ENFORCE24401 - Laserfiche WebLink

Home Browse Search

:. ~ • FF Wesr Elk Mint t, :: mining in the B seam are included and are based on data and evaluations of the F sue. 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-yeaz permit a: is included in Exhibit 60. The monitoring plan will provide additional data which v.. coupled with the F seam data and can be utilized for future mine planning considerati'" The effect ofmining-induced subsidence on renewable resources, structures, and geologic: unstable areas in the 5-year permit area is discussed in a report entitled Subside Evaluation for West Elk Mine. This repon is included in this Mining and Reclamation r as Exhibit 55. A limited mining buffer zone has been designed to protect the Dry Fork is included as Appendix B to Exhibit 55 and is shown on Map 50. Until approved by CMLRD, Mountain Coal Company will not mine under or adjacet~ any perennial streams. Additionally, there exists on or near the property no aquifers supply any public water system or any public buildings as described in CMLRD's Reeulai for Coal Mining. All surface owners will be notified by mail at least six months prig mining beneath their property. Mining will not approach the two perennial streams-South Prang and Horse Creek- 25 to 35 years into the mine life. These streams will be protected, at a minimum, by b~ t zones similar 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 workings at a site approximately 3 miles from the proposed site occurs at 485 fe: overburden thickness, with a greater concentration of cracks at or below the 40C' thickness. With one exception all cracks shown in Dunrud's figure 14 occur whert overburden is less than 500 feet thick. The principal areas of sub-500 foot cover at We: are near the outcrop and under the Dry Fork of Minnesota Creek. These areas w adequately protected by pillars shown in the mine layout. The mine cited by Dunru~ page 14) is situated in a different seam in an area cut off from the Mountain Coa] Con property by the North Fork of the Gunnison River. Dunrud's study contains n~ to/measurements of strata on the south side of the river. Geologic features such as cited in Dunrud's p.13, are not common in the Bear Mine. In any event, Dunrud's "c was a superficial tension crack which is probably of limited vertical extent, say 3 or ~ Dunrud presents no data to define vertical extent. On pages 16 and 17, Dunrud recol the "healing" propenies of the clayey soil and colluvium and erosion of surficia] subsi effects. l ~.os-147