Mill Drive Systems for Copper Processing Efficiency

ABB and Harmony Gold are collaborating on the deployment of high-power mill drive systems for the Eva Copper Mine Project in Queensland, Australia. The cooperation focuses on integrating gearless and ring-geared drive technologies to improve grinding efficiency in large-scale copper ore processing.

Context of the Cooperation
Harmony Gold is developing the Eva Copper Mine as a large open-pit operation with an expected annual output of approximately 60,000 tonnes of copper over a projected 15-year lifespan. The project responds to increasing demand for copper driven by electrification and energy-related infrastructure.

ABB has been selected to supply the electrical drive systems required for ore comminution. The cooperation reflects the technical complexity of large grinding circuits, where energy consumption, mechanical reliability, and system integration must be optimized simultaneously. Combining mining operations expertise with advanced drive technology enables a more controlled and efficient processing environment.

Technical Solution and Responsibilities
The solution consists of a gearless mill drive (GMD) system rated at 24 MW for a 40-foot semi-autogenous grinding mill and a variable-speed ring-geared mill drive (RMD) system rated at 18 MW for a 27-foot ball mill. These mills represent the highest electrical loads within the concentrator, making drive efficiency a key design parameter.

The GMD system directly drives the mill without intermediate gearboxes, reducing mechanical losses and minimizing wear components. The RMD system uses a dual-pinion configuration with variable-speed control, allowing precise adjustment of rotational speed to match ore characteristics and process conditions.

ABB is responsible for the design, engineering, and integration of these systems, including control architectures aligned with industrial automation requirements. Engineering is distributed across international teams while ensuring compliance with Australian standards.

Deployment and Implementation
Implementation includes the delivery of a modular electrical house (eHouse), engineered and manufactured in Australia. This unit integrates power distribution and control systems in a pre-assembled structure, simplifying on-site installation and ensuring adherence to local safety and regulatory requirements.

Local manufacturing supports shorter logistics chains and facilitates integration with site infrastructure. Installation and commissioning are coordinated with the construction of the concentrator to align mechanical and electrical systems.

Applications and Use Cases
The drive systems are applied in the grinding stage of copper ore processing, where ore is reduced in size to enable downstream separation processes. Variable-speed operation allows adaptation to changing ore properties, improving process stability and throughput consistency. Reduced mechanical complexity also supports maintainability in continuous mining operations.

Expected Impact
The combined use of GMD and RMD technologies is expected to provide high availability and energy-efficient operation over the life of the mine. By reducing transmission losses and enabling precise control of grinding conditions, the system supports stable production rates and predictable maintenance cycles.

The cooperation illustrates how integrated electrical drive systems contribute to improved performance in mining infrastructure, supporting long-term copper supply through more efficient processing operations.

Edited by an industrial journalist Sucithra Mani with AI assistance.

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