Comment
Author: Admin | 2025-04-28
Extracted above gateways in CLTCC are shown in Figure 7a. Assume that the top coal above four end shields is not recovered, the width of each shield is 1.5 m, the height of the gateway is Hg, the width of the coal pillar is Lc, coal seam thickness is Hc, panel width is Lp, then the CLTCC panel recovery ratio η can be calculated by Equation (1): η = 1 − L c × H c + 4 × 1.5 × 2 × ( H c − H g ) ( L c + L p ) × H c = 1 − L c × H c + 12 ( H c − H g ) ( L c + L p ) × H c (1) In Tangshan coal mine, Hg is 3 m, Lc is 20 m, Hc is 8.7 m, Lp is 90 m, thus coal loss is calculated as 242.4 m2, and η = 74.7%, which is just below the 75% that is required by law in China.While coal loss in the LMSG is significantly reduced as shown in Figure 7b. Top coal above end shields is approximately 15.6 m2, and triangular coal loss is approximately 10 m2. Since the length of the panel is 1028 m, and the volume of total coal that can be recovered using LMSG for one panel is (242.4 − 25.6) × 1028 = 222,870.4 m3, the total amount is 222,870.4 m3 × 1.48 t/m3 = 329,848.2 t, increasing recovery
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