Research Article
Dynamic Effect and Control of Key Strata Break of Immediate Roof in Fully Mechanized Mining with Large Mining Height
Table 2
Modelling material ratio.
| Lithology | Accumulated height/cm | Model height/cm | Layer volume/cm3 | Sand weight/kg | Gypsum weight/kg | CaCO3 weight/kg | Water weight/kg |
| Packsand | 140 | 4.5 | 22500 | 32.8 | 3.9 | 2.2 | 4.6 | Medium sandstone | 135.5 | 5 | 25000 | 36.4 | 3.6 | 3 | 5.1 | Sandy mudstone | 130.5 | 6 | 30000 | 44.6 | 4.5 | 2.6 | 6 | Packsand | 124.5 | 4 | 20000 | 29.1 | 3.5 | 1.9 | 4.1 | Medium sandstone | 120.5 | 2 | 10000 | 14.6 | 1.5 | 1.2 | 2 | Sandy mudstone | 118.5 | 4 | 20000 | 29.8 | 3 | 1.7 | 4 | Mudstone | 114.5 | 7.5 | 37500 | 55.8 | 4.8 | 4 | 7.5 | Coal | 107 | 1 | 5000 | 7.4 | 0.5 | 0.6 | 1 | Sandy mudstone | 106 | 5.5 | 27500 | 40.9 | 4.1 | 2.4 | 5.5 | Packsand | 100.5 | 1 | 5000 | 7.3 | 0.9 | 0.5 | 1 | Mudstone | 99.5 | 10 | 50000 | 74.4 | 6.3 | 5.3 | 10 | Coal | 89.5 | 1.5 | 7500 | 11.2 | 0.8 | 1.0 | 1.5 | Sandy mudstone | 88 | 7.5 | 37500 | 55.8 | 5.7 | 3.2 | 7.5 | Medium sandstone | 80.5 | 5 | 25000 | 36.4 | 3.6 | 3 | 5.1 | Limestone | 75.5 | 3 | 15000 | 21.3 | 2.6 | 2.1 | 3.6 | Sandy mudstone | 72.5 | 6.5 | 32500 | 48.4 | 4.9 | 2.8 | 6.5 | Packsand | 66 | 5.5 | 27500 | 40.1 | 4.8 | 2.7 | 5.6 | Mudstone | 60.5 | 4.5 | 22500 | 33.5 | 2.9 | 2.4 | 4.5 | Limestone | 56 | 6 | 30000 | 42.5 | 5.1 | 4.3 | 7.3 | Coal | 50 | 1 | 5000 | 7.4 | 0.5 | 0.6 | 1 | Sandy mudstone | 49 | 6 | 30000 | 44.6 | 4.5 | 2.6 | 6 | Mudstone | 43 | 4.5 | 22500 | 33.5 | 2.9 | 2.4 | 4.5 | Limestone | 38.5 | 5 | 25000 | 35.4 | 4.3 | 3.5 | 6.1 | Mudstone | 33.5 | 6 | 30000 | 44.6 | 3.8 | 3.2 | 6 | Packsand | 27.5 | 2 | 10000 | 14.6 | 1.7 | 1 | 2 | Sandy mudstone | 25.5 | 3 | 15000 | 22.3 | 2.3 | 1.3 | 3 | Packsand | 22.5 | 6 | 30000 | 43.7 | 5.2 | 2.9 | 6.1 | Mudstone | 16.5 | 6 | 30000 | 44.6 | 3.8 | 3.2 | 6 | 15# coal | 10.5 | 5.5 | 27500 | 40 | 4 | 2.6 | 5.2 | Sandy mudstone | 5 | 5 | 25000 | 37.3 | 3.6 | 2.5 | 4.7 |
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