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The solution was complemented by the integration of Weir’ s NEXT intelligent monitoring system, including roping detection. This provides continuous feedback on cyclone operation, enabling operators to identify and correct inefficient conditions – such as roping – before they affect throughput or separation efficiency. Following a staged implementation, the upgraded configuration was deployed across all grinding lines, supported by collaboration between site metallurgists and Weir process specialists.
CAVEX hydrocyclones improve recovery by up to 2 % at Montana Resources
Montana Resources’ open-pit copper and molybdenum operation in Butte, Montana, has improved recovery and circuit stability following an upgrade to its grinding classification stage. The plant, which processes around 50,000 t / d through a rod mill – ball mill circuit, identified hydrocyclone performance as a key limiting factor.
Classification inefficiencies and downtime
Previously, the classification circuit relied on competitor hydrocyclones that were constraining both metallurgical performance and plant availability. Frequent failures – sometimes several times per week – resulted in unplanned downtime of up to two hours per incident, contributing to losses of approximately 10,000 t of ore per month.
At the same time, poor classification efficiency allowed coarse particles to bypass grinding and enter downstream flotation circuits, reducing recovery while increasing wear rates on downstream equipment. The operation also lacked real-time visibility into cyclone performance, limiting the ability to proactively manage process conditions and maintain optimal separation efficiency.
Retrofit approach and digital monitoring
To address these issues, the classification circuit was retrofitted with CAVEX ® hydrocyclones, with additional units incorporated to provide operational flexibility without altering the existing plant footprint.
Recovery, wear life and reliability gains
The upgrade resulted in improved circuit performance across several key metrics. Copper recovery increased by up to 2 %, driven by improved separation efficiency and reduced bypass of coarse material to flotation.
Hydrocyclone wear life also improved significantly, with liner life extending beyond 24 months – approximately 2.5 times longer than the previous installation. This reduced the frequency of maintenance interventions and enabled work to be carried out without interrupting mill operations.
Unplanned downtime associated with cyclone failures was eliminated, while operating stability improved through continuous monitoring and control. The system enabled all cyclones to operate consistently at peak efficiency without roping conditions.
Looking to improve classification?
For operations facing similar constraints, reassessing classification performance offers a practical route to improve recovery, extend wear life and reduce downtime – particularly in brownfield plants with limited scope for major modification.
For more information visit: https:// www. global. weir / NEXT
International Mining | JUNE 2026 19