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n_ { ~' '' i~-l U~,T -51- ~-----_-- Comparison of the survey subsidence monitoring results with the subsidence predictions included within the amended permit application results in several apparent contradictions: (1) Limited development extraction does result in limited but detectable subsidence, evidencing magnitudes exceeding 0.25 feet. This contradicts the applicant's projection of zero "maximum predicted subsidence" within areas of limited extraction. (2) Areas of retreat pillaring demonstrate relatively rapid lnitial subsidence response within several months following extraction. Initial subsidence is then followed by continued, but greatly decreased, additional subsidence. The maximum observed vertical subsidence within pillared areas of the 3rd-East area of the Eagle No. 5 Mine appears to have obtained a magnitude of approximately 75% of the originally projected "maximum predicted subsidence". Rule 2.05.6(6)(d) requires the applicant to complete a projection of worst possible consequences of subsidence for the structures and renewable resource lands identified during the required inventory. The applicant presents projections of "Worst Case Predicted Subsidence" in Table IV-1]. The applicant projects "Maximum Predicted Subsidence" of 0.0 feet and "Worst Case Predicted Subsidence" of 1.1 feet for the rivers and associated alluvial valley floor areas above the No. 9 Mine. Based upon this projection, the applicant concludes that insignificant impacts would result upon these renewable resource lands due to subsidence. Subsidence of the worst case magnitudes would result in minimal (.2 to .3 percent) changes in ground surface gradient, whose effects could be mitigated to prevent material impact upon the hydrologic balance of the alluvial valley area. C. Subsidence Control Plan Briefly summarized, Empire Energy Corporation proposes to limit subsidence to areas of planned subsidence by leaving sufficient support pillars to prevent ground surface subsidence above these areas. As stated on page IV-186 of the permit application; "areas to be protected by partial extraction include the State Highway, the railroad, the oil pipeline, the Williams Fork River, the Yampa River, and the Big Bottom area." The pillar sizes projected to prevent subsidence under protected structures and renewable resource lands are presented on Table IV-16 of the amended permit application. The private residence, located within the NE quarter of the SE quarter of Section 30 of T6N, R91W, is located outside of the angle of draw for the neighboring proposed A West Mains, 1st South Mains and the North Mains of the No. 9 Mine. The permit application documents include Map IV-3, which depicts the Eagle No. 9 mine plan. As shown, partial extraction of coal will occur under all areas planned to be undermined. The applicant proposes to limit all operations within the No. 9 Mine to the partial extraction configurations characterized by the pillar dimensions presented on Table IV-16 of the permit application.