Laserfiche WebLink
Revised 11/85 <br />• prevent recovery of the E and F Seams, although it may increase the cost <br />of mining in those seams and result in slightly lower recovery in some <br />areas. <br />Increases in roof control costs in the E and F Seams can be expected <br />when mining through the transition zone between subsided and unsubsided <br />adjacent areas. A disturbance of the existing stress field can be <br />expected in the transition zone, as well as a minimum amount of <br />translation and slippage of the coal seams through the transition zone. <br />These effects will result in increased ground control costs when driving <br />through the transition zone and will probably lower the overall recovery <br />available in the transition zone. Although costs may be slightly higher <br />when mining in the transition and recovery somewhat lower, the overall <br />effect on recovery of the E and F Seams will be minimal because the <br />transition zone will not be large in lateral extent. There will be no <br />transition zone in the E and F Seams on the north side of the permit <br />area. The subsidence line falls outside or very near the E Seam outcrop <br />• on the north side of the permit area. <br />Subsidence Effect on Existing Man-Made Structures. There are no <br />existing man-made structures in the proposed additional permit area. In <br />addition, a file search conducted by ARCO for the Mt. Gunnison Mine <br />found no known cultural or historical resources listed or eligible for <br />listing on the National Register of Historical Places in the general <br />area. <br />Field inspections indicate no known structures, i.e., fences, utility <br />corridors, roads (other than old drill roads), in the area subject to <br />subsidence from mining by the Bear Coal Company. <br />Subsidence Effect on the Surface and Groundwater Hydrology. There are <br />no known regional or continuous aquifers within or adjacent to the <br />permit boundaries. No water has been reported to be encountered during <br />. exploration drilling, and no water has been encountered in either the <br />old Edwards Mine workings or the current Bear No. 3 Mine workings. <br />-24- <br />