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<br />review included the Bowie #1 mine (then the Orchard Valley mine). As a result of the <br />review, DMG required the permittee to reconstruct diversions and ditches associated <br />with the refuse piles to increase their capacities from those required to safely pass <br />runoff from 10-year, 24-hour precipitation events to capacities required for 100-year, <br />24-hour events. <br />Findings <br />I. Records Review <br />I reviewed design information in the mine plan and as provided by DMG. The Team <br />previously decided the review would assume approved designs comply with DMG's <br />rules. Only those permit provisions approved by DMG by the date of my review were <br />included in my review. I reviewed permit information at DMG's Denver office on July <br />29, 1997, and at WRCC's Denver office. We also reviewed information at the mine <br />office on August 19, 1997. Design criteria are summarized below for the respective <br />refuse piles. <br />I reviewed engineer's inspection reports that were submitted to DMG over the period of <br />August 1983 through the first quarter of 1997 for the two piles. I reviewed a total of 40 <br />engineer's quarterly inspection reports. Evaluating reporting timeliness was limited to a <br />small number of reports because almost all the file copies either had report dates and <br />not submittal dates or vice versa, and not both. Thirteen reports had submittal dates; <br />the only one that also had an inspection date showed that it was submitted a month <br />late. The remaining 12 reports were submitted within about two weeks of the report <br />dates, though 4.09.1(11)(b) requires their submittal within two weeks of the inspection <br />dates. Apparently, quarterly reporting for the OWDA stopp~c~after the Ju_~y 6 _1986 <br />j <br />Engineer's reports included descriptions of the piles' conditions and addressed critical <br />construction activities that occurred during the respective quarters. They included a <br />list of items relating to the plies' physical condition. Those items described: quantity of <br />coal waste material added during the quarter; material deposited and compacted in 24- <br />inch layers; drainage alterations constructed; height of waste material; construction of <br />new benches; outslope steepness; grading of the top of the piles; bench grading; <br />coverage with non-toxic, non-combustible material; berm construction on outslopes; <br />evidence of structural defects; topsoil salvaging and storage; trash removal; and any <br />additional comments. Comments typically noted if the drainage systems were working, <br />described efforts to increase compaction, etc. Notably, most reports submitted <br />between the period of August 1983 and July 31, 1990, included an engineer's <br />certification that the pile(s) had been constructed as required in the permit. DMG <br />further directed the permittee to certify that the pile(s) had been constructed as <br />designed in March 1986. In September 1995, DMG directed the permittee to include a <br />4 <br />