The campaign comprises diamond, reverse circulation (RC) and aircore drilling along with an airborne electromagnetic (EM) survey.
Metallurgical test work is also progressing on core samples from diamond drilling at the project in the Eastern Goldfields.
Managing director Stefan Murphy said exploration at Mt Venn was now entering the phase where it could generate substantial value for shareholders.
“We have a confirmed discovery,” he said, “and are pushing ahead with defining how large the system is given the significant amount of mineralisation delineated, which remains open in every direction.”
Shares are up more than 6% to 34 cents in early trade.
Two diamond tails and one diamond hole from the surface have been completed in the Central zone of the Mt Venn complex.
Visual logs of these holes have extended mineralisation down dip, with assay results expected in late April.
Second diamond hole underway
A second and final diamond hole from surface is underway.
Following completion of the diamond drilling, an RC program of about 2,000 metres will be carried out.
This will test extensions to the Mt Venn mineralised trend within the Central zone and along strike to the north and south.
Great Boulder has started a 500-metre aircore drilling program at the Eastern Mafic complex designed primarily to gather bedrock geochemical information.
This will enable the company to develop a geological model of the intrusions which make up the complex.
Airborne survey planned
Planning for an airborne EM survey over the Eastern Mafic complex is well advanced.
A contract has been signed and work is scheduled to start after Easter.
This is expected to take up to two weeks to complete.
Mt Venn forms part of the broader Yamarna project.
Murphy said: “Identification of the Eastern Mafic complex is a breakthrough as it has potential to host high-grade nickel and cobalt mineralisation associated with a feeder structure into the larger intrusive complex.
“Exploration is aimed at both growing the existing mineralisation footprint at Mt Venn and identifying the most prospective intrusions of the Eastern Mafic complex for nickel-copper-cobalt mineralisation.”
Sulphide mineralisation readily floats
Preliminary test work on diamond core samples shows that the sulphide mineralisation readily floats.
Much of the recent work has focused on grind size and reagent use to maximise separation of the copper and nickel-cobalt concentrate.
A bulk flotation test will be carried out next week with the intention of producing 15-20 kilograms of nickel-cobalt concentrate to begin leach test work.
It also aims to produce sufficient copper concentrate to optimise the cleaning stage ahead of producing a final copper product.