Friction rock stabilizers

A friction stabilizer for installation in a structure such as a roof or side wall of a mine shaft or other underground opening for anchoring the structure, said stabilizer comprising a generally annular body having longitudinally extending portions which overlap circumferentially of said body, said body being of dimension predetermined to be substantially larger than the diameter of the bore in which it is to be inserted such that insertion of said body in such bore causes substantial circumferential compression of said body, said overlapping portions of said body being relatively movable circumferentially of said body to permit such substantial circumferential compression of said body, the stabilizer being free of structure precluding said substantial circumferential compression of said body, and said body being of material permitting its said substantial compression during its said insertion and, after such insertion, causing the body outer circumference to frictionally engage the wall of the bore for frictionally anchoring the structure and wherein said body is defined by inner and outer circumferential walls formed of a single thickness of said material, which inner and outer walls, in cross-section, are of common annular configuration;

• said inner and outer walls each having a prescribed, common discontinuity which extends, uniformly, fully longitudinally of said body;
• and said discontinuities of said inner and outer walls are spaced apart, one from the other thereof, circumferentially of said body.