Aeon Metals is seeking potential sulphuric acid offtake clients to support the development of a roaster and acid plant as part of its Walford Creek project, in north-west Queensland.
A recently released cobalt roasting scoping study for the project proposes a large-scale, 2.5Mtpa open pit mine and onsite processing utilising a concentrator, roaster and acid plant to produce copper, zinc, and lead concentrates with payable silver as well as cobalt metal and sulphuric acid over a 15-year mine life.
The estimated total capital cost is about $668 million, including $33 million mining pre-strip costs and $55 million contingency funds.
It would produce on average some 1200tpa of cobalt, 8000tpa of copper, 15000tpa of zinc and 13000tpa of lead and would generate some 1.3Mtpa of sulphuric acid for sale.
Aeon Metals managing director Hamish Collins said the key issue of acid sales would need to be resolved to tap the full potential of Walford Creek.
“Currently, there is no market for this quantity of sulphuric acid but there are a number of proximate phosphate resources held by third parties which are potential offtakers of this acid,” he said.
“Other potential offtakers may emerge as the volume and security of this potential acid supply becomes more widely known. The study estimates a capital cost of $668 million with a three-year payback.”
Aeon has already completed a preliminary economic assessment based on mining the Vardy high-grade section of the Walford Creek resource and is proceeding to a bankable feasibility study on the Vardy project.
This would aim to produce, in its first year, some 10,000 tonnes of copper, 2000 tones of zinc and 500 tones of cobalt as early as 2019, for an estimated capital cost of $97.4 million.
But the Vardy resource only makes up about 9 per cent of the currently estimated Walford Creek Global Resource.
The wider scoping study – compiled in conjunction with AMEC Foster Wheeler – envisions a production start date of Q1-2022, assuming the receipt of all necessary government approvals.
A cogeneration plant would be installed at Walford Creek to utilise the waste heat from the roaster and acid plant to generate the majority of the project’s power requirements.