London BTC Company (LSE:BTC) has said that maiden field sampling at its Black Star project in Nevada has identified antimony and high-grade copper, in addition to the gold and silver mineralisation the claims were staked for.
Black Star is one of four Nevada projects London BTC is advancing as part of a capital-light gold exploration programme designed to hedge its Bitcoin-mining and treasury business.
The company collected 69 rock chip samples along a 2.5km corridor between the project's Western and Eastern targets, analysed in the field using a handheld pXRF device.Antimony was detected above the instrument's detection limit in 35 of those samples, with readings of up to 0.44% antimony at the Eastern Target and 0.17% and 0.15% at the Western Target.
Copper readings reached as high as 30.0%, with bismuth up to 0.73% and silver up to 811 parts per million.
"Black Star was originally staked for its high-grade gold and silver potential, so identifying antimony within our own claims and high-grade copper is a particularly encouraging development," said Hewie Rattray, chief executive of London BTC.
He said the multi-element signature of antimony, copper, bismuth and silver appearing at both ends of the corridor "appears consistent with the historical mineral occurrence immediately to the south of the project."
Antimony is designated a critical mineral by the US government, which remains substantially reliant on imports for the commodity, according to the US Geological Survey.
David Lenigas, London BTC's chairman, said the readings matched what the company had hoped to find after flagging antimony potential at the site in August, when a historical 1985 sample located 120 metres south of the claims returned grades above 1% antimony, 2% copper, 700ppm silver and 1,000ppm bismuth.
The company cautioned that pXRF readings are preliminary and indicative only; the technique does not determine gold content and its silver readings are qualitative.
All 69 samples have been sent to MSALABS in Nevada, where gold and silver will be measured using PhotonAssay technology, followed by sodium peroxide fusion testing for the full multi-element suite including antimony, tungsten and copper.
Previous due diligence sampling at Black Star, carried out in June, had already returned grades of up to 16.23 g/t gold and 50.5 g/t silver, confirmed through PhotonAssay and fire-assay quality checks.
The field team is now moving to the Amonett-Frank project, where earlier testing reported a peak gold grade of 143.1 g/t, to be followed by Huntington-Whitman.
Multi-element results from the Black Star samples, including antimony and tungsten, are expected from late October.