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MLG is delivering an integrated civil and mining services package for Greatland Gold at the Havieron Project in Western Australia, focused on constructing a tunnel system designed to greatly reduce water ingress into the underground portal.

The existing shotcreted, funnel-shaped boxcut has historically allowed significant volumes of rainwater to enter during heavy wet-season events, resulting in ongoing inrush issues for the Principal. By installing a reinforced tunnel structure and then backfilling the surrounding void to surface, the project dramatically reduces exposed surface area and provides far greater control over water entering the underground workings.

To achieve this, MLG produced and installed 123 intricate precast concrete base elements onsite, each measuring 10 metres by 1.3 metres and weighing approximately 26 tonnes. These elements form the foundation on which the concrete arches are placed. The project then involved installing 88 pairs of Humes precast concrete arches, each weighing around 10 tonnes. Due to their size and weight, these arches were installed using two of the largest all-terrain cranes in Australia—650-tonne and 750-tonne units—to ensure precise and safe placement.

Once installed, the arches were sealed and grouted to create a waterproof tunnel environment, after which the entire structure was backfilled to the surface, effectively eliminating the original boxcut void. This system provides a durable, long-term solution that enhances portal integrity, prevents excessive water ingress and supports the safe continuation of underground mining operations.

In addition to tunnel construction, MLG has been responsible for the maintenance and grading of the Northern Access Road (NAR) and internal site roads, ensuring safe and reliable vehicle movement throughout the project area. Together, these works demonstrate MLG’s capability to deliver highly specialised civil works, large-scale structural installations, remote precast production, and comprehensive site support services across Western Australia’s mining regions.