Tensionable elongated bolt disposed with a sleeve and method of use thereof

Abstract

An anchorable mine support for anchoring in a borehole with resin or grout. The anchorable mine support comprises a tensionable elongate metal member and a sleeve disposed on at least a portion of the tensionable elongate metal member. The sleeve has a thickness of less than about 1 mm. A method of reducing frictional resistance between a tensionable elongated bolt and a hardened resin nut in a borehole formed in a face of a mine passage. The method reduces the frictional resistance between a tensionable elongated bolt and a hardened resin nut, thus improving the ability to tension a tensionable elongated bolt and stabilize a rock formation or structural body.

What is claimed is: 
     
         1 . An anchorable mine support for anchoring in a borehole with resin or grout, said anchorable mine support comprising a tensionable elongate metal member and a sleeve disposed on at least a portion of the tensionable elongate metal member; wherein the sleeve has a thickness of less than about 1 mm. 
     
     
         2 . The anchorable mine support of  claim 1  wherein the sleeve is disposed on at least a portion of the elongate metal member sufficient to allow the elongate metal member to turn within the sleeve while the sleeve is embedded and fixed in a hardened resin or grout. 
     
     
         3 . The anchorable mine support of  claim 2  wherein frictional resistance between the tensionable elongate metal member, disposed with the sleeve, and the hardened resin or grout is reduced as compared to frictional resistance between a tensionable elongate metal member, not disposed with a sleeve, and a hardened resin or grout. 
     
     
         4 . The anchorable mine support of  claim 1  in which the sleeve comprises a plastic, paint or metal; wherein a permanent bond is not formed between the plastic, paint or metal sleeve and the elongate metal member. 
     
     
         5 . The anchorable mine support of  claim 1  wherein the sleeve comprises a plastic selected from the group consisting of a polyolefin, polyvinyl chloride (PVC), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a fluoro elastomer, fluorinated ethylene propylene (FEP) and fluorinated elastomer. 
     
     
         6 . The anchorable mine support of  claim 1  wherein the sleeve is an injection molded sleeve. 
     
     
         7 . The anchorable mine support of  claim 1  wherein the sleeve forms to contours of the elongate metal member such that an outer surface of the sleeve maintains threaded contours of the elongate metal member. 
     
     
         8 . An apparatus for installation in a borehole formed in a face of a mine passage, said apparatus comprising:
 a tensionable elongated bolt including a proximal end having a fixed head, a distal end without an attachment, and an externally threaded portion for positioning in the borehole; and   a stationary, hardened resin nut formed in a portion of the borehole, said resin nut including an internal thread extending continuously along the entire length of the resin nut, said continuous thread surrounding at least part of the threaded portion of the bolt;   wherein a sleeve is disposed on at least part of the threaded portion of the tensionable elongated bolt surrounded by the resin nut continuous thread; wherein the sleeve has a thickness of less than about 1 mm.   
     
     
         9 . The apparatus of  claim 8  wherein frictional resistance between the tensionable elongated bolt, disposed with the sleeve, and the hardened resin nut is reduced as compared to frictional resistance between a tensionable elongated bolt, not disposed with a sleeve, and a hardened resin nut. 
     
     
         10 . A method of reducing frictional resistance between a tensionable elongated bolt and a hardened resin nut in a borehole formed in a face of a mine passage, said method comprising:
 providing a tensionable elongated bolt including a proximal end having a fixed head, a distal end without an attachment, and an externally threaded portion for positioning in the borehole; wherein a sleeve is disposed on at least part of the threaded portion of the bolt surrounded by the resin nut continuous thread; wherein the sleeve has a thickness of less than about 1 mm;   providing a stationary, hardened resin nut formed in a portion of the borehole, said resin nut including an internal thread extending continuously along the entire length of the resin nut, said continuous thread surrounding at least part of the threaded portion of the bolt; and   rotating the threaded portion of the bolt disposed with the sleeve relative to the resin nut to thread the threaded portion of the bolt disposed with the sleeve along the continuous internal thread of the resin nut.   
     
