The Lake Wells potash project represents an exciting development in Western Australia, where Australian Potash (APC) is leading the charge towards a brine-based sulphate of potash (SOP) operation in the Yilgarn Craton region.
The project’s journey began with a comprehensive scoping study completed in March 2017, followed by a definitive feasibility study (DFS) in August 2019. The DFS outlined a promising projection of producing 150,000 tonnes of SOP annually over a mine life of approximately 30 years, with an initial capital investment of £114.6m (A$208m).
Environmental responsibility is a priority, and in May 2020, the project received authorization from Australia’s Environmental Protection Authority (EPA) for preparatory works.
Presently, APC is actively engaged in the front-end engineering design (FEED) study, securing crucial offtake agreements, and arranging financing to propel the Lake Wells project. Notably, this venture is considered a low-cost solar salt SOP operation, with the potential for an extended operational life of up to 50 years.
The company has already secured off-take agreements for 70,000 tonnes per annum (tpa) of potash from the Lake Wells project as of May 2020, showing strong market interest.
Location, geology, and mineralisation
Geographically, the Lake Wells project is strategically located in the Eastern Goldfields region of Western Australia, approximately 160km away from Laverton and 500km northeast of Kalgoorlie. APC holds three mining leases and 17 exploration licenses, covering an expansive total area of 2,100km2 for the Lake Wells SOP project.
The project centers around a palaeochannel brine-hosted SOP deposit, situated on the north-eastern margin of the Archaean Yilgarn Craton. The valuable potash-rich brine resources are found within layers of aquifers and clay-rich sediments.
Potash reserves at Lake Wells
Lake Wells boasts substantial potash reserves, with estimates indicating 3.6 million tonnes (Mt) of proven and probable SOP reserves and a substantial 18.1Mt of SOP in measured and indicated resources.
Mining and brine processing
The mining and brine processing operations are ingeniously designed. The potash-rich brine is efficiently extracted through a network of 78 bores across the project area, with a pumping rate of 540 liters/second.
The extracted brine undergoes sun-evaporation for potassium-bearing mineral recovery in three evaporative ponds, including buffer and pre-concentration ponds spanning 10km2 and a 2.7km2 harvest pond.
After the evaporation process, potash-bearing salts are transported to a nearby processing plant with a capacity to produce 150,000t of SOP per year. At the plant, the salts are crushed and converted into potassium-bearing schoenite using an exothermic conversion reactor.
To ensure high purity, the schoenite is separated from the gangue material through flotation, with additional schoenite obtained via precipitation in a leaching process. The final product, SOP crystals, are formed by dissolving Muriate of Potash (MOP) and amalgamating it with the high-purity schoenite.
Lake Wells has solidified its market position with substantial off-take agreements. APC secured a 10-year binding agreement with Redox, a prominent chemical and ingredients distributor in Australia and New Zealand, for 20,000tpa of SOP from the Lake Wells project in March 2020.
Additionally, a second long-term offtake agreement for 50,000tpa of SOP was signed with Singapore-based Migao International in April 2020.
Infrastructure facilities are well-planned to support the project’s growth. The Lake Wells site is accessible through Lake Wells Road and the Great Central Road, situated east of Laverton. A 12MW gas-fired power station operating on trucked LNG will supply electricity through power cables to the bore field. Furthermore, a permanent camp accommodating up to 100 people will be built at the site to ensure efficient operations.
Throughout this impressive venture, various reputable contractors have contributed their expertise. The mineral resource estimate for the project was provided by AQ2, while process plant design and engineering services were undertaken by NovoPro. The evaporation and harvest pond design were entrusted to Knight Piésold Consulting, with process plant capital and sustaining cost estimates offered by Lycopodium. Lastly, Origin Capital Group provided valuable financial modeling services for the project.
The Lake Wells Australian Potash Project embodies the vision of sustainable and responsible resource extraction, offering a bright future for the Australian potash industry and contributing to the global demand for SOP.