2013-10-07_REPORT - C1981019 (2)

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West Pit Fill Inspection Certification On September 17, 2013, 1 inspected the area in which the West Pit Excess Spoil Fill is being constructed. The purpose of this inspection was to observe the surface rock drain that borders the 3H:1 V Excess Fill Slope, inspect the areas dumped to final grade below the 7,400 dump elevation, inspect the revegetation on the fill surface, inspect the fill for areas of water seepage or surface drainage, inspect the final grade slopes below the 7,300 elevation of the Excess Fill Slope, and satisfy the requirements of CDRMS Rule 4.09. 10 (1a) and Rule 4.09.1 (1 b). Based upon my observations from two prior inspections I completed with Tom Peterson, the visible portion of the regraded fill was observed to be stable and unchanged. The underdrain below the West Pit Fill was not flowing at the time of inspection. No seeps in the fill or signs of erosion were noted. Active reclamation was ongoing at the time of inspection to achieve the post- mining topography. The crown of the west pit fill is now at the approximate 7406 elevation. The current water level of the monitoring piezometer was obtained. The water level taken at the time of inspection was 84.6' from the lip of the piezometer pipe, a decrease of 0.4' from the June 25, 2013 inspection. I reviewed the monument survey data collected September 20, 2013. This data was compared to the survey data collected during the prior quarter on June 19, 2013. These data indicate that the elevations of most of the monuments have not significantly changed (typically less than 0.05 feet of elevation change per calendar quarter). The most change was recorded at the 7250 West monument. This site registered a decrease of 0.202 feet when compared to the June 19, 2013 data; however it matched the October 3 2012 data within 0.001 feet. Due to the changing of survey personnel and used equipment, it is my opinion that the survey of the 7250 West monument taken on June 19, 2013 was in error. The next quarterly survey will confirm or reject this conclusion. Based on the September 20, 2013 data, the total displacement of the monument is not of concern with regard to the stability of the dump. There was also no evidence of structural weakness, slumps, seeps or other hazardous conditions associated with this dump. The monument survey data is available for review upon request at the Colowyo Mine site. I am a Registered Professional Engineer in the State of Colorado. Being familiar with the Colowyo operation, and relying on the information provided to me by Colowyo Personnel, the construction activities related to the West Pit Excess Spoil Fill are in conformance, to the best of my knowledge and experience, as specified in pages I a -2 through I a -4, Exhibit 19 1 b and other applicable requirements of the approved permit documents, a portion of CDRMS Permit C -81 -019. 111111111 41/41, /i0 47031 S