2015-07-30_INSPECTION - C1981019

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July 28, 2015 C-1981-019/Colowyo Coal Mine RDZ Division requests that a small dozer basin be constructed above the existing portion of the Final East Pit Ditch. Also, the diversion ditches above this area require sediment removal. The buffer zone along Taylor Creek and the road to West Taylor Pond was inspected. Along most of the lower portion of the road, the facilities that were built or improved by Colowyo are more than 100 feet from the creek (although the road existed before Colowyo's activities, it was improved significantly by Colowyo). This includes Sumps 2, 3, 4, and 5 (Sump 5 is on the edge — it is approximately 100 feet from the creek). However, the upper portion of the road crosses the creek and is mostly within the 100 -foot buffer. Although the Division has authorized the location of the road and ditch -outs (low spots in the berm), Colowyo staff needs to briefly discuss these authorized exception to the buffer zone rule in the PAP (Rule 4.05.18). This discussion should also include text regarding the buffer zone along Good Spring Creek (particularly Streeter Pond and Gulch A Pond). Also along the Taylor Creek road, no problems with sediment loading from ditch -outs (aka, berm cuts) were observed. The following ponds were inspected: Section 28, Prospect, Streeter, West Taylor, East Taylor, Work Area, and Gossard. The following were discharging: Prospect (very small, through dewatering valve), Streeter, West Taylor, East Taylor, and Gossard. From these discharging ponds, no sign of pollutants was observed. The leak at Prospect Pond has been almost completely eliminated. There is a very small amount of water getting through the valve, and this can be seen as wetness on the primary spillway discharge structure. This water dries up below the culvert under Highway 13, and it does not reach the flume (the CDPS discharge point). The Division believes that this is only a minor problem now, since the amount of water is extremely small, and effluent limitations have not been exceeded. However, the concern is that the leak could get bigger, and the flow could reach the flume. Colowyo staff will continue to try to eliminate all leaking. Erosion control wattles were in place below the Work Area Pond; maintenance of these BMPs was done by Kurtis Blunt during the inspection. No sediment loading was observed below the wattles. The Division recommends that these wattles be trenched in rather than just placed on top of the ground; this would make them more effective in trapping sediment and possibly reduce dislocation by elk (and the need for maintenance). Other observations regarding the ponds: • Several contain significant amount of aquatic vegetation. • No problems were observed with any of the embankments of the ponds, although bare spots are a minor concern at West Taylor and East Taylor. • Some emerging vegetation was seen on the Prospect embankment. • The flume below the East Taylor Pond needs to be cleared of aquatic vegetation. • Sediment removal is planned for Gossard Pond (as well as the Rail Loop and West Pit forebay) per Colowyo staff. • The dam for the Work Area Pond is not showing any problems related to the rushes (at northwest corner of pond), however many thistle plants were also seen at that location. GENERAL MINE PLAN COMPLIANCE: The mine was in compliance with their plan. Number of Partial Inspection this Fiscal Year: 1 Number of Complete Inspections this Fiscal Year: 0 Page 3 of 8