Underground Mine and Method of Mining

Abstract

A method of underground mining includes mining material using a continuous miner to form at least one set of entries comprising a plurality of entries. A plurality of crosscuts extend between and connect the entries. A plurality of pillars are defined by the entries and crosscuts. The entries and crosscuts define a passage having a roof, a floor, and sidewalls. The pillars at least in part are adapted to prevent the roof of the passage from collapsing. Roof bolts are installed in the roof of the passage. Material is mined from the sidewalls of the passage with the continuous miner to form perimeter cuts extending outwardly from the passage. The perimeter cuts are free of roof bolts. At least approximately 30 percent of the material mined from within the set of entries is derived from the unbolted perimeter cuts.

1 . A method of underground mining comprising:
 mining material using a continuous miner to form at least one set of entries comprising a plurality of entries, a plurality of crosscuts extending between and connecting the entries, and a plurality of pillars being defined by the entries and crosscuts, the entries and crosscuts defining a passage having a roof, a floor, and sidewalls, the pillars at least in part being adapted to prevent the roof of the passage from collapsing;   installing roof bolts in the roof of the passage; and   mining material from the sidewalls of the passage with the continuous miner to form perimeter cuts extending outwardly from the passage, the perimeter cuts being free of roof bolts, at least approximately 30 percent of the material mined from within the set of entries being derived from the unbolted perimeter cuts.   
   
   
       2 . A method as set forth in  claim 1  wherein material is mined to form at least one set of perimeter wall entries comprising a plurality of perimeter wall entries, a plurality of perimeter wall crosscuts, and a plurality of perimeter wall pillars. 
   
   
       3 . A method as set forth in  claim 2  wherein material is mined to form four perimeter wall entries. 
   
   
       4 . A method as set forth in  claim 2  wherein material is mined to form three perimeter wall entries. 
   
   
       5 . A method as set forth in  claim 2  wherein material is mined to form two perimeter wall entries. 
   
   
       6 . A method as set forth in  claim 2  wherein at least approximately 37 percent of the material mined from the set perimeter wall entries is derived from the unbolted perimeter cuts. 
   
   
       7 . A method as set forth in  claim 2  wherein at least approximately 48 percent of the material mined from the set perimeter wall entries is derived from the unbolted perimeter cuts. 
   
   
       8 . A method as set forth in  claim 1  wherein the entries are formed to have a length greater than 600 feet. 
   
   
       9 . A method as set forth in  claim 1  wherein a plurality of continuous miners is operated in the set of entries to form the perimeter cuts. 
   
   
       10 . A method as set forth in  claim 9  wherein two continuous miners are operated in the set of entries. 
   
   
       11 . A method as set forth in  claim 1  further comprising installing stoppings in the crosscuts to direct ventilation air to flow in two separate streams through the set of entries. 
   
   
       12 . A method as set forth in  claim 1  further comprising conveying the mined material out of the set of entries using a conveyor belt.