Down-hole electromagnetic surveying work that followed up on a significant drilling campaign by ASX-listed nickel hopeful, Auroch Minerals, has identified a strong conductor, pointing to the possible base of a modelled nickeliferous channel zone at the Valdez prospect at the company’s Leinster nickel project in WA.
According to Perth-based Auroch, the channel target was coincident to an anomalous magnetic high and a historic surface electromagnetic, or “EM” conductor with a strike length of 1.2km.
Management says these are encouraging signs for a potential Kambalda-style massive nickel sulphide mineralised system.
Channels mostly host the thickest and highest-grade massive nickel sulphide mineralisation in the world-class Kambalda minerals province.
While massive nickel sulphides in the Kambalda district often occur on the flanks of the channels and in the hanging-walls due to subsequent historic lava flows, the main feeder channels are where the most nickel-bearing lava generally flows through, culminating in more nickel sulphides accumulating at the base of such channels.
Valdez is located in the Norseman-Wiluna Greenstone Belt and north-east of the company’s advanced Horn prospect. It also sits along strike from the Waterloo nickel sulphide deposit owned by Saracen Mineral Holdings and which was mined by Norilsk Nickel between 2005 and 2008.
Auroch carried out 4,400m of aircore drilling at Valdez this year aimed at confirming the basal contact and possible channel.
It encountered elevated nickel values in a weathered zone that is coincident with surface EM and mag highs. The company says this geological setting has all the hallmarks considered favourable for hosting significant massive nickel sulphide mineralisation.
The DHEM surveys that detected the exciting conductor are coincident with the ultramafic-basalt lithological contact in the modelled channel position.
They were conducted after the recently concluded 1,500m deeper RC drill program intercepted thick fertile ultramafic rock units in all four holes in the modelled basal channel.
Given the proximity of Valdez to Saracen’s Waterloo high-grade nickel sulphide deposit, the company has always believed that a systematic exploration strategy at Valdez has the potential to discover significant nickel sulphide mineralisation. We utilised first the historic magnetics and surface EM work to get us in the right area, and then narrowed in on the main channel zone via aircore drilling and the subsequent deep RC program.
This exploration strategy and use of DHEM has proven successful at the company’s Saints nickel project in targeting and drilling massive nickel sulphides, and we have recently seen other nickel sulphide discoveries in WA identified by our peers using DHEM. This strong DHEM conductor at Valdez now presents a high-priority drill target that we are eager to test with a diamond drill program in November.
The diamond drilling is planned to vector in on the high-priority DHEM target at Valdez. In the meantime, Auroch is set to kick off 2,000m of RC and diamond drilling at the nearby Horn deposit that it hopes will lead to an upgrade of the historic inferred mineral resource estimate of 600,000 tonnes grading 1.4 per cent nickel and 0.3 per cent copper for 8,300 tonnes of contained nickel and 1,800 tonnes of contained copper.
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