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Australia’s Mining Legacies by Gavin M. Mudd

The impacts of mining waste will be felt for years to come.

Mining is, by its very nature, a dirty business—it excavates and processes billions and billions of tonnes of rock and dirt every year to extract a wide variety of metals and minerals demanded by modern industrial and technological society. These include metals used in pipes, electronics, buildings and gadgets, such as copper, zinc, iron, nickel and lithium, as well as energy resources for heating and electricity, such as coal, gas and uranium. Australia has, without doubt, a vast resource base in these metals and minerals and we commonly export most of our production to overseas customers who aren’t so luckily endowed. The great scale of modern mining, however, comes at a real cost whether on the local landscape, public health or the global environment, and it is understanding these real costs and how the environmental and social impacts intertwine with economic issues that is the crux of the great mining debate in Australia and globally.

This paper will briefly review the basics of mining, present some important statistics on Australia’s cumulative mining to date, discuss the present state of known mineral resources and link these to the great debates at present: What commodities should (or could) Australia mine? Where should we allow such mining? How are the impacts to be identified? How should such impacts be monitored, regulated and managed? These are the crucial questions of the day, and it is not just environmentalists asking them, but farmers, city dwellers, Indigenous people and ordinary people all over the country. This is placing unprecedented pressure on politicians, the mining industry and increasingly the investment community to recognise that, in the mutated words of Bill Clinton, ‘it’s about the IMPACTS STUPID’.

A Brief History of Mining in Australia

Australia has gone through numerous cycles of boom-bust periods of mining often led by a new commodity being discovered (e.g. gold) or a major new mineral field being found and developed (e.g. Broken Hill). Coal, Australia’s first ever export, was mined near Sydney in New South Wales, and sent to Bengal in India in 1799. Almost every decade from the 1840s to the 1900s was the focus of a new mining rush or boom. A brief timeline is given below:

  • 1840s—copper in South Australia (Kanmantoo, Burra Burra), lead (Glen Osmond)
  • 1850s—gold across eastern Australia (Bendigo, Ballarat, Bathurst)
  • 1870s—tin rush across eastern Australia (Mt Bischoff, Chillagoe, New England)
  • 1880s—silver-lead rush at Broken Hill, gold in the Kimberley and Mt Morgan
  • 1890s—gold in central Western Australia (Kalgoorlie, Coolgardie), copper-gold at Mt Lyell
  • 1900s—iron ore in South Australia (Middleback Ranges)

The early twentieth century saw a period of consolidation, with major companies emerging such as Broken Hill Proprietary (BHP) and the Zinc Corporation (later to be merged into Rio Tinto). With the 1930s Depression, gold mining entered a mini-boom as people sought to prospect for gold to eke out a living and Mt Isa’s lead-zinc-silver mining and smelting complex in western Queensland emerged. The post-war booms, however, have redefined and changed the mining industry forever, including the following:

  • 1950s—uranium (Rum Jungle, Mary Kathleen), bauxite (Gove, Weipa), copper (Mt Isa)
  • 1960s—manganese (Groote Eylandt), iron ore (Pilbara, Savage River, mid-west WA), nickel (Kambalda, Mt Keith, Greenvale), oil and gas (Bass Strait, Cooper Basin, North West Shelf)
  • 1970s—uranium (again) across Australia (Ranger, Jabiluka, Yeelirrie), copper-uranium-gold (Olympic Dam)
  • 1980s—return of gold (Australia wide), major growth in metals, coal and oil-gas
  • 1990s—nickel laterite boom (Murrin Murrin, Cawse, Bulong), copper (Nifty), copper-gold (Ernest Henry, Cadia-Ridegway)
  • 2000s—mega-boom in coal and iron ore and emergence of coal seam gas (CSG).

Production, Exports and Resources

The primary steps involved in the mining chain are mining and milling, with additional smelting and refining for most metals. Mining can be either by underground or open cut methods, with the two primary materials being ore, containing the minerals or metals of interest, plus waste rock (often called overburden in coal). Open cut mining can produce up to 10 tonnes of waste rock or more for every tonne of ore, while underground mining produces a fraction of a tonne of waste rock for every tonne of ore. For most ores, the concentrations or grades range from grams per tonne (g/t, such as gold or silver) to per cent (e.g. uranium at 0.3 per cent U3O8; copper at 0.5–3 per cent Cu; lead-zinc at 0.5–5 per cent Pb or 2–12 per cent Zn) or the majority of the ore (e.g. iron ore at 50 per cent Fe). Coal processing generally extracts 80 per cent of the raw coal as saleable coal. After ore processing, the remaining solid wastes are called tailings and, depending on ore grade, can range from minor fractions of the ore (e.g. iron ore, bauxite, coal), to most or all of the ore as tailings (e.g. gold, copper). Thus, to generate a tonne of a given metal or mineral, the amount of waste rock and tailings (i.e. total mine wastes) can range from one tonne to several million tonnes.

