Mineral Resources Ltd. and its joint venture partner Jiangxi Ganfeng Lithium have made a final investment decision (FID) to invest AU$490 million to develop underground mining at the Mt Marion lithium mine in Western Australia’s Goldfields.
The capital investment will be deployed across the 2026-27 and 2028 fiscal years to transition the site into a combined open-pit and underground operation and install an advanced processing flotation circuit.
The funding package comprises AU$240 million for a flotation plant, AU$220 million for underground pre-production development, and AU$30 million for secondary infrastructure.
Backed by strong market demand, the project boasts an estimated payback period of less than one year based on current spot spodumene prices of roughly US$2,700 a tonne.
The combination of a flotation plant with underground mining is expected to support mine life by tapping deeper, high-grade ore bodies locked beneath the existing open-cut footprint, pushing processing recoveries toward 70 per cent.
Total production capacity at Mt Marion will climb from 500,000 tonnes per annum to 600,000 tonnes per annum. Additionally, the flotation plant will completely eliminate the lower-grade SC3.5 stream, leaving a premium, uniform SC5 spodumene concentrate product.
MinRes Managing Director Chris Ellison said: “This high-return brownfield investment sets up Mt Marion for decades to come.
“Underground mining and flotation will work together to access deeper high-grade ore, lift recoveries and produce a single 5 per cent product.”
Tendering for an underground mining contractor is currently under way, with development scheduled to commence in the first quarter of FY27. By FY28, open-stoping underground operations will supply up to 40 per cent of the mill’s processing feed.
The site’s accommodation camp will also expand from 500 to 750 rooms to handle the influx of workers. MinRes’s own Mining Services division has been tasked to construct and operate the new flotation circuit, with commissioning slated for the final half of fiscal 2028.
