Metso saw record sales of stirred mills in 2025 as mining customers opted for energy-efficient grinding solutions. In minerals processing, there is growing demand for optimized technology combinations and multi-stage grinding to boost energy efficiency and reduce carbon emissions, as well as to improve productivity with optimized operating costs. In milling, these can be achieved by using Metso’s Vertimill® and HIGmill™ stirred mills and high-pressure grinding (HPGR) technology. Overall throughput and recovery can be further enhanced by combining the stirred mills with Concorde Cell™ flotation technology.
Metso stirred mills. Image Credit: Metso
Vertimills with Record Installed Power Deliver Significant Emissions Savings
In 2025, Metso sold over twenty Vertimill grinding mills with a combined installed power of 67 MW. With these stirred mills delivering up to 35 % energy savings compared to conventional ball mills, the total power saved amounts to approximately 36,550 kW. This impressive reduction is equivalent to avoiding 135,000 metric tons of CO2 emissions annually, based on 8,500 operating hours per year. To put this in perspective, the emissions savings are comparable to the annual carbon footprint of approximately 20,200 people, using the Finnish per capita average of 6.7 tons of CO2.
“The growing preference for stirred milling technology extends not only to established markets but also to new regions where this technology has previously not been considered. Additionally, many existing concentrator plants are choosing to enhance their operations with add-ons to incorporate these solutions. Stirred mills are now increasingly being deployed in secondary and tertiary grinding applications, handling a wide range of ores including copper, gold, and iron ore,” said Alan Boylston, Vice President, Stirred Mills at Metso. “Our comminution solutions portfolio is focused on future-oriented, energy-efficient technologies to meet our mining customers’ diverse requirements and support them with value-adding services.”
Comprehensive Stirred Mills Portfolio with a Large Installed Base
Metso has a leading stirred milling technologies portfolio, consisting of Vertimill®, HIGmill™, Stirred Media Detritor (SMD) mills, and Vertical Power Mills (VPM). These mills are based on?gravity-induced and fluidized technologies, allowing for an optimum equipment solution for all comminution circuits in secondary, tertiary, fine, ultrafine, regrind, and lime slaking applications. Stirred mills are part of the Metso Plus offering - a qualified?group of selected Metso products, services, or digital solutions that provide significant environmental performance improvements.?We also provide digital solutions as well as extensive support through a global network of service and repair centers.
With more than five decades of expertise in stirred mill technology, Metso has developed, tested, and delivered ~1,000 stirred mills to hundreds of sites worldwide.