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News & Media

17/01/2017
Zinfra delivers power infrastructure in tough outback conditions


Dugald_Utility_Magazine
The outback town of Cloncurry in Queensland is alive with Zinfra field workers contracted by mining company MMG to design, construct and commission the high voltage electricity infrastructure to power their Dugald River zinc mine.

The work was awarded to Zinfra in two separate packages. The first package of works involves the design and construction, using helicopter stringing methods, of a 220kV transmission line. The line covers a distance of 63.4 kilometres and extends from the existing Ergon Energy Chumvale substation to the Dugald River Mine site.

The second contract scope is for the design, procurement, construction, testing and commissioning of the 220/11kV substation to power the mine’s 11kV distribution network.

The works require impeccable timing and project management by Zinfra. Up to 75 Zinfra employees and sub-contractors, working on a FIFO roster, are working on the project at any one time to deliver the many moving parts of this large-scale project.

The project commenced in June. The arrival of the helicopter in November and commencement of conductor stringing signified a critical milestone for the project.

Zinfra has several separate teams working concurrently to construct the transmission line. All workers face daily challenges with variable rock conditions, difficult access in the remote location and hot working conditions. The average day time temperature is almost 38 degrees Celsius at this time of year, and soars above 45 degrees in the height of summer.

The leading crew’s task is to drill the holes in which to stand the power poles. While some holes drill easily, others are hard work through rock in the rugged outback terrain.

Shortly behind the borers is the pole assembly crew, whose job is to construct and dress the poles. The poles are delivered in three separate parts that must be aligned, clamped and have insulators attached.

Following these crews is the pole erection team who, using large cranes, lift and align the assembled 9.5 tonne poles into their vertical position, ready to receive concrete foundation within a 24 hour timeframe to fix them in place. The pole erection team has just reached their own milestone with over half of the 182 poles in the ground and they expect to have all poles erected by early December.

Meanwhile the stringing crews are busy at the start of the transmission line, stringing the three phases and the OPGW in sections of approximately 21 poles.

At the end of the transmission line, the substation team is working on the foundations of the substation. Apart from the civil and conduit portion of the project, Zinfra is self-performing the substation build, including all services, steel and bus work and commissioning.

The client, MMG, is based in Melbourne, Australia and listed on the Hong Kong Stock Exchange and Australian Securities Exchange. MMG operate and develop copper, zinc and other base metals projects across Australia, the Democratic Republic of the Congo, Laos and Peru. Dugald River is one of the world’s highest-grade known zinc deposits. The mine is expected to be producing zinc concentrate with first production and shipment of product during the first half 2018.

This challenging project bears all of the hallmarks of the type of project that brings Zinfra’s capabilities to the fore – complex procurement, critical logistics, remote location, innovative construction methodology and stringent time-frames.

The entire transmission line and substation project is tracking to time and budget and is scheduled for completion in March 2017.

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