Stope development for raise mining at the Namew Lake mine
Raise mining at the Namew Lake Nickel Mine in Manitoba uses 3 m diameter bored raises driven at 45 to 50 degrees dip for slope access and drilling. These raises are developed within the orebody on 20 m centres to accommodate electric-hydraulic longhole jumbos and charging wagons. Critical elements ofstope development include delineation of ore contacts, control of deviation during raise development, optimal slope sequencing to permit a high extraction rate, drill anchorage installation, production drilling and blasting, and ground control. Procedures to deal with these elements are described, with emphasis on the geotechnical investigation for design of open slopes and pillars.
Although mining with drilled raises does not have the flexibility to follow large variations in orebody dip, results to date indicate that it can be used successfully in the thicker ore zones. Thinner zones are currently mined using a modified Avoca method. Some flexibility to accommodate variations in orebody dip in thin ore zones may be obtained by using alimack raise climbers to drive access raises, and carry longhole drills and charging equipment. Rock quality has been sufficiently good to maintain stable slope walls for full-height mining of primary slopes at 20 m strike length.
Raise mining, Namew Lake mine, Nickel deposits, Manitoba.