• IPT has completed 80% of metallurgical test work for Lake Hope High Purity Alumina (HPA) project pre-feasibility study
  • Scoping study due for release shortly, with PFS due in late 2024
  • Company expects to produce 99.99% purity 4N HPA early next year
  • 4N HPA will be used for product testing with potential offtakers


Impact Minerals says metallurgical test work for its Lake Hope High Purity Alumina (HPA) project in WA is 80% complete, and that the Pre-Feasibility Study (PFS) remains on track for completion by Q3-Q4 2024.

Lake Hope is unique deposit of clay which contains a resource of 3.5Mt at 25.1% Al2O3 for a contained 880,000t of alumina.

The alumina will be converted into HPA via Playa One’s proprietary and patented ‘Sulphate Process’. Because of the extremely fine-grained nature of the lake clays, the company expects to see ‘significant’ cost advantages to the mining and processing of the ore to produce HPA.

The clays are free-digging and require no crushing, screening or other on-site preparation and accordingly, it is envisaged that the clay will be trucked offsite to a pre-permitted industrial site, most likely either in Kalgoorlie or Perth.

The PFS is progressing on schedule, with Impact Minerals (ASX:IPT) able earn an 80% interest in the project from Playa One Pty on completion of the study.

“Our work continues to highlight the competitive advantages of the unique mineral deposit at Lake Hope and its potential to become one of the lowest-cost producers of HPA globally,” MD Dr Mike Jones said.


Producing 4N HPA by early next year

“We continue progressing rapidly across the entire pre-feasibility study on Lake Hope, particularly with the metallurgical test work,” MD Dr Mike Jones said.

“The test work has shown the Playa One sulphate process is straightforward and very effective in leaching the unique clays at Lake Hope.

“We are delighted with the results that have replicated or improved Playa One’s previous work.

“We have zeroed in on the ideal process conditions to make HPA in quantity and are very focused on making improvements that will reduce processing costs.

“We aim to produce 99.99% or 4N HPA by early next year.”

4N HPA is used in lithium-ion batteries as a battery separator, as a ceramic coating on an inorganic polyvinyl insulating membrane placed between the battery anode and cathode.

It’s also an essential ingredient to produce synthetic sapphire and LED lights.


Metallurgical test work optimisation underway

The PFS metallurgical test work has focused on replicating and optimising the Playa One sulphate process, which produced 99.99% Al2O3 (4N HPA) from representative material.

So far, the metallurgical optimisation program for Stage 1 to Stage 3 (out of the 5 stage process) has delivered results consistent with or exceeding Playa One’s previous test work.

It has also produced significant data for future process modelling work.

Impact has now produced high-quality intermediate salts with several elements below the detection limits of 100 ppm which have been submitted for Stage 4 purification with the subsequent Stage 5 process to produce HPA.

Preliminary results are expected by the end of 2023 to commercial low detection limits of 0.1 ppm to 2 ppm for 70 elements.

Further test work will then focus on using the optimised conditions for each stage on bulk samples in one run to demonstrate the repeatability of the process and its ability to produce significant quantities of HPA.

This work is expected to start in Q1 2024 and will lead to further refinements before engaging in metallurgical and hydrometallurgical flow sheet modelling to complete this part of the PFS.


Scoping study pending and PFS expected by Q4 24

The scoping study, which will provide preliminary economics for the Lake Hope project, is being independently reviewed based on the positive results from the metallurgical test work, financial modelling, and marketing information received to date.

“We look forward to releasing our scoping study shortly, following an independent review, which will give a first look at the economics of this exceptional project,” Dr Jones said.

The PFS remains on track for completion by Q3-Q4 2024, with ongoing work including environmental baseline studies which will commence in early November, along with a geotechnical drill program, shallow water bores and a bulk sample program to commence this quarter.

The company also has a meeting scheduled with the WA Department of Mines, Industry and Safety Regulations in late October to discuss the lodgement of a Mining Lease application.

In addition, ongoing discussions with industry analysts, marketing representatives and end users have commenced to secure agreements for product testing – which will be crucial next year when Impact can produce meaningful quantities of HPA for product qualification.



This article was developed in collaboration with Impact Minerals, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.