Tag Archives: dry comminution

OZ Minerals’ West Musgrave copper-nickel plan receives board approval

Automation, Base metals, Comminution of minerals, Environmental, Mineral processing, Mineral project development, Mining equipment, Mining services, Power supply for mines, Sustainable mining, Water management, , , , , , , , , , , ,

The OZ Minerals Board has greenlit the build of the West Musgrave copper-nickel project in Western Australia, paving the way for the development of a remote asset using dry grinding technology, autonomous haulage and a significant volume of renewable power.

West Musgrave is set to become OZ Minerals’ fourth operating asset when it starts producing concentrate in the second half of 2025, in the process becoming the company’s cleanest and greenest mine with plans to reach net zero Scope 1 emissions by 2038.

The feasibility study the board signed off on details a 13.5 Mt/y operation with average production of circa-28,000 t/y of nickel and circa-35,000 t/y of copper over a 24-year operating life. Coming with a A$1.7 billion ($1.1 billion) direct initial capital expenditure bill, West Musgrave could provide cash flow generation of circa-A$1.9 billion during the first five years of production based on OZ Minerals’ projections.

One of the interesting additions to the process flowsheet – which has been mentioned in previous economic studies – is the use of LOESCHE’s Vertical Roller Mill (VRM) technology.

Two VRMs will operate in parallel after the primary and secondary crushing circuit at West Musgrave, with OZ Minerals noting benefits in reducing power consumption by around 20%, supporting higher flotation recovery and the operational flexibility to be ramped up and down. The latter is particularly important given OZ Minerals plans to make West Musgrave one of the largest fully off-grid, hybrid renewable powered mines in the world with an initial circa-80% renewable penetration rate, powered off wind and solar energy with a battery energy storage system in tow.

Dr Thomas Loesche, Managing Shareholder and owner of LOESCHE, said: “As a mining engineer with a degree in mineral processing, it has always been a vision of mine to develop dry-comminution technologies that enable better sorting efficiencies, reduced power and consumables. We are very pleased to be involved in such an important project. OZ Minerals is breaking new ground and proving that sustainability does not stand in the way of project development, but rather makes such projects possible.”

The application of the VRM technology has been peer reviewed for the project by independent experts and has been de-risked through pilot test work campaigns, OZ Minerals added.

Further upstream of the VRMs, OZ Minerals has stated plans to operate the mining fleet remotely from day one at West Musgrave, with the acquisition of an autonomous haulage system-enabled fleet on a leasing basis in the feasibility study outline.

OZ Minerals did not include details of the size of truck involved in the latest study, but the prefeasibility study originally released in 2020 highlighted the use of up to 25 220-t payload haul trucks.

There is also potential for these haul trucks to be electric in the future, with OZ Minerals saying its pathway is aligned with the potential transition to an electric haulage fleet at the first engine change out.

While OZ Minerals says it has the capacity to fully fund West Musgrave with a new A$1.2 billion syndicated facility supported by key relationship banks awaiting final binding agreements, it said potential strategic partnership in the project via a minority interest was being explored.

The next steps for the project involves award of contracts with major partners – it has already signed up GR Engineering to build the process plant; increasing the capacity of its camp to around 250 beds by early 2023; mobilisation of equipment to commence earthworks; finalise the power purchasing agreement and Living Hub – the latter of which has 350 permanent ensuite rooms; and increasing its owner team resources in line with the plan, including operational-readiness personnel.

OZ Minerals, Loesche team up following West Musgrave vertical roller mill test work

Automation, Base metals, Comminution of minerals, Environmental, Mineral processing, Mining equipment, Mining services, Sustainable mining, , , , , , , , , , , ,

OZ Minerals, following a successful prefeasibility study of vertical roller mills (VRM) at the West Musgrave project in Western Australia, has signed a “Partnering Agreement” with Loesche.

The agreement with the leading original equipment manufacturer (OEM) of VRMs will help the company as it moves to the next phase of the project, OZ Minerals said.

“By working in a collaborative, innovative and transparent way, we believe we will deliver superior outcomes for the project when compared to more traditional ways of engaging with suppliers,” OZ Minerals said.

In November 2017, OZ Minerals and Cassini, which owns 30% of West Musgrave, announced that the West Musgrave project would progress to a prefeasibility study. This prefeasibility study timeline was extended in 2019 to complete a detailed evaluation of additional value-add opportunities, the most significant of which was the use of a dry VRM to reduce power consumption.

The study, released earlier this year, showed off plans for a 26-year open-pit mine with “bottom quartile cash costs” and average production of circa-28,000 t/y of copper and circa-22,000 t/y of nickel in concentrates, OZ Minerals said.

It also included details of an “innovative mineral processing plant” that would be built on site.

The grinding circuit for West Musgrave was expected to consist of two stages of crushing followed by two parallel VRMs treating nominally 5 Mt/y each. The second stage of crushing and VRMs replaced a traditional SAG mill, ball mill and pebble crushing circuit.

OZ Minerals explained in the study: “Vertical roller mills are widely used in the grinding of cement plant feeds and products, slag, coal and other industrial minerals, with thousands currently in operation worldwide. The mill has benefits in reducing power consumption by circa-15%, no ball charge grinding media, higher flotation recovery and can be ramped up and down in response to the availability of low-cost renewable energy.”

The VRM uses compression-style comminution principles taking 75 mm rock to flotation feed size in the one machine, according to OZ, adding that the application of the VRM had reduced processing costs and provided a circa-2% improvement in nickel recovery compared with a previous scoping study.

“The technology has been peer reviewed for West Musgrave by an independent expert and has been substantially de-risked through a series of pilot tests whereby 5 t of West Musgrave ore has been tested,” the company said.

Reviewing the prefeasibility study, OZ Minerals Chief Executive Officer, Andrew Cole, said: “We have been able to achieve a further significant reduction in carbon emissions and power demand through the adoption of vertical roller mills as the grinding mill solution and a flotation flowsheet which achieves metal recovery at a much coarser grind size than was previously considered in the design.

“This lower power usage has resulted in a reduction in operating costs, while the use of dry grinding from the vertical roller mills has also resulted in an improvement in nickel recovery.”

Another innovation the company plan to use at West Musgrave include the use of hybrid renewables that could include a combination of wind and solar energy, battery back-up, and diesel or gas.

Mining at West Musgrave is modelled to be conventional drill, blast, load and haul and is assumed to be contractor operated during the first five years of operation, transitioning to owner operate in year six.

The haulage fleet will comprise up to 25 220 t haul trucks and optionality is being maintained to allow for these trucks to be fully autonomous in the future, OZ Minerals said.