ASX-listed Vietnam nickel hopeful Blackstone Minerals has produced a series of encouraging results from a maiden drilling program targeting the Ban Khoa disseminated nickel sulphide prospect at its Ta Khoa project about 160 kilometres west of Hanoi in northern Vietnam. The pick of the first batch of assays from Ban Khoa was 147 metres averaging grades of 0.31 per cent nickel, 0.04 per cent copper, 0.01 per cent cobalt and 0.14 grams per tonne PGEs from 62m depth.
Despite the lowish grades, the 147m hit shows Blackstone is in a significant mineralised system that suits its bulk tonnage mining strategy.
Other notable intersections returned in the recent round of 20 diamond core holes for an aggregate drilling coverage of 4,373m included 67.7m at 0.33 per cent nickel, 0.04 per cent copper, 0.01 per cent cobalt and 0.19 g/t PGEs from 105.3m and 32.1m at 0.48 per cent nickel, 0.08 per cent copper, 0.01 per cent cobalt and 0.33 g/t PGEs from 193.1m.
Another thick zone encountered weighed in at 60.2m going 0.37 per cent nickel, 0.07 per cent copper, 0.01 per cent cobalt and 0.09 g/t PGEs from 208.6m.
According to Blackstone, Ban Khoa represents a bulk tonnage disseminated sulphide open-cut mining opportunity potentially complementing its keystone Ban Phuc open-pittable deposit about one kilometre to the south.
The Perth-company says the Ban Khoa prospect has been earmarked for inclusion in its forthcoming pre-feasibility study on the proposed development of the Ta Khoa mining, processing and concentrator operation known as its “upstream business unit”.
Blackstone Minerals Managing Director Scott Williamson said: “We look forward to presenting a maiden resource for Ban Khoa as part of Blackstone’s upstream business unit PFS. We are confident that the current reported drilling results are indicative of the significant geological upside that Blackstone will continue to unlock at our flagship Ta Khoa nickel-copper-PGEs project.”
Ban Khoa mineralisation occurs in broad zones of lower-grade nickel sulphides disseminated throughout serpentinite rocks similar to the company’s Ban Phuc deposit. It contains lenses of heavily disseminated higher-grade nickel sulphides and PGEs.
Almost a year ago now Blackstone tabled an inaugural indicated mineral resource statement for its Ban Phuc disseminated nickel sulphide deposit of 44.3 million tonnes grading an average 0.52 per cent nickel for 229,000 tonnes of contained nickel.
It also hosts a further indicated mineral resource tipping the scales at 14.3 million tonnes at an average grade of 0.35 per cent nickel for 50,000 tonnes of contained nickel.
Blackstone’s scoping study preceding the advanced pre-feasibility study on Ta Khoa points to a base-case production scenario for the Ban Phuc disseminated nickel sulphide deposit of an ultimate 12,700 tonnes of nickel per annum across an initial projected mine life of eight and a half years.
The upstream operation was foreshadowed in the scoping study to churn out impressive average annual free cash flows before tax of about US$179 million a year.
Estimated CAPEX and pre-production capital payback period numbers for the proposed Ta Khoa project development came in at US$314 million and two and a half years, respectively.
The company is also running the ruler over a possible “downstream business unit” involving hydrometallurgical refining or upgrading of nickel sulphide concentrate to produce battery-grade nickel-cobalt-manganese precursor products for use in the manufacture of lithium-ion batteries.
Blackstone suggests the concentrate feed for a proposed new Ta Khoa refinery may be supplied from its Ta Khoa nickel-copper-PGE mine and also from third parties on a 50:50 basis.
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By Matt Birney
