Conversion from "post" pillar cut-and-fill mining to blasthole— a case study at Falconbridge

CIM Bulletin, Vol. 76, No. 849, 1983

S. BHARTI, J. LEBL and D.J. CORNETT, Falconbridge Limited, Canadian Nickel Division, Sudbury Operations Sudbury, Ontario

This paper presents the design and application of blasthole mining to an area at Strathcona Mine previously employing post pillar cut-and-fill. Extensive mining in the area had led to gradually deteriorating ground conditions and post pillar stop-ing was no longer considered acceptable. Alternative methods had to be investigated. Conventional methods for mining in poor ground were rejected because of the high cost. Blasthole mining was selected because it offered good productivity and safety with acceptable costs. The design of this approach involved field investigations and the use of numerical modelling to simulate the different blasthole options and their impact on ground stability. The blasthole design incorporated reinforcement with ca-blebolts, use of a radio-controlled remote LHD unit, large-diameter holes, blast design and wall control. Potentially unstable areas were outlined during mining with ground monitoring instruments and the results used to modify mining plans during the production phase.
Keywords: Underground mining, Post pillar mining, Cut-and-fill mining, Blasthole mining, Falconbridge, Strathcona Mine, Rock mechanics, Ground support.