Super Pit Gold Mine Life Extended by New Ore Reserves

An ongoing exploration campaign beneath Kalgoorlie's Super Pit is starting to pay off, with significant new ore reserves set to extend the life of the iconic gold mine.

The dimensions of the Super Pit have continued to expand since operations began in 1989, digging up historic workings on what was famously known as the Golden Mile.

But since 2021, when Australian gold miner Northern Star Resources took full ownership, there has been a renewed push underground at what was once considered the richest square mile on Earth.

Eight underground access portals were established on the western wall of the gigantic pit, providing new exploration platforms in an area Northern Star has dubbed the Fimiston underground mine.

When the ABC visited last August, nine drill rigs were running around the clock searching for new gold reserves as part of a $48 million exploration campaign during the 2025–26 financial year.

The fruits of that labour were finally revealed to the stock market on Wednesday, when Northern Star released its annual resource and reserve statement.

What are resources and reserves?

Resources represent a geological estimate of what is physically in the ground, while reserves are what a mining company considers it can mine for a profit.

The latest estimates say gold reserves at the Super Pit have increased from 14.4 million to 15 million ounces in the past 12 months.

At current production rates, that adds at least another year of mine life to a globally significant deposit which has produced more than 60 million ounces since 1893.

It also continues a rapid turnaround since the mine's former owners, US giant Newmont and Canada's Barrick Gold, sold their stakes.

The Super Pit's reserves have increased 54 per cent from 9.7 million ounces in the past six years.

Significantly, most of the new ounces that have been discovered are from underground sources.

The reserves for the Fimiston underground mine grew by 600,000 ounces this year to 2.4 million ounces, up from a maiden estimate of 800,000 ounces two years ago.

New reserves were also added to Kalgoorlie's historic Mount Charlotte underground mine, which has been operating continuously since 1963 and contains reserves of 928,000 ounces.

Mining boss to step down

While the mineral endowment of the Golden Mile continues to shine, the immediate future of Australia's biggest gold miner is less certain amid a leadership transition and ongoing takeover speculation.

Northern Star this week revealed it has engaged an international recruitment firm and discussions are underway with potential candidates to replace outgoing managing director Stuart Tonkin.

Mr Tonkin has been CEO since 2016 and transitioned to managing director in 2021, but will step down after the commissioning of the $1.6 billion mill expansion at the Super Pit.

The three-year project to more than double the capacity of the Fimiston Mill — from 13 million to 27 million tonnes a year — is on track for commissioning early in the new financial year.

About 800 people have been working on the project, which has suffered two blowouts this year amid poor construction productivity and cost inflation.

Northern Star allocated an additional $110 million towards the project in January and increased the budget by another $60 million in April.

Record production forecast

With the Australian dollar gold price trading at $6,254 per ounce at midday AWST on Wednesday, the commissioning cannot come soon enough for Northern Star, which downgraded its production outlook earlier this year amid equipment failures in the old mill.

Post-commissioning, the Super Pit is forecast to hit production rates of 900,000 ounces a year during the 2028–29 financial year and then maintain that rate for the next decade.

That would ensure the Super Pit reclaims its crown as Australia's biggest-producing gold mine, currently held by the Boddington mine in WA's South West after producing 565,000 ounces in 2025.

According to Melbourne-based gold consultancy Surbiton Associates, the best year on record for the Super Pit was 2011 when it produced 796,000 ounces.