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<br />Page 2 <br />Preliminary Adequacy -Apex No. 2 <br />April 20, 1981 <br /> <br />2.04.6 The Mesa Verde group is known to produce a great deal of <br />western Colorado groundwater supplies; a more detailed <br />description of the Mesa Verde group stratigraphy, lith- <br />ology, and the relative position of the Lower Pinnacle <br />coal seam and the Tow Creek sandstone are required. The <br />geologic description should be extended to the first aquifer <br />below the coal seam being mined and should include a repre- <br />sentative stratigraphic column. <br />A chemical analysis of the coal seam (to include iron sulfide), <br />and an analysis of the roof and floor materials (as per <br />attached "Baseline Overburden Chemical-Mineral Analysis" <br />guideline) are required. <br />The regional geologic map must provide more stratigraphic <br />and structural information about the mines relation to the <br />Isles Formation and the Mancos Shale: coal outcrops and <br />landslides must also be shown. <br />2.04.7 Unless the applicant defines and justifies another definition, <br />the adjacent area for surface and groundwater investigations <br />should be taken as Sections 9, 10, 15, 16, 20, 21, 22 of <br />T4N, R86W. <br />2.04.7(1) The description of the groundwater hydrologic system is in- <br />adequate: the depth below surface, areal extent, and outcrops <br />of the Tow Creek sandstone and alluvial aquifers must be pro- <br />vided; the lithology, thickness, storitivity and recharge/ <br />discharge of the aquifers in the permit and adjacent area <br />must be discussed; the quality of alluvial and bedrock <br />aquifers must be discussed. For monitoring purposes, water <br />level or flow, total dissolved solids, sulfide, and iron <br />should be added to the list of water quality parameters to <br />be reported. <br />The application indicates that no flowing artesian wells <br />were drilled; page 64 appears to contradict; where is this <br />well?...please clarify. Was groundwater encountered in other <br />test borings? Wells? <br />The application indicates that mine working below the 7300 <br />foot contour produce small amounts of water; this should be <br />discussed in association with plans to develop workings to <br />as low at the 7150 foot contour. <br />Description and analysis of samples representative of the fill <br />materials in the "operations bench" constructed in the Trout <br />Creek valley bottom ust be provided. The hydrologic conse- <br />quences of this construction must be discussed. (see comment <br />