By 2012, Australia has developed a large mining industry across a wide range of commodities combined with a substantial resource base. A compilation of cumulative production, 2012 production, mining method (based on proportion of ore), exports, economic resources and sub-economic resources is shown in Table 1. In production tonnage terms the coal, iron ore and bauxite sectors stand out, with the dominance of open cut mining clear across most sectors.

Throughout Australia’s colourful mining history, different commodities have dominated export volumes and values at different periods (such as gold in the mid-1800s). The big shift in recent years is the rise of iron ore as the dominant mineral export, reaching $54.8 billion in 2012 and overtaking coal at $41.6 billion. Uranium, despite dedicated political support and literally glowing industry and government rhetoric, curiously doesn’t even reach a measly billion dollars and on average over the past decade has earnt less per year than wine and cheese. Based on existing and future mines and market prices, it is most likely that iron ore will continue to dominate mineral exports as well as Australia’s exports in general.

Table 1: The hard statistics of Australia’s mining industry

Table 1: The hard statistics of Australia’s mining industry

 Mine Yer Wastes

If you were to ask a member of the public about solid wastes produced annually in society, they would almost definitely think of the garbage we commonly dump in landfills, some might even add construction wastes, while many might even acknowledge the rubbish which ends up in waterways, but rarely would anyone be able to give a reliable estimate of the solid wastes from mining. The mining industry has been very adept at minimising public perception of this aspect of the solid wastes debate for a long time, but the sheer massive scale of modern mining makes it a gigantic source of solid wastes, in Australia as well as globally. Based on extensive research on historical statistics for the Australian mining industry, an estimate of 2012 and cumulative ore, tailings and waste rock is given in Table 2.

Table 2: Mega-massive statistics of ore, tailings and waste rock from Australia’s mining industry

Table 2: Mega-massive statistics of ore, tailings and waste rock from Australia’s mining industry

As can be expected, the total mine wastes are dominated by the giant coal and iron ore industries, although considerable data remains incomplete and not documented. For 2012, total mine wastes are of the order 6.5 billion tonnes—dirty business indeed. Assuming a low ratio of 2:1 for waste rock to ore for the iron ore sector suggests a bare minimum cumulative waste rock of some 15 billion tonnes. Adding up these sectors alone, and allowing for crude estimates of the missing data, suggests that the Australia mining industry has already produced in the order of 100 billion tonnes of solid mine wastes, making the scale of landfills pale into insignificance at just hundreds of millions of tonnes.

Short and Long Term Impacts 

Mine wastes can be tricky stuff—a lot of it may be relatively benign rock, but some of it may be chemically reactive or even simply contain elements of concern if they were to escape into the environment.

In the early days, Aussie miners often dumped tailings and waste rock onto adjacent ground, allowing the wastes to erode into nearby rivers and streams and leading to sedimentation problems and sometimes chemical pollution risks (e.g. mercury exposure). These impacts were relatively local due to the generally modest scale of wastes involved. By the twentieth century, miners realised that tailings often still had some metals left and that dumping wastes into rivers was not really the done thing and so practices evolved to include dams to store tailings with waste rock dumped into specific piles (though with minimal engineering). There were the aberrations though, such as the Mt Lyell copper-gold mine in Tasmania continuing to dump tailings into rivers until 1994 (the Tasmanian government passed legislation in 1929 banning riverine tailings disposal—except at Mt Lyell !!) or the Rum Jungle uranium mine dumping tailings and liquid wastes to the adjacent floodplain and creek system for several years in the 1950s–60s. Meanwhile, by the 1970s, the growing scale of mine wastes combined with ongoing environmental impacts from abandoned mines led to the need to more forcefully regulate mining, and require rehabilitation after mine closure. Since this time, the mining industry has been very proactive in promoting its environmental credentials and successes—all the time carefully avoiding the issue of the exponentially growing scale of modern mine wastes.

In general, for most mineral commodities, ore grades or quality are in terminal decline, meaning you have to mine ever more ore to produce the same amount of a metal or mineral. Gold and copper ores are now ten times lower than a century ago and while others have not declined as much, sometimes it is ore quality and impurities which matter—some ores are very fine grained or rich in arsenic, both requiring more expensive processing. As ore grades decline, this means yet more tailings—more dirt work for engineers.

Why should we even care about mine waste? Simple—it can leak pollution for centuries or even millennia. This pollution can be in the form of wind-blown dusts or sediment eroded by water scouring waste rock dumps or tailings dams, or it can be more pernicious in the form of seepage from mine wastes into groundwaters or surface waters. A major form of seepage is called acid and metalliferous drainage, or more commonly known as acid mine drainage (‘AMD’). AMD can form when sulfide minerals, mostly pyrite (iron sulfide and its close mineralogical cousins), are exposed to water and oxygen in the surface environment, causing sulfide oxidation and the formation of sulfuric acid, which in turn leaches salts and heavy metals (including sometimes radionuclides). If AMD leaks into a stream, the metals concentrations are often hundreds or thousands to hundreds of thousands times higher than the levels which can kill most biodiversity, effectively wiping out the ecology of that stream. As the AMD flows downstream, it will be diluted along with chemical reactions removing some or most of the metals (especially as the acid is removed) and so at some point there will be a return to a ‘normal’ ecosystem. The distance a stream can be impacted varies depending on the size of the AMD source, hydrological characteristics (especially rainfall and flow frequency), the geochemical nature of the mine wastes and geology of the catchment, among other factors.

