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CALCULATIONS OF SUBSIDENCE DAMAGE POTENTIAL <br /> <br />A. Fault Block 2 <br />(Lower Pinnacle Seam only) <br />1. Area 111 <br />a. seam thickness range 48" - 54" <br />b. approximate range in depth of cover 360' - 420' <br />c. maximum width of extraction 500' <br />d. method of mining - room and pillar with pillar extraction on retreat <br />from rooms and room entries. Estimated extraction @ 80X in-place coal. <br />e. w/d critical width <br />S00 _ 1.39 1.3 x 360 = 468' <br />360 <br />500 __ 1.19 1.3 x 420 = 546' <br />420 <br />critical width - maximum subsidence @ any given depth. <br />from chart: 1.3 w/d is critical width ratio. This is based upon <br />emperical data gathered in Great Britain and is at <br />• full extraction. <br />f. expected maximum subsidence with full extraction is 90X of <br />mining thickness or .9 x 48" -54" = 43.2" - 48.6" <br />g. expected range in subsidence, if subsidence occurs, based upon <br />subsidence studies in Illinois @ 80X extraction is: <br />]8% x 48" - 54" = 8.6" - 9.7" <br />65% x 48" - 54" = 37.2" - 35.]" <br />li. Area 1 is partially overlain by cleared area used for grazing <br />and natural liay field. <br />2. Area U2 <br />a. seam thickness range 48" - 60" <br />b. approximate range in depth of cover ]20' at recovery line near <br />outcrop to "S70' . <br />c. maximum widtl~ of extraction 375' @ recovery line and 500' downdip <br />d. method of mining - same as Arca lil <br />r1 <br />U <br />Z~ T <br />D. H. EMLING COMPANY <br />