Method of Surface Borehole Mining Using Horizontal Drilling Techniques

Abstract

A method of horizontal directional drilling is provided. The proposed method utilizes directional drilling in which boreholes are arranged in a pattern such that the surface area of extraction is maximized. The pattern can be achieved using a vertical borehole, multiple lateral boreholes and multiple subsidiary portions of the lateral boreholes. A lateral borehole is drilled extending beyond a vertical borehole towards the orebody, from which a subsidiary borehole is drilled into the orebody. Once the extraction is complete, the subsidiary borehole is back filled. A new subsidiary borehole is drilled extending beyond the lateral borehole and adjacent to the first subsidiary borehole. The subsidiary boreholes are planned to form a honeycomb or direct stacked pattern. Once all extraction is complete from a lateral borehole and its subsidiary boreholes, a new lateral borehole is drilled from the vertical borehole and the process is repeated.

1 . A method of directional drilling comprising:
 drilling a vertical borehole from a surface near an orebody;   drilling a lateral borehole extending beyond the vertical borehole towards the orebody;   drilling a first subsidiary borehole extending beyond the lateral borehole and into the orebody;   extracting ore from the orebody wherein the ore is transported to the surface via the first subsidiary borehole, the lateral borehole and the vertical borehole;   back-filling the first subsidiary borehole with a back-filling material;   drilling a second subsidiary borehole extending beyond the lateral borehole into the orebody, such that the second subsidiary borehole is positioned adjacent to the first subsidiary borehole;   extracting ore from the orebody wherein the ore is transported to the surface via the second subsidiary borehole, lateral borehole and the vertical borehole; and   back-filling the second subsidiary borehole with a back-filling material.   
     
     
         2 . The method of  claim 1 , wherein at least a second lateral borehole is drilled extending beyond the vertical borehole towards the orebody; such that:
 a subsidiary borehole is drilled extending beyond the second lateral borehole and into the orebody;   ore is extracted from the orebody wherein the extracted ore is transported to the surface via the subsidiary borehole, the second lateral borehole and the vertical borehole; and   the subsidiary borehole is back-filled with a back-filling material.   
     
     
         3 . The method of  claim 2 , wherein the method is repeated until the orebody has been substantially fully extracted;
 drilling subsequent subsidiary boreholes extending beyond the lateral borehole into the orebody; and   back-filling the subsequent subsidiary boreholes with a back-filling material after the ore is transported to the surface.   
     
     
         4 . The method of  claim 3 , wherein the vertical borehole is permanently drilled. 
     
     
         5 . The method of  claim 4 , wherein the back-filling material is selected from a group consisting of: soil cuttings, cement grout, wet bentonite chips and dry bentonite chips. 
     
     
         6 . The method of  claim 3 , wherein the first, second and subsequent subsidiary boreholes form a pattern for extracting ore from the orebody. 
     
     
         7 . The method of  claim 6 , wherein the formed pattern is a nested honeycomb pattern. 
     
     
         8 . The method of  claim 6 , wherein the formed pattern is a direct stacking honeycomb pattern. 
     
     
         9 . The system of  claim 3 , wherein the subsequent subsidiary boreholes are spaced apart to maximize recovery of the ore. 
     
     
         10 . A directional drilling system comprising:
 a vertical borehole;   a lateral borehole extending beyond the vertical borehole towards an orebody; and   a plurality of subsidiary boreholes extending beyond the lateral borehole and into the orebody;   wherein the plurality of subsidiary boreholes form a pattern for extracting ore from the orebody;   wherein the ore is transported to the surface via the plurality of subsidiary boreholes, the lateral borehole and the vertical borehole;   wherein the plurality of subsidiary boreholes are back-filled with a back-filling material after the ore is transported to the surface.   
     
     
         11 . The system of  claim 10 , wherein the vertical borehole is permanently installed. 
     
     
         12 . The system of  claim 7 , wherein the back-filling material is selected from a group consisting of: soil cuttings, cement grout, wet bentonite chips and dry bentonite chips. 
     
     
         13 . The system of  claim 10 , wherein the formed pattern is a nested honeycomb pattern. 
     
     
         14 . The system of  claim 10 , wherein the formed pattern is a direct stacking honeycomb pattern. 
     
     
         15 . The system of  claim 10 , wherein plurality of subsidiary boreholes are spaced apart to maximize recovery of the ore.