Laserfiche WebLink
Table 83 <br />WIDTH:DEPTH RATIOS FOR MULTIPLE, ADJACENT LONGWALL PANELS - Part 2 <br />Overburden <br />Depth W /H1 <br />Mining Layout (feet) Ratio Classification <br />2 <br />4 Longwall panels <br />(2800 -ft extraction width) <br />5 Longwall panels <br />(3550 -ft extraction width) <br />• <br />NOTES: <br />600 <br />4.67 <br />Super- critical <br />800 <br />3.50 <br />Super - critical <br />1000 <br />2.80 <br />Super - critical <br />1200 <br />2.33 <br />Super - critical <br />1400 <br />1.75 <br />Super- critical <br />1600 <br />1.56 <br />Super - critical <br />600 <br />5.92 <br />Super - critical <br />800 <br />4.44 <br />Super - critical <br />1000 <br />3.55 <br />Super - critical <br />1200 <br />2.96 <br />Super - critical <br />1400 <br />2.22 <br />Super - critical <br />1600 <br />1.97 <br />Super - critical <br />1. W/H = ratio of extraction area width (W) to overburden depth (H) <br />2. Subcritical = W/H ratio less than 1.00 <br />Critical = W/H ratio 1.00 to 1.40 <br />Super - critical = W/H ratio greater than 1.40 <br />0 <br />