Laserfiche WebLink
West Pit Fill Inspection Certification <br />On September 13, 2010, i inspected the area in which i:he West Pit Excess Spoil Fill was <br />constructed. The purpose of this inspection was toobserve the surface rock drain that borders the <br />3HAV Excess Fill Slope, inspect the areas dumped to final grade, inspect the revegetation on the <br />fill surface, inspect the fill for areas of water seepage or surface drainage, inspect the final grade <br />slopes, and satisfy the requirements of CDRMS Rule 4.09.1(1)(c) and Rule 4.09.1(11). At the time <br />of inspection, weather conditions were approximately 80°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 81.8 feet from the ground surface, a decrease in water level of 0.8 feet from <br />the previous quarterly inspection. <br />I reviewed the monument survey data collected on August 29, 2018. This data was compared to <br />the survey data collected during the previous quarter on June 14, 2018. After review of the August <br />29, 2018 data, the largest indicated vertical displacement from the first quarter 2018 survey was <br />-0.061' at the 7150 West prism. All other prisms measured less than 0.050 feet of vertical <br />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 vertical elevation survey data of the prisms has plateaued, especially over <br />the last 4 years. It is the authors opinion that the elevation variations between quarterly surveys are <br />caused by minor survey variations, and not an indication of true movement. 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 />PO L,C' <br />47031 <br />AL <br />