McArthur River Mine

Glencore’s McArthur River lead and zinc mine operates 60km north of Borroloola, in the monsoonal tropics and floodplains of the South West Gulf country. The river flows into the Sir Edward Pellew Islands archipeligo, home to dozens of endangered species and the surrounding seas shelter dugong and turtles. The McArthur River is the lifeblood of the Gulf, with residents, tourists and recreational fishers reliant on its abundant fish. Hundreds of pastoral stations, outstations and communities rely on its freshwater.

smoking pit

Mining approval flawed from the outset

Mining started at McArthur River in 1995 as an underground operation with the lead and zinc orebody located underneath the mighty tropical McArthur River. At the time it received significant financial assistance from both the Commonwealth and NT Governments including funding of major infrastructure, tax and royalty concessions.

The McArthur River Mine Environmental Impact Assessment process had been fast-tracked, taking less than six months to complete in 1992 despite serious reservations being expressed by the NT Environmental Protection Authority and the region’s Traditional Owner groups about the enlarged scale of the mine’s ecological footprint and inability to contain contaminants on the mine site during Wet season flooding. Much of the documentation of the EIS process was deemed commercial-in-confidence and not made available to public scrutiny.

On the 11th of February the original operator Xstrata announced its intention to expand the mine, converting it to an open-cut operation. Under the proposal the McArthur River would be diverted through a  5.5 kilometre channel and require the construction of a 25m metre high bund wall to act as artificial river banks around the open cut pit.

Despite successful legal challenges by Traditional Owners to halt the expansion, on Friday 13th October 2006, the NT Minister for Mines and Energy approved the McArthur River open-cut mine, relying on the retrospective application of legislation to prevent the approval being further challenged. One week later on Friday, 20th October 2006, the Minister for Environment from the Australian Government approved the McArthur River Mine under the EPBC Act 1999.

Evidence emerges of wide-spread environmental contamination

Since the controversial expansion proceeded, evidence has continued to mount about the escalating environmental, public health and economic risks posed by McArthur River Mine.

In 2014 a litany of major problems were identified at the mine including lead contamination in fish, cattle and waterways and parts of the mine catching fire from reactive chemistry in its waste rock dump. Over 90% of fish sampled exceeded safe eating standards for heavy metals. Water quality tests showed mine operators were regularly discharging contaminated water into the river in violation of allowable limits.


The mine’s waste rock dump had caught fire and acid-forming rock was smouldering and belching toxic fumes for 30km downwind of the mine site. This prompted Glencore to undertake a reclassification of its waste rock dump, finding that more than 85% of the waste rock was acid-forming material instead of the previously assumed 15%. If its Phase 3 expansion plans are allowed to proceed a further 50% acid forming waste rock would be brought to the surface and require isolation and long-term management to prevent acidic runoff.

An EIS is expected to be delivered in mid-2016 but already the mine’s Independent Monitor and the Department of Mines and Energy have confirmed there is less than 9% benign materials on site available for Glencore’s clay capping strategy which will leave the rock vulnerable to erosion creating an uncontrolled sulphuric acid runoff into nearby waterways.

In August Freedom of Information requests on behalf of Traditional Owners revealed the NT Government was aware of the scale of the looming environmental catastrophe and public health risks posed by heavy metal contamination, but took no action.

In September a petition with more than 30,000 signatures was presented to the NT Government calling for production at the mine to stop until waste rock and water contamination problems have been addressed and a comprehensive clean up plan enacted. So far the NT Government has failed to act, saying it will wait for Glencore to produce

In October as revelations of Glencore’s financial liabilities totalling more than $50 billion emerged Traditional Owner’s concern that the inadequate security bond held by the NT Government for rehabilitation of the mine site would allow Glencore to cut and run from its responsibilities erupted in protests. Traditional Owner’s occupied sacred sites within the McArthur River mining lease, damaged as a result of the river diversion, calling for the rehabilitation bond to be increased.

The protests prompted the NT Government to require Glencore to pay an increased rehabilitation bond though the exact amount and form of liability remains protected under ‘commercial in confidence’ arrangements.

A ticking timebomb

Fresh evidence was presented to the Borroloola community of the mine’s escalating risks in December 2015 by the Independent Monitor in a report detailing how major environmental risks have worsened since its 2014. The report confirmed Glencore’s operations are a ticking time-bomb for downstream communities and the environment. Reactive chemistry in, and the potential for collapse of, the mine’s toxic tailings dam and uncontrolled acid runoff into the McArthur River from its massive waste rock dump were upgraded to extreme risks ‘with likely catastrophic consequences’ for downstream people and the environment.

A copy of the 2014 and 2015 Independent Monitor’s reports available here.

The NT Environmental Protect Authority has required Glencore to submit a new Environmental Impact Statement detailing how it will manage the huge volumes of acid forming waste rock on site, but with just six months left til operator Glencore must present the NT Government with a long-term management strategy its clay-capping trials have failed to so far contain the problem. The Independent Monitor estimates there is just 9% non-acid forming material available on site to contain the reactive rock, which presents a major pollution hazard for downstream waterways for hundreds of years.

Despite overwhelming evidence supporting the case to backfill the pit and transition to clean up and closure of the mine, the NT Government has given no reassurance that it will refuse Glencore’s band-aid solution, even as the company risks shifting huge financial and environmental management costs to the public.

Community action to support pit backfill and closure

In the face of company and government inaction Borroloola clan groups have vowed to re-double efforts in 2016 and are calling for support from the broader Territory, national and international community.

We are working on a number of fronts including advocacy support work with young community leaders, legal challenges, civil disobedience actions and an alternative EIS report demonstrating that backfilling the reactive waste rock into the pit and rehabilitating the site is the most sensible solution to a looming environmental crisis.

To find out how you can help get in contact at


Additional information can be found in the documents below

Public Environment Report

‘Failed Again’ – ECNT assessment of EPA report 54

EPA Report 54 on the PER

Environment Centre NT PER submission

PER – Public Environment Report

Environmental Impact Statement 2006

ECNT – Reasons why the EPA did not approve the EIS

EPA Report 51 on the EIS

EIS Supplement

Environment Centre NT submission on EIS

Environmental Impact Statement

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