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Rain, runoff and rare metals – the toxic threat to the Dorrigo Plateau

Hands up those who’ve heard of antimony. Now, keep them up if you can name its chemical symbol, list the world’s leading producers, or even name a single commercial product that contains the element. Most…

Is this the place for an antimony mine? I guess that depends what an antimony mine is… Karl Vernes

Hands up those who’ve heard of antimony. Now, keep them up if you can name its chemical symbol, list the world’s leading producers, or even name a single commercial product that contains the element.

Most of us struggle to answer any of these questions. But the residents around Dorrigo, a quiet hamlet on the edge of the Great Escarpment in north-eastern New South Wales, are mounting a campaign against a mining company that plans to mine for this precious metal adjacent to Dorrigo’s World Heritage-listed rainforest.

A World Heritage listed rainforest

Approach Dorrigo from the west and you’re greeted by rolling hills of vivid green scattered with patches of remnant rainforest. Black and white dairy cows dot the hills.

As you get nearer the escarpment, the pastures give way to larger areas of rainforest. There are four distinct varieties – warm temperate, cool temperate, sub-tropical and dry rainforest.

These forests are rich in biodiversity and globally important; they are included in the World Heritage listed “Gondwana Rainforest of Australia”.

Beneath the canopy of coachwood, sassafras, prickly ash, giant strangler figs and dozens of other rainforest trees, threatened species abound. There are red-legged pademelons (a type of rainforest wallaby), spotted-tailed quolls, powerful owls, Wompoo fruit doves, and sphagnum frogs, to name a few.

The red-legged pademelon. Peter Jarman

Turn over a log and you might reveal some of Dorrigo’s smaller wildlife treasures, such as the world’s biggest earwig, or Australia’s largest weevil.

Understandably, the residents around Dorrigo are worried that the nearby biological wonder is under threat from a local mining boom.

Why come to Australia for antimony?

China is the leading supplier of antimony. In 2009 it produced about 140,000 tonnes of the stuff, or about 90% of worldwide production. Australia is at the other end of the scale, producing in that same year a mere 1,000 tonnes.

So why is Chinese-owned Anchor Resources looking for antimony on the Dorrigo Plateau? Part of the reason lies in a surge in the value of the metal.

Traditionally, antimony has been used in lead-acid batteries and fire retardants. Recently, it has become increasingly important to the microelectronics industry for use in semiconductors.

And the Chinese government has recently clamped down on antimony mines in China – closing a number of them – because of apparent concerns over safety of mine workers, and threats to the environment.

In 2009, an accident at an antimony mine in Hunan Province left 26 people dead. It led to the closure of all antimony mines owned by Hsikwangshan Twinkling Star Co. Ltd. – the world’s biggest producer of antimony.

This sent the global price of antimony skyrocketing from $4,000 a tonne in 2009 to a record $10,000 a tonne today, and sparked a worldwide hunt for the commodity.

This search led Anchor Resources to begin exploring reserves at an old antimony mine site at Wild Cattle Creek, north of Dorrigo. With test drilling now complete, the company is confident the antimony reserves will yield “positive financial returns”.

Is this the place for a mine?

But things have changed in Wild Cattle Creek. Since the 1970s, when the mine last produced commercial quantities of antimony, and even since 2009 when Anchor Resources began test drilling, much of the forest around the existing mine shaft has come under the umbrella of the National Parks estate. Some of this has now been listed as World Heritage.

Concerns about mining in this area include the increased noise, dust and traffic associated with mining. These are at odds with the scenic beauty of the rainforest and the thriving ecotourism industry that it supports.

Not just quolls might be in danger. Jane Rawson

But the most serious concerns relate to the inescapable geographical realities of where the mine is located.

It sits atop a mountain within a World Heritage listed catchment that receives very high rainfall. The runoff supports rural and urban populations, livestock, crops, nature-based tourism, and the natural environment of the thriving “Banana Coast” region around Coffs Harbour, a mere 20 kilometres from the mine, and directly downstream.

