Jane Bardon | ABC | 12.02.2016
When a giant toxic waste dump spontaneously ignited at one of the world’s largest zinc mines, serious questions were asked about how it could have happened. Jane Bardon investigates how regulators allowed a mine to operate with no known solutions to its massive waste problem.
In the Northern Territory’s Gulf country, Indigenous residents fear they’re on the cusp of an environmental disaster.
They’re calling for the McArthur River Mine, the world’s largest bulk zinc-lead-silver concentrate exporter, owned by the Anglo-Swiss company Glencore, to be closed because its waste rock dump and tailings dam are leaching acid, metals and salts into the McArthur River system.
But Glencore says its operation hasn’t contaminated fish in rivers outside its mine lease. It’s hoping to find solutions to the challenges it faces managing reactive waste rock on its site so it can get approval under a federal and Northern Territory government environmental impact statement (EIS) to keep on mining.
Approved as an underground mine in 1995, the mine was allowed to go open cut in 2006. In an move that outraged the area’s four Indigenous clans, the miner Xstrata was allowed to divert five kilometres of the McArthur River to get to the ore body underneath, and plough through the Rainbow Serpent dreaming site.
That move still hurts some of the clans’ leaders, including Garawa elder and well-known Indigenous painter Jack Green.
‘The hole was hurting me a lot. It’s part of that old rainbow. A lot of old people that were fighting for it; they’re all gone now,’ he says.
‘If they were still here today I think they would be still here with me arguing about that hole. It looks like I am only one person standing up on behalf of myself and my kids and my missus.’
In 2013 the territory government approved another expansion of the mine, to double its size, increase its production rate, produce 500 million tonnes more waste rock, and extend the mine life to 2038.
But six months later, by the end of 2013, the mine’s waste dump spontaneously started combusting. The fire sent a plume of toxic iron sulphide smoke over the pristine coastal floodplains and savannah of the Gulf Country.
Residents, including painter and Garawa traditional owner Nancy McDinny, were horrified.
‘It was really smoking. We saw smoke all around it,’ she says. ‘It made people really scared. We thought it was turning into a volcano or something, getting burst and going down to the river again.’
Pyrite iron sulphide stacked in the dump had heated up in oven-like conditions and ignited.
Glencore had misclassified its waste rock during the EIS as 12 per cent reactive potentially acid-forming rock, and the rest non-acid-forming.
When it received the results of new geotechnical studies in August 2013 it realised it actually had 90 per cent reactive rock—made up of several categories that were potentially acidic, alkaline or metals leaching.
The company had dismissed warnings from the Northern Territory Environment Centre during the expansion EIS process that there was potential for misclassification.
In its reply to the Environment Centre’s objections, the company said in its EIS Supplement: ‘ECNT’s interpretation of the basis for conducting further geochemical work on the non acid forming material is incorrect. Significant information and understanding on the geochemical properties and behaviour of the non acid forming is held.’
Former campaigner Lauren Mellor says the Environment Centre recognised problems before the expansion went ahead.
‘Our submission to the phase 3 expansion for MRM pointed out the fact that no classification for the waste rock had been done adequately to determine the sulphur content, the pyritic nature of the rock material that was on site and what we thought that might pose further down the track,’ she says.
There were also delays in the company informing the NT government it needed to deal with majority reactive rock.
The Territory Mines Department complained in a briefing paper to the chief minister, Adam Giles, that the information was buried in a mine management plan lodged in November 2013, three months after the discovery. It did not call the company in to find out what was going on until February 2014.
The Mines Department also says that although the combustion started in 2013, it was not notified until 2014.
‘The department was advised of a change in the waste rock classification in February 2014 and was alerted that on site practices were not adequately controlling combustion by a complaint from the public about smoke emanating from the wasted rock dump early in the dry season of 2014,’ the department said in a statement.
Glencore’s McArthur River mining manager Sam Strohmayr says there was no attempt by the company to hide the information.
‘That’s not the case at all,’ he says.
‘It’s very clear in the mining management plan about the changes in the classification and we’d already started to put in place changes on the actual mine site at the same time. It’s very clear in the MMP about the changes in the classification.’
The Mines Department’s chief executive, Ron Kelly, says the department has historically dealt with issues that come up on mine sites through the annual and biannual mine management plan process, and that has led to delays in tackling issues at mines.
But he says that is changing, ‘so that when a new technology, or when a new issue is uncovered, that we can move quickly to address those issues’.
