Blackstone Minerals Ltd (ASX:BSX, OTCQX:BLSTF) has delivered an impressive 73% increase in the mineral resource for its Ta Khoa Nickel Project in northern Vietnam, bringing the asset up to 485,000-tonnes of nickel with strong upside potential.
A global resource update is founded on an upgrade for the cornerstone Ban Phuc deposit along with maiden inferred resources at the Ban Chang, King Snake and Ban Khoa targets.
Combined, the key prospects deliver a newly minted mineral resource estimate (MRE) equal to 130 million tonnes of ore at 0.37% nickel for 485,000 contained tonnes (or 0.44% nickel equivalent for 571,000 tonnes of ore).
In the lead up to the upgrade, Blackstone completed extensive exploration from 2019 — campaigns that included geochemical and geophysical activities, drilling and mapping programs, analytical testing and resource evaluations.
“Enviable scale, increased confidence”
Speaking to the major update, Blackstone managing director Scott Williamson said: “An aggressive drill out over the past 12 months has culminated in a global Ta Khoa mineral resource of enviable scale and increased confidence.
“Our mineral resource is an early indication of the potential of the Ta Khoa nickel sulphide district, with further aggressive testing already ongoing.
“Ban Phuc, our large bulk tonnage disseminated sulphide deposit, will underpin base load feed to a large concentrator that is being examined in our upstream pre-feasibility study.
“Ban Chang and King Snake are the first of many high-grade massive sulphide opportunities and the company continues to work diligently to increase surety of nickel supply for our downstream refinery in Vietnam, with exploration and resource delineation at Ta Khoa being a core part of our strategy.”
Upgraded Ban Phuc mineral resource
The MRE for Ban Phuc deposit now stands at 123 million tonnes of ore at 0.37% nickel for 452,000 tonnes of nickel resource (or 0.43% nickel equivalent for 523,000 tonnes of ore).
This marks a major increase on the previous estimate, reported at 58.7 million tonnes at 0.48% for 280,000 tonnes, unveiled in June last year.
Of the bolstered resource, 102 million tonnes at 0.38% nickel (or 0.44% nickel equivalent) is in the indicated category, while 21 million tonnes at 0.33% (or 0.37% equivalent) is classified as inferred.
The Ban Phuc mineral resource is reported using a 0.25% nickel cut-off grade for the sulphide component and a 0.3% cut-off grade for the oxide and transitional component.
Ultimately, Blackstone believes the updated resource will underpin higher throughputs, with a large, 8-million-tonne-per-annum concentrator now being adopted as the base case in the company’s upcoming pre-feasibility study (PFS) for Ta Khoa.
What’s more, the shape and width of mineralised domains and the continuity of mineralisation are driving low strip ratios for the final Ban Phuc PFS pit design.
Maiden inferred resources
Ban Khoa
The maiden inferred mineral resource for Ta Khoa’s Ban Khoa disseminated sulphide (DSS) deposits is 6.2 million tonnes at 0.31%.
Promisingly, preliminary mining studies have indicated there is the potential for an open-pit mine at the target.
Drill rigs continue to turn the soil at the deposits, with a resource update on the cards once all the information is finalised.
Massive sulphide vein targets
Maiden resources have also been established for two massive sulphide vein (MSV) targets at Ta Khoa: the Ban Chang and King Snake prospects.
Ban Chang’s inferred resource is 700,000 tonnes at 1.2% (or 2.0% equivalent) and King Snake stands at 430,000 tonnes at 1.3% (or 2.4% equivalent).
Higher grade MSV resources are intended to be developed as underground mines and will provide supplementary feed to the large concentrator, which remains the focus of the upcoming PFS.
Additional test-work is being performed to confirm the metallurgical recovery of blended Ta Khoa ore, which comprises predominantly Ban Phuc DSS deposit and smaller quantities of the Ban Khoa DSS resource along with the MSV resources.
In addition to primary nickel content, the Ban Chang and King Snake deposits feature strong copper, cobalt, gold, palladium and platinum by-product credits.
Drilling continues at the Ban Chang and King Snake MSV deposits, where resources will be updated once all information is finalised.