South African miner Harmony would burn an estimated 76 million litres of diesel a year running the Eva copper mine off-grid, a conference in North West Queensland was told.

VisIR chief executive officer Joseph O’Brien made the point at the recent Meeting of the Mines conference in Cloncurry. Mr O’Brien designed and initiated the CopperString project which would link North-West Queensland to the electricity grid.

Concerns have been raised that the state has been strong on rhetoric but short on committing to CopperString project timelines.

The 60,000-tonne-a-year Eva copper mine located north of the historic mining town is scheduled for delivery in 2028.

In the meantime proponents like Harmony were having to pay prices for power which were multiples of that charged to industry on the east coast, Mr O’Brien said.

“They will be burning eye watering amounts of diesel to produce that copper at embarrassingly high electricity prices for Queensland,” Mr O’Brien said.

Harmony chief development officer Johannes van Heerden also addressed the conference saying diesel was their least preferred power source but they had no option until CopperString was built. 

Mr van Heerden said a ‘behind the meter’ fuel solution involving renewables had been developed for the Eva project in the absence of a connection to the national electricity market (NEM).

He said the package was expensive and sat outside the more than $2.5 billion budgeted for the project’s development.

“This is a IPP (independent power) process,” he said. “When we quote our capital estimate for the project, this obviously excludes this. So this is over and above.

“Having said that, we do believe that there’s a huge opportunity for us as well as for the region in terms of coming up with a shared infrastructure solution.

“In terms of our quality of infra-power supply, you will see it requires quite a significant diesel power station. There are two challenges with running a big processing plant on diesel. I mean, we basically will consume 70 megs of power.

“Now you can just understand the volumes of diesel you will burn if you were to run a plant on that. So thermal power onsite definitely only as a backup and because we don’t have any other option.

“In a perfect world, we would’ve plugged into a grid and then we’d have regional power that could support the development. Over and above that, diesel, obviously, from a carbon intensity point of view, is not where we want to be. We do want to reduce the carbon intensity of our development over time.”

The Queensland Government pledged $420 million in the 2026-27 Budget to advance the CopperString transmission project connection to the NEM, which is part of a total $3.2 billion investment. 

Local government leaders had expressed concern that no construction dates had been announced. The Queensland Investment Corporation has taken over as project lead.

Member for Traeger Robbie Katter said the region was no more confident about grid access. Mines west of Hughenden were still uncertain of connecting to the national electricity market through CopperString, he said.

Harmony’s fuel projections were repeatedly cited by conference speakers to illustrate the frustration of operating in North-West Queensland.

The conference was told in July the North-West Mineral Province paid about $300 a MW/h for electricity. On the connected National Electricity Market, the east coast wholesale price figure was $67.