ABSTRACT
The underground mines in People’s Republic of Bulgaria are characterized by weak country rocks of the ore bodies with strongly expressed tectonic disturbances. Application of the conventional anchore in these conditions is of low efficiency. The frictional pipe anchor, developed in the Higher Institute of Mining and Geology, Sofia, and patented in a number of countries, satisfies most of requirements. Investigations in laboratory and underground mines conditions have been carried out aiming at determining exploitation properties of the pipe anchor. It compares well with the conventional anchors, for making an active contact with the rock along the whole length and realizing a self -control elastic bond with it. It possesses constant resistance with high flexibility. It makes possible the control upon the initial anchoring force during the insertion. The anchoring force increases in the course of time.
