Method for roof bolting of rock and arrangement for its performance and a roof bolting unit

摘要

In roof bolting, when an anchor rod (24) is to be inserted in a borehole (26) in the rock, a cement grout is ejected as a jet from a nozzle (22) located at the mouth of the borehole to partially fill the hole before the rod is forced into the borehole. The jet of grout should have such a velocity that it reaches the bottom of the borehole. A grout pump (45, 60) forces the grout through a hose (28) to the nozzle (22).