Blasthole sloping at Inco's Birchtree Mine

CIM Bulletin, Vol. 72, No. 806, 1979

R. H. BROOKS Senior Layout Designer, R. E. MYERS Survey Party Leader, Inco Metals Company, Manitoba Division Thompson, Manitoba

Blasthole sloping methods were introduced at Birchtree Mine as an alternative to the original cut-and-fill and shrinkage stoping methods. The object was to take advantage of the ore structure and conditions, and achieve increased productivity. This paper outlines the design, operation and economics of three areas which utilized blasthole sloping. The 108 area from 2300 level to 1500 level was converted from cut-and-fill to sub-level blasthole sloping based on a block mining-and-filling sequence. The second area, the crown pillar of 110 mechanized cut-and-fill slope below 500 level, was recovered using horizontal rings drilled from raises within the ore zone. The third area, the 83 orebodyfrom 1300 level to 1100 level, used the vertical crater retreat (VCR) method with large-diameter blastholes.Blasthole stoping has increased productivity and improved operating conditions.
Keywords: Underground mining, Stoping, Blasthole stoping, Birchtree Mine, Pillar recovery, Vertical crater retreat mining, Drilling, Blasting.