Antimony is toxic, with side-effects not unlike those seen with arsenic poisoning. The byproducts of the antimony mine at Wild Cattle Creek will include (along with antimony) arsenic and mercury.

All this water – and antimony – has to go somewhere

Apart from being an area of great natural beauty and rich biodiversity, the Dorrigo Plateau is also very wet.

Rainforest needs rain, and Dorrigo gets plenty. The town has an average annual rainfall that exceeds two metres, and in 2008 had its wettest year on record, with a whopping 2,650 millimetres.

The Dorrigo plateau is a rainy place. Karl Vernes

All this water has to go somewhere. In the case of Dorrigo, runoff finds its way via myriad creeks and streams (including Wild Cattle Creek) into the Nymboida River, where it’s captured by the Nymboida Weir.

Water from that weir is pumped to the new Shannon Creek Weir, which provides drinking water for the 250,000 people living in the Coffs region from Iluka to Sawtell.

Suspended sediments from the Dorrigo Plateau do wind up in Coffs Harbour’s drinking water, because eroded red soils that sometimes cloud the reservoirs below can be traced directly back up the hill to potato farms on the plateau.

If the mine at Wild Cattle Creek has trouble controlling its toxic wastes, the costs to people and the environment might make the profits from antimony look like a drop in the ocean.

Contaminated water does escape antimony mines in northeastern New South Wales. In August 2011, following heavy rainfall, a sediment erosion control dam at an antimony mine at Hillgrove near Armidale on the New England Tableland overflowed.

It released arsenic, copper and zinc downstream into the Macleay River, adding to previous contaminated outflows from the mine. The NSW government conceded contaminants will be detectable in river sediments for millennia.

In April 2009, a spill from the Hillgrove mine of up to 3000 litres of slimes containing high levels of antimony, arsenic and lead washed into a nearby creek. The mine operator, Straits Gold, was fined $50,000 dollars in the Land and Environment Court of New South Wales for that leak. The long-term environmental costs of leaks like this can only be guessed at.

More recently, a report commissioned by Anchor Resources has shown elevated levels of antimony and arsenic in waterways adjacent to their exploration lease at Wild Cattle Creek. Antimony levels were recorded at 126 times the Australian and New Zealand Environment Conservation Council’s (ANZECC) guidelines for drinking water.

In the song “Blue Sky Mine”, Midnight Oil’s Peter Garrett sang (with some sarcasm): “nothing’s as precious as a hole in the ground”. At Dorrigo, where “blue sky” days are a cherished reprieve between the days of steady rain, the potential environmental damage that “hole in the ground” might cause needs some careful consideration.

Join the conversation

33 Comments sorted by

  1. John Chapman

    At large

    Thanks very much for this article Karl. Very well written and informative.

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  2. Mark Duffett

    logged in via Facebook

    "The long-term environmental costs can only be guessed at."

    Translation: We can't find any.

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    1. Karl Vernes

      Associate Professor, School of Environmental & Rural Science at University of New England

      In reply to Mark Duffett

      Thanks for your guess Mark. But for some information about this, please see Mark Graham's comments below regarding fish kills and warnings issued to residents regarding contact with the Macleay River.

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    2. John Malcolm

      Musician/Sculptor

      In reply to Mark Duffett

      Your "translation" confirms that we can not find what does not yet exist. This in no way invalidates the idea of caring about long term consequences.

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  3. Bernie Masters

    environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

    The proposed mine may or may not have the environmental impacts that the author claims, but what I find professionally unacceptable is the author's apparent disregard for due process, specifically, the need for the the NSW EPA's independent assessment of the project and advice to government. By listing every conceivable threat and assuming the worst, the article seems to me to be attempting to preempt what should be a science-based assessment of the proposal's likely impacts.
    To be honest, I believe this type of emotional worst-case scenario prediction is inappropriate for inclusion in The Conversation. It would be far more at home in The Wilderness Society's website.

