Research Article
Height of the Fractured Zone in Coal Mining under Extra-Thick Coal Seam Geological Conditions
Table 2
Identification results of key strata.
| | No. | Lithological characters | Thickness (m) | Key strata | Failure span (m) | Distance from roof of coal seam (m) |
| | Y25 | Kernstone | 25.4 | Main key strata | 104.18 | 174.6 | | Y22 | Fine sandstone | 10.7 | Inferior key strata III | 76.82 | 143.5 | | Y9 | Fine sandstone | 14.8 | Inferior key strata II | 67.44 | 32.4 | | Y2 | K3 sandstone | 5.3 | Inferior key strata I | 52.18 | 3.2 |
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