The board of ASX-listed aspiring Vietnam base metals developer Blackstone Minerals has given the green light to a definitive feasibility study on its proposed downstream refinery and a related downstream pilot plant at its flagship 90 per cent-owned Ta Khoa nickel-copper-PGE project about 160km west of Hanoi. The move comes after the Perth-based company’s release last week of a “compelling” pre-feasibility study or “PFS” on hydrometallurgical processing of nickel sulphide concentrates to produce a battery-grade nickel-cobalt-manganese for use in lithium-ion batteries.
During the proposed phase one of pilot testing, Blackstone aims to process 20 kilograms of nickel concentrate feed per hour and produce various grades of nickel-cobalt-manganese precursor products – including NCM811 and NCM622 – at the rate of about 1.75kg per hour.
The $142 million market-capped company says pilot plant production is slated to kick off in the March quarter next year.
Design of the pilot plant, which will be stationed in Son La Province north-west of Ta Khoa, has been wrapped up now and the company expects to start acquiring equipment for the plant in the current quarter.
Test work data from the initial piloting will be incorporated into the Ta Khoa refinery definitive feasibility study or “DFS”, for which Blackstone has submitted scope of works to engineering firms.
It hopes to complete the DFS by mid-2022.
Blackstone Minerals Managing Director Scott Williamson said: “The board’s endorsement of the recent PFS milestone has been rapidly followed by approval of the first phase of piloting and the Ta Khoa refinery DFS. The pilot plant process is an opportunity for Blackstone to optimise, with respect to quantity and quality, recent successful outcomes which include the production of its first battery-grade NCM811 precursor sample.”
According to the PFS, processing of about 400,000 tonnes per annum of nickel concentrate by Blackstone’s proposed Ta Khoa refinery is predicted to deliver about 85,600t a year of nickel-cobalt-manganese precursor products and 43,500tpa of refined nickel over an initial 10-year life of operations.
Base-case annual operating cash flows have been tipped to average a cracking US$451 million a year and free cash flows after tax are estimated by the company at around US$365 million a year.
The pre-production CAPEX has been calculated in the PFS at US$491 million, with the processing plant soaking up half of the total.
The capital payback period has been estimated at a stunning 1.5 years.
All-in costs of production have been predicted to weigh in at an average of US$11,997 per tonne of NCM811 across the initial decade of operations.
Blackstone is targeting a final investment decision next year, production start-up in 2024 and eventual ramp-up to steady-state operations about two years later.
Mr Williamson said: “The base-case PFS financial outcomes are compelling based on an NCM811 precursor price forecast that is conservative compared to current observable market rates.”
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By Matt Birney
