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Mr. Mark Johnson <br />July 17, 2017 <br />Page 2 <br />• Waterline (Western Boundary)(Town of Windsor) <br />• Residents (eastern boundary) (Osbome, McCosh, Brown) <br />CONCLUSIONS <br />The original La Poudre Mine has been mined out and no further dewatering or mining will occur. The east area has <br />been mined out for approximately ten years and the west area for approximately two years. The west area (wildlife <br />lake) is not slurry lined and will be backfilled or slurry lined in the future. The east area has been slurry lined and is <br />being used by Central Colorado Water Conservancy District. <br />The proposed amendment of the La Poudre Amendment to the La Poudre Mine is for completeness purposes as <br />eth area has been disturbed for at least 15 —years. A stability analysis and structure agreement letter has been <br />mailed out to the structure owners concerning the slope stability of the proposed mining area. <br />LIMITATIONS <br />Our review is based on regional geologic mapping, present mining plans, public well construction data, and stability <br />analyses using typical strength parameters for the various strata in the critical sections. Should the mining plans <br />change or subsurface conditions vary from those portrayed in this letter, we should be contacted in order to re- <br />evaluate the potential effects on permanent man-made structures. Stability analyses were run at the structure in <br />question and were not run on failure surfaces closer to the highwall. Note also that surcharge loads due to <br />temporary material stockpiles and overburden berms were not considered in the analysis as there are no plans to <br />have berms or stockpiles around the perimeter of the mine. <br />Please call with any questions or comments. <br />Sincerely, <br />Civil Resources, LLC <br />Andy Rodriguez, P.E. <br />Civil Engineer <br />J:0estway-2131WinsdoALA POUDRE AMEN DMENTIExhibitslStability AnalysislStability analysis existing La Poudre mine.doc <br />