Ark Mines has expanded its reporting from the Sandy Mitchell rare earths and heavy minerals project to an 11-mineral monazite-equivalent formula
A scoping study is expected within weeks, which will incorporate the latest MRE, upgraded to 379.4Mt and additional products
More drilling and a pre-feasibility study planned for next year as Ark targets mining in late 2028
After supersizing the resource tonnage at its Sandy Mitchell rare earths and heavy minerals project Ark Mines is now focused on releasing a scoping study within weeks while looking to production in 2028.
The push behind Ark’s (ASX:AHK) momentum follows Sandy Mitchell’s mineral resource estimate (MRE) increasing by a whopping 428% to 379.4Mt at 5,430ppm monazite equivalent (MzEq). Significantly, just 9.8Mt of the total resource is in the inferred category, with the remaining 97% classified as measured and indicated.
Monazite is one of the two source minerals that have historically supplied most of the world’s light rare earth elements.
CEO Roger Jackson says this makes Sandy Mitchell the largest rare earths 2012 JORC Code MRE of its type – that is, hosted in residual heavy mineral sand derived from a metamorphic basement complex.
More importantly, the resource upgrade has strengthened Ark’s case for a broader revenue stream with garnet, muscovite and other heavy mineral products set to join monazite, zircon and titanium minerals in the planned product basket.
Jackson says this gives the company a much stronger framework for assessing the North Queensland project’s commercial potential.
But he says Ark is using a monazite equivalent number on the basis that monazite remains Sandy Mitchell’s main commercial driver.
Bonus minerals
One of the potentially significant additions to the resource is garnet, which Jackson says represents about 2.7% of the quoted sand volume.
Garnet is well-known for its use in abrasive cutting and polishing, as well as ceramics.
With the other additional minerals, garnet could provide a meaningful credit because it is recovered alongside heavy minerals rather than requiring a separate mining operation.
“They add to the bottom line because we get them for free along with the monazite, the zircon and titanium,” Jackson says.
Zircon is used in a wide range of applications from high-temperature manufacturing through to jewellery.
Titanium faces high demand from the usual critical mineral customers – defence and aerospace – as well as paints and pigments, including the growing recycling sector because it brightens up dull-coloured products.
Muscovite is another potential commercial product, with applications including electrical and thermal insulation, capacitors and semiconductors.
Biotite also has potential applications in paints, plastics and rubber, as well as fertiliser, which Jackson says makes it relevant to a very local market.
“We’re in the Atherton Tablelands, which is a huge agricultural food basket. With all the irrigation and agriculture up there, there is a strong market for fertiliser,” he says.
“A lot of people haven’t really considered these products, myself included, until I started digging deeper into the project.
“We’ve learned a lot, but regardless of the exact value these products have, they add to the bottom line because we get them for free along with the monazite and the zircon.”
Test work and scoping study
With the resource now substantially larger and broader, and 97% of the tonnage classified as Measured and Indicated, Ark is turning its attention to the project’s economics.
“The company is working through a comprehensive metallurgical program aimed at optimising recovery of the various minerals,” he says.
“We’re working through a very comprehensive set of metallurgical tests, which are ongoing and that work will run through into next year.
“We understand to a point that we can recover these components from the project, but the next step is optimising the process and understanding how it needs to be designed and built to achieve the best recovery percentages we possibly can.”
Jackson says the project has approximately 400Mt of material available for processing, with the nature of the deposit meaning much of the material could potentially be reprocessed rather than lost through mining.
That could support a long mine life and potentially higher annual throughput, while the additional mineral products could provide low-cost credits.
While the test work is ongoing, Jackson says the company still has sufficient metallurgical understanding to release a scoping study, incorporating the latest MRE, within the next few weeks.
“Next year we’ll do more drilling, but we’ll also be plugging all the numbers from the metallurgy into a PFS, with the ambition of mining in late 2028,” Jackson says.
More resource upside
Ark’s mineralised footprint currently covers only about 14% of its tenure, although Jackson said the more meaningful comparison was with the company’s exploration target.
“We believe that target is very accurate and robust because our rare earths, particularly monazite, produce a radiometric signature from the thorium in the monazite. It stands out very well because it is near surface, so we can see it and map it,” Jackson says.
“We’ve drilled a good part of that exploration target, which was at the lower end around 1.32 billion tonnes and at the upper end around 1.5 billion tonnes.”
He says the company is confident it can potentially add a significant amount to the resource.
“The exploration target will also change when we add in the other commercial minerals,” he says.
Government backing
Adding strength to Ark’s tailwinds is its $4.5 million in support from the Queensland government’s Critical Minerals and Battery Technology Fund, administered through Queensland Investment Corporation.
Jackson describes the funding as a stepping stone towards the PFS and boost to investor interest.
“It also inspires confidence in other funders to become involved in our project because the Queensland government has already stepped in,” he says.
“We’re in a friendly political environment and we’re fortunate to be in a locality that’s ideal for mining. Our project is very low impact on the environment and has no effect on real farming, and we’re close to the mining town of Chillagoe.”
At Stockhead, we tell it like it is. While Ark Mines is a Stockhead advertiser, it did not sponsor this article.
This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.
Originally published as Ark Mines charts a course beyond rare earths at Sandy Mitchell