China's First Gearless Mill Drive Ball Mill Sets Global Records at 5,300 Metres

Why the world’s largest, most powerful, and highest-altitude GMD ball mill marks a milestone for large-scale mineral processing – and what it means for mining operators worldwide

On July 30, 2026, Metso announced the successful commissioning of China’s first gearless mill drive (GMD) ball mill at the Julong Copper Mine Phase II project in Tibet, operated by Zijin Mining Group. The mill, measuring 8.53 metres in diameter by 14.63 metres in length and powered by a 24,000 kW ring motor, achieves a single-line average ore throughput of 46,000 tonnes per day. Installed at an altitude of approximately 5,300 metres, it is the largest, most powerful, and highest-altitude GMD mill ever deployed. For mining operators and project developers, this installation demonstrates that gearless mill drive technology – previously only proven in overseas mega-projects – is now a viable and proven solution for large-scale, high-altitude operations in China. At OCP Mechanical Company, with over 40 years of manufacturing experience, we supply a comprehensive range of mineral processing equipment – including jaw crushers, cone crushers, and screens – designed to support large-scale mining operations, all at factory-direct prices.

GMD technology – a paradigm shift in grinding drive systems

The gearless mill drive represents a fundamental departure from conventional gear-driven mills. In a GMD system, the ring motor’s rotor is mounted directly onto the mill shell, with the stator positioned around the outside, and a frequency converter provides the direct drive. This eliminates the gearbox, pinion, girth gear, couplings, and other mechanical components found in traditional drive systems. Conventional gear-driven mills are typically limited to a maximum power of approximately 2 x 11,000 kW due to manufacturing constraints on large gears. GMD technology breaks through this limitation, enabling significantly larger mill sizes and higher throughput. Since the 1980s, GMDs have been progressively adopted in large-scale mining operations outside China, but until now, the technology had not been deployed domestically. The successful commissioning at Julong Phase II closes that gap, bringing Chinese mining operations into the forefront of large-scale, high-efficiency grinding technology. At OCP Mechanical, we recognise the importance of robust, reliable equipment for large-scale operations. While GMD technology represents the pinnacle of grinding drive systems, our comprehensive range of crushing and screening equipment is engineered to deliver consistent performance and low operating costs for mining operations of all scales.

Breaking three global records – scale, power, and altitude

The Julong Phase II GMD ball mill sets three world records simultaneously. At 8.53 metres in diameter and 14.63 metres in length, it is the largest GMD ball mill ever built. Its 24,000 kW ring motor makes it the most powerful, and its installation at approximately 5,300 metres above sea level makes it the highest-altitude GMD mill in operation anywhere in the world. This combination of scale, power, and extreme altitude places extraordinary demands on equipment design, installation, and commissioning. The successful operation of the mill at such high altitude – where lower air density affects cooling and electrical performance – demonstrates the maturity and reliability of GMD technology in the most challenging environments. For mining operators considering large-scale projects in high-altitude regions, the Julong installation provides a proven reference case. At OCP Mechanical, our equipment is built to withstand demanding conditions, and our engineering team can provide guidance on equipment selection and installation for high-altitude and remote operations.

Single-line throughput of 46,000 tonnes per day – the productivity advantage

The GMD ball mill at Julong Phase II delivers a single-line average ore throughput of 46,000 tonnes per day. This level of productivity is made possible by the combination of the mill’s large size and the efficient power delivery of the GMD system. By eliminating the mechanical losses associated with gear drives, the GMD system delivers more of the input power directly to the grinding process, improving energy efficiency and reducing operating costs. The high single-line throughput also enables operators to reduce the number of production lines required for a given total capacity, simplifying the plant layout and reducing capital expenditure. For large-scale mining projects, the ability to achieve high throughput with fewer lines is a significant advantage, reducing both initial investment and ongoing maintenance costs. OCP Mechanical’s complete mineral processing solutions are designed to support high-throughput operations, with equipment that delivers reliable performance and consistent product quality.

Key advantages of GMD technology for large-scale mining operations

Compared to conventional gear-driven mills, GMD technology offers several key advantages that make it particularly well-suited to large-scale, high-intensity grinding applications. First, the elimination of mechanical drive components removes the primary sources of wear and failure – gear teeth, pinions, and couplings – significantly reducing the risk of unplanned downtime. Second, the direct drive system improves energy efficiency by eliminating gear train losses, delivering long-term operational savings. Third, the ability to achieve larger mill sizes and higher power ratings enables higher single-line throughput, reducing the number of lines required and lowering capital expenditure. Fourth, the GMD system provides precise speed and torque control, enabling operators to optimise the grinding process for different ore types and feed conditions. These advantages are particularly valuable in high-altitude environments, where equipment reliability and efficiency are paramount. While GMD technology represents a significant capital investment, the long-term operational benefits – higher availability, lower energy consumption, and reduced maintenance – deliver a compelling return on investment for large-scale operations. At OCP Mechanical, we offer a comprehensive range of mineral processing equipment designed to deliver reliable performance and low operating costs, helping operators achieve their production targets efficiently.

Sample GMD ball mill specification summary (For reference only)

All figures and recommendations are for reference only and are continuously updated. For the latest parameters, please consult our online customer service. Prices are for reference only and are subject to change based on configuration and market conditions. Actual results may vary depending on feed characteristics, operating conditions, and maintenance practices. OCP Mechanical reserves the right to update technical data and pricing without prior notice.

Why OCP Mechanical is your partner for reliable mineral processing equipment

With over 40 years of manufacturing experience, OCP Mechanical combines engineering excellence with a deep understanding of the global mining and aggregate sectors. We are a factory-direct supplier, meaning you avoid the markups charged by dealers and intermediaries. Our comprehensive range of crushing and screening equipment – including PE Series jaw crushers, HST Series cone crushers, and VSI 6X sand making machines – is built with high-quality components and is designed for reliable performance in the most demanding applications. We provide comprehensive after-sales support, including spare parts availability, technical assistance, and on-site training. Our logistics team has extensive experience shipping to global destinations, ensuring timely delivery of equipment and parts. We are committed to helping you achieve efficient, productive mineral processing that supports your business growth.

Conclusion – Invest in reliable equipment for large-scale operations

The successful commissioning of the world’s largest, most powerful, and highest-altitude GMD ball mill at Julong Phase II demonstrates the transformative potential of advanced grinding technology for large-scale mining operations. For operators planning new projects or upgrading existing plants, the proven performance of GMD technology in extreme conditions provides a clear reference for equipment selection. OCP Mechanical offers reliable mineral processing equipment that meets the needs of modern operators, backed by expert guidance and responsive after-sales support. Our online customer service team is available 24/7 to provide free consultation, technical data, and a customised quotation for your operation. Click the chat button now – let us help you find the right equipment for your mining operation.