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Mr. Jeff Gregg <br />January 5, 2006 <br />Page 5 <br />STABILITYANALYSES RESULTS <br />~~ <br />CIVIL RES'?JU RCES,LLC <br />Setbacks listed in Table 1 indicate the minimal setback from the structure to the mining limits. The setback distance can <br />be increased as needed to address other restrictions. <br />TABLE 1 -SLOPE STABILITY RESULTS AND SETBACKS <br />Section Location Critical Structure Modeled Surchar e, sf Minin Setback, ft Factor of Safet <br />AA' North Phase 1 WCR 23.75 250 50 from Pro a 1.25 <br />BB' South Phase 1 Concrete Ditch 250 50 from Ditch 1.096 <br />CC' West Phasel Stora a Buildin 1500 32 from Pro a 1.030 <br />DD' West Phase 2 Storage Building 1500 50 from Affected <br />Land Bounda 1.056 <br />EE' West Phase 2 UtilitiesNVCR 23.5 250 30 from Pro a 1.009 <br />FF' South Phase 2 Gas Well/Pie 250 12 from Pro ert 1.052 <br />GG' North Phase 3 Residence 250 50 from Pro a 2.11 <br />HH' West Phase 3 Waterline/WCR 23.5 250 501rom Pro ert 2.29 <br />CONCLUSIONS <br />Based on the stability analyses, the Phase 3 (former Dersham Property) proposed extent of mining limits were greatly <br />influenced favorably by the proposed 3:1 (H:V) mining slope. As a result, the minimum distances proposed are <br />recommended more for construction and maintenance than for stability. <br />LIMITATIONS <br />Our review is based on regional geologic mapping, present mining plans, borehole data tram the adjacent Baseline <br />Resource property, and stability analyses using typical strength parameters for the various strata in the critical sections. <br />Should the mining plans change or subsurface conditions vary from those portrayed in this letter, we should be <br />contacted in order to re-evaluate the potential affects on permanent man-made structures. Stability analyses were run at <br />the structure in question and were not run on failure surfaces closer to the highwall. Note also that surcharge loads due <br />to temporary material stockpiles and overburden berms were not considered in the analysis. <br />Please call with any questions or comments. <br />Sincerely, <br />Civil Resour es, LL /~~ <br />Tic / ~I~ ,~rh e,~ <br />Mark Reine , P.E., P.G. <br />Project Engineer <br />Attachments: Figure showing site location, boring and cross-section locations, and proposed extent of mining. Input <br />and output files and graphic profiles of stability analyses are also included. <br />J:WaIIlnvinl8aselinelShabiliryanalysis repod.doc <br />