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West Pit Fill Inspection Certification <br />On March 27th, 2018, 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 3HAV 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 45°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 80.2 feet from the ground surface, a decrease in water level of 1.2 feet from <br />the previous quarterly inspection. <br />I reviewed the monument survey data collected on March 21 It, 2018. This data was compared to <br />the survey data collected during the previous quarter on December 13th, 2017. After review of the <br />March 21st, 2018 data, the largest indicated vertical displacement from the fourth quarter 2017 <br />survey was 0.038' at the 7250 West prism. All other prisms measured less than 0.030 feet of <br />vertical displacement. <br />Based on the prism data, the displacement of the monuments are not a 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 />,,`,����111i11 itll►1��,' <br />L <br />» 47031 <br />y + ; 3-a71a <br />(� .•�~ <br />