Mine roof support method and apparatus

Claim 1

Apparatus for installation in a drill hole in a rock formation to fracture a resin cartridge and mix the contents thereof, said apparatus thereafter being firmly anchored in the drill hole by the hardened resin mixture and serving to reinforce the rock formation, said apparatus comprising: (a) an elongated anchor bar; (b) means carried by one end of said bar, and having an internally threaded portion coaxial with said bar, said bar and said bar-carried means including means limiting the extent to which said bar and bar-carried means may be relatively rotated in one direction; (c) an elongated bolt having a head at one end and threaded from the other end for a portion of its length for advance into said internally threaded portion of said bar-carried means; (d) at least one fixed element extending radially outward from said bolt at a predetermined distance from the end of said threaded portion; (e) a hollow collar having an axial length less than said predetermined distance and greater than the distance from said fixed element to said threaded portion of said bolt, and an axial bore or larger radius than said bolt and smaller than the radial distance by which said fixed member extends outwardly therefrom; and (f) one of said fixed element and said collar being breakable upon application to said bolt of a predetermined torque for threaded advancement into said internally threaded portion with said collar encircling said bolt between said bar-carried means and said fixed element while said bar is held rotationally stationary.

Claim 7

A method of reinforcing a rock formation comprising the steps of: (a) drilling a blind hole of predetermined dimensions into a face of the rock formation; (b) inserting a destructible resin cartridge into said hole; (c) inserting an elongated anchor bar into said hole with the leading end of said bar engaging said cartridge; (d) said bar carrying on its trailing end means rotationally restrained in one direction with respect to said bar and having an internally threaded portion coaxial with said bar; (e) forming a rock bolt having a head on one end and threaded from the other end for a portion of its length for advance into said internally threaded portion of said bar-carried means; (f) forming at least one fixed element extending radially outward from said bolt at a predetermined distance from the end of said threaded portion; (g) forming an open, hollow collar having an axial length less than said predetermined distance and an axial bore of larger radius than said bolt and smaller than the radial distance by which said fixed element extends outwardly therefrom; (h) placing said collar over said other end of said bolt to rest upon said fixed element; (i) advancing said threaded end of said bolt into said internally threaded portion of said bar-carried means until said collar is engaged between said fixed element and said bar-carried means; (j) rotating said bolt, and thereby said bar, while advancing the same into said hole to break said resin cartridge and mix the contents thereof within the hole around said bar; (k) stopping rotation for a period of time sufficient for the resin mixture to harden about said bar; (l) applying sufficient torque to said bolt, as said bar is held stationary by the resin mixture, to break at least one of said fixed element and said collar as said bolt is threadedly advanced into said internally threaded portion of said bar-carried means; and (m) continuing rotation of said bolt to bring a support plate carried thereby into supporting contact with the face of the rock formation surrounding said hole.

Claim 8

A method of reinforcing a rock formation comprising the steps of: (a) drilling a blind hole of predetermined dimensions into a face of the rock formation; (b) inserting a destructible resin cartridge into said hole; (c) inserting an elongated anchor bar into said hole with the leading end of said bar engaging said cartridge; (d) said bar carrying on its trailing end means rotationally restrained in one direction with respect to said bar and having an internally threaded portion coaxial with said bar; (e) forming a rock bolt having a head on one end and threaded from the other end for a portion of its length for advance into said internally threaded portion of said bar-carried means; (f) forming at least one fixed element extending radially outward from said bolt at a predetermined distance from the end of said threaded portion; (g) forming an open, hollow collar having an axial length less than said predetermined distance and an axial bore of larger radius than said bolt and smaller than the radial distance by which said fixed element extends outwardly therefrom; (h) placing said collar over said other end of said bolt to rest upon said fixed element; (i) advancing said threaded end of said bolt into said internally threaded portion of said bar-carried means until said collar is engaged between said fixed element and said bar-carried means; (j) rotating said bolt, and thereby said bar, while advancing the same into said hole to break said resin cartridge and mix the contents thereof within the hole around said bar; (k) stopping rotation for a period of time sufficient for the resin mixture to harden about said bar; (l) applying sufficient torque to said bolt, as said bar is held stationary by the resin mixture, to break at least one of said fixed element and said collar as said bolt is threadedly advanced into said internally threaded portion of said bar-carried means; and (m) continuing rotation of said bolt to bring a support plate carried thereby into supporting contact with the face of the rock formation surrounding said hole.