Sirius Resources (ASX: SIR) is focused on gold and base metal exploration in Australia. The company's 70% owned Youanmi project covers an area of 597 square kilometres, largely over the Youanmi layered igneous intrusion and its immediate country rocks.
Youanmi is a relatively unexplored area that is prospective for magmatic-style nickel-copper-platinum group metal (PGM) mineralisation.
Sirius Resources confirms nickel sulphide gossan at Polar Bear during sampling
Sirius Resources (ASX: SIR) has confirmed the presence of a strongly nickel-copper‐ platinum‐palladium enriched gossan grading during initial rockchip sampling at the Polar Bear Project in the Goldfields region of Western Australia.
The announcement follows its recent agreement to purchase of a 100% interest in the project, with grading up to 1.2% Ni, 3.1% Cu, 3.95g/t Pt and 21.05g/t Pd.
Rock chip samples were collected along 40 metres strike length, with key samples comprising 0.47% Ni, 2.34% Cu, 3.67g/t Pt, 8.18g/t Pd in copper stained limonitic gossan; Sample PBHK0010: 1.05% Ni, 0.7% Cu, 3.82g/t Pt, 3.84g/t Pd in porous hematitic gossan and Sample PBHK0014: 1.02% Ni, 3.12% Cu, 2.02g/t Pt and 5.04g/t Pd in copper stained limonitic gossan.
The level of nickel, copper, platinum and palladium in these samples far exceeds that usually found in nickel sulphide gossans in Western Australia. In particular, the high palladium content is diagnostic of gossans derived from massive nickel sulphides like those at Kambalda.
It crops out on a small island known as Halls Knoll and is traceable over a strike length of 40 metres before it becomes concealed beneath the thin sediments of Lake Cowan, a largely dry salt lake.
Final results and assays for other base metals and platinum group metals (PGM’s) are awaited.
In addition to the gossan results, assays of adjacent weathered ultramafic rocks indicate that these are also mineralised, with three separate samples averaging 0.55% Ni, 0.46% Cu, 0.13g/t Pt and 0.41g/t Pd.
The location of the gossan ‐ within a high magnesium ultramafic unit rather than on its basal contact ‐ suggests it has either been structurally remobilised along a shear zone, and spatially detached from its original location, or that it is a hangingwall mineralised position.
Nickel sulphide orebodies usually occur on the basal contact of the host ultramafic unit, so the focus of Sirius’ exploration will therefore be to locate the as yet unexplored basal contact and identify the source of this sulphide, which, if present, may be up to one or two kilometres from the gossan.
A review of historic data has also confirmed that previous drilling in the vicinity of this gossan has been very restricted, with several shallow (up to ~100 metre) holes drilled in 1968. Several of these holes are reported to have intersected narrow intervals of nickel sulphide mineralisation, but a lack of surviving core precludes verification.
Sirius will have full ownership of the tenements and all mineral rights on completion of the transaction, which is expected within a matter of weeks.
Sirius Managing Director Mark Bennett said ghe important thing about the gossan was that it contained very high levels of platinum and palladium as well as nickel and copper, and was undoubtedly the real deal as far as nickel sulphide gossans go.
"Whilst we don’t expect to walk up and find an orebody directly beneath it, the gossan shows we have the right rocks and the right processes," Mr Bennett said.
“These things, together with the masking effect of the cover and the lack of previous effective exploration make it a compelling exploration play.
"The potential structural remobilisation and the extent of cover create their own challenges but that is also where the opportunity is."
