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Author: Admin | 2025-04-28
19.30 125 275AU-3 17.24 130 200AU-4 16.03 180 130AU-5 6.33 475 200AU-6 11.79 240 145AU-7 12.48 405 250AU-8a 13.62 513 227AU-8b 8.85 510 237AU-9 10.00 365 250US-1a 9.51 594 195US-1b 8.74 625 183Table 3Summary of mine geometries for the new cases.Case Depth(m) Panel width(m)Seam thickness(m)Entry width(m)HR(%)AU-1 265 205 2.5 5.1 N/AAU-2 125 280 3.6 5 48AU-3 130 205 3.1 5.2 57AU-4 180 135 3.2 5 33AU-5 475 205 2.5 4.8 71AU-6 240 150 6.5 4.9 23AU-7 405 250 2.5 5.2 21AU-8a 513 227 5.5 5 72AU-8b 510 237 5.5 6.1 95AU-9 365 250 6.7 5 61US-1a 594 195 1.7 6.1 54US-1b 625 183 1.7 6.1 54114 D. Tuncay et al. / International Journal of Mining Science and Technology 30 (2020) 111–118 of stronger overburden cases at lower abutment angles. More com-prehensive geological analysis with additional geological informa-tion is needed for a better conclusion.Fig. 5 shows the results for the abutment angles back calculatedusing the laminated model together with previously calculatedcases [1,3,17]. For the mines deeper than 200 m, the abutmentangle values are distributed from the maximum value of 23.4°tothe minimum value of 4.7°, with the mean of 12.2°. For the mineswith overburden depth less than 200 m, the scatter is much larger,but the average abutment angle of 21°is appropriate to assume.As seen in Fig. 6, there is also an apparent trend of decreasingabutment angles with increasing ratios of overburden depth topanel width (HPW). A regression analysis to determine the abutmentangle for deep cover cases (H>200 m) is conducted. The 200
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