SPECIALIST EQUIPMENT MODERN MILLS
The mining drive expert Sankar Singha tells us how geared mill drive systems are reshaping the grinding circuit
M
ill drive systems are essential in mineral processing plants, particularly for
commodities like copper and gold, where ore must be reduced in size for extraction. As demand for larger and more efficient grinding solutions grows, the industry is re-evaluating drive technologies.
THE RISE OF ADVANCED GEARED SOLUTIONS Geared drive solutions are reshaping industry preferences. As mining companies seek efficient, cost- effective, and reliable solutions, the latest geared drive innovations are gaining traction. With recent advancements such as enhanced scalability, improved torque distribution, and self-aligning pinion technology, they are poised to play a key role in the next generation of mineral processing plants.
A SHIFT IN DRIVE TECHNOLOGY Historically, mills up to about 30 feet in diameter were driven by ring gear and pinion systems, powered by motors and gearboxes. As torque demands increased, engineering challenges in designing high-power gearboxes and large-diameter ring gears led to the rise of gearless mills in the late 1970s. These systems eliminate traditional mechanical components, relying on magnetic torque transmission via an air gap between the stator and rotor. However, over the past few
decades, metallurgy, precision gear manufacturing and computational engineering have improved significantly. Leading gear manufacturers like Flender have developed next-generation geared solutions, such as the DMG series, enabling mill drive configurations up to 30 MW. These improvements offer
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www.engineerlive.com The Flender DMG Series - geared mill drive system
a cost-effective and operationally flexible alternative to gearless drives.
ENHANCING POWER DISTRIBUTION AND RELIABILITY Modern geared drive systems now feature quad-pinion girth gear engagement, effectively distributing mechanical power across multiple pinions for optimal torque control and load sharing. The Flender DMG series
incorporates self-aligning pinions, which automatically adjust alignment, ensuring consistent contact patterns and reducing uneven wear. This extends component lifespan, minimises unplanned maintenance, and enhances operational efficiency. Additionally, integrated inching drives improve safety and operational flexibility, while locked charge detection adds extra protection.
EFFICIENCY AND COST COMPARISON While gearless drives have been favoured for their mechanical efficiency, a more holistic analysis of total system efficiency, including electrical components and auxiliary losses, shows that modern geared drives offer comparable efficiency. A detailed study on large mills shows around 90% overall efficiency for
both gearless and quad-pinion geared drive, considering all peripheral and auxiliary systems.
COMPARED WITH GEARLESS MILL DRIVES, FLENDER’S GEARED MILL DRIVE SYSTEM OFFERS THE FOLLOWING ADVANTAGES:
A 50% reduction in capital expenditure
Equivalent overall drive system efficiency
Faster delivery and easier installation
Simplified maintenance and far less operational downtime
No additional cooling units Minimised long-term operational risk Flexibility in procurement
DIGITAL MINING The mining industry is undergoing a gradual but consistent transformation through the integration of automation, data analytics, and the Internet of Things (IoT) to enhance efficiency, safety, and sustainability. In line with this global trend, Flender has developed its proprietary AIQ monitoring system, now embedded into the DMG series gearboxes. This intelligent solution can be fully integrated into a plant’s automation pyramid, enabling optimised mill utilisation while significantly improving system reliability and operational transparency.
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