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Bob Liddle -3- December 2, 1981 <br />A. Geology (2.04.6) <br />1) Geologic cross-section B-B' <br />by the coal to be mined to the north in <br />be redrafted and resubmitted. <br />does not transect the area underlain <br />the N3 mine. This cross-section should <br />2) The geologic maps for the mine and loadout areas are illegible. <br />These maps should be redrafted and should include the following additional <br />information: geologic cross-section locations, faults, landslides bodies, <br />names of all geologic structures (i.e., synclines, anticlines, major faults), <br />and strikes and dips of beds. <br />3) A more detailed description of the unnamed syncline to the west of <br />the mining operation should be made. This description should include strike <br />and dips on both flanks of the syncline and the direction of synclinal plunge. <br />4) Appendix 3-H gives the physical characteristics of only the Anderson <br />seam in the fl3 mine. A similar analysis should be conducted for the A-seam <br />and submdtted to the Division. <br />5) Appendix 4-H gives sulfur form analyses, but lacks analyses of <br />soluble salts and toxic heavy metals. Snowmass should have new analyses per- <br />formed on the coal according to the list of parameters on Attachment A, These <br />analyses are needed to assess the impacts of exposed coal in the mine cavity <br />and within the refuse pile on the quality of surface and ground waters. <br />B. Hydrology - Cround [9a ter (2.04.7, 2.05.6(3) and 4.05) <br />1) The statements made within the ground water hydrology sections <br />should be reevaluated to reflect regional Flow within a synclinal structure <br />instead of regional flow towards the center of the Piceance Basin. An evaluation <br />should be made of the recharge and discharge areas on the western flank of <br />the syncline; of the potential for depleting or recharging strata within the <br />western limb in response to the mining and the post-mining hydrology within <br />the eastern limb (e.g., the U-tube effect); and the regional movement of ground <br />water along the synclinal axis. <br />2) Snowmass Coal Company should recalculate the projected stream <br />depletion for both North and Middle Thompson Creeks due to mining with the <br />b1 and H3 mines. This recalculation should take into account both depletions <br />through the coal and depletions through the overlying and underlying sandstone <br />aquifers. <br />3) The projected life of mine area (a I1 adjacent leases now held by <br />Snowmass) should be plotted on the geologic and hydrologic maps to aid the <br />Division in its assessment of cumulative hydrologic impacts of all anticipated <br />mining within the area. <br />4) The piezometric map for the Upper Sandstone should be redrafted <br />on a topographic map with the outcrop and sub crop (recharge area) of this <br />sandstone plotted on the map. <br />