Phosphate and Potash

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.

In approvals process

• Ammaroo – Verdant Minerals Ltd 1.145 Bt @ 14.26% P₂O₅ including 348 Mt @ 18% P₂O₅

Under feasibility

• Highland Plains – Gibb River Diamonds Ltd 53 Mt @ 16% P₂O₅
• Wonarah – Avenira Ltd 842 Mt @ 18.1% P₂O₅ including 5.3 Mt @ 30% P₂O₅ (Main Zone) and 4.4 Mt @ 30% P₂O₅ (Arruwurra)

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.

Advanced phosphate projects

In approvals process

• Nolans – Arafura Resources Ltd 56 Mt @ 11% P₂O₅, 2.6% REO, 0.02% U₃O₈

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.

Under feasibility

Batchelor Phosphate - GTFT Australia Ltd - no published JORC resource

• Kruse et al 2013. Georgina Basin. In Geology and mineral resources of the Northern Territory. NTGS Special Publication 5, Chapter 28.
• Khan et al 2007. Phosphate testing of waterbores and diamond drillcore in the Georgina, Wiso and Daly basins, Northern Territory. NTGS Record 2007-003.