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III. COMMENTS -COMPLIANCE <br />Below are comments on the inspection. The comments include discussion of observations made <br />during the inspection. Comments also describe any enforcement actions taken during the inspection <br />and the facts or evidence supporting the enforcement action. <br />Roads (cont'dl <br />The upper 18" CMP road culvert just below mine bench; outlet fabric sleeve blown out and will need to <br />be replaced. <br />The 3r° 18" CMP road culvert down from the mine bench; outlet fabric sleeve blown out at the <br />attachment to the lower end of the fiberglass tube, and will need to be replaced. <br />Between the 3'" and 4`" road culvert sumps down from the mine bench, the road surface was rilled and <br />rutted, with sediment deposited in some locations. Grading will be necessary along the length of this <br />segment, and particularly just up-gradient from the culvert inlet sump at the lower end, to insure that <br />road drainage will be properly diverted toward the inside ditch, rather than down the road. Installation of <br />a series of water bars to direct road drainage to the inside ditch may be warranted along the steep <br />canyon sideslope segment of the access road. <br />Road drainage ditches and culverts recently installed in association with the recent waste disposal area <br />development and road realignment appeared to have functioned well, with only minor road ditch <br />maintenance required to restore design capacity. <br />The 36" CMP road culvert located adjacent to the waste disposal area sediment pond had been over- <br />topped. Maintenance is warranted to clean out minor debris accumulation at the culvert inlet, and also <br />to eliminate gully channel where flow had escaped the main drainage channel and flowed to the west. <br />The large 72" CMP culvert at the road crossing of Munger Creek had been overtopped, and debris was <br />deposited along a segment of the road in this vicinity. Grading will be necessary to remove the debris <br />and repair minor erosion in the area where flow ran across the road. <br />Hydrologic Balance <br />Peak flows in Munger Creek and tributary drainages resulting from the September 9 storm event appear <br />to have been as high or higher than those resulting from the July 25 storm event. Runoff in the <br />immediate vicinity of mine facility areas appears to have exceeded the peak runoff from the July storm. <br />The operator had completed dewatering and sediment removal from the waste disposal area sediment <br />pond (necessitated by the July 25 storm) shortly prior to the September 9 storm. The drainage channel <br />adjacent to the pond embankment had been cleaned out and the berm on the embankment built up, the <br />road culvert had been opened up, and the sediment pond primary spillway had been cleaned out. <br />Sediment had been placed as authorized within two of three storage cells that had been approved on the <br />top of the cover material stockpile. A complete technical revision addressing long term drainage <br />modifications, including a modified spillway system designed to prevent pond inundation through the <br />emergency spillway had been submitted in a timely manner. Unfortunately, the large storm event of <br />September 9 occurred before the Division had been able to review and approve the technical revision <br />application. <br />As a result of the September 9 storm event, the ephemeral stream channel adjacent to the sediment pond <br />again flowed out of its banks, overtopped the road at the 36" CMP culvert, and flowed into the sediment <br />pond through the open channel spillway. The pond filled with water and an unknown quantity of <br />sediment. The 36" CMP did not become clogged as a result of the most recent flood flow, however, and <br />the lower segment of the channel adjacent to the pond embankment did not fill in with sediment. <br />4 <br />