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MINIP]G AND RECLAMATION PLAN April 1989 <br />MT. GUNNISON C1O. 1 MINE <br />prone to ha~ig at~d with low bulking factors. Thus, support <br />capacities may vary to an equivalent rock weight of two to eight <br />times tl~e mining height depending upon the geology and structural <br />behavior of the immediate roof. Experience from western coal mines <br />indicates that two-leg shields with a yield capacity of 500 to 600 <br />tons should be ade<;irate for West ELk conditions. Table 3.4.A.27 <br />summarized the face support types and longwall characteristics of <br />most of tl~e western coal mines. A few of these mines experience <br />considerably worse geologic conditions than those expected in the <br />E acid B Seams at West Elk. <br />TABLE 3.4.A.25 <br />OFFSET BOUNDARY FILLAR RE9UIRFMFNTS <br />• <br />• <br />Seams I Cover Interbui-dPn Offset <br />(ft) (ft) ~ (ft) <br />- --- -_- _-~ - -~1 <br />AREA I <br />F and B 750* 3A0 175 <br />AREA II <br />B and E 1,200+ 200 80 <br />E and F 100 _ 40 <br />AREA III <br />-B and 1,500+ 240_--- y 120 <br />E and F 80 40 <br />ARF,A IV <br />B and E 900+ 190 60 <br />E acid F 110 20 <br />AREA V <br />E acid F 1,U00'~ 110 50 <br />* = F Seam <br />+ = B Siam <br />N = E Seam <br /> <br />