A friction bolt assembly to frictionally engage a bore formed in rock strata. The assembly includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break.

A self-drilling differential grouting combined bolt and method of anchoring the same are described. The bolt consists essentially of a drill (1), a grouting pipe (2), a spindle (3), a bolt head mechanism and a bolt tail mechanism, wherein the bolt head mechanism comprises a fixed ring (4), a slip ring (7), a limiting pipe (6) and several pairs of driven linkages (501) and driving linkages (502); and the bolt tail mechanism comprises a bolt disc (11), a connecting cap (12), a spring (13) and a nut (14). The method of anchoring includes the steps of hole drilling, hole expanding at inner anchor end, differential grouting rock bolt fastening.

The invention discloses a retrievable sand consolidation anchor head prestressed anchor rod, an anchoring jack and an application method thereof, and belongs to the technical field of geotechnical engineering. The retrievable sand-consolidated anchor head pre-stressed anchor includes a bolt body 6, a rigid frame 5, a load member 1, a sand column 2, a pressure receiving member 4, a cut-off member 3, and an anchor pier 8. The anchoring jack includes a force transmitting frame 12, a first guiding plate 25, a second guiding plate 28, and a housing 13. The application method includes an anchoring method using the retrievable sand-consolidated anchor head prestressed anchor rod and a method of recovering the retrievable sand-consolidated anchor head pre-stressed anchor rod. After the anchoring of the reclaimed sand-consolidated anchor head pre-stressed anchor rod, the bolt body can be recovered and reused, and the operation is simpler and more environmentally friendly.

A system for re-tensioning mine roof channels includes a roof plate having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, where the first side is configured to engage a surface of a mine roof, and where the sidewall defines a radially extending slot configured to receive a mine roof bolt. The system also includes a spacer having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, with the first side of the spacer configured to engage with the second side of the roof plate, and the sidewall defining a slot configured to receive a mine roof bolt, and a nut having a first side, a second side positioned opposite the first side, a sidewall therebetween, and a threaded opening, with the sidewall defining a radially extending slot configured to receive a mine roof bolt.

The invention discloses a retrievable sand consolidation anchor head prestressed anchor rod, an anchoring jack and an application method thereof, and belongs to the technical field of geotechnical engineering. The retrievable sand-consolidated anchor head pre-stressed anchor includes a bolt body 6, a rigid frame 5, a load member 1, a sand column 2, a pressure receiving member 4, a cut-off member 3, and an anchor pier 8. The anchoring jack includes a force transmitting frame 12, a first guiding plate 25, a second guiding plate 28, and a housing 13. The application method includes an anchoring method using the retrievable sand-consolidated anchor head prestressed anchor rod and a method of recovering the retrievable sand-consolidated anchor head pre-stressed anchor rod. After the anchoring of the reclaimed sand-consolidated anchor head pre-stressed anchor rod, the bolt body can be recovered and reused, and the operation is simpler and more environmentally friendly.

A self-drilling differential grouting combined bolt, as described consists essentially of a drill (1), a grouting pipe (2), a spindle (3), a bolt head mechanism and a bolt tail mechanism, wherein the bolt head mechanism comprises a fixed ring (4), a slip ring (7), a limiting pipe (6) and several pairs of driven linkages (501) and driving linkages (502); and the bolt tail mechanism comprises a bolt disc (11), a connecting cap (12), a spring (13) and a nut (14), the bolt disc (11) is sleeved on a rear end of the grouting pipe (2), the connecting cap (12) is passed through by the spindle (3) and blocks off the rear end of the grouting pipe (2), the connecting cap (12) is provided with a grouting hole in communication with the grouting channel in the grouting pipe (2), and a grouting hole and an air vent are provided in the bolt disc (11).

A friction bolt assembly to frictionally engage a bore formed in rock strata. The assembly includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break.

A system for re-tensioning mine roof channels includes a roof plate having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, where the first side is configured to engage a surface of a mine roof, and where the sidewall defines a radially extending slot configured to receive a mine roof bolt. The system also includes a spacer having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, with the first side of the spacer configured to engage with the second side of the roof plate, and the sidewall defining a slot configured to receive a mine roof bolt, and a nut having a first side, a second side positioned opposite the first side, a sidewall therebetween, and a threaded opening, with the sidewall defining a radially extending slot configured to receive a mine roof bolt.

A friction bolt assembly to frictionally engage a bore formed in rock strata includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break.

A mine roof bolting system including a bearing member having a first member, a second member spaced apart from the first member, and apertures defined through each of the first and second members, and a mine roof bolt extending through the apertures. When a load is applied to the mine roof bolting system, the bearing member yields or deforms. Also, a method for providing a roof support in an underground mine including providing the bearing member and inserting a mine roof bolt through the apertures of the bearing member and into a borehole in a mine roof, wherein the bearing member yields upon application of a load in excess of a predetermined load.