Laserfiche WebLink
EXHIBIT 55B <br />STREAM CHANNEL PARAMETERS AND CHANGES <br />DUE TO MINING-INDUCED SUBSIDENCE <br />INTRODUCTION TO STUDY <br />Wright Water Engineers, Inc. (WWE) and Ernest Pemberton, P.E. 1, determined the extent to <br />which projected subsidence would impact stream channel stability and sediment transport at <br />Mountain Coal Company, LLC's (MCC) West Elk Mine. Exhibit 55 was originally prepared for <br />the B-seam longwall panels in the Apache Rocks and Box Canyon mining areas in May 1995, <br />with revisions in November 1997 and November 1999. Exhibit 55A was prepared to address the <br />E-seam longwall panels in the South of Divide (SOD) mining area in April 2004, with a revision <br />in November 2004. Subsequent to Exhibit 55A, MCC obtained the coal lease to the adjacent Dry <br />Fork mining area. Tetra Tech prepared Exhibit 55B in September 2007 using Exhibit 55A as a <br />base and incorporating the Dry Fork mining area. <br />Planned and maximum projected mining in the Dry Fork mining area will occur in panels E2, E3, <br />E4, E5, and E6 under the upper areas of Dry Fork, a tributary to Minnesota Creek, and the upper <br />areas of Deep Creek. Panels El, E7, E8, and E9 are totally within the boundaries of the South of <br />Divide mining area. The effects on the lower reaches of the affected streams are not changed by <br />mining in the Dry Fork mining area. <br />WWE has updated Exhibit 55B to reflect the approximate maximum projected areal extent of <br />potential longwall mining (also referred to as the Projected Potential Mining Area shown on <br />MCC's permit Map 51) within the Dry Fork mining area. MCC's projected E-seam mining <br />(depicted with solid lines in Figure 1) has not changed from PR-12 and continues to reflect the <br />best available information (including exploration and actual E-seam mining data) regarding the <br />mineable E-seam coal. However, during ongoing panel development, additional mineable coal has <br />Adjunct Scientist with WWE, Former Head of Sedimentation and River Hydraulics Section, Hydrology <br />Department, Chief Engineer and Assistant Commissioner's Office, U.S. Bureau of Reclamation. <br />831-032.810 Wright Water Engineers, Inc.