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XBOW MINING LLC <br />/0 <br />ENGINEERING INSPECTION <br />EAST YARD, WEST VALLEY FILL AND II WEST <br />COAL MINE WASTE DISPOSAL PILES <br />The approved Oxbow Mining, LLC (OMLLC) Mine permit includes a requirement for quarterly inspections of <br />coal mine waste piles for stability. The inspection is to be performed by a registered engineer or other qualified <br />professional specialist, who is experienced in the construction of earth and rockfill embankments. On June 30, <br />2011 visual inspections were performed of the East Yard, West Valley Fill and 11 West coal mine waste disposal <br />areas. Four successful compaction tests were performed during the quarter on June 20, 2011. Copies of the tests <br />are attached herein for the Division's information. <br />EAST YARD - The East Yard disposal area has reached its design capacity, and no new waste material has been <br />placed since June of 2001. The revegetated slope was inspected for signs of erosion or instability. No erosional <br />features were noted on the slope. The covering of the waste pile is considered complete. Nothing was observed <br />during the inspection that would indicate the pile has a potential for structural failure. <br />WEST VALLEY FILL — During the second quarter, no waste was hauled to the West Valley Fill area. The <br />elevation of the waste pile was surveyed at the approximate 6218.2' elevation. The active waste storage area <br />will continue to be an interim storage area for refuse rehandled later to II West and a staging area for projects . <br />The revegetated outslope located between the fill slope toe to the approximate 6200' elevation was inspected for <br />signs of erosion and instability. No erosional features were noted on the slope. The third bench (approximate <br />6200' elevation) setback remains established for the final lift of waste material and the ramp constructed on the <br />waste pile to provide access to the 11 West Coal Refuse Facility light use road and haul road. These two roads <br />continue to be utilized. No springs or seeps were noted. Surface drainage control features are performing <br />according to the plan. Nothing was observed during the inspection that would indicate the West Valley Fill has a <br />potential for structural failure. <br />II WEST — The II West disposal area received approximately 990 CY of additional coal mine waste material <br />during the second quarter of 2011. The elevation of waste material is at the approximate 6117.4' elevation. The <br />material continues to be worked to meet compaction requirements. The rock underdrain crest has been extended <br />to accommodate additional waste. The portion of the outslope area seeded in 2010 appears stable with no rills or <br />gullies. The new seeding establishment is performing well. Older seeded areas are performing according to plan. <br />No springs or seeps were noted. Surface drainage control features are performing according to the plan. A <br />portion of the East Surface Rock Channel remains temporarily covered with fabric and road materials while <br />being used as an access ramp to the pile. Nothing was observed during the inspection that would indicate the II <br />West Fill has a potential for structural failure. <br />k, <br />r Inspected by James a. Kiger <br />Thomas C. Anderson D <br />Colorado Licensed Professional Engineer No. 14726 <br />3737 Hwy 133 • P.O. Box 535 • Somerset, Colorado 81 434 USA <br />TEL (970) 929 -5122 • FAX (970) 929 -51 77 <br />