The release of a Definitive Feasibility Study is the end of a long, exciting, and productive journey for our Company, and the beginning of an exciting new stage in the Lake Wells Sulphate of Potash Project development.
This exciting journey has been quite remarkable. In 2014 a Company geologist following a hunch dug a hole in the salty crust of a section of the Lake Wells lake system and collected samples of brine. In mid-2014, those assays came back with significantly elevated potassium and sulphate levels.
These assay results were not a complete surprise, however. In 2013, Geoscience Australia had released the findings of a research program where they had assessed and ranked all of Australia's salt-lake systems for the potential to host a range of elements, including; lithium, potassium, magnesium, sodium, and other minor industrial minerals. This research leads to the initial interest in looking at the Lake Wells area for minerals other than gold and base metals.
In September 2014, the Company started shallow air core drilling into the lake. The drilling provided samples of brine to depths of 60 metres and confirmed the potassium (K) content of the brine. Along with potassium, the second key element of interest is sulphur (S) in the form of sulphate (SO4), and again the concentrations of SO4 met or exceeded guidance for a potential economic deposit: the brine could make SOP.
A program commenced determining the volume of brine that could be extracted, following confirmation that the SOP grade of the brine was potentially economic.
As with other well-known palaeovalley systems in the Eastern Goldfields, the target was a deep palaeochannel with a coarse basal sand aquifer. Geophysical test work involving passive seismic techniques was successfully employed in identifying an extensive paleovalley system.
Drilling in 2015 confirmed the thickness of the valley fill and the types of brine bearing sediments. The lithology was encouraging. Confirming maximum depth to the basement of 170 m, two sandy horizons that could act as aquifers, and a thick sequence of clay-rich sediments was identified. Sampling of brine throughout the sedimentary sequence confirmed the grade of the brine reported in the surface sampling, and indicated a thick layer of sediments that could drain into the basal sands for abstraction (abstraction is the technical terms for extraction of water/brine via a bore from its source) from a series of bores or a borefield.
More drilling was completed along the interpreted length of the palaeovalley targeting basal sands, and a series of bores were constructed to allow test pumping to be completed to thoroughly test aquifer parameters. Exploration drill holes and water bores continued to intercept both upper and lower sandy aquifers, and test pumping showed that the bores could produce brine at high volumes. An assessment of the potential economic viability of the discovery was necessary to justify further work on the project, and a scoping study commenced.
In March 2017, the scoping study to develop the LSOP was released, along with a maiden resource estimate. The study indicated a robust and economically viable project that would produce 150,000tpa SOP over a mine life exceeding 20 years. Based on the positive scoping study, work continued at the Project to increase the size and confidence in the resource. Also, evaporation, processing, and other engineering studies for a definitive feasibility study (DFS) were progressed.
The findings of the DFS were released in August 2019, confirming the strong financial underpinning of the pending LSOP development. Good grades, healthy flow rates and optimal logistics all point towards a long-lived project with exceptional outcomes for stakeholders.