‘That is something that the independent monitor has said we need, to be more reactive and ensure that we don’t allow a problem to occur, and then wait a year until a new mine management plan is put in place to address an issue. That’s how we are working into the future,’ Kelly says.
The dump problems were referred to the Environment Protection Authority, and its chairman Bill Freeland decided that the company must submit a new EIS to explain how it was going to deal with the reactive waste rock.
‘They haven’t got there yet but they have done an immense amount of work,’ Freeland says.
‘I think we have to give them a bit of credit, that after this long, long period of probably negligence, what’s happening now is they are actually actively doing things and seem to be looking for answers.’
The federal government has also realised it needs to be involved. It will assess the plan under its EPBC Act, because that act is responsible for making sure threatened species, including the freshwater sawfish, are protected from mine impacts.
Glencore plans to submit its EIS by the end of this year, two and a half years since it was called for.
In the interim, Borroloola residents including Nancy McDinny have been increasingly concerned that the dump’s reactions may have contaminated fish in the McArthur River and its tributaries.
When iron sulphide gets wet, it turns into corrosive sulphuric acid, and other reactive rocks in the dump can leach salts and metals if wet.
‘Fish, sea turtle, dugong that we eat along the sea, shells, we’re too frightened to eat all of our bush tucker now, we grew up eating that stuff,’ she says.
By May 2013 Glencore had doused the dump fire by uncovering the reactive rock and cooling it down, and it has attempted to keep it dry by covering the dump with a layer of clay. It’s also pumping seepage away from the dump into dams.
But the residents’ concerns have not been allayed, because for four years now, since 2012, testing of fish in the Barney Creek on the mine site, by the mine’s consultant, and by the Territory Department of Primary Industries, has found that small species, including rainbow fish and bony bream, have been contaminated with lead above maximum-permitted concentrations, which denote safe eating levels.
Glencore and the government-appointed independent monitor, David Browne from Erias Group, point out there are several possible sources for the Barney Creek fish contamination, including dust off haul trucks on the Barney Creek bridge, dust from the processing plant and seepage from both the waste rock dump and tailings dam.
The company says it’s addressing these problems by catching more dust and better managing seepage from the dump and tailings dams.
But in 2014 and 2015 the fish tests picked up elevated lead, zinc and mercury in fish people catch off the mine site.
Glencore has continued to deny that it has contaminated fish off its site. It has pointed to the fact that many rivers in the region are naturally heavily mineralised. And it says analysis of the isotopes of the lead in the fish caught off the mine site show that they contain non-mine derived lead.
Sam Strohmayr says the isotopes act like a kind of signature for the metals. ‘Each ore body or source of lead has an isotope, or a signature if you like, and you use that to determine where the lead is coming from. So that is the basis of our understanding so far,’ he says.
But the Territory Health Department’s Steven Skov, who works in the Centre for Communicable Diseases, says the science isn’t conclusive.
‘I couldn’t say that what we were seeing was because of the mine and I couldn’t say that it wasn’t because of the mine either,’ he says.
‘Unfortunately, there doesn’t seem to be any data or testing of fish from that area from before the mine was put in place, either when it was an underground mine or when it moved to open cut. I haven’t been able to find anything; nobody’s been able to tell me about anything. So there’s no before and after stuff to make an comparison to.’
He wants signs to be put up warning people about the risks of eating fish, particularly from Surprise or Barney Creeks, or the mine’s Bing Bong port, because he feels the current advice he’s giving to Borroloola people, to just eat a bit of fish two to three times a week, needs to be made clearer.
He is also pushing the NT government to make sure there’s a better fish testing program put in place.
Ron Kelly from the Mines Department also doesn’t believe the isotopes argument is conclusive.
‘There’s no evidence of any minerals or contaminants leaving the mine site and having an impact on fish stocks, there’s no evidence that there’s not, but if there were issues, the department of health through the public warning system would take action,’ Kelly said.
The EPA’s Bill Freeland also thinks the jury is out, but says there doesn’t appear to be a major off-site pollution problem yet.
‘They have detected isotopes in the fish downstream, which clearly come from the mine, but they are in trace levels so it’s not a significant issue in that sense,’ he says.
‘I think, though, that we need more data and better understanding and I think we just have to be patient. These things can’t be done overnight. It’s very complex.’
The NT government is still investigating the fish contamination, and the federal government is also investigating whether the fish contamination has breached the EPBC Act.
