Pantoro Gold Ltd (ASX:PNR, OTC:PNTOF, FRA:RKN) plans to develop a third underground mine at its Norseman Gold Project in Western Australia, with work expected to begin in early FY27 as part of the company’s strategy to expand production from the historic goldfield.
The proposed development will target the high-grade O’Briens Reef within the Norseman Mainfield, with first ore development anticipated during the December 2026 quarter once rehabilitation and dewatering of the Bullen Decline are completed.
Isometric view of O’Briens Mine Plan and Crown South access from the existing Bullen Decline.
Pantoro said development of the nearby Crown South ore zone is expected to follow in the March 2027 quarter, with both deposits remaining open in all directions and drilling continuing to test extensions.
“Work in the Mainfield has progressed extremely well during the past year with significant rehabilitation, new development and extensive underground diamond drilling completed,” Pantoro managing director Paul Cmrlec said.
“Drilling results have confirmed the presence of multiple high-grade mineralised zones and support development of our first new producing area within the prolific Norseman Mainfield.
“Importantly, ongoing drilling continues to demonstrate the significant scale of the Mainfield, providing confidence that O’Briens will be the first of several new underground mining areas to be developed in the coming years.”
High-grade resource underpins development
The decision to proceed with development at O’Briens is based on an existing mineral resource of about 130,000 tonnes grading 9.57 grams per tonne gold for roughly 40,000 ounces.
Pantoro noted the investment decision was made without assuming further resource growth at either O’Briens or Crown South, despite ongoing drilling returning high-grade intersections.
Recent results from the area include hits such as:
- 0.32 metres at 71.14 g/t gold
- 2.40 metres at 43.19 g/t gold, including 0.3 metres at 195.87 g/t
- 1.15 metres at 38.95 g/t gold
- 0.3 metres at 263.61 g/t gold
Pantoro expects continued drilling at O’Briens and Crown South to support a mineral resource update during the second half of 2026, followed by a revised ore reserve and mine plan.
The company said feasibility work carried out by its internal technical team confirmed the current resource is economic to mine.
Drill results in upper Crown Reef target areas.
Mining plan and production benefits
Pantoro plans to mine O’Briens using an inclined-room-and-pillar method, combining development and stripping to maximise extraction from the relatively flat-lying lodes.
Stylised Inclined Room and Pillar mining method.
The high-grade ore produced from the Mainfield is expected to replace lower-grade feed currently sourced from open pits and stockpiles, lifting the overall grade processed at the Norseman plant.
Key development milestones include:
- Completion of Bullen decline dewatering and rehabilitation — July 2026
- Access development to O’Briens Reef — July–August 2026
- First ore development at O’Briens — November 2026
- First ore development at Crown South — February 2027
Pantoro is also expanding exploration activity across the Mainfield, with a fifth underground drill rig scheduled to arrive at Norseman in April 2026 to accelerate drilling programs.
Broader Norseman growth strategy
The new mine forms part of Pantoro’s broader plan to establish at least two additional underground mining areas at Norseman during FY2027 as it scales up production.
The company is targeting longer-term output of around 200,000 ounces of gold per year, supported by a pipeline of underground development opportunities across the Mainfield.
The growth strategy set for Norseman at the commencement of drilling in September 2024.
Pantoro is currently undertaking resource modelling across the Crown, Crown South and expanded O’Briens areas, with updated mineral resource and ore reserve estimates expected in the September 2026 quarter.
Plan view of the southern end of the Norseman Mainfield.
Located in Western Australia’s Eastern Goldfields about 725 kilometres east of Perth, the Norseman Gold Project hosts total mineral resources of about 4.6 million ounces and ore reserves of about 859,000 ounces.
The development update follows the company’s strong half-year financial result released yesterday, which highlighted improving earnings and cash generation driven by production at Norseman.
Pantoro has been steadily rebuilding operations at the historic field, which has produced more than 5.5 million ounces of gold since mining began in 1935, with the latest underground expansion expected to play a central role in the project’s next growth phase.