There was some discussion about HPGR back when the Preliminary Feasibility Study came out. I haven't found any more recent info but it would be interesting to know why they decided to use SAG mills instead. The nearby KSM project plans to use HPGR.

"The Schaft Creek resource is a potential candidate for High Pressure Grinding Roll (HPGR) technology. The material is hard and only moderately abrasive."

"Approximately 260 kg of sample was crushed to 25 mm for HPGR testing by Polysius in
Germany. Testing began in early June 2008 so the results of these tests are pending.
However, it is anticipated that Schaft Creek materials should be good candidates for HPGR grinding because the material is relatively hard but not overly abrasive. Polysius will provide a report indicating the applicability of HPGR grinding for the Schaft Creek resource and, if appropriate, the approximate equipment sizes and wear rates for a 100,000 tonnes per day operation. If the results are encouraging, additional tests will be conducted on a larger sample. Samples of HPGR ground material will be returned to G&T for additional metallurgical testing to determine if there is any metallurgical benefit associated with HPGR grinding of Schaft Creek materials."