The future of SAG mills

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SAG mills are a well-established technology within the mining industry. But they are not without challenges, notably around energy and water consumption. North American Mining asked a group of leading experts for their opinion of the future of these workhorses of the mineral processing world.

Samuel Hearn, Global Sales Director, Multotec

Indirect energy consumption: grinding media and wear liners

Improving the wear life of mill liners is one way to tackle indirect energy consumption; it also improves mill productivity as downtime for liner replacement is reduced. Sam Hearn, global sales director at Multotec, explained how the company’s use of discrete element analysis (DEM) and finite element analysis (FEA) plays a key role when developing improved liner designs and formulations.

“DEM software enables us to simulate the interaction between the mill charge and the liners, and to evaluate liner profile over the life of the liner,” Hearn said. “The analysis considers a range of variables, such as the ore’s bond work index, its specific gravity, the size of the grinding media, the mill speed, and the slurry density, allowing us to accurately model the performance and wear of our mill liners. This includes predicting the liners’ wear life to avoid unscheduled downtime and to extend the time between replacements.”

Emphasising that no two mill liner applications are identical, this simulation “can guide very specific refinements in the liner design for each customer,” added the Multotec expert. “But a detailed understanding of the operating conditions is vital to ensure that the final solution delivers optimal results.”

Hearn concluded by saying that “the traditional use of steel liners in large SAG mills presents a number of challenges. For instance, there may be bending stress inside the steel liner due to inexact fitting on the mill’s curved surface, and the higher rigidity of steel compared to rubber makes it less than optimal for absorbing the energy of material inside the mill. This is where composite liners come into their own, combining the impact resistance of Hardox 500 steel inserts or chrome molly casting inserts with the absorption capacity of a specially formulated wear-resistant compound.”

Full article on: https://northamericanmining.com/index.php/2024/06/05/the-future-of-sag-mills/.