Mining waste rock could become ‘aggregate revenue stream’

Bluestone quarry in Australia. Image: TORMA Mining

TOMRA said its X-ray Transmission (XRT) sorting technology enables mines to remove acid-forming material early in the process, creating a low-sulphide waste stream suitable for reuse or sale as aggregate.

Mining operations generate large volumes of waste rock, much of which is hauled, stockpiled and monitored long term due to the presence of sulphides and acid-forming material. At the same time, many mines import aggregate for haul roads, plant foundations and tailings dams, particularly in remote locations where suitable material is costly to transport.

At the Mt Carbine tungsten operation in Queensland, Australia, operator EQ Resources is using XRT sorting to generate a barren waste stream that is sold as aggregate. The company said the approach adds around A$5 million (US$3.5 million) in annual revenue and has prompted plans for a third sorter.

TOMRA said the ability to certify waste rock as low in sulphides can reduce environmental risk while creating opportunities for on-site infrastructure use or external aggregate sales.

The company argues that as mines face tighter margins and sustainability pressures, waste-to-aggregate solutions could unlock both cost savings and new revenue streams.

Wolfram Bergbau Mittersil in Austria has also unlocked value from its waste, turning it into material for its infrastructure and for sale. Between 25-40% of run-of-mine material is removed as coarse waste through XRT sorting.

“Coarse barren material produced by XRT sorting at Wolfram Bergbau Mittersill is used for road construction at the tailings dam and in the mine, crushed as aggregate in shotcrete in the mine and local aggregate supply,” says Alexander Mosser, operations engineer at Wolfram Bergbau und Hütten AG.