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Table 82 <br />WIDTH:DEPTH RATIOS FOR LONGWALL PANEL NO. 1 <br />(600 -ft. Extraction Width) <br />Mining Layout <br />Overburden <br />Depth <br />(feet) <br />W /H1 <br />Ratio <br />2 <br />Classification <br />Longwall Panel No. 1 <br />200 <br />3.00 <br />Super - critical <br />400 <br />1.50 <br />Super - critical <br />600 <br />1.00 <br />Critical <br />800 <br />0.75 <br />Subcritical <br />NOTES: <br />1. W/H = ratio of <br />extraction area width (W) to overburden <br />depth (H) <br />2. Subcritical = W/H <br />ratio less than 1.00 <br />Critical = W/H <br />ratio 1.00 to 1.40 <br />Super - critical <br />= W/H ratio greater than <br />1.40 <br />