Paper presented by Dr. Rajiv Chandramohan (Ausenco) and Kevin Erwin (Newmont Goldcorp) at SAG Conference 2019, Vancouver, Canada, 25 September, 2019.
Newmont Goldcorp’s Peñasquito operation, located in the state of Zacatecas in northwest Mexico, is currently undergoing a series of optimisation works to increase throughput through the comminution circuit. Primary crusher product feeds the comminution circuit, comprising a parallel train of two SAG mills, pebble crushers and four ball mills. Additional feed is augmented through the primary comminution circuit from a separate circuit consisting of a secondary crusher and an HPGR.
As part of the optimisation plan, Ausenco, Peñasquito, and Newmont Goldcorp Technical Services defined clear strategies classified into short, medium, and long-term opportunities in preparation for the future competent ore sources. The comminution circuit at Peñasquito was operating below its full potential due to some unit operations not fully drawing installed power as well has material handling bottlenecks limiting individual circuit throughput.
Some of the critical comminution optimisation strategies included:
De-constraining the SAG mill throughput with optimized operational load set points and revised process control
Redesigning the SAG mill liners for optimum load and speed control
Optimising crushing and HPGR operation for maximised throughput rates at the minimised product size distribution.
Ausenco’s comminution optimisation tool, Ausgrind, was used to benchmark and analyse plant data with empirical models, predict circuit performance for varying ore characteristics, evaluate SAG mill liner wear and predict the life for varying operating parameters. Variances between the actual and the predicted values were assessed in detail to identify missed opportunities and help guide operations with re-defined operating parameters to maximise throughput and productivity.