COMMINUTION & CRUSHING
One of the recent applications the IsaMill is being lined up for is secondary grinding with a test at Hudbay’ s Stall Mill site in Manitoba – involving 8-mm and 10-mm ceramic media – demonstrating over 50 % reductions in specific energy consumption compared with traditional tumbling mills
technologies in this field to potentially show further synergies between the primary mills and secondary stirred milling technologies.”
And on the subject of CPF, Glencore Technology was expected to see many synergies between IsaMills in“ secondary duties” and downstream CPF units to already exist.
“ We know that the presence of steel media and steel internals can create pulp chemistry challenges with downstream flotation and one of the existing benefits of this IsaMill technology is the inert ceramic media and rubber lined components to mitigate this effect,” he said.“ Coarser media selection inherent with this duty not only allows coarse particles to grind more effectively through momentum transfer but also not grind fines excessively. Coupling this with the internal classification system inside the mill and automatic power control / media addition systems allows for tight control of the product size distribution and sharp top sizes before entering the downstream CPF stage.”
Testing the vertical roller mill waters
The emerging market dynamics that inspired privately-owned Gebr. Pfeiffer to enter the mining market a few years ago are undoubtedly still in play: the need to reduce the energy intensity associated with
38 grinding, to use less water during mineral processing and to produce products in a more sustainable fashion.
One only needs to look at the most recent CEEC Medal Winners list to reinforce this fact, with projects related to hydraulic dewatered stacking, sensor-driven insights for sustainable mineral processing and CPF all gaining recognition.
Mathias Dülfer, CEO of Gebr. Pfeiffer, sees an adaptation of the MVR vertical roller mill technology it has deployed across the cement sector coming into this list of technologies in the near future.
“ We are seeing a steadily growing interest in dry grinding technology with the vertical roller mill,” he told IM.“ While the maturity and readiness of emerging technologies such as ours remain challenging, innovations in the field of grinding are being acknowledged as important solutions to reduce energy and water consumption and improve sustainability.”
Yet, he and his colleague Dr Caroline Woywadt, Managing Director of Gebr. Pfeiffer Mining, acknowledge that the VRM solution is not a one-size-fits-all application.“ The overall benefits in terms of capital and operating expenditure must be evaluated for each project alongside the sustainability benefits, taking into account not only the grinding plant but also downstream processes,” Dülfer explained.
It may not be a one-size-fits-all solution, but, from the conversation IM had with Dülfer and Woywadt in February, it appears there should be a sizeable field of advantageous applications for its technology.
VRM technology, the company says, offers substantial benefits in terms of energy savings, improving liberation with higher recoveries at coarser grinding, delivering a uniform size reduction with a narrow PSD and having a high reduction size ratio of up to 1,000.
The company has created a new MVR duty series for iron ore and non-iron ore applications by adapting the existing proven technology that has been in operation in other sectors for more than two decades.
“ Plant layouts for different mill sizes have been finalised capable of throughputs from 500 t / h to 2,500 t / h for iron ore,” Dülfer said.
The company has also confirmed layout and maintenance concepts that are ready to be implemented, looking to appease miners and engineering firms that seek standardisation in the flowsheets they are developing.
The layouts Dülfer and Woywadt shared with IM showcased a compact footprint for a 2,500 t / h plant( 46-m wide by 74-m long), with conveyor belts, VFD-enabled fans and ceramic-lined cyclones all featuring in an MVR dry grinding setup.“ Due to the dry operation, the ground material can be stored in silos before further processing downstream,” Dülfer says.“ So, the grinding unit is de-coupled from downstream processing systems and gives an additional degree of freedom in process application.”
Alongside this, the company has devised a maintenance concept that sees worn MVR rollers exchanged in a matter of two days and the ability to use new wear protection materials produced in the company’ s foundry suitable for mining applications.
The company’ s test centre in Germany is helping refine such concepts and layouts, with Gebr. Pfeiffer technicians working flat out to process the client samples that it has received to this point.
“ We are completely loaded with samples as far as our test centre goes,” Dülfer said.
This test centre forms the backbone of pilot test work, looking to process up to 10 t of material for interested clients, which is in contrast to the 20-50 kg of material often requested for conventional grindability tests.“ We carry out extensive and relevant tests with significantly more tonnes,” Woywadt said, adding that the information that comes from these tests indicates not only material“ grindability” but also specifics about wear and process behaviour.
Ores featuring copper, gold, zinc and titanium have all been tested at its centre while most of the testing remains focused on a variety of iron-bearing ores.
“ We also are looking at the VRM’ s potential use in a pebble crusher setup after the AG or SAG mill where we could discharge the material directly to the flotation circuit,” Woywadt said, adding that the machine’ s compressive strength and shear force capabilities make it a good and energy-efficient candidate for such size reduction work.
Woywadt singled out some test work with an Indian iron ore sample to illustrate how extensive this type of work is.
“ In one instance, we looked at applying a selective grinding mode on our MVR during pilot tests with banded hematite quartz from India to separate the quartz material from the graded material,” she explained.“ The classifier coarse material and the classifier fines material were then separated downstream with dry magnetic separation technology, with the results for yield and total iron content( verified by Gebr. Pfeiffer’ s own X-ray Fluorescence analysis technology) showing promise.”
This type of testing also relates to Dülfer’ s assertion some two years ago that, in addition to using bulk sorting in front of the MVR mill to reduce the mill’ s load and increase the grinding circuit’ s efficiency with NextOre’ s magnetic resonance-based solutions, dry magnetic sorting should
International Mining | MARCH 2026