ASX-listed Northern Star Resources has revised its 2026 financial year production and cost guidance after a series of one-off operational events across its portfolio weighed on gold sales and costs in the December 2025 quarter.

The gold miner sold 348 061 oz in the quarter at an all-in sustaining cost (AISC) of A$2 937/oz, with a negative free cash flow of A$328-million and net mine cash of A$129-million. 

MD Stuart Tonkin said on Thursday that the softer quarter reflected "a number of one-off operational events" that resulted in the revised production and cost guidance. “Looking ahead, our team remains firmly focused on driving productivity improvements and strengthening cost discipline.”

At Kalgoorlie, productivity across the KCGM openpit and underground operations remained in line with the original yearly guidance, but gold sales were impacted by lower throughput following a primary crusher failure. Normal operations resumed in early January.

At Yandal, recovery works at Jundee took longer than planned, while Thunderbox was affected by unplanned mill downtime.

At Pogo, mined grades were lower as new mining areas were accessed, although grades improved later in the quarter.

For the full year, Northern Star has revised its gold sales guidance to 1.6-million to 1.7-million ounces, down from 1.7-million to 1.85-million ounces previously. AISC guidance has been lifted to A$2 600/oz to A$2 800/oz, reflecting lower production volumes and higher royalties linked to elevated gold prices.

Despite the downgrade, the company maintained its operational growth capital guidance of A$1.14-billion to A$1.2-billion, highlighting its commitment to advancing major growth projects.

The KCGM Mill Expansion Project remains on schedule for commissioning early in the 2027 financial year, Northern Star reported, but stated that capital expenditure for the 2026 financial year had been revised higher to A$640-million to A$660-million to mitigate lower-than-planned labour productivity and protect the schedule. Mill operational readiness capital has also increased to A$370-million to A$390-million, with the tailings dam project tracking ahead of schedule.

Tonkin said the December quarter delivered meaningful progress at Northern Star’s two flagship growth projects.

“The December quarter delivered positive advances at our two key growth projects that will structurally reshape our cost base and support delivery of higher-margin ounces,” he said. “The KCGM Mill Expansion remains on track for commissioning in early FY27, while we continue to optimise the engineering and design of the Hemi development project as approvals progress.”

Northern Star ended the half year with net cash of A$293-million and cash and bullion of A$1.18-billion, after paying A$370-million in corporate tax instalments during the quarter. Hedge commitments continued to unwind, with 158 000 oz delivered in the quarter, positioning the company to benefit more fully from the higher gold price environment.

Tonkin said the balance sheet strength and advancing growth pipeline positioned Northern Star for improved free cash generation as production lifts in the second half of FY26 and beyond.

“Northern Star’s balance sheet remains in a net cash position and we expect future free cash generation to increase materially as production lifts and our hedge book unwinds into this elevated gold price environment,” he said.