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' W MINING, LL C <br />ENGINEERING INSPECTION <br />EAST YARD, WEST VALLEY FILL AND ff WEST <br />COAL MINE WASTE DISPOSAL PILES <br /> <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 December <br />21, 2010 visual inspections were performed of the East Yard, West Valley Fill and II West coal mine waste <br />disposal areas. Four successful compaction tests were performed during the quarter on October 4, 2010. Copies <br />of the tests 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 fourth quarter, no waste was hauled to the West Valley Fill area. The <br />elevation of the waste pile was surveyed at the approximate 6226.8' elevation. The active waste storage area <br />will continue to be an interim storage area for refuse rehandled to II West at a later time. <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 II 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 570 CY of additional coal mine waste material <br />during the fourth quarter of 2010. The elevation of waste material is at the approximate 6112.4' elevation. The <br />material continues to be worked to meet compaction requirements. The approximate 13' lift of material received <br />during 2010 has continuously been covered with soil materials and was broadcast seeded with the approved <br />mixture on October 29, 2010. The 2009 outslope area seeded on November 19, 2009 appears stable with good <br />initial seedling response, and no rills or gullies. No springs or seeps were noted. Surface drainage control <br />features are performing according to the plan. A portion of the East Surface Rock Channel is temporarily <br />covered with fabric: and road materials while being used as an access ramp to the pile. Nothing was observed <br />during the inspection that would indicate the II West Fill has a potential for structural failure. <br />a4l? kc <br />Inspected by James . Kiger <br />Thomas C. Anderson <br />Date <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