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    1. Karl Vernes

      Associate Professor, School of Environmental & Rural Science at University of New England

      In reply to Bernie Masters

      Bernie,

      I don't feel the article is emotion-laden, nor does it present a 'worst-case scenario'. I didn't state whether the mine will or will not cause environmental damage - but the potential is there, and as a conservation biologist and environmental scientist, I think it's worth raising that possibility (note my careful use of the words 'if', 'might' and 'potential' in the article). You are right - the proposed mine may or may not have a serious environmental impact - but you are wrong that I claim it will. If you read the article carefully, you will see that.

      I haven't disregarded due process either - I've brought together published, open-access information that is available to anyone. This in no way impacts upon independent assessment of the project, or preempts a science-based assessment.

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    2. Bernie Masters

      environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

      In reply to Karl Vernes

      Thanks for the reply, Karl. I've re-read your original article and I count a total of 11 statements which you may claim are factual, unemotional and/or science-based but, in reality, they are written so as to create an impression of catastrophe waiting just around the corner, should this mine go ahead. Let me give you a few examples of what I mean:

      "And the Chinese government has recently clamped down on antimony mines in China – closing a number of them – because of apparent concerns over safety…

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    3. Mark Graham

      Ecologist

      In reply to Bernie Masters

      Bernie

      Sadly what should, in both theory and practice, be an independent science-based assessment of impact never is. In the real world a proponent finds a favourable consultant and pays them large sums of money to tell the story that they want told.

      In the case of many industries (including mining) the proponents then make donations to the political masters of the agencies meant to be independently ensuring that our society and environment are protected from harm and that our laws are upheld. The end result - pollution, loss of biodiversity and an erosion of our life support systems.

      Do you truly believe that independence and truth underpin environmental assessments?

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    4. Bernie Masters

      environmental consultant at FIA Technology Pty Ltd, B K Masters and Associates

      In reply to Mark Graham

      Thanks for the comment, Mark. Sadly, as much as I would like to disagree with you, there is a grain of truth to most of the issues you raise. But this in no way diminishes my concern that, if due process is not followed as the original article seems to hope, then where are we as a mature, intelligent, law-based and respectful society? Anarchy or the person with the biggest cheque book wins or do we accept whichever side manages to get the most articles into the media or we do leave it to private armies as in Mogadishu to decide who's right or wrong?
      There are many problems and failings with our current system of deciding whether a development proposal proceeds or not, but we shouldn't consign what we have to the rubbish heap; we should make it stronger and more effective. This is not the goal of Karl's original article, hence my many concerns with it.

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    5. John Malcolm

      Musician/Sculptor

      In reply to Mark Graham

      While it may be true that "independent" investigations may not be entirely so, it does not follow that the impact statements from the mining companies themselves have less bias.

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    6. John Malcolm

      Musician/Sculptor

      In reply to Bernie Masters

      I think there is a need to discuss the value of worst case scenarios and emotional thinking.

      I wish to point out that worst case scenarios are possible scenarios. The degree of harm that would occur in the worst case scenario determines the amount of care necessary. Take a real example. When we and our families put on seatbelts before we drive off, it is because of the seriousness of the worst case scenario. It is not because we think catastrophe is waiting just around the corner, it is because…

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    7. John Malcolm

      Musician/Sculptor

      In reply to Karl Vernes

      Karl I was compelled to come to the rescue of worst case scenarios, and emotional thinking, in a comment below. (Sorry about the length of the comment) I feel it is invalid to exclude either from risk assessment.

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  4. Mark Graham

    Ecologist

    Karl

    Thank you for writing this article.

    Dorrigo is renowned as the highest rainfall catchment in NSW. On 31 March 2009 the site of the proposed mine received 900mm of rainfall, this is one of the highest rainfall events ever documented in NSW. In such extreme rainfall events it is impossible to capture all runoff. The Stibnite ore body at the proposed mine site contains not just Antimony, but Mercury, Lead and Arsenic.

