Northern Star Resources boss Stuart Tonkin announces exit once issue-plagued Super Pit expansion is finished

Northern Star Resources’ long-serving boss Stuart Tonkin is set to quit his post within months, but not before the gold miner starts up a troubled expansion project that will double throughput at its world-famous Kalgoorlie Super Pit. Northern Star dropped the bombshell news on Thursday, saying Mr Tonkin had advised the board he would step down during the first quarter of the new financial year. His departure is set to come right after the problematic Fimiston Mill expansion at the Super Pit is due to be completed and in the wake of two production downgrades since the start of 2026 — and three since April last year. Shares in the $27.7 billion miner dived 3 per cent in early trade to $18.78 — well off their 2026 peak of $31.73, reached just days after the outbreak of war in he Middle East — taking losses so far this year to more than 23 per cent. Mr Tonkin joined Northern Star in 2013 as chief operating officer and was appointed chief executive in 2016, later seeing the company through its $16b merger with Saracen Minerals in early 2021. “Under Mr Tonkin’s leadership, Northern Star has grown from a small-cap Western Australian-focused miner into Australia’s largest ASX-listed gold producer with three production centres and over 10,000 staff and contractors across Western Australia and Alaska, with a leading safety record,” Northern Star stated. “Mr Tonkin’s long list of achievements includes the significant growth of the company through acquisition, integration and operation of Plutonic, Kanowna Belle, Kundana, Jundee, South Kalgoorlie, Pogo in Alaska, Kalgoorlie Consolidated Gold Mines, the merger with Saracen Minerals, and the takeover of De Grey Mining to add a significant development project, Hemi, to the group.” Issues at the famed, and ageing, Super Pit have plagued Mr Tonkin’s tenure in recent months. Northern Star told investors in January that multiple plant failures afflicting its anchor processing hub in Kalgoorlie would drive up costs and weaken production. At the time it also revealed the $1.6b expansion of its Super Pit mill would cost at least $110 million more than expected to build, forcing a delay for capital expenditure on infrastructure including a thermal power plant. The flurry of bad news led to grievances by some investors over Northern Star’s timeliness in disclosing market-sensitive information. It came to a head on a fiery conference call between Mr Tonkin and analysts that at one stage resulted in the Northern Star chief telling Matthew Frydman of MST Financial to “let me finish”. Northern Star faced more disclosure scrutiny in March when it divulged another production downgrade, largely again due to problems at the Super Pit, which wiped billions of dollars from the company’s value. In a note to staff on Thursday obtained by The West Australian, Mr Tonkin said his resignation represents “a significant change”. “But I am confident that the company is in a strong position to manage a leadership transition over the coming months,” he said in the email. “The board will commence a recruitment process that will consider both internal and external candidates. “I have been incredibly privileged to work alongside such a talented and committed team during Northern Star’s significant growth over the past 13 years. “I commenced as COO in 2013 with only the Paulsens operation and around 250 staff; and today, we operate as a global company with more than 10,000 staff and contractors and decades of mine life ahead.” Northern Star chair Michael Chaney thanked Mr Tonkin for his “phenomenal efforts” over the past 13 years. “He can be rightly proud of his achievements, and he will leave a legacy in the form of assets and growth opportunities that will deliver benefits for all stakeholders for decades to come,” Mr Chaney said.