Macmahon’s $38m Groundrush contract: decline design and ventilation notes for engineers
Reviewed by Joe Ashwell
First reported on Australian Mining
30 Second Briefing
Macmahon has secured a $38 million contract from the Central Tanami Project Joint Venture, owned by MGX Resources and Tanami Gold, to construct an underground decline at the Groundrush Gold Deposit in the Northern Territory. The decline is planned to run 3.5km to a depth of about 350m, with a scheduled construction period of 14 months. Geotechnical and mine design teams will need to plan for long decline ventilation, ground support over a relatively shallow but extended access, and integration with future stoping layouts.
Technical Brief
- Contract scope is limited to decline development, not full underground mining or stoping operations.
- Macmahon’s role focuses on early-stage underground access, enabling later production ramp-up by the JV.
- Surface infrastructure for decline collar, power, water and workshops will be required but is outside the disclosed scope.
- For similar Australian gold projects, such early decline contracts often precede separate tenders for stoping and haulage.
Our Take
The 3.5 km, 350 m deep decline at the Groundrush gold deposit is relatively modest compared with some long-life Australian underground gold mines, suggesting this phase is geared to exploration access and early ore definition rather than full-scale production development.
Our database shows MGX Resources recently earmarked a $412.1 million funding pool for the Central Tanami Project, so this $38 million Macmahon scope likely represents an early work package within a much larger staged capital rollout in the Northern Territory.
Macmahon’s move from preferred contractor status in the April 2026 item to a formal award here reinforces its positioning in our coverage as a go-to underground contractor for gold projects in remote Australian regions, which can influence pricing benchmarks for similar decline-access scopes.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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