Pencil bit tooling for continuous miners in potash

CIM Bulletin, Vol. 74, No. 836, 1981

ERIC BEST, Senior Mine Maintenance Engineer, Potash Corporation of Saskatchewan Mining Limited, Lanigan Division

In the past two to three years, all continuous mining machines at the Potash Corporation of Saskatchewan Mining Limited, Lanigan Division, have been changed over to a new cutting pattern using 1-inch- and 1-3/16-inch-diameter self-sharpening pencil bits. The bits are arranged in a cone-type pattern across the face on 2'A-inch and 3-inch spacing. The result is that the ore is removed by chipping and flaking. Previously, rap-lock bits were used, with the pattern being several bits in single rows at wide spacings. The cutting action was grinding and breaking.Besides improved penetration rates and lower bit costs, there are many other advantages. The ore size is much smaller, resulting in less wear and tear on conveyors and other associated equipment. Feeder-breakers are no longer routinely set up at the head end of every extensible belt, as the banana-shaped chunks of ore that used to require breaking are no longer produced. Also, less dust is generated by the cutting heads and fewer stops are required for bit changes. Even the mill operation has been improved, as fewer fines are produced.Further improvements are still sought after, but, all in all, the new cutting pattern is considered to be a giant step forward from the old method.
Keywords: Industrial minerals, Potash, Underground mining, Continuous miners, Bits, Pencil bits, Lanigan mine.