This paper examines the development of several order of magnitude trade-off studies to evaluate the application of High Pressure Grinding Rolls (HPGR) technology in comparison to the SAG mill grinding technology. These studies were prepared by Wardrop Engineering Inc. on eight different projects at various magnitude tonnages.
Studies for two molybdenum projects, one disseminated gold/sulphide project, and five copper/gold porphyry deposits located in Canada, Greenland and Russia, were carried out. These projects included for Pacific Booker Minerals, Imperial Metals Corporation, Abacus mining and Exploration and Seabridge Gold Inc. These processing plants were each designed to operate at 30,000 for, 60,000 and 120,000 tonnes per day capacities.
For abovementioned projects, the HPGR option indicated a gross power consumption reduction over a similar SAG mill grinding circuit. The overall operating cost savings were of the order of 15%. Indications are that the capital costs for the HPGR option was higher than the SAG mill option.