 Hydrology Description. <br />(1) (a) (i)(ii)(iii) and (iv) <br />Method of Study: In order to es[ablish base- <br />line data, six exploration drill holes were <br />converted into moni[oring wells during 1982. <br />During drilling, each hole was cased with fl- <br />inch steel, flushjoint pipe from the surface <br />to within approximately 50 feet from the top <br />of the "D" coal seam. Due to down-hole condi- <br />tions, this pipe cannot be retrieved from the <br />hole, In order to protect the open portion of <br />the drill holes, 2-inch diameter P.V.C. pipe <br />was installed from approximately 20 feet above <br />the base of the steel casing to total depth. <br />Alternate 20 ft. sections were perforated <br />with 0.25-inch hand-drilled holes and instal- <br />lation was accomplished by fabricating the <br />wireline "lifting ears" onto the P.V.C. pipe. <br />By using the overshot apparatus, the P.V.C. <br />pipe was lowered into the drill holes and <br />wireline assembly retrieved. The "lifting <br />ears" remain in the hole, centering the pipe <br />within the steel casing, and act as guides for <br />water level detection instruments lowered into <br />the holes. <br />As a result of expansive mudstone layers in <br />the overburden, near surface, colluvial <br />groundwater is effectively sealed off from the <br />deeper saturated bedrock horizons. During <br />geophysical logging, and prior to cementation, <br />CWI determined sta[ic water levels in drill- <br />hole numbers 50 through 72. In conjunction <br />with USGS-[dRD personnel, water quality samples <br />were bailed from selected holes employing mod- <br />ified wireline procedures (refer to the <br />Groundwater Appendix, Volume 4). <br />Subsequently, during 1983, CWI contracted a <br />consulting firm to install pressurized gas <br />driven water samplers and depth indicators, <br />during which time DH-68 was found to be silted <br />in to the extent that it was dropped from the <br />monitoring well network. Depth and downhole <br />conditions rendered all but two of the <br />Revised 10/01(87 <br />27 <br />