2013-01-14_REPORT - C1996083 - Laserfiche WebLink

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BOWIE RESOURCES, LLC Bowie No. 2 Mine Coal Mine Waste Bank Nos. 1, 2 & 4 Inspections — 4 Quarter 2012 On December 27, 2012, I performed a visual inspection of the Bowie No. 2 Mine coal mine waste banks in accordance with Rule 4.10.2. This inspection includes Gob Pile Nos. 1, 2 and 4. I, J. E. Stover, P.E., have a wide variety of experience in the design and construction of earth fill embankments. Nothing was observed during the inspections that would indicate the piles have a potential for failure. The gob disposal areas were snow covered except in active areas. All organic material and topsoil has been removed ahead of the waste bank foundings. The upper diversion ditches were not inspected due to heavy snow cover. The new upper diversion ditch was constructed during the quarter. A significant amount of the gob pile no. 2 was covered with three feet of cover and one foot of topsoil during the 4 quarter 2006. Most of the first and second benches were covered. Cover material from gob pile no. 4 is stockpiled on the west side of pile no. 2. Cover material has been removed from the east end of bench number two (pile no. 2). The slope inclination of the coal mine waste has been increased in this area (5h:1 v to 3h:1 v. TR -61). Soil has be replaced on the east side of the second bench. Most of the coal mine waste was generated from the preparation plant. Approximately 146,200 tons of gob were hauled to the gob piles. Coal mine waste is to be placed in the pile in approximately horizontal lifts no more than 24- inches thick. The coal mine waste is spread and compactive effort is provided by self propelled sheepsfoot compactors. Thirteen (13) compaction tests were performed during the quarter. Three (3) of the tests failed. The three (3) test failures were all in the same area (755, 755A & 755B). One test (738) failed during the previous quarter and was not retested. A test passes if the test attains at least 90% of the maximum dry density attained in a laboratory compaction test in accordance with ASTM D698. Due to inclement weather the Operator is placing gob in temporary piles to be re- handled as weather improves. A failure of the gob pile no. 1 would probably not be a hazard to human life. The pile is located above a large flat bench. The bench is approximately 80 to 150 -feet wide directly below the pile. Additionally, the gob pile sediment pond is located below the pile. If the coal mine waste bank failed, the material would very likely be contained on the bench below the pile and or within the gob pile sediment pond. A failure of the gob piles no. 2 and 4 would probably not be a hazard to human life. A residential dwelling is located over 300 -feet below pile no. 2. The piles are located above Bowie Road. A failure of the piles might damage Bowie Road but would not likely impact e-:resi ptial dwelling. R` f5' I certify that to the best of my knowledge and belief, that the r dbther aVVetiaof the coal mine waste banks have been constructed as permitted in the de f l g 1 *pro ed by A` EAMS. v ,' s S � E►Z ef 1 1`' a • e / /,i /z0i �o Jame', Cover. r `Se's' Date Colorad3 Wi engineer Registration X15."1