Forward multi-stage large-diameter reaming technology for directional high-level borehole in roof
Directional high-level borehole in roof is an important means to control mining pressure-release gas in coal mine underground. Due to limitation of drilling device, the borehole diameter is small in once-through drilling, and borehole group arrangement is needed to achieve good drainage effect. In o...
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| Format: | Article |
| Language: | zho |
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Editorial Department of Industry and Mine Automation
2020-08-01
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| Series: | Gong-kuang zidonghua |
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| Online Access: | http://www.gkzdh.cn/article/doi/10.13272/j.issn.1671-251x.2020010044 |