TSX-listed Deep-South Resources reports that, using a heap leach treatment operation, its openpit Haib copper project, in Namibia, demonstrates robust economics.

An updated preliminary economic assessment (PEA), conducted by METS Engineering Group, considered an indicated mineral resource of 456.9-million tonnes and a grade of 0.31% copper.

The inferred resource is 342.4-million tonnes at a grade of 0.29% copper.

The PEA also estimates a pre-tax net present value of $977-million, an internal rate of return of 30.1% at a commodity copper price of $2.50/lb of copper. With a mine life of 24 years, mine throughput would need to be 20-million tonnes a year, with copper recovery of 80% and production of 35 300 t/y of copper cathodes and 51 080 t/y of copper sulphate.

With further metallurgical work and testing, Deep-South’s goal is to attain higher recovery rates.

The PEA update was carried out to incorporate the results from South African State-owned mineral and metallurgical analysis company Mintek’s metallurgical test work programme, which ran from 2019 to this year, and is based on the PEA report completed by METS in February 2018.

The updated PEA presents the findings of the enhanced PEA focussed on the heap leaching process route and is the only process technology option updated from the 2018 PEA.

The recent leaching test work was carried out by Mintek. Amenability test work confirmed copper recoveries of up to 95% in bacterially-assisted heap leaching of the Haib mineral. Recoveries of 80% and 82% were shown to be achievable and sustainable for the project by the test work to date.

Further work is required to refine and enhance process conditions to improve recoveries and operating costs.

Run-of-mine mineral bio-heap leaching was determined to be the most viable process route for the Haib mineral. Six processing scenarios were established with the key variables being recoveries, final products (copper cathode and copper sulfate) and metal price.

Deep-South president and CEO Pierre Léveillé says the past year's metallurgical work has enabled the project to show a potential low capital expenditure of $341-million and operational expenditure operation in a challenging copper price environment.

“With our recent management nominations, we are well positioned to enhance and advance the project further.”

Deep-South COO Paul Smith adds that the updated PEA has set the scene for the company to move towards a feasibility phase on the Haib project, with ever-improving economics.

“The application of great technological advances in geological exploration, mineral processing and extractive metallurgy, will most likely see Haib rapidly becoming a global ‘tier one’ copper project, with the right economics for development.”