<p>A <strong>rock bolt</strong> is a long anchor bolt, for stabilizing rock excavations, which may be used in tunnels or rock cuts. It transfers load from the unstable exterior to the confined (and much stronger) interior of the rock mass. Rock bolts work by 'knitting' the rock mass together sufficiently before it can move enough to loosen and fail by unraveling (piece by piece). Rock bolt, in tunneling and underground mining, steel rod inserted in a hole drilled into the roof or walls of a rock formation to provide support to the roof or sides of the cavity. Rock bolt reinforcement can be used in any excavation geometry, is simple and quick to apply, and is relatively inexpensive. there were 4000mm size rock bolt is used. For more details and information download drawing file.</p>