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_ Ir <br />)XBOW i1 ��Ilil N� LL C <br />ENGINF,ERING 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 (or quarterly inspections of <br />coal mine waste piles for stability. 1 he inspection is to be performed bN a registered engineer or other qualified <br />professional specialist, who is experienced in the construction of earth and rockfill embankments. On June 24, <br />2013 visual inspections were performed of the East Yard, West Valley Fill and 11 West coal mine waste disposal <br />areas. Seven (7) compaction tests were performed during the quarter, (copies attached) with all meeting design <br />requirements. <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 />refuse pile was surveyed at the approximate 6227' elevation. The active waste storage area will continue to be <br />an interim storage area for wet refuse rehandled later to 11 West and a staging area for miscellaneous 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 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. A few thistles were sprayed. Nothing was observed during the inspection that would <br />indicate the West Valley Fill has a potential for structural failure. <br />11 WEST — The 11 West disposal area received 7,940 cy of additional coal mine waste during the second quarter <br />of 2013. 11 West waste is at the approximate 6139' elevation. The material continued to be worked to meet <br />compaction requirements. The 2012 regraded outslope seeded on November 15, 2012 shows no significant <br />erosion. Older seeded areas have performed according to the plan. No springs or seeps were noted. The slope <br />was checked for weeds and a few thistles were sprayed. Surface drainage control features are performing <br />according to the plan. The East Surface Rock Channel was extended and the lower access ramp filled with refuse <br />and covered with soil material to achieve final grade. The underdrain was also extended to the north and covered <br />with filter fabric material according to the plan. Nothing was observed during the inspection that would indicate <br />the 11 West Valley Fill has a potential for structural failure. <br />1\ /A <br />iInspected by James Ay iger <br />of 3 <br />Thomas C. Anderson Date <br />Colorado Licensed Professional Engineer No. 14726 <br />3737 Hwy 133 • P O Box 535 m r;et, CuIor�:do 81 434 USA <br />TE1_ (970) 929 -5122 FAX (970) 929 -51 77 <br />