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Creek. As such, they should be installed at an appropriate distance from the creek and <br />readily visible. The operator representative committed to addressing this issue <br />posthaste. <br />Topsoil Markers (Rule 4.02.7) <br />The topsoil stockpile was marked as required. No issues were observed. <br />Diversions (Rule 4.05.4) <br />The undisturbed area diversions at the mine portals area were evaluated. The trash <br />racks of two of the 900 culverts were partially obstructed by sediment and require <br />maintenance in order to function as designed (Figure 3).The operator representative <br />committed to performing this work. <br />Sediment Control Measures (Rule 4.05.5) <br />DRMS has granted small area exemption (SAE) status to the mine office area (SAE -1). <br />Disturbed area drainage reports to an incised sump with a silt fence backstop which is <br />within the Stream Buffer Zone. The sump was impounding water at the time of this <br />evaluation due to recent precipitation. No discharge was noted. The sump measured 28 <br />feet in length by 13 feet in width with a depth of four feet to the top of the incised <br />embankment at the center and three feet to the top of the embankment at the inlet end. <br />The sump and silt fence were functioning as intended, though evidence was present, in <br />the form of minor sedimentation and a limited number of small pieces of coal, that their <br />sedimentation -control capabilities had been exceeded in the past. The OSMRE <br />inspector recalled a high-volume storm event occurring in the area in the fall of 2014. A <br />historical review of DRMS inspection reports for the McClane Canyon Mine confirmed <br />this: <br />On September 9, 2014, a large precipitation event occurred in the <br />area encompassing the McClane Canyon Mine. The amount of <br />precipitation was measured on site with a rain gauge and measured <br />approximately 2 inches of rain in a 24 hour time period. Additional crews <br />were hired and on site to help with the clean up of the mine site at the time <br />of the inspections. (DRMS Complete Inspection Report, September, 2014). <br />The McClane Canyon Mine's 2014 Annual Hydrology Report (AHR) notes that one of <br />those inches of rain fell within a single hour, overcoming the mine's approved <br />sedimentation control system design/build. This event filled the sediment pond with mud <br />and water and overtopped the emergency spillway as well as the sediment pond's north <br />and west embankments. Water also flowed offsite into the ephemeral channels (AHR at <br />5). The operator representative stated he would remove the small pieces of coal and <br />sediment from within the Stream Buffer Zone to the extent additional disturbances are <br />not created. <br />2 1 P a g e <br />