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West Pit Fill Inspection Certification <br />On June 27, 2017, 1 inspected the area in which the West Pit Excess Spoil Fill was constructed. <br />The purpose of this inspection was to observe the surface rock drain that borders the 3H:1 V Excess <br />Fill Slope, inspect the areas dumped to final grade, inspect the revegetation on the fill surface, <br />inspect the fill for areas of water seepage or surface drainage, inspect the final grade slopes, and <br />satisfy the requirements of CDRMS Rule 4.09.1(1)(c) and Rule 4.09.1(11). At the time of inspection, <br />weather conditions were approximately 90°F and sunny. <br />Based upon my observations, the regraded fill was observed to be stable and unchanged. The <br />underdrain below the West Pit Fill was seeping at the time of inspection. No other seeps, slumps or <br />signs of significant erosion were noted on the fill surface. <br />The current water level of the monitoring piezometer was obtained. The water level taken at the <br />time of inspection was 82.1 feet from the ground surface, an increase of 0.9 feet from the previous <br />quarterly inspection. <br />I reviewed the monument survey data collected on June 16, 2017. This data was compared to the <br />survey data collected during the previous quarter on March 29, 2017. After review of the June 16, <br />2017 data, the largest indicated vertical displacement from the first quarter 2017 survey was 0.043' <br />at the 7150 West prism. <br />Based on the prism data, the displacement of the monuments are not of concern with regard to the <br />stability of the fill. The degree of measured displacement can be caused by normal settlement, <br />survey variation, and monument disturbance from animal traffic, weather etc. During inspection, I <br />observed no evidence of structural weakness, slumps, seeps or other hazardous conditions <br />associated with this fill. The monument survey data is available for review upon request at the <br />Colowyo Mine site. <br />I am a Registered Professional Engineer in the State of Colorado. Being familiar with the Colowyo <br />operation, and relying on the information provided to me by Colowyo Personnel, the West Pit <br />Excess Spoil Fill is observed to be stable, at the time of inspection, and in compliance with CDRMS <br />Rule 4.09.1(1)(c) and Rule 4.09.1(11) , and Permit C-1981-019. <br />`�wuuuu//1i <br />►NN ^ L <br />0 C- <br />47031 47031 t <br />o� �' <br />