Gold Mountain says it has put its foot on a big chunk of ground it believes to be prospective for rare earths and niobium in the mineral-rich Brazilian State of Minas Gerais, with 20 new tenements covering 388sq km.
The company says its new tenure comprises four groups disposed across a tract of country surrounding and within an 80km radius of the world’s biggest niobium mine in the State’s Araxá region. That operation contains 94 per cent of the world’s niobium reserves and Brazil currently has a firm grip on 82 per cent of the element’s global market.
The Araxá region is about 450km north of Sao Paulo and its famed apatite-niobium deposit is hosted by the Barreiro carbonatite-alkaline igneous complex about 6km south of Araxá city. Three of Gold Mountain’s tenement groups lie within 40km of the Araxá operation.
And more importantly, all four of its tenement groups enclose or are on the margins of intense magnetic and radiometric signatures it says are similar to those which characterise the Araxá mine carbonatite complex. They also include parts of the wall rock zones of nearby carbonatites that display typical evidence of hydrothermal alteration.
The overall area around the tenements appears to comprise eight or nine Late Cretaceous carbonatite intrusives that are between 70 and 85 million years old and which are mapped or strongly indicated by geophysics, including magnetics and radiometrics.
Two niobium mines, including Araxá, are established on two of the known carbonatites, while the company’s tenure lies on or within the margins of four others. Other features that characterise carbonatite intrusives are circular “ring” structures, including ring-dikes within or immediately adjacent to the company’s new ground and wide alteration zones around their margins due to the influences of their magmatic fluids.
Such zones are well-recognised among carbonatites globally as they carry a range of potentially economic mineralisation styles.
Gold Mountain says the laterite zone over the Araxá carbonatite may be up to 230m thick and mine ore is derived from its weathered magmatic and hydrothermally-altered zones. The niobium orebody is totally contained within the weathered zone.
Carbonatites generally may include the rare earths that are now increasingly in demand, accompanied by minerals in the tantalum-niobium solid solution series. Variants in that series have many industrial uses in electronics, high quality lenses, super conductors and diodes and metal alloys capable of withstanding extreme temperatures, including turbine engines.
That augurs well for Gold Mountain's niobium and rare earths prospects that include altered wall rock zones of some of the intrusives, especially with compound annual growth rates for niobium being estimated at between 6 to 9 per cent through to the end of the decade.
Management says it plans to undertake reconnaissance work comprising stream sediment and channel sampling of weathered exposures to define targets for follow-up geophysics and higher-density soil sampling to identify niobium and rare earths mineralisation. It is expected to be tested by drilling as necessary.
Gold Mountain looks to be onto a winner with its new acquisitions and it is almost certain its growing understanding of carbonatites and their minerals markets will open up new acquisitions and opportunities.
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By Doug Bright