There are numerous mines across Australia which are famous—or more to the point infamous—for their AMD impacts on streams: Rum Jungle, Northern Territory; Mt Lyell, Tasmania; Mt Morgan, Queensland; Brukunga, South Australia; Captain’s Flat, ACT (to name but a select few). There are also heaps of virtually unheard of abandoned mines which are causing AMD pollution problems: Redbank, Northern Territory; Mt Todd, Northern Territory; Tabletop, Queensland; Mt Oxide, Queensland; Canyon, New South Wales; Teutonic Bore, West Australia; Luina-Cleveland, Tasmania; Mt Bischoff, Tasmania; to name but a small selection. Many modern mines are having to manage sulfidic tailings and waste rock with careful attention to AMD risks, including iron ore mines, gold mines, copper mines, coal mines and others.

In a bizarre twist of fate, or perhaps a twisted sense of irony, the very name Rio Tinto effectively translates from Spanish to ‘tainted river’. The lead and copper mines of the Roman era were still causing pollution more than a millennia later in the 1870s when a bunch of British investors founded a new company to mine copper in the southern Tinto region of Spain. They used the process of sulfide oxidation to leach the copper from the ore and produce copper cheaply, making a tonne of cash and creating the profitable foundation of a global mining empire we now call Rio Tinto Limited. The Tinto region of southern Spain is still polluted from the collective history of intense mining. Rio Tinto has gone on to be involved with AMD impacts at Rum Jungle and Bougainville (Papua New Guinea), let alone other mines and they have still never paid a cent towards clean-up at any of these sites. It is incorrect to say miners never understood AMD, of course they did, they just ignored the severe environmental impacts from it.

In fact, the severe pollution from the Rum Jungle uranium mine was one factor, and an important factor, which led many people to actively oppose new uranium projects in the 1970s such as Ranger. After some $25 million worth of engineering works to try and rehabilitate the Rum Jungle site in the mid-1980s, environmental monitoring was conducted for a decade, showing some short-term success in reducing pollution loads to the Finniss River and even some biological recovery. For the past decade I have regularly visited Rum Jungle to observe the ‘success’ of the rehabilitation and all you can see is ongoing and severe AMD pollution of the Finniss River. Reluctantly, the Australian government has recently allocated several million dollars to undertake further assessments before deciding on yet more rehabilitation.

The gold-copper mine of Mt Morgan—the mountain of gold—was so rich in its early 1880s–90s that the original investors went on to found the Walter & Eliza Hall Institute for Medical Research andinvest in oil exploration in Persia, leading to the Anglo-Persian Oil Company which was later to become British Petroleum (BP). Mining at Mt Morgan, just 45 kilometres west of Rockhampton, lasted from 1882 to 1982—a rare feat to last a century, but the mine was never rehabilitated and continues to cause extreme AMD pollution of the Dee River, which is a minor tributary of the mighty Fitzroy River (the Dee is about 0.5 per cent of the Fitzroy’s annual flow). Once mining in the open cut stopped, AMD-rich waters began to fill the open cut. To be fair the Queensland government invested in detailed technical studies in the late 1990s to early 2000s to examine rehabilitation options – and has even built and operates pit water treatment facilities (the current government has not slashed this funding for Mt Morgan either, although in reality the current funding is minimal compared to the scale of the problems). But in early 2013, the inevitable happened – a massive storm swept through the region and for the first time in history the pit over-flowed and locals claim this allowed AMD polluted waters to push further down the Dee River than living memory can ever recall. The rehabilitation plan of 2003 estimated costs could be of the order of a hundred million dollars or so, which you could probably multiply to several hundred million dollars now, given a decade of inflation and big cost increases across the mining industry. Dirty business indeed.

In the southern coal fields near Wollongong, AMD is allowed to go on unabated from former underground or longwall coal mines, sometimes it’s even approved by regulators from existing mines. And the coal (and coal seam gas) industry still finds it perplexing to understand why so many communities are opposing mining near or even inside drinking water catchments?

The modern mining industry now acknowledges and even includes AMD risks in its environmental impact assessments, and on rare occasions even publishes conference papers on environmental management of AMD issues. For example, the iron ore industry of the Pilbara is now mining progressively deeper and below the regional groundwater table, leading to mining of the shales which contain some reactive sulfides (e.g. Mt Whaleback, Mt Tom Price). The AMD risks were identified due to explosives detonating early (due to the heat released by sulfide oxidation) – not exactly a safe outcome for an active mine. Hence even iron ore mines are forced