The present application relates to a system for supporting a roof of a portion of a mine. The system includes a first plurality of stabilizing members disposed above the roof at a first elevation. The first plurality of stabilizing members originate from a first common location and terminate at a second elevation that is higher than the first elevation. The system further includes a second plurality of stabilizing members disposed above the roof and the first plurality of stabilizing members at a third elevation. The second plurality of stabilizing members originate from a second common location and terminate at a fourth elevation that is higher than the third elevation. The second plurality of stabilizing members are disposed generally perpendicular to the first plurality of stabilizing members.

Disclosed is a cable anchor assembly including: a cable anchor body longitudinally extending between leading and trailing ends; a tensioning device with an outer member having first and second ends and a threaded through passage between the ends and an inner member which threadedly engages the threaded passage of the outer member and fixedly attached to the cable anchor body at or towards the trailing end; a faceplate engaging the cable anchor body between the leading end and the tensioning device. In use, with the cable anchor body inserted in a borehole and anchored therein, the faceplate positioned against a rock face and the first end of the outer member abutting the faceplate, the outer member is rotatable relative to the inner member, causing the inner member to move within the passage towards the second end of the outer member, drawing on the cable anchor body, tensioning the body.

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 rock bolt assembly includes a rock bolt with an elongate body between distal and proximal ends, a tubular sleeve with first and second ends, proximal and distal ends of the bolt projecting from first and second ends of the sleeve, a load bearing barrel centrally bored to engage the rock bolt between the sleeve's first end and the bolt's proximal end, which barrel is adapted at a forward end to engage with the sleeve's second end in sealing contact, and which barrel has at least one grout conduit between the barrel's exterior surface and the bore, which at least one conduit defines a part of a grout passage which communicates the exterior surface of the barrel with an interior of the sleeve, when the barrel is engaged with the sleeve, and a seal which seals the grout passage to grout outflow but accommodates inflow of grout from a source.

A high-strength confined concrete support system for an underground tunnel. The support system includes multiple confined concrete arches, bolts and cables, and a prestressed steel strand backfilling system. The confined concrete arches all support the surrounding rock of the tunnel and are sequentially arranged along the tunnel. Every two adjacent confined concrete arches are connected by a longitudinal connection structure. The support system is provided with a plurality of layers of steel bar meshes on the surrounding rock side and the tunnel side, and shotcrete layers are sprayed on the support system and the steel bar meshes. The prestressed steel strand backfilling system comprises a prestressed steel strand system and a filling material. The filling material fills the space between each confined concrete arch and the surrounding rock to equalize a load on the confined concrete arch and generate prestress.

A cable bolt for providing support and balance to a rock mass, comprising: a multi-strand cable having a plurality of steel wires being twisted together, said multi-strand cable having a first end portion for anchoring in a borehole of rock mass and a second end portion for being positioned adjacent to the opening of the borehole, a fixture secured to the second end portion of said multi-strand cable, wherein at least one of the plurality of steel wires is made from steel having as steel composition: a carbon content ranging from 0.20 weight percent to 0.95 weight percent, a silicon content ranging from 0.5 weight percent to 2.0 weight percent, a manganese content ranging from 0.40 weight percent to 1.0 weight percent, a chromium content ranging from 0.0 weight percent to 1.0 weight percent, a sulphur and phosphor content being limited to 0.025 weight percent, the remainder being iron and unavoidable impurities, and said steel has as metallurgical structure: a volume percentage of retained austenite ranging from 4 percent to 25 percent, the remainder being tempered primary martensite and untempered secondary martensite.

An inflatable rock bolt including an expansion tube, a bushing arranged at each end of the expansion tube, and at least one reinforcing member arranged outside the expansion tube. The at least one reinforcing member includes at least one of a strand extending along the expansion tube or a sleeve at least partially surrounding the expansion tube. A method for reinforcing an inflatable rock bolt.

A tunnel constraint anchor cable and a method for improving stability of an initial support structure. The tunnel constraint anchor cable comprises steel strands (1) anchored in surrounding rock, first anchor plates (2) and first anchorage devices (3) which are installed on the surface of the surrounding rock, longitudinal connection members (5) installed between two adjacent steel ribs (4), and second anchor plates (6) and second anchorage devices (7) which are installed on the longitudinal connection members (5). With the support of the tunnel constraint anchor cable, the ability of the initial support structure to resist self instability and destruction is improved, overall settlement and convergence deformation of the initial support structure can also be suppressed. The method for improving stability of an initial support structure has the characteristics of simplicity, speed, reliability, and avoiding interference with subsequent construction processes of tunnels.

A strand (20) for a cable bolt (14) comprises a plurality of metallic elongated members (22, 24) twisted together. At least one of the elongated members has a corrosion resistant coating (54) and surface deformation, so as to improve the bodig efficiency and the anchorage of the strand.

Disclosed is a cable anchor assembly including: a cable anchor body longitudinally extending between leading and trailing ends; a tensioning device with an outer member having first and second ends and a threaded through passage between the ends and an inner member which threadedly engages the threaded passage of the outer member and fixedly attached to the cable anchor body at or towards the trailing end; a faceplate engaging the cable anchor body between the leading end and the tensioning device. In use, with the cable anchor body inserted in a borehole and anchored therein, the faceplate positioned against a rock face and the first end of the outer member abutting the faceplate, the outer member is rotatable relative to the inner member, causing the inner member to move within the passage towards the second end of the outer member, drawing on the cable anchor body, tensioning the body.