In a statement issued in late February, South Australian exploration company Minotaur Exploration expressed plans to divest the Lake Purdilla gypsum deposit discovered in the western part of the Eyre Peninsula.
The deposit is estimated to contain 87 million tonnes of gypsum with 91 per cent purity, which Tony Belperio, Minotaur’s executive director of business development, said was considered “a high grade for gypsum, comparing favourably to other Australian gypsum projects”.
Lake Purdilla is currently classified as an “inferred resource” – meaning it is yet to be verified through sampling – but Belperio said Minotaur believed that only a small amount of drilling would be required to upgrade “a substantial portion” of the deposit to the more assured classification of “indicated resource”.
The resource comprises deposits of crystalline lake gypsum (selenite) as well as an extensive system of wind-blown gypsum dunes (gypsarenite).
“[The dunes] provide an economic advantage as the gypsum is unconsolidated and more easily excavated,” Belperio commented. “Both dune and lake gypsum are comparable to those found at Australia’s largest gypsum deposit, Lake MacDonnell [also in SA].”
Export opportunity
Minotaur estimated that at an extraction rate of one million tonnes per annum, Lake Purdilla could support an export operation for more than 50 years.
“The resource is suitable for key gypsum uses, including plasterboard, cement and agricultural applications,” Belperio stated. “Beyond the domestic market, gypsum from Lake Purdilla could be shipped economically to Southeast Asia where the gypsum market is growing rapidly. International interest is highly possible.”
The resource is located near the existing Ceduna bulk handling port but Belperio said Minotaur would also be willing to work with the deposit’s new owner to progress the development of a new port immediately adjacent to the site.
“A port trans-shipment study has been completed on this which highlights the cost-effectiveness of the logistics solution,” he stated.
Belperio added that Lake Purdilla had already started attracting industry attention. “Minotaur is receiving expressions of interest from a range of parties, including plasterboard manufacturers, quarry operators, agricultural fertiliser businesses and private equity firms,” he said.
According to Minotaur, SA produces approximately four million tonnes of gypsum per year, which accounts for about 80 per cent of Australia’s production and supplies most of the country’s domestic requirements.
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