Octava Minerals has fired the starter’s gun on a staged exploration program at its West Sierra Grande fluorspar project in Argentina, aiming to breathe new life into a district peppered with historical high-grade mines.
The company is targeting hydrothermal fluorspar veins across 400 square kilometres of exploration patch of ground in the Río Negro Province. The project lies 17km west of the town of Sierra Grande, near a paved national highway and 47km west of the Punta Colorada export port.
It includes four historical mines where production peaked in the late 1970's. The district's structurally controlled hydrothermal veins can reach 12m thick and extend for hundreds of metres. Historical reports cite grades of 58 to 70 per cent calcium fluoride, with some clean vein material exceeding 80 per cent.
Still widely regarded as Argentina’s biggest and highest-grade fluorspar province, the area has seen little or no modern exploration. Shallow surface mining and limited underground development left the continuity of the veins below the old workings, along strike and at depth, untested.
The historical workings are Octava’s immediate priority. The initial program will map geology and collect rock chips along with soil sampling to test and extend the existing interpretation. Trenching and other intrusive surface work await approvals.
In parallel, a remote sensing survey will begin shortly across the wider project area and is expected to take four to six weeks. It will combine multispectral and hyperspectral satellite data with terrain information and artificial intelligence (AI) assisted interpretation to map structural corridors and alteration features associated with fluorspar veins.
The results will be used to rank locations for follow-up field investigation and guide subsequent geochemical, geophysical and drill testing. Octava says it's also considering drone magnetics and selective induced polarisation and resistivity surveys to help define drill targets.
Octava Minerals managing director Bevan Wakelam said: “We have a clear, staged approach to the exploration, targeting drill testing extensions around the historical fluorspar mines and drill target generation across the wider exploration portfolio.”
Permit applications covering the project ground have been submitted to the mining authority and remain pending. Once granted, the proposed initial drilling program will test selected targets for possible mineralisation extensions along strike and at depth around the historic workings.
As part of the permit applications, the company must provide technical information, including baseline environmental studies. Environmental consultants are heading to site to complete the work ahead of submitting the applications to Río Negro authorities within the next month.
On 28 September, Octava entered a binding conditional share sale agreement with Argentina Critical Minerals (ACM), a subsidiary of Global Strategic Commodities, to acquire up to 100 per cent of Aybull S.A., the local company holding West Sierra Grande. ACM is an Argentina-focused critical minerals project generator and developer, while Aybull is its portfolio company and the registered holder of the West Sierra Grande exploration tenure.
It is a try-before-you-buy deal. The option can lead to a 70 per cent interest, with the remaining 30 per cent conditional on defining a maiden JORC-compliant resource of at least 500,000 tonnes grading a minimum 30 per cent calcium fluoride.
Calcium fluoride is the mineral fluorite, commonly known as fluorspar. Australia, the US and the EU list it as a critical mineral. It is used to make hydrofluoric acid, which has applications in semiconductor manufacturing, battery materials and refrigerants. Octava recently reported that acid-grade fluorspar prices had doubled since 2017, adding a supply-chain angle to its interest in the commodity.
The Argentinian fluorspar play is a new focus for Octava, which also holds a portfolio of other critical minerals projects in Australia. These include the Byro project in Western Australia, host to a conceptual exploration target for rare earths, lithium and vanadium, and the East Kimberley project, prospective for nickel and platinum group elements.
With a well-defined exploration plan now in motion, Octava is looking to apply modern techniques to a district largely untouched for decades. If the company can prove the old-timers left plenty behind, it could quickly put its name on the map as a new player in the critical fluorspar supply chain.
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