Macmahon blasts portals at Central Tanami: development and ground control notes for engineers
Reviewed by Joe Ashwell
First reported on International Mining – News
30 Second Briefing
Blasting of the central and ventilation portals for the Groundrush Exploration Decline has been completed by Macmahon at the Central Tanami Project Joint Venture (CTPJV) in Australia’s Northern Territory, allowing underground development to move beyond surface boxcuts into fresh rock. Tanami Gold and MGX Resources each hold a 50% interest in the CTPJV, with the decline targeting the Groundrush orebody beneath the historic open pit. Portal establishment now enables installation of initial ground support, services and ventilation infrastructure critical for subsequent long-hole drilling and resource definition.
Technical Brief
- Dual portals (central and ventilation) immediately enable separated intake–exhaust airways and improved early ventilation control.
- Location in the Tanami Desert implies hot, dry conditions, so decline design must manage heat load and dust.
- Historic Groundrush open pit geometry constrains portal siting, haul gradients and interaction with legacy pit slopes.
- Early decline access typically allows tighter-spaced resource drilling, improving orebody definition before major capital commitment.
- Similar Australian gold projects have used staged exploration declines to de-risk full-scale underground mine design and scheduling.
Our Take
The 50:50 JV structure between Tanami Gold and MGX Resources at CTPJV, combined with MGX’s previously reported A$412.1 million funding pool for the Central Tanami gold project, suggests MGX is effectively bankrolling a rapid transition from exploration decline to full underground development while preserving shared control.
Earlier coverage naming Macmahon Underground as preferred contractor and then awarding it a A$38 million decline contract indicates a relatively quick move from contractor selection to execution, which is notable in the Northern Territory where underground approvals and mobilisation often drag timelines.
Within our mining-projects coverage, Central Tanami in the Northern Territory stands out as one of the few gold-focused JVs where both partners hold equal ownership, which typically requires tighter governance but can also de‑risk single‑sponsor balance sheets for high-capex underground builds.
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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