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• <br />• An insp~tion of ttxe Blue Flame Coal ktine workings slow no <br />significant faults or strata displacEruents. TY,e coal is strong and <br />pillars are structurally competent showing a lack of syue~ing <br />(cxvshing) or rib spalling. The mine floor does not 1~uckle due to <br />stress from the overburden and because the water table is lower than the <br />seam, pore water pressure is nonexistent in the vnnediately overlying <br />acid underlying strata of the coal seam. The inr.,ediate mine x•oof <br />consists of thinly lami~iated shales and sand:; tones. These beds rise up <br />the the Lase of the Cliff House sandstone an avera;;e of twenty feet <br />above the coal seam. The thick Cliff Houue sandstone provides a great <br />deal of bround sta2xility and prevents subsidence from reaching the <br />sux•fax:e after pillars are extracted during second nuning. <br />The overburden above the Blue Flame Coal Mine (upper 61enefee) <br />• seam consists exclusively of sandstone and shale. <br />• <br />- B - <br />