REP49128 - Laserfiche WebLink

Home Browse Search

~~..,,~~ ,~ .f>' S~~'31 y l l j 1 ' a ~ _ .. ~ ' ~_ ~, _ _ _ FIRST QUARTER 2004 ENGINEERING INSPECTION EAST YARD AND WEST VALLEY FILL COAL MINE WASTE DISPOSAL PII.ES The approved Oxbow Mining, LLC (OMLLC) Mine permit includes a requirement for quarterly inspections of coal mine waste piles for stability. The inspection is to be performed by a registered engineer or other qualified professional specialist, who is experienced in the construction of earth and rockfill embankments. On March 10, 2004, a visual inspection was performed of the East Yard and West Valley Fill coal mine waste disposal areas. The East Yard disposal area has reached its design capacity, and no new waste material has been placed since June of 2001. The East Yazd pile outslope was seeded with the approved OMLLC seed mix in the Fall of 2002. Additional supplemental hydromulch and seed was applied on October 21, 2003. The seeded slope was inspected for signs of erosion or instability after spring snowmelt. No erosional features were noted requiring repairs to seeded areas. Nothing was observed during the inspection that would indicate the pile has a potential for structural failure. Safety berms confinue to be required by the Mine Safety and Idealth Administration on the downhill edge of the access ramp. The West Valley Fill has received some additional waste material during the first quarter of 2004. Compaction tests aze required, as necessary, based upon the amount of material added to the waste area. Compaction tests are planned as material is added to the waste area. During 2003, the outslope located between the second bench (approximate 6150 elevation) and the present approximate 6200 elevation of waste material had been graded and covered with at least four feet of suitable, non-toxic and noncombustible soil substitute materials. This portion of the outslope had received final grading and surface scarification. Hydro-mulching, 18-46-0 fertilizer, and seeding with the approved seedmix was applied on October 21, 2003. The seeded slope was inspected for signs of erosion or instability after spring snowmelt. No erosional features were noted requiring repairs to seeded areas. The third bench (approximate 6200 elevation) setback has been initiated in preparation for the final lift of waste material. The ramp constructed on the west limit of the waste pile to provide access to the II West Coal Refuse Facility light use road and haul road construction continues to be utilized and developed. No springs or seeps were noted. Surface drainage control features aze performing according to the plan. Nothing was observed during the inspection that would indicate the West Valley Fill has a potential for structural failure. Cho ~. /~, - ~ Ins ectedb James ° ,°' P Y °" _@~~s~eA 2G Thomas C. Anderso +fT°T ;~onA s~ ~~~aN° ate Colorado Registered Fr ~if3fi~ er No. 14726 3737 H~,vy 133 P. x 535 Somerset, Colorado 81434 USA TE= (9?0) 924-5122 FAX (970) 929-51 77