6. Rock bolting

6.1 Principle

In underground work, bolting is the term used to describe the reinforcement of the ground surrounding the excavation by means of bars, usually metal, 1.50 to 5 m long, embedded in the ground and fitted with a bearing plate and nut at the visible end. These bolts are passive and can be used, for example, to pin down unstable boulders. The quarry face is sometimes reinforced with bars that are easily destroyed as the work progresses.

Anchor bolts are sealed using cement mortar or resin (see [C 5 565], ref. [23] ).