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West Pit Fill Inspection Certification <br />On September 19, 2011, I inspected the area in which the West Pit Excess Spoil Fill is being <br />constructed. The purpose of this inspection was to observe the surface rock drain that borders the <br />3H:1V Excess Fill Slope, inspect the areas dumped to final grade below the 7,400 dump elevation, <br />inspect the revegetation on the fill surface, inspect the fill for areas of water seepage or surface <br />drainage, inspect the final grade slopes below the 7,300 elevation of the Excess Fill Slope, and <br />satisfy the requirements of CDRMS Rule 4.09.10 (1a) and Rule 4.09.1 (1b). <br />During the inspection, it was observed that the condition of the fill was unchanged and stable. All <br />portions of the fill were visible. A small flow of about two gallons per minute is evident from the toe <br />of the underdrain. A second small flow of less than two gallons per minute was noted near the point <br />where the toe of the fill intersects the access road for the West Pit Pond. This flow was primarily a <br />result of surface water runoff but is probably supported by some contribution from the toe of the <br />underdrain. No erosion problems were noted. No other seeps or springs were noted. <br />In addition, I reviewed the monument survey data collected September 9, 2011. These data <br />indicate that the elevations of most of the monuments have not significantly changed (typically less <br />than 0.05 feet of elevation change per calendar quarter). The most change was recorded at the <br />7250 East monument. This site registered a decrease of 0.17 feet. Based on these data, the total <br />displacement of the monument is not of concern with regard to the stability of the dump. There was <br />also no evidence of structural weakness or other hazardous conditions associated with this dump. <br />These monument survey data are available for review upon request at the Colowyo Mine site. <br />I am a Licensed Professional Engineer in the State of Colorado and a representative of <br />Environmental Solutions, Inc, P. O. Box 2996, Cheyenne, Wyoming. Being familiar with the <br />Colowyo operation and the coal program permitting process in Colorado, the construction activities <br />related to the West Pit Excess Spoil Fill are in conformance, to the best of my knowledge and <br />experience, as specified in pages I a -2 through I a -4, Exhibit 19 I b and other applicable <br />requirements of the approved permit documents, a portion of CDRMS Permit C -81 -019. <br />xc: Mr. Kurtis Blunt <br />cf 17.15.1 <br />cf 24.20 (West Pit) <br />• <br />32257 <br />45 ': V /eli «r =�4, <br />6 , •.....• 6\ ` . <br />i 4 � S / OVAL E, • <br />te <br />THOMAS C PETERSO <br />P.E. No. 32257 <br />DAT <br />