Laserfiche WebLink
EVALUATION OF POTENTIAL SUBSIDENCE IMPACTS OF <br />LONGWALL MINING IN THE SPRUCE STOMP LEASE AREA TO <br />AQUATIC LIFE AND WATER SUPPLY <br />1.0 REPORT PURPOSE <br />Wright Water Engineers, Inc. (WWE), with the assistance of C. Richard Dunrud, P.E., prepared <br />this report to present results of an investigation of the potential impacts to aquatic life in West <br />Fork Terror Creek resulting from vertical displacement (subsidence) associated with mining the <br />Spruce Stomp Lease Area (see Figure 1). The results of this investigation are intended to <br />facilitate U.S. National Forest Service (NFS) and U.S. Bureau of Land Management (BLM) <br />decisions regarding the lease and the environmental permitting feasibility of the Potential <br />Project. It should be noted that Bowie Resources, LLC (Bowie) currently operates the Bowie <br />No. 2 Coal Mine which abuts the Spruce Stomp Lease Area on the south. Bowie has proposed <br />specific lower B -seam longwall coal mining activities within the Spruce Stomp Lease Area <br />(Potential Project). This report reviews potential subsidence impacts on West Fork Terror Creek <br />aquatic life and water supply due to potential mining of the Spruce Stomp Lease Area. If the <br />Spruce Stomp Lease Area is mined in another manner, the results of this report may not be <br />applicable. <br />2.0 SUMMARY OF FINDINGS <br />The Potential Project is expected to result in a maximum subsidence of about 5.7 feet at the <br />center, near the eastern edge, of the longwall panel with the smallest overburden thickness. This <br />location is approximately 300 feet south of the West Fork Terror Creek channel. Based on <br />existing topography and geologic modeling, a maximum estimated 5.1 feet of subsidence along <br />the West Fork Terror Creek channel is expected to create no more than a 1.5 percent channel <br />slope change. In light of the fact that the Potential Project area generally consists of steep terrain <br />(often in excess of 25 percent slopes), the expected change in slopes is expected to be mostly, if <br />not completely, imperceptible without the aid of survey equipment. Other subsidence related <br />impacts, such as surface cracking or water loss are not expected to the degree that they would <br />121 - 014.000 Wright Water Engineers, Inc. Page 1 <br />January 2013 <br />