COMMINUTION & CRUSHING
saving exercise when it comes to power ; it is also about the grinding media . To put the energy and environmental resources into manufacturing steel grinding media that is designed to be destroyed is wasteful .”
With the use of HPGRs and VSMs , the only grinding media that is manufactured is a ceramicbased solution built to last . Similarly , the tyres on HPGRs are expected to have a life of one-totwo years . And , on top of that , Weir now offers a 10-year ( 100,000 hours ) guarantee on its HPGR bearing arrangement .
Lundquist added : “ The big shift in flowsheet design and development is going to occur when investors start pushing back on the selection of inefficient equipment by mine operators and realise there are solutions out there that can prove a company ’ s sustainability credentials .”
What is helping the cause further is the proliferation of Enduron HPGRs across the mining sector , with Weir having won several contracts over the past five-to-six years , many of which have translated into operating units in the field .
This has resulted in more widely publicised trade-off studies showcasing Enduron HPGRs in a better light – from a capital cost perspective – than previous , confirmation of the operating cost benefits over the SAG mill equivalent , and the ability to conduct more direct comparisons from one mine to another .
“ This benchmarking needs to be as close to 1:1 as you can find ,” Lundquist explained . “ Mine operators can easily do that with SAG mills due to the high population across the industry ; we ’ re now approaching the point where they will be able to carry out the same comparisons with HPGR installations at existing operations to compare to a possible new site .”
Lundquist highlights two installations in Canada that could become industry “ benchmarks ” in the future – the 2.4 m x 2.4 m HPGR now installed at the Côté gold project in Ontario , Canada , and a similar sized unit in place at the Equinox Gold operated Greenstone gold mine , also in Ontario .
After start-up , both units will likely be operating under extreme temperatures during the next winter , providing the benchmark other gold mining operations in the northern hemisphere will likely require to progress similar HPGR investigations .
Lundquist and his colleague Nick Logan , Product Manager – Comminution ( USA ), were keen to clarify that not all operations are necessarily suited for HPGR processing , explaining Weir was keen to test any thesis before making flowsheet assumptions .
Logan said : “ We want to make flowsheet recommendations based on test work to assess how to liberate the chosen minerals with the lowest amount of energy .”
This test work can vary from enough material to carry out a “ first pass ” trial with 150 kg at one of Weir ’ s facilities , to 1-1.5 t of material for a “ full scale ” test , Lundquist added . “ Both of these are typically designed to verify feasibility assessments and make sure the material processes as designed with the same expectations around installed power , circulating load , product size , etc .”
Weir is also able to conduct HPGR and VSM testing at its Venlo , Netherlands , facility where Enduron HPGR and STM VSM technology are both installed .
This test work , on top of Weir ’ s expanding digital platform , is helping more operations understand the realities of installing and operating HPGRs in the design stage . And , on the digitalisation topic , Lundquist said “ connected ” HPGRs that have cloud-based access and remote monitoring for machine diagnostics are now installed and operating in the field .
As well as a slew of new greenfield applications coming through the commissioning stages , the business case for Enduron brownfield installations is strengthening .
Already the company has shown how one or two HPGRs can replace upwards of 10 crushers in outdated and complex circuits , and Weir is now going modular to win market share .
“ In Canada – and I expect in the US – there is a big shift towards what I would refer to as ‘ modular ’ HPGRs ,” Lundquist said . “ These are smaller , more flexible units that can be dropped into existing operations to boost throughput and size reduction capabilities .
“ Weir already has some of these projects in the pipeline . Hopefully we can say more soon .”
Metso ’ s flowsheet thinking on energy and water use
Eliminating water from the mineral processing dynamic is , of course , part of Metso ’ s Planet Positive aims , but it is also cognisant of the fact that many segments of the industry still rely on water resources to carry out their jobs effectively .
Brian Knorr , Vice President , Technology & Innovation , Minerals , says the company is continuing to strengthen its portfolio of crushing and screening products , with Metso seeing growing demand in terms of integrated crushing systems – especially those that include bulk and particle sorting .
The incorporation of sensor-based sorting into
the processing mix , if deployed effectively and with good ore characterisation processes at the very beginning , could reduce both the energy and water requirements associated with downstream processing .
“ In addition , high pressure grinding rolls ( HPGRs ) offer excellent energy efficiency and are amenable to dry processing when operated in combination with air classifiers ,” Knorr told IM , explaining that this arrangement is most useful when physical separation can also be dry , such as using dry LIMS ( low-intensity magnetic separation ).
At the same time , Metso is homing in on developing products and processes that make efficient use of water , with water recycling and metallurgical water management remaining important areas of development .
When it comes to screening equipment , Metso has developed several solutions that meet its Planet Positive criteria . The use of ultrafine screens ( UFS ) in fine wet separation in grinding circuits can provide better energy efficiency than hydrocyclones . They can also be used in conjunction with hydrocyclone equipment in a two-stage classification setup to form a combination circuit and help achieve a better balance between cost and efficiency , according to the company .
BSE banana screens use elliptical motion with 6G acceleration that eliminates blinding and plugging in high-moisture screening . In regions with long rainy seasons , these can be an option to effectively replace wet screening and help reduce the use and storage of water , the company claims . With less water usage needed , pulp handling equipment can often be removed ( eg pumps , dewatering equipment and thickeners ), leading to a reduction in energy consumption .
Metso is taking a similar tack when looking at integrating its products into grids leveraging
The incorporation of sensor-based sorting into the processing mix , if deployed effectively and with good ore characterisation processes at the very beginning , could reduce both the energy and water requirements associated with downstream processing , Metso says
40 International Mining | APRIL 2024