Autogenous (AG) and Semi Autogenous (SAG) grinding mills are the conventional selection for large-scale grinding circuits. It is accepted that these forms of comminution are not the most energy efficient available. This efficiency combined with escalating energy prices, steel prices and the requirement to process larger, lower grade deposits has necessitated that better comminution techniques are found to challenge the dominant position of AG/SAG mills in the grinding circuit._x000D_
Recent advances in high pressure grinding rolls (HPGR), particularly in terms of roll surface protection have meant that, depending on the application, an economic alternative is available to the large diameter AG/SAG mills._x000D_
Mining companies now recognise the potential benefits of HPGR and so they need proper assessment in the design of new or upgrade of existing grinding processes._x000D_
Of course, the answer to the question AG/SAG or HPGR is not straightforward and the impact of the grinding process on the whole metallurgical process needs to be evaluated. Clearly this is a complex decision to make and requires substantial metallurgical knowledge, test work, and objective analysis._x000D_
The perceived downstream processing benefits will differ between different plants depending on the ore type and processing conditions._x000D_
The optimal design of the comminution circuit requires that a robust methodology is followed to objectively characterise the ore, size the equipment and determine the downstream processing benefits._x000D_
The paper gives a brief comparison of the capital and operating costs for both grinding systems, and then outlines the appropriate test work that is required to make an informed decision._x000D_
FORMAL CITATION:Koenig, R L and Hudson, J, 2006._x000D_
Design selection for large-scale grinding operations - AG/SAG or HPGR? in Proceedings Metallurgical Plant Design and Operating Strategies 2006, pp 234-251 (The Australasian Institute of Mining and Metallurgy: Melbourne).