2008-04-11_REPORT - C1981019 - Laserfiche WebLink

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West Pit Fill Inspection Certification On March 24, 2008, I 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:1V 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 CDMG Rule 4.09.10 (1 a) and Rule 4.09.1 (1 b). During the inspection, it was observed that the condition of the fill was good. About 40 percent of the slope was still snow-covered and obscured from view. No seeps or springs were noted. The collection ditches at the 6,950, 7,050, and 7,150 elevations all were in relatively good shape. The ditch at the 7,250 elevation needs to be completed to the west end of the fill. All three of the completed terrace ditches showed some evidence of flow following recent snowmelts. No erosion problems with the ditches were noted. Only a very minimal flow of less than 5 gpm is evident from the toe of the underdrain. No erosion problems were noted. In addition, I reviewed the monument survey data collected March 17, 2008. These data indicate that the elevations of most of the monuments have not significantly changed (typically less than 0.05 feet of elevation change). The 7050 West monument registered the most change. This was an increase in elevation of 0.46 feet and is probably indicative of a bad survey point. This result will be checked next quarter. Discounting this data point, the most vertical displacement was seen in the 7150 Mid monument with a decrease of 0.07 feet. Based on these data, the total displacement of the monuments is not of concern with regard to the stability of the dump. There was also no evidence of structural weakness or other hazardous conditions associated with this dump. These monument survey data are available for review upon request at the Colowyo Mine site. I am a Licensed Professional Engineer in the State of Colorado and a representative of Environmental Solutions, Inc, P. O. Box 2996, Cheyenne, Wyoming. Being familiar with the Colowyo operation and the coal program permitting process in Colorado, 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 I b and other applicable requirements of the approved permit documents, a portion of CDMG Permit C-81- 019. _...uuu,,._ `~~~~°Pp0 L / C ~'~~i~~ ~o '~ C Af lF~~y~o "- 32//257 z /OVAL ~,~,`,`~ ~~ xc: Mr. Kurtis Blunt, Colowyo Coal Compar~i',Ft~' 32257 cf 17.15.1 2005 3 3/~0 cf 24.20 (West Pit)