Upgrades and optimization of hard rock applications with HPGRs

Procemin 2013

In greenfield hard rock operations, High Pressure Grinding Roll technology is nowadays most often used in the tertiary crushing stage to prepare a ball mill feed. These installations, for instance Cerro Verde, Boddington, Mogalakwena, have been very successful over the past years.

However, HPGRs can also be used to up-grade or optimize existing hard rock installations. This could mean the retrofit of HPGRs in sAG-mill-based plants (Cadia Hill, Australia), as well as in conventional 3-stage crushing plants (Freeport Grasberg, Indonesia.)

The objective of retrofitting HPGRs in existing plants may be basically to increase capacity and / or recovery as well as to reduce operating cost. HPGR satellite plants are typically installed inside the concentrator —using available space— without disturbing the production during implementation.

Retrofitting HPGRs in some conventional crushing plants has been driven by the need to compensate reduced plant capacities caused by the requirement of processing harder ores than treated in the earlier stages. In such conventional crushing plants ‘harder’ ore results in reduced plant capacity due to limitations or constraints either in the crushing or most often in the ball mill plant.

This paper summarizes potential flow sheet options to incorporate HPGRs in existing hard rock plants, showing the potential benefits which are achievable in terms of increased capacity and recovery as well as operating cost savings.

This paper also refers to existing plants which have been using HPGRs for optimization, indicating the benefits achieved by incorporation of this technology.

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