Abstract: A tensionable mine roof cable bolt having a resin grouted upper portion and a mechanically anchored lower portion. The lower portion includes a shaft which is swaged to the cable and accepts a mechanical anchor. The cable bolt is rotated during installation in a mine roof to mix resin and simultaneously engage the mechanical anchor with the rock. A drivehead attached to the lower end of the cable fails upon tensioning of the bolt to a predetermined load.

Abstract: An improved expansion assembly for a mine roof bolt for use in a nominal one inch diameter bore hole with a nominal 5/8" diameter roof bolt is provided. The expansion assembly has a tapered plug with four tapered surfaces, an expansion shell that has four leaves extending axially upwardly from a support ring and into contact with the four tapered surfaces on the tapered plug, and a threaded support washer to support the expansion shell on the threaded end of a mine roof bolt. The tapered plug has a threaded bore therethrough for threading onto the mine roof bolt. The tapered plug tapered surfaces have an angle of taper of at least 6.5.degree. to the axis of the mine roof bolt. The expansion leaves each have seven serrations formed on the surface such that the serrations are formed by the intersection of a planar surface perpendicular to the axis of the mine roof bolt and a frusto-conical surface. The frusto-conical surface is at an angle of 72.3.degree. to the planar surface.

Abstract: An improved expansion assembly for a mine roof bolt for use in a nominal one inch diameter bore hole with a nominal 5/8" diameter roof bolt is provided. The expansion assembly has a tapered plug with four tapered surfaces, an expansion shell that has four leaves extending axially upwardly from a support ring and into contact with the four tapered surfaces on the tapered plug, and a threaded support washer to support the expansion shell on the threaded end of a mine roof bolt. The tapered plug has a threaded bore therethrough for threading onto the mine roof bolt. The tapered plug tapered surfaces have an angle of taper of at least 6.5.degree. to the axis of the mine roof bolt. The expansion leaves each have seven serrations formed on the surface such that the serrations are formed by the intersection of a planar surface perpendicular to the axis of the mine roof bolt and a frusto-conical surface. The frusto-conical surface is at an angle of 72.3.degree. to the planar surface.

Abstract: An improved roof support system for a mine or the like is of the type which includes a pair of plates secured to the roof of the mine at opposite sides thereof adjacent opposing ribs of the mine and a horizontal, transverse reinforcing member extending between the pair of plates. The improvement includes the reinforcing member having a first rod with a first end thereof secured to a first of the plates and a second end extending toward the second plate. The second plate includes a vertical portion with a transversely extending opening therethrough. The reinforcing member also includes a second rod in the form of a bolt which has a bolt head located against the vertical portion of the second plate with the threaded second end thereof extending through the opening toward the first plate. The second end of the first rod includes a sleeve mounted thereon having a threaded bore therethrough for receipt of the threaded end of the bolt.