Research Article
Study on the Mechanism of Gas Ignition by Friction Effect of Hard Quartz Sandstone Instability
Table 1
Roof lithology of 1007 working face.
| Lithology | Thickness (m) | Features |
| Sandstone and conglomerate | 3.7 | Gravel, quartz content is high, harder | Fine sandstone | 2.9 | Fine grain structure, calcium, clay cementing | Sandy mudstone | 11.2 | Sand and shale, high sand content partly, sandstone layer interbed | Quartz sandstone | 13.9 | High quartz composition, partly quartz stone, very hard | Fine sandstone | 6.9 | Glued calcium clay, hard, high quartz composition | No. 10 coal seam | 5.5 | Powdery or fragmented, brittle, vertical fissure development |
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