ElectraNet has completed new high-voltage transmission line and electricity substation works to provide transmission services for OZ Minerals’ Prominent Hill and Carrapateena mine sites.

Chief Executive, Steve Masters, said the project was the largest ElectraNet has ever undertaken to date and the new OZ Minerals connection will play a critical role in powering the mines’ operations.

“This project is the first significant transmission line in terms of length and size that we have built in about 30 years and it’s the biggest we have constructed for a single customer” Mr Masters said.

“OZ Minerals is one of South Australia’s key mining companies and successfully delivering this project means they now have direct access to the main electricity grid and power they need for their operations.

“We worked closely with OZ Minerals to understand their requirements and deliver a solution that met their current needs, but also provisions for future needs.

“This is not only a great outcome for OZ Minerals, but it also delivers more broader benefits to South Australia from an economic perspective.

“We will be providing transmission services for OZ Minerals’ Carrapateena and Prominent Hill sites, delivering approximately 100MW of power to meet their operational requirements.

“There is also now increased electricity capacity in the state’s north which will also provide opportunities for other new connections to the transmission network in the future.

“This project builds on the trusted relationship between ElectraNet and OZ Minerals following the successful delivery and connection of the Carrapateena Mine in July 2019.

“Works delivered by ElectraNet and its project contractors included design and construction of approximately 300 kilometres of 132kV and 275kV transmission lines from the Davenport substation (near Port Augusta) by UGL, a member of the CIMIC Group, expansion of the Davenport substation by Enerven and the expansion of the new Mount Gunson South substation by CPP, to support the original Carrapateena mine and the new Prominent Hill connections.

“Construction works for the $270 million project began in late 2018 and commissioning was completed in October 2020. With additional safety plans in place, works continued throughout the COVID-19 pandemic to ensure the project’s delivery schedule was met.

“It has been a mammoth effort from everyone involved, and this project also supports the broader state-wide work ElectraNet is undertaking to improve electricity supply reliability and security.”

OZ Minerals’ CEO, Andrew Cole, said successful completion of construction of the new power line ensures reliable, secure and affordable power transmission for the company’s South Australian mining assets.

“What’s really pleasing to see is that in addition to enabling our potential future expansion aspirations in the region, construction of this power line has brought additional power capacity to the region for others to tap into as well,” Mr Cole said.

Project at a glance

  • The Prominent Hill Connection is the largest contracted (direct customer) project undertaken by ElectraNet to date.
  • The new line supplies OZ Minerals’ Carrapateena and Prominent Hill sites with approximately 100MW of power with significant additional capacity available for future connections.
  • New infrastructure is owned, operated and maintained by ElectraNet.
  • Works included approximately 140 km of 275 kV transmission line, the expansion of the Mount Gunson South switching station involving voltage transformation from 275 kV to 132 kV, and approximately 130 km of 132 kV transmission line.
  • ElectraNet also installed (but does not own) 170 km of telecommunications fibre to provide a secure communications network from Prominent Hill to where the new line joins the existing Prominent Hill line.
  • ElectraNet’s lead line contractor’s (UGL) experience on transmission projects interstate meant an innovative tower type was introduced to SA for the first time. Originally, the project design planned to replace existing tower infrastructure with like for like, however a taller tower design which lifted transmission lines well above the culturally significant areas was chosen instead.
  • Project took approximately three years to complete from connection enquiry to energisation.
  • Approximately 300 people worked to successfully deliver the project.
  • Cost of $270 million.
  • Despite the challenges of COVID-19, ElectraNet, its contractors and OZ Minerals worked to ensure the project could be delivered safely and within its delivery schedule.


New transmission line key statistics

  • Project team peak of 270 people.
  • 272 km of access tracks.
  • 3 km of foundation drilling.
  • Almost 13,000 m3 of concrete poured.
  • 370 drums of conductor wire (925 km) and 65 drums of optical ground wire (318 km).
  • 515 pieces of plant and equipment was mobilised.
  • Project vehicles travelled over 4,000,000 km.
  • 868 Project Inductions and over 600,000 project hours with a collaborated safety approach.
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