     
         11 . The method of  claim 10  wherein the sleeve is disposed on at least a portion of the elongate metal member sufficient to allow the elongate metal member to turn within the sleeve while the sleeve is embedded and fixed in a hardened resin nut. 
     
     
         12 . The method of  claim 10  wherein frictional resistance between the tensionable elongated bolt, disposed with the sleeve, and the hardened resin nut is reduced as compared to frictional resistance between a tensionable elongated bolt, not disposed with a sleeve, and a hardened resin nut. 
     
     
         13 . The method of  claim 10  in which the sleeve comprises a plastic, paint or metal; wherein a permanent bond is not formed between the plastic, paint or metal sleeve and the elongate metal member. 
     
     
         14 . The method of  claim 10  wherein the sleeve forms to contours of the elongate metal member such that an outer surface of the sleeve maintains threaded contours of the elongate metal member. 
     
     
         15 . An apparatus for installation in a borehole having a proximal opening and a distal end formed in a face of a mine passage, said apparatus comprising:
 a tensionable elongated bolt including an externally threaded portion for positioning in the borehole; wherein a sleeve is disposed on at least part of the threaded portion of the bolt, and wherein the sleeve has a thickness of less than about 1 mm;   a stationary, hardened resin nut having an internal thread extending continuously along the entire length of the resin nut for receiving at least part of the threaded portion of the bolt disposed with the sleeve; and   a drill head for rotating the bolt relative to the hardened resin nut.   
     
     
         16 . The apparatus of  claim 15  wherein frictional resistance between the tensionable elongated bolt, disposed with the sleeve, and the hardened resin nut is reduced as compared to frictional resistance between a tensionable elongated bolt, not disposed with a sleeve, and a hardened resin nut. 
     
     
         17 . A method of supporting a face of a mine passage including a borehole, said method comprising:
 inserting resin and a tensionable bolt including an externally threaded portion in the borehole, the tensionable bolt having a distal end spaced from an upper, distal end of the borehole and a proximal end adjacent an open, proximal end of the borehole; wherein a sleeve is disposed on at least part of the threaded portion of the tensionable bolt, and wherein the sleeve has a thickness of less than about 1 mm;   forming a stationary, hardened resin nut having an internal thread extending continuously along the length of the resin nut along the threaded portion of the bolt disposed with the sleeve; and   rotating the threaded portion of the tensionable bolt disposed with the sleeve relative to the resin nut to thread the threaded portion of the bolt disposed with the sleeve along the continuous internal thread of the resin nut.   
     
     
         18 . The method of  claim 17  wherein frictional resistance between the tensionable bolt, disposed with the sleeve, and the hardened resin nut is reduced as compared to frictional resistance between a tensionable bolt, not disposed with a sleeve, and a hardened resin nut. 
     
     
         19 . An apparatus for installation in a borehole formed in a face of a mine passage, said apparatus comprising:
 a tensionable elongated bolt including an externally threaded portion for positioning in the borehole; wherein a sleeve is disposed on at least part of the externally threaded portion of the tensionable elongated bolt, and wherein the sleeve has a thickness of less than about 1 mm; and   a stationary, hardened resin nut formed in a portion of the borehole, said resin nut including an internal thread extending continuously along a length of the resin nut, said length of said resin nut surrounding at least a first part of the externally threaded portion of the tensionable elongated bolt disposed with the sleeve while exposing a second part of the externally threaded portion of the tensionable elongated bolt disposed with the sleeve.   
     
     
         20 . The apparatus of  claim 19  wherein frictional resistance between the tensionable elongated bolt, disposed with the sleeve, and the hardened resin nut is reduced as compared to frictional resistance between a tensionable elongated bolt, not disposed with a sleeve, and a hardened resin nut.