It said in a statement: ‘The independent monitor in their 2012-13 report identified that lead isotope ratios in the environment indicate that the mine could be a source of this contamination. The Department of the Environment is investigating whether identified impacts constitute a breach of the Environmental Protection and Diversity Act.’
While the Territory and federal governments wait for Glencore to submit its EIS, a series of other problems with the waste rock dump have continued to grow. The company has kept adding to the dump, even though the clay used to line its base has failed many of its moisture and compaction tests. The liner is meant to be a key barrier against leaching.
The company has also admitted that because of the waste rock classification mistake, reactive rock has been stored in the base of the dump below the one-in-100-year flood line. Bill Freeland says that’s a major problem for a mine on a floodplain.
‘It’s not acid-generating, but what happens with some rocks, say they’ve got a high level of arsenic or, or lead or whatever it might be, that will leach out and it will become soluble and it will go into the environment,’ he says.
‘It’s exactly the same as acid metalliferous drainage, but it’s not acidic—it’s alkaline. And you get the same sorts of effects.’
To tackle that in the short term, Sam Strohmayr says the company is building a clay and rock flood wall around the dump base.
‘What we’re doing there is putting in flood protection bunding so that in the case, the rare occurrence of a one-in-100-year flood, that the water can’t ingress into the base of the dump,’ he said.
Neither the Mines Department nor the company have been able to yet say whether the reactive rock will have to be taken out of the already-giant dump’s base in the long term.
The company’s key long term problem will be convincing the regulators it can it can find a solution that safely encapsulates all of the reactive rock it needs to dump, with the amount of benign rock available to do that on the site now severely limited—just 10 per cent of the waste it’s mining out. Strohmayr is confident a solution will be found, however.
‘Glencore is 100 per cent committed to McArthur River,’ he says. ‘We have invested a lot of money in McArthur River over the last years. We see McArthur River as a long-life asset. We have 20 years of resource to go.
‘We’re 100 per cent committed to doing things correctly, making sure we’re running the operation firstly in a safe manner, doing it in an environmentally safe manner, and ensuring it’s profitable into the future.’
Instead of waiting to see what Glencore proposes in the EIS, Borroloola residents have commissioned an alternative plan to close the mine.
Activist Lauren Mellor has facilitated the plan, and says residents are worried Glencore’s mine will be left leaking into the environment like many other old mines in the area.
‘They want to see a fully costed and comprehensive closure plan and so they’ve actually fundraised, through the sale of artworks, to raise their own funds to bring on a team of experts who are recognised around Australia as being experts in lead pollution and legacy mine containment and acid metalliferous drainage,’ she says.
‘These experts are coming on board to write this report to look at an option for backfilling that reactive material into the pit.
‘The job will be for the community and those experts to convince the government that this is the most sensible, this is the most cost-effective, this is the best way to deal with this problem.’
One of the closure plan’s authors is Monash University civil engineering department senior lecturer Gavin Mudd.
‘We cannot leave tens to hundreds of millions of tonnes of sulphidic mine waste above ground, and expect that it’s going to be safe forever,’ he said.
‘Sometimes you have to wait 20 years for acid mine drainage problems to really become apparent. At the former Goldsworthy iron ore mine in Western Australia, which was closed in 1994, acid mine drainage problems, like those at McArthur River, only became apparent in 2004, 10 years later.’
Worried that taxpayers could be left carrying the cost of cleaning up the mine site, the NT government last year demanded an increase in the financial bond it holds against Glencore, under the threat of ordering the mine to close.
Chief minister Adam Giles says the bond would pay for a 100 per cent clean-up. But he won’t say how big it is.
‘I don’t make comments about the level of the bond,’ he says.
‘They are commercial in nature, but we just take advice from independent experts to guide is on what the bond should be, and then it’s a negotiation process with the company themselves.’
Bill Freeland hopes the company will be able to keep mining and come up with viable solutions to deal with its problems while protecting the environment.
He says bond or no bond, the last thing Borroloola’s residents and the Australian public need is another legacy mine site. And he says it will be on the taxpayer if the mine goes bust.
‘We would much rather the miner did it and the complexity of what’s got to be done is huge,’ he said.
‘We don’t have, as yet to my mind, an adequate closure plan just for the waste rock dumps. It makes it very difficult to predict how much you’re going to need and all the rest of it.
‘The only certainty is if we’ve got someone there to pay for it, and if they stay there then it solves a lot of problems for everybody.’