Trade-Off Realities in HPGR vs. SAG Milling—A Practical Comparison of Tropicana and Gruyere Comminution Circuits
*I.A. Lovatt, M. Becker and B. Putland1, R. Radford2, J. Robinson3
- Orway Mineral Consultants Level 5, 1 Adelaide Terrace, East Perth, Western Australia 6004
- Gold Fields Level 4, 235 St Georges Terrace, Perth, Western Australia 6000
- AngloGold Ashanti Australia Level 10/140 St Georges Terrace, Perth, Western Australia 6000
(*Corresponding author:
Abstract
The uptake of HPGR technology in mineral processing has been accelerated by the drive for energy-efficient comminution solutions. A HPGR trade-off study is now part of the typical due diligence process when assessing the suitability of SAG milling circuits, particularly for large-scale, hard rock applications with moderate to high power cost.
The energy consumption savings are now reasonably well established for HPGR circuits, however the overall trade-off outcome in practice is less understood. To provide an operating benchmark, the authors undertook a collaborative review of the neighbouring Gruyere and Tropicana operations in Western Australia.
Construction of the Tropicana Gold Mine (Tropicana) commenced in November 2010, with first ore processed during July 2013. The comminution circuit is secondary crush, HPGR ball-milling now achieving 8.6-9.5 Mt/a. The Gruyere project construction commenced during 2017, with first ore processed in May 2019. The comminution circuit flowsheet is primary crush, SABC (SAG mill, ball mill and pebble crusher) treating about 8.5-9.0 Mt/a of fresh ore. Orway Mineral Consultants (OMC) has been involved with both projects from scoping-level study to current optimisation. This paper presents the energy efficiency and relative costs of both circuits, adjusted to provide a relative comparison of the two flowsheets.
Keywords: Circuit design, energy efficiency, SAG milling, HPGR grinding, cost comparison, trade-off economics.