Grade Control Practices At Steep Rock Iron Mines Limited

CIM Bulletin, Vol. 70, No. 788, 1977

R. H. Duthle, Senior Geologist, Steep Rock Iron Mines Limited, Atlkokan, Ontario

As at any other mine in Canada, grade control procedures are used at Steep Bock Iron Mines (1) in order to ensure that concentrator and pellet-plant operators have a uniform feed so that they can manufacture a pellet to suit buyers' specifications and (2) to maximize ore recovery so that as little as possible finds its way to the waste dump or is downgraded by contamination. At Steep Rock, material grading 40% to 66% Fe is considered ore. The ore may contain up to 10% sulphur. These ranges create six different stockpile types, with the possibility of more if large concentrations of arsenic are encountered. Although grading and mining techniques used to accomplish these ends are fairly standard, there is an appreciation and willingness by hourly and staff pit personnel to make grade control effective. This produces vertical and horizontal communication, which is necessary for success in this field. At Steep Rock, the waste-to-ore ratio is greater than at any other iron ore mine in Canada. Also, a high percentage of the ore mined is direct pellet feed. For these reasons, grade control is very important.

Keywords: Grade control, Steep Rock Iron Mines Ltd., Open-pit mining, Iron ore, Sampling, Assaying, Stockpiling.