Geophysical surveys completed in late 2022 identified large anomalies, while petrology confirmed the presence of high-tenor nickel mineral vaesite and copper mineral chalcocite.
It led Bellavista to fast-track its 2023 exploration program.
A seven-hole diamond drilling program is now underway to test targets that sit close to regional targets.
Bellavista executive director Mick Wilson said the company was looking for higher-grade mineralisation and increased thickness.
Brumby is already large - extending for 10km of strike by 4km width.
"We're just looking for the goalposts on the footy field," Wilson said.
The program is expected to take four weeks with a helicopter-borne VTEM survey to be carried out over Brumby and adjoining Vernon prospect.
Historical drilling by CRA at Brumby in the 1990s returned results including 29m at 1.3% zinc, 0.22% copper and 24.5 grams per tonne silver.
Wilson said CRA was looking for the next Century back in those days - something Bellavista still thinks is a real possibility.
CRA abandoned the project due to frustrating drilling conditions.
"We're just finishing the job basically," Wilson said.
To assist with its efforts Bellavista has appointed major shareholder and former Bellevue Gold managing director Steve Parsons as a corporate consultant.
Parsons described Bellavista's ground as "elephant country" but still very underexplored.
"There's no reason you can't find a big deposit," he told MNN.
"If this was in the Yilgarn, there'd be 20,000 holes in it."
The area has attracted the interest of the majors with Canada's Teck Resources securing a large package of ground to the north.
Bellavista listed on the ASX in May 2022 after a heavily oversubscribed A$6.5 million initial public offering.
Parsons and Capricorn Metals executive chairman Mark Clark each hold 10% of Bellavista with former Bellevue chief financial officer and current non-executive director Michael Naylor and Capricorn CEO Kim Massey each holding 6%.
The top 20 shareholders, mostly linked to Bellevue, hold about 60%.