Liner system for salt mine shafts

Abstract

A mine shaft protective barrier includes an undercut in a wall surface of the mine shaft proximate to and below a water ingress ingress elevation. A fire-resistant material is applied within the undercut and downward along the wall surface below the to form a coating barrier that extends from the undercut downward along the mine shaft such that water entering the wall surface at the ingress location tends to flow downward into contact with and along an inward facing surface of the coating barrier so as to inhibit such water from flowing in contact with and degrading the wall surface of the mine shaft below the ingress location.

What is claimed is:  
     
         1 . A method of rehabilitating a wall surface of a salt mine shaft, the method comprising, comprising:
 (a) identifying an ingress location along a height of the wall surface at which water passes through the wall surface into the shaft;   (b) forming a recess or undercut in the wall surface below the identified ingress elevation;   (c) utilizing a plural component spray process to apply a fire-resistant material, in the form of a first polyurethane or polyurea compound, into the recess or undercut and along the wall surface below the recess or undercut forming a coating barrier that extends from the recess or undercut downward along the mine shaft such that water entering the wall surface at the ingress location tends to flow downward into contact with and along an inward facing surface of the coating barrier so as to inhibit such water from flowing in contact with and degrading the wall surface of the mine shaft below the ingress location.   
     
     
         2 . The method of  claim 1 , further including:
 (d) identifying a void recess in a configuration of the coating barrier resulting from a configuration of the wall surface;   (e) utilizing a plural component spray process to apply a structural foam material, in the form of a second polyurethane or polyurea compound, into the void recess;   (f) utilizing a plural component spray process to apply the fire-resistant material over the structural foam material.   
     
     
         3 . The method of  claim 2  wherein steps (d), (e) and (f) are performed multiple times corresponding to multiple void recesses. 
     
     
         4 . The method of  claim 2  wherein in step (f) the fire-resistant material is applied so as to bond with the coating barrier of step (c) such that the structural foam material is completely encased in the fire-resistant material. 
     
     
         5 . The method of  claim 1  wherein the fire-resistant material is applied in multiple passes. 
     
     
         6 . The method of  claim 1  wherein the fire-resistant material is sprayed onto the wall from a dispensing device aperture that is at least ten feet from the wall surface. 
     
     
         7 . The method of  claim 1  wherein the fire-resistant material is sprayed onto the wall from a dispensing device aperture that is at least fifteen feet from the wall surface. 
     
     
         8 . The method of  claim 2  wherein:
 the fire-resistant material includes an isocyanate in combination with (i) one or more of an alcohol, a hydroxyl, a polyol or an amine and (ii) a fire retardant, but not including any foaming agent; and 
 the structural foam material includes an isocyanate in combination with (i) one or more of an alcohol, a hydroxyl, a polyol or an amine and (ii) a fire retardant and (iii) a foaming agent to create a foaming characteristic. 
 
     
     
         9 . The method of  claim 8  wherein:
 the isocyanate of the structural foam material is 4,4-diphenylmethane diisocyanate; 
 the isocyanate of the fire resistant material is selected from the group consisting of isophorone diisocyanate, methylene diphenyl diisocyanate, toluene diisocyanate or hexamethylene diisocyanate. 
 
     
     
         10 . The method of  claim 1  wherein the wall surface comprises a salt material. 
     
     
         11 . A mine shaft protective barrier, comprising:
 an undercut in a wall surface of the mine shaft proximate to and below a water ingress ingress elevation;   a fire-resistant material applied within the undercut and downward along the wall surface below the to form a coating barrier that extends from the undercut downward along the mine shaft such that water entering the wall surface at the ingress location tends to flow downward into contact with and along an inward facing surface of the coating barrier so as to inhibit such water from flowing in contact with and degrading the wall surface of the mine shaft below the ingress location.   
     
     
         12 . The mine shaft protective barrier of  claim 11 , further comprising:
 multiple recessed pockets formed by the fire-resistant material, each recessed pocket having a structural foam material, in the form of a second polyurethane or polyurea compound, applied therein, and an additional application of the fire-resistant material over the structural foam material.   
     
     
         13 . The mine shaft protective barrier of  claim 12  wherein, for each recessed pocket, the fire-resistant material completely encases of the structural foam material in the recessed pocket.