    The Dorrigo Plateau has one of the highest concentrations of threatened…

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    1. Karl Vernes

      Associate Professor, School of Environmental & Rural Science at University of New England

      In reply to Mark Graham

      Mark - you've presented some really interesting additional information that adds weight to some of the points raised in the article. Many thanks for your comments.

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    2. Mark Duffett

      logged in via Facebook

      In reply to Mark Graham

      "Stibnite ore body at the proposed mine site contains not just Antimony, but Mercury, Lead and Arsenic." So does just about every natural soil. Your point?

      And "26 deaths at an antimony mine in Hunan". Did these deaths have anything at all to do with the properties of antimony, or were they the result of an accident that could have occurred at any mine anywhere? If the latter, to bring them up in this context is misleading to the point of outright dishonesty.

      "...three weeks ago when a fishkill…

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    3. Karl Vernes

      Associate Professor, School of Environmental & Rural Science at University of New England

      In reply to Mark Duffett

      Mark - the deaths in China (because of poor mine safety - sorry if that missed that point - there is a link you can follow) were mentioned because this led to widespread closures of antimony mines in China, which appears to be linked to a global price hike in the commodity (mentioned in the very next sentence). I wasn't attempting to mislead anyone over inclusion of this information - I think you, as well anyone who read the article, know that I was trying to informing the reader why there seems…

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    4. Mark Graham

      Ecologist

      In reply to Karl Vernes

      Karl

      Thanks for highlighting Mark Duffett's professional role and affiliations. All of Mark's contributions here make perfect sense now. 'Nuff said.

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    5. Mark Duffett

      logged in via Facebook

      In reply to Mark Graham

      Are you saying they didn't make sense before? Exactly how are the merits of what I say affected by who I am? Why is the latter more important?

      And yes, kudos to Karl on his ability to use Google.

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    6. John Malcolm

      Musician/Sculptor

      In reply to Mark Duffett

      It is apparent to me that he is saying that in the light of your connections, it now makes sense that you are saying what you are saying. This is different from saying that your statements now have more merit.

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  5. Mark Graham

    Ecologist

    Another important point to consider is that the exploration activities undertaken by the mining company to date have resulted in:
    1. the clearance of an extensive area of rainforest
    2. the destruction of the known habitat of at least four threatened species
    3. the mobilisation of sediments, some containing toxic Arsenic and Antimony.

    There has been no attempt to remediate the exploration site, nor has there been the implementation of even basic environmental protection measures such as sediment…

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    1. Mark Duffett

      logged in via Facebook

      In reply to Mark Graham

      Never mind a thousand words, how about some numbers? How big is an "extensive area"? As a percentage of the total area of rainforest? How big a habitat area was "destroyed"? Again, as a percentage? What was the As and Sb concentration in the 'mobilised' sediments?

      "When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind"
      Lord Kelvin

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    2. Mark Graham

      Ecologist

      In reply to Mark Duffett

      Rainforest is an endangered forest ecosystem. It is known to support a large proportion of Australia's biodiversity. Over 75% of the pre-1750 rainforest of NSW has been cleared. The exploration activities have completely removed several hectares of an ancient rainforest community that is recognised as having internationally significant conservation values. These forests are some of the most ancient vegetated habitats on earth. They are essentially unchanged since the breakup of Gondwana.

      The clearance…

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    3. Mark Graham

      Ecologist

      In reply to Mark Graham

      Rainforest is an endangered forest ecosystem. It is known to support a large proportion of Australia's biodiversity. Over 75% of the pre-1750 rainforest of NSW has been cleared. The exploration activities have completely removed several hectares of an ancient rainforest community that is recognised as having internationally significant conservation values. These forests are some of the most ancient vegetated habitats on earth. They are essentially unchanged since the breakup of Gondwana.

      The clearance…

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    4. Mark Duffett

      logged in via Facebook

      In reply to Mark Graham

      Ah, so now we come to it. Your fundamental problem is with the enterprise of mining itself. 'Nuff said.

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    5. Mark Graham

      Ecologist

      In reply to Mark Duffett

      Mark I do not have a fundamental problem with the enterprise of mining at all. I recognise that a considerable portion of our nation's current phenomenal wealth is derived from our mineral resources. I also recognise that our civilisation requires mining to function as it does.

      I have a problem when evidence of existing problems caused by mining is dismissed by those with vested interests. For example, when people who are involved in mining industry research and development, such as yourself, do not openly and transparently disclose their affilliations and funding sources and then dismiss the legitimate concerns of others. I have an even bigger problem when they then attack others who are publicly raising important facts and highlighting the risks associated with dangerous mineral extraction proposals and practices.

      'Nuff said.

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  6. Mark Graham

    Ecologist

    Mark

    The Hillgrove Mine contributed a toxic plume of Arsenic and Antimony to the Macleay River less than a month ago. This arose from current "best practice" mining techniques. Yes, some of the existing contamination has arisen from historic mining, but pollution is occurring to the present day under what are purportedly more advanced or better mining techniques.

    What is your address? Shall I arrange for a dead catfish to be sent to you, you will find high levels of both Arsenic and Antimony in…

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    1. Mark Duffett

      logged in via Facebook

      In reply to Mark Graham

      That's an odd way of communicating scientific results. I'm sure you can do better.

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  7. Tom Barrett

    Research Fellow, Landscape Ecologist at University of New England

    Karl, Did you know that these Eastern Australian forests are soon to listed as the 35th international biodiversity 'Hot Spot'? This is the reference:

    Williams KJ, Ford A, Rosauer D, De Silva N, Mittermeier R, Bruce C, Larson F, Margules C. (2011). Forests of East Australia: The 35th Biodiversity Hotspot. In: Mittermeier et al (eds), Biodiversity Hotspots - earth´s conservation priority areas under change. Springer Press.

    In prehistoric times these areas provided an important refuge for many rainforest species during dryer and hotter climatic conditions, a role that will become even more important under predicted climate change. But extensive clearing and fragmentation of these forest will make it extremely difficult for species to migrate to these refuge areas as Mark Graham pointed out. This has to be factored in when considering development that will cause further loss of these important habitats.

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  8. Michael Kottek

    logged in via Facebook

    Antimony isn't all that toxic, and from memory most of the tox data is derived from a dozen rats poisoned in the 50s. When I had to look at the underlying data about 15 years ago, I was somewhat underwhelmed by the material available. Elevated Sb levels in surface waters wouldn't ordinarily be compared to ANZECC drinking water guideline levels. To me it looks like scaremongering to go on about them being 100 times above drinking water guidelines and comparing it to blue asbestos mining in Wittenoom: apples and oranges I am afraid.

    I would be worried about tailing control in such a high rainfall area just from a sediment perspective: I suggest you ease up on the spooky toxin scaremongering. There is plenty of arsenic and antimony about in lots of other old gold mining areas; nothing to see there I am afraid.

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    1. John Malcolm

      Musician/Sculptor

      In reply to Michael Kottek

      Whether or not Antimony itself is "all that toxic" (you do not say it is non-toxic), are you prepared to state as a fact that Antimony MINING is non-toxic in terms of run off etc.?
      If it is invalid to bring up Wittenoom, why is it valid to bring up old gold miming areas?
      Do you have a business connection with Antimony mining?
      Please tell us plainly just how toxic Antimony is.

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  9. Jane Rawson

    Editor, Energy & Environment at The Conversation

    Karl and I have just updated this article to better reflect the detail of the 2009 spill.

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  10. Michael Cunningham

    logged in via Facebook

    Thanks again Karl. Dorrigo forests have a very sorry history, as does the Antimony mine at Hillgrove (see the long-term environmental scar down the valley from there - also World Heritage).

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