Major Impact on new Lake Hope LTL Process 

A new proprietary metallurgical process has been identified for producing high-value High Purity Alumina (HPA) from the lake clays at Impact Minerals’ (ASX:IPT) Lake Hope Project in Western Australia 

The company has uncovered a ‘breakthrough’ alternative HPA metallurgy route at Lake Hope, located 500 km east of Perth, after the use of the new low-temperature leach (LTL) Process. 

The $31.51 million market capitalisation company says the LTL Process has produced HPA at 99.999% purity from the raw lake clay in only a few months of laboratory testwork — one of the fastest times to produce HPA from raw materials reported by ASX-listed companies. 

The LTL Process is a simpler process that may lower the capital and operating costs to produce HPA compared to the Sulphate Process, which has been the focus of testwork to date.

Impact says this result attests to the relatively straightforward nature of the process, which utilises a range of reagents to those used in the Playa One Sulphate Process, which has also recently produced 4N HPA, as reported by

The company has now started further optimisation studies for the LTL Process and will push forward with our Prefeasibility Study (PFS) using both process routes for the time being to determine the best strategic choice for processing at the project.

Managing Director Dr Mike Jones given Impact can run all these tests in parallel for little extra cost, it is still on course to finish the PFS later this year and continue to look forward towards producing HPA from Lake Hope.

“The LTL Process is simpler than the sulphate process that underpinned our recent Scoping Study and showed that at less than US$4,000 per tonne, Lake Hope may produce HPA at up to 50% cheaper than our peers. 

We think that further work on the LTL Process could result in even lower operating and capital costs, and this would only further enhance the already immersive economics of the project, which has a NPV (net present value) of well over $1 billion.”

Given the potential for chemical and fertiliser products as a valuable by-product from both the sulphate process and the LTL Process, an assessment of the mineral potential of the wider Lake Hope playa system is in progress. 

The PFS is scheduled to be completed in late 2024. Metallurgical testwork is the critical component of the work to be completed for the PFS and is the focus of the forward work program, which will now include batch production from both processes. 

All results are due in the next quarter and will allow a final choice to be made of the process route required for commercial production of HPA. 

The recently released Scoping Study on Lake Hope, which was based on the Sulphate Process, showed that at an operating cost of less than US$4,000 per tonne, Lake Hope could be the lowest-cost producer of HPA globally by a significant margin of up to 50% over Impact’s peers.

Therefore, the company says this margin could be increased should testwork on the new process support these initial results and further demonstrate the potential world-class economics of the Lake Hope project.

Impact Minerals is an explorer which manages ‘extensive’ tenement holdings within Australia. 

The Lake Hope Project sits in Western Australia about 500km east of Perth. Impact can earn an 80% interest in Playa One, which owns the project, by completing the aforementioned PFS.

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Images: Impact Minerals
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Written By Adam Drought
Born and raised in the UK, Adam is a sports fanatic with an interest in Rugby League and UFC/MMA. When not training in Muay Thai and Brazilian Jiu Jitsu, Adam attends Griffith University where he is completing his final year of a Communication & Journalism degree.