BHP will begin testing next year to determine the severity of an acid leak from the mine which started the Pilbara’s lucrative iron ore trade.
BHP will begin a fresh round of testing next year to determine the severity of an acid leak from the mine which started the Pilbara’s lucrative iron ore trade.
The mining giant applied to the Department of Water and Environmental Regulation in November to clear 15 hectares of native vegetation at the Mount Goldsworthy site.
Mount Goldsworthy is a mothballed iron ore mine owned by BHP about 100 kilometres east of Port Hedland.
It was the first iron ore mine in the Pilbara and was developed by a conglomerate of Consolidated Goldfields, Cyprus Mines Corporation and the Utah Construction and Mining Company.
BHP’s work will determine the extent and impact of acid leaching out of the former mine’s waste dump into the surrounding environs, which sit on the De Grey Station pastoral lease.
Documents submitted to DWER outline a project spanning up to 10 years with the purpose of “contaminated site investigations and associated activities”.
Data from the study will guide remediation of the site – the project is not expected to take the full decade to complete.
BHP has hired environmental consultants to draw up a soil and water sampling plan as part of the body of work.
A legacy issue
The acidic material at Mount Goldsworthy has been a thorn in BHP’s side for more than two decades.
It has been subject to broad studies by the company.
Mount Goldsworthy was developed in 1965 and was closed in 1982 after producing about 55 million tonnes of iron ore.
BHP has been involved in Mount Goldsworthy since 1977 when it bought a stake in the project, according to the Journal of Australasian Mining History.
The big Australian gained full control of the asset in 1990 when it bought out the remaining partners so it could streamline its growing infrastructure and operations in the region.
That deal also brought the Finucane Island port hub at the Port of Port Hedland under BHP’s control.
Some remediation at Mount Goldsworthy was undertaken by BHP in the 1990s, but the open pit was left exposed as was standard practice.
BHP’s attempts to sell the mine to a company owned by Kalgoorlie mining legend Douglas Daws in 2013 were derailed by material in waste dumps at the site which could produce acid.
That material – pyrite – was discovered in 2000 and was found by a 2009 study to have not spread too far and was hence reparable.
In 2013 BHP told the state government it needed to bury the material under the water table and asked to be released from its environmental obligations at Mount Goldsworthy, according to reports at the time.
Former premier Colin Barnett declined this request, leaving responsibility for an estimated $100 million remediation bill with BHP.
The mine is not currently listed on the state government's contaminated sites register.
Junior explorer Macro Metals is proposing to develop an iron ore mine immediately east of Mount Goldsworthy.
