Laserfiche WebLink
• 2.05.3(2) <br />3. Mining in the C-Seam preceded mining in the S-Seam. <br />This logic will provide for maximum recovery of coal from all seams <br />within the permit boundary. Extraction of coal from the C-Seam was <br />maximized by pillar extraction in the panels and by extraction of <br />selected barrier pillars upon final retreat from the mining area. <br />The extent of mining performed in the C-Seam is shown on Map 9 and <br />Map 16. <br />Extraction of the B-Seam below the C-Seam is being maximized by <br />superimposing the barrier pillars to the greatest extent possible. <br />Superimposing the pillars assures that the vertical stresses <br />generated by the upper pillars will bear directly through solid <br />pillars in the lower mine area. The high recovery rates achieved <br />in C-Seam should result in the pillar stumps crushing out. The <br />crushed pillar stumps should allow the areal type subsidence to <br />take effect in the post-mining area. With pillar stumps crushed <br />out and areal subsidence taking place, the stress distribution in <br />• the lower B-Seam has been manageable. Areas in the B-Seam that <br />underlie barrier pillars in the C-Seam exhibit the effects of high <br />stress. Superimposed barrier pillars minimize the effects of <br />stresses transferred from the C-Seam to the B-Seam. The mine plan <br />to the west of First North Mains is outside of the influence of the <br />C-Seam workings. <br />The Operator's Mine Plan in the C-Seam and B-Seam should result in <br />the crushing of pillars in the mine panel areas and areal type <br />subsidence. Areal type subsidence will provide the best <br />opportunity for future recovery of the upper coal seams by others. <br />The upper coal seams (E and F Seams) range from 180 to 410 feet <br />above the C-Seam within the permit area. <br />• 2.05-5 Rev. 09-26-94 <br />