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MINING AND RECLAMATION PLAN January, 1986 <br />MT. GUNNISON NO. 1 MINE ~ Revised April, 1989 <br />Revised October, 1989 <br />A limited mining buffer zone has been designed to protect the Dry <br />Fork of Minnesota Creek and is included as Appendix B to Exhibit • <br />3.4.S.A. and shown on Exhibit 3.4.4.B.1. When a mine plan is <br />submitted to undermine the Dry Fork, this subsidence protection <br />plan will be evaluated and altered, if necessary, based upon <br />subsidence data collected during earlier mining. <br />Until approved by CMLRD, WECC will not mine under or adjacent to <br />any perennial streams. Additionally; there exists on or near the <br />property no aquifers that supply any public water system or any <br />public buildings as described in Section 4.20.4 of the CMRLD's <br />Regulations for Coal Mining. <br />Mining will not approach the two perennial streams--South Prong and <br />Horse Creek--until 25 to 35 years into the mine life. These <br />streams will be protected, at a minimum, by buffer zones similar <br />to that designed for the Dry Fork. <br />All surface owners will be notified by mail at least six months <br />prior to mining beneath their property. See Section 1. <br />A crack reported by Dunrud (1976, p. 14) to be 1.5 feet wide and <br />515 feet above the coal workings at a site approximately 3 miles <br />from the proposed site occurs at 485' of overburden thickness, with <br />a greater concentration of cracks at or below the 400' thickness. <br />With one exception, all cracks shown in Dunrud's Figure 14 occur <br />where the overburden is less than 500' thick. The principle areas <br />of sub-500' cover at Mt. Gunnison are near the outcrop and under • <br />the Dry Fork of Minnesota Creek. These areas will be adequately <br />protected by pillars shown in the mine layout. The mine cited by <br />Dunrud (on page 14) is situated in a different seam in an area cut <br />off from the WECC property by the North Fork of the Gunnison River. <br />Dunrud's study contains no data\measurements of strata on the south <br />side of the river. Geologic features such as dikes, cited in <br />Dunrud's p.13, are not common in the Bear Mine. In any event, <br />Dunrud's "crack" was a superficial tension crack which is probably <br />of limited vertical extent, say 3 or 4 feet. Dunrud presents no <br />data to define vertical extent. <br /> <br />• <br />3-79 <br />