The Georgina Basin is a world-class phosphate province with numerous large Cambrian sedimentary phosphorite deposits in both the Northern Territory and Queensland.
Advanced phosphate projects
Verdant Minerals Ltd’s Ammaroo phosphate project is located ~80 km east of Barrow Creek. The company have completed a Bankable Feasibility Study, and environmental approvals are in place. A second major phosphate project in the Georgina Basin is Avenira Limited’s Wonarah project, where scoping studies are being progressed on the potential development of the resource. Both companies are investigating the potential for production of super-phosphoric acid.
The Nolans rare earths deposit in the Aileron Province near Aileron, is hosted within fluorapatite, and contains 11% phosphate. A definitive feasibility study by Arafura Resources has proposed annual production of 144,400 tonnes of merchant grade phosphoric acid as a by-product of rare earths processing.
Significant potential for potash resources occurs within brines in aquifers associated with salt lakes in Central Australia as well as in evaporitic deposits within the Neoproterozoic to Palaeozoic Amadeus Basin.
Advanced potash projects
The Karinga Lakes potash project, southwest of Alice Springs, contains hundreds of salt lakes with associated sub-surface brines enriched in salts containing potassium, magnesium and sulfate. The project is a joint venture between Verdant Minerals and Parkway Minerals NL.
A prefeasibility study was released in November 2020 based on an operation targeting sulfate of potash (SOP) production of 40 000 tonnes per annum over an initial mine life of 20 years. The project has an Indicated Mineral Resource of 1 Mt of potassium over 24 salt lakes, of which 520 000 t is ‘mineralisation contained in drainable porosity’. The mine plan is based on 8 salt lakes with a combined Resource of 580 000 t K. In total the planned production comprises ~430 000 t K dissolved in ~130 million m3 brine at an average life of mine grade of ~3.3 kg/m3 K.