Mining & Operation
 

The Cantung Mine produces ore at a rate of 1,160 short tons per day ("stpd"). Mineral Reserves support a mine life ending in Q4 2014. Primary mining methods include, longhole stoping and pillar-remnant ore recovery using different techniques. Currently, longhole methods are planned for mining the majority of the remaining reserves, both for pillar recovery and for primary mining in areas with favourable geometry.

 

The open pit mine is located west of the main underground ore body, at the 4900 level and contains the Open Pit and PUG Zones. Access is limited to the summer months, as the steep road is prone to icing and avalanche danger during the winter. 

 

Mining is carried out by use of conventional open pit methods. The pit utilizes a triple bench with the bench height being 20 ft, 25 ft safety berm, and 12% grade for the haul road. 

 

Pit ore is hauled over a three mile haulage road to a stockpile located in the vicinity of the primary crusher, directly above the mill. The ore, grading approximately 0.5% WO3, is occasionally blended with underground feed whenever underground production lags below planned levels.

 

Underground, the majority of remaining reserves are mined using longhole methods. Access drifts are driven under the old workings, providing drill locations for upholes into remnant pillars above. 

 

Cut and fill methods are used in areas with narrower ore widths, such as the West Extension, and for a few primary stopes in other areas. Mining widths for cut and fill are approximately 15 ft. Waste rock is used as backfill for the working areas. Backfill material comes from waste development.

 

From both the open pit and underground sections of the mine, ore is either taken from a stockpile by a loader or directly dumped from haulage truck into a 30 ton receiving bin equipped with 42 in x 10 ft apron feeder, which, in turn, feeds a 42 in x 48 in jaw crusher reducing the ore to a nominal five inch crushed product. A vibratory feeder and a conveyor then feed a 4¼ ft (secondary) standard head cone crusher, which produces a minus 1½ inch product. Any oversize remaining is fed into a tertiary short head cone crusher. Finally, 5/8 inch marerial is screened out and conveyed to grinding mills in the concentrator.