Research Article
Bending Moment Characteristics of Hard Roof before First Breaking of Roof Beam Considering Coal Seam Hardening
Table 1
Engineering example of hard roof fracturing ahead of working face.
| Hard roof of working face | Advanced fracturing distance |
| Old roof of coal mine in western of Xuzhou | About 4m [1] | Roof of 741003 working face of Muchengjian mine | 5-8 m [24] | Roof of coal seam 2 of Beijing Mining Bureau | About 6m [24] | Old roof of coal seam of Xinqiu mine | 6.3m, 8m [23] | Roof of 8320 working face of Dafeng mine | 9.98m [25] | Old roof of Sanhejian mine in Xuzhou | About 10m [26] | Roof of east 708 working face of Zhangxiaolou mine | 11.56m [25] |
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