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Revised 11/85 <br />• 3. Mining in the C Coal Seam will precede mining in the B Coal <br />Seam with eventual. mining in the B Coal Seam being similar to <br />mining in the C Coal Seam. <br />This logic will provide for maximum recovery of coal from all seams <br />within the permit boundary. Extraction of the C Seam will be maximized <br />by pillar extraction in the panels and by extraction of the barrier <br />pillars upon final retreat from the mining area. The pillar extraction <br />sequence as shown on Figure 1, Typical Pillar Extraction Sequence, and <br />on the Mine Plan Map (Map 9) will result in a minimum recovery of 67 <br />percent with probable recoveries in excess of 75 percent in the panel <br />areas. The high recoveries will come as a result of slabbing the <br />remaining pillars shown on Figure 1. Recoveries in excess of 70 percent <br />are considered to be the maximum passible using the room and pillar <br />system. <br />Extractions of the B Seam below the C Seam will be maximized by <br />superimposing the barrier pillars to the greatest extent possible in the <br />two seams. Superimposing the pillars will assure that the vertical <br />stresses generated by the upper pillars will bear directly through solid <br />pillars in the lower mine area. The high recovery rates planned for the <br />C Seam will result in the pillar stumps crushing out after mining. The <br />crushing of the pillar stumps will allow area type subsidence to take <br />effect in the post-mining area. With pillar stumps crushed out and area <br />type subsidence taking place, the stress distribution in the lower B <br />Seam will return to a condition close to the premining stress conditions <br />found in the area. The only exception to this will be the areas of the <br />B Seam which will underlie any barrier pillars in the C Seam which <br />cannot be recovered. Superimposed barrier pillars will minimize the <br />effects of stresses transferred from the C Seam to the B Seam on mining <br />in the B Seam. <br />The Bear Coal Company Mine Plan will result in the crushing of pillars <br />• in the mine panel areas and area type subsidence over the C Seam. Area <br />type subsidence will provide the best opportunity for long-term recovery <br />of the upper coal seams. The upper coal seams (E and F Seams) range <br />-16- <br />