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Wut Elk Mine mining in the B seam are included and are based on data and evaluations of the F seam subsidence, as well as current industry data for the mining methods employed. A subsidence monitoring plan to monitor mining in the B seam for the 5-year permit area is included in Exhibit 60. The monitoring plan will provide additional data which when coupled with the F seam data and can be utilized far future mine planning considerations. The effect ofmining-induced subsidence on renewable resources, structures, and geologically unstable areas in the 5-year permit area is discussed in a report entitled Subsidence Evaluation for West Elk Mine. This report is included in this Mining and Reclamation Plan as Exhibit 55. A limited mining buffer zone has been designed to protect the Dry Fork and is included as Appendix B to Exhibit 55 and is shown on Map 50. Until approved by CMLRD, Mountain Coa] Company will not mine under or adjacent to any perennial streams. Additionally, there exists on or near the property no aquifers that supply any public water system or any public buildings as described in CMLRD's Regulations for Coal Mining. All surface owners will be notified by mail at least six months prior to mining beneath their property. Mining will not approach the two perennial streams--South Prong and Horse Creek-- until 25 to 35 years into the mine life. These streams will be protected, at a minimum, by buffer zones simiiar to that designed for the Dry Fork. A crack reported by Dunrud (1976, p. 14) to be 1.5 feet wide and 515 feet above the coal workings at a site approximately 3 miles from the proposed site occurs at 485 feet of overburden thickness, with a greater concentration of cracks at or below the 400 feet thickness. With one exception al] cracks shown in Dunrud's figure 14 occur where the overburden is less than 500 feet thick. The principal areas of sub-S00 foot cover at West Elk are near the outcrop and under the Dry Fork of Minnesota Creek. These areas will be adequately protected by pillars shown in the mine layout. The mine cited by Dunrud (on page 14) is situated in a different seam in an area cut off from the Mountain Coal Company property by the North Fork of the Gunnison River. Dunrud's study contains no da- ta/measurements of strata on the south side of the river. Geologic features such as dikes, cited in Dunrud's p.13, are not common in the Bear Mine. In any event, Dunrud's "crack" was a superficial tension crack which is probably of limited vertical extent, say 3 or 4 feet. Dunrud presents no data to define vertical extent. On pages 16 and 17, Dunrud recognized the "healing" properties of the clayey soil and colluvium and erosion of sutficial subsidence effects. ti ~h, « 2.05-147 /~ / ~ ll ~ ~ _ r i ti/ 2 ~r ~ ~ o cu ~ i' ~I c ~'~i~4ac~ ~ ~i-~ z