The appointment marks a significant milestone in the progression of underground mining at Mt Marion and signals the next phase of development at one of Australia's leading lithium operations.
MinRes Underground Mine Planning Manager Andrew Cooper said the appointment brings the right expertise to unlock the long-term potential of the Mt Marion orebody.
"We're focused on systematically building the technical and operational capability to unlock the full potential of the Mt Marion orebody," Cooper said.
"We had to pause and be patient while the market worked through its challenges, but that time wasn't wasted. We've come back sharper, better planned and with a team ready to deliver.
"Macmahon brings proven underground expertise to support our mining plans and together we're focused on executing this safely and efficiently."
Cooper said the relationship with Macmahon goes beyond a typical contractor arrangement.
"Macmahon will be an integral part of our team. Close collaboration is what it takes to deliver a project of this scale,” he said.
Macmahon Managing Director and Chief Executive Officer Michael Finnegan welcomed the contract award, highlighting the opportunity for both companies to forge a strong and productive working relationship.
“Macmahon is excited to partner with MinRes and Jiangxi Ganfeng Lithium to deliver the next phase of underground mining at Mt Marion," Finnegan said.
"This is a high-quality, long-term opportunity to collaborate alongside strong, aligned partners and positions Macmahon Underground firmly on the global stage as a tier one contractor in future-facing commodities.
"We look forward to working closely with the joint venture to unlock the full potential of this operation and support its continued growth as a globally significant lithium asset.”
From exploration to development
This appointment is the culmination of a journey that began in early 2024, when MinRes commenced preliminary works to support future underground mining at Mt Marion.
A diamond drilling program followed, significantly increasing confidence in the underground resource within the mine's upper North Pit and confirming the orebody's potential.
The program was placed on hold in response to softened lithium prices, but sustained improvement in market conditions has since prompted MinRes and Ganfeng to push ahead with underground development.
In May 2026, MinRes announced a Final Investment Decision (FID) for underground mining at Mt Marion, alongside the construction of a flotation plant and camp expansion.
Underground development is expected to commence in the first quarter of FY27, with Mt Marion operating as a combined open pit and underground operation from FY28.
Underground development and a new flotation plant are together expected to support mine life, improve plant recovery towards 70%, increase installed capacity to approximately 600ktpa SC6 and deliver a single, higher-quality SC5 product.
MinRes Chief Executive Lithium Joshua Thurlow said the underground program represents a defining moment for the business.
“We’ve barely scratched the surface of what Mt Marion can deliver,” Thurlow said.
“Underground mining is the next step in realising the full value of this world-class asset and we’re building the team and the infrastructure to make it happen.”
