When operating a grinding circuit (at Granny Smith) under a wide range of conditions: campaigning very competent underground ore followed by soft oxide, primary versus secondary crushed feed and finally single-stage SAG and conventional SAG, ball mill and pebble crusher (SABC) configurations.  Economics changed and a review of the circuit performance including modelling and simulation resulted in the circuit being converted to single-stage SAG, with the ball mill being idled at the lower tonnage.

Suddenly, a toll milling agreement resulted in the circuit having to return to SABC configuration; campaigning very competent underground ore (secondary crushed) followed by third party, soft oxide feed (primary crushed).  Do not miss what happened at SAG 2015.