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~ i~ <br />XBOW M/NING,LLC '^ <br />SECOND QUARTER 2007 <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 28, <br />2007 visual inspections were performed of the East Yard, West Valley Fill and II West coal mine waste <br />disposal areas. Compaction testing performed on 4/18/07, 4/23/07, 5/11/07 and 5/21/07 met design criteria. <br />EAST YARD -The East Yard disposal area has reached its design capacity, and no new waste material has <br />been placed since June of 2001. The revegetated slope was inspected for signs of erosion or instability and <br />vegetation establishment. No erosional features were noted requiring repairs to revegetated areas. The covering <br />of the waste pile is considered complete. The lower portion of the ramp was seeded in the 4'" quarter, 2006. <br />Nothing was observed during the inspection that would indicate the pile has a potential for structural failure. <br />WEST VALLEY FILL -The West Valley Fill received no additional waste material during the second quarter <br />of 2007. The elevation of the waste pile remains at the approximate 6226' elevation. Spreading and <br />compaction of materials hauled to the waste pile during the 4'" quarter 2006 was completed eazly during the <br />second quarter of 2007. Compaction testing indicated the design criteria was met. <br />The revegetated outslope located between the fill slope tce to the approximate 6200' elevation was inspected <br />for signs of erosion and instability. No erosional features were noted requiring repairs to any vegetated areas. <br />The third bench (approximate 6200 elevation) setback remains established for the fmal lift of waste material <br />and the ramp constructed on the waste pile to provide access to the II West Coal Refuse Facility light use road <br />and haul road. These two roads continue to be utilized. No springs or seeps were noted. Surface drainage <br />control features are performing according to the plan. Additional broadcast seeding, with the approved <br />seedmix, was completed on the advanced outslope up to the approximate 6225' elevation. Nothing was <br />observed during the inspection that would indicate the West Valley Fill has a potential for structural failure. <br />II WEST - The II West disposal area received 1,330 cy of additional coal mine waste material during the 2nd <br />quarter of 2007. The elevation of waste material is approximately 6061' elevation. Compaction testing <br />indicated the design criteria was met. The regraded outslope of the pile was broadcast seeded with the approved <br />mix. No springs or seeps were noted. Surface drainage control features are performing according to the plan. <br />Nothing was observed during the inspection that would indicate the II West Fill has a potential for structural <br />failure. <br />~. I <br />spected by James A. I r er <br />_ 7 <br />°°~ ~©~ <br />Thomas C. Anderson D e ~ <br />Colorado Licensed Professional Engineer No. 14726 <br />3737 Hwy 133 P.O. Box 535 Somerset, Colorado 81434 USA <br />TEL (970) 929-5122 FAX (970) 929-5177 <br />