| 摘要 |
A pre-bolting system for underground mines which comprises narrow, deep slots in the working face and in drilling through at an angle and bolting from inside these slots with equipment specially designed for this purpose. The drilling, bolting equipment uses high pressure water to assist drilling by water jet. The bit can also be driven by an axial water turbine of small diameter located at the bit. The equipment includes a ventilation system to dilute gas inside the slot when drilling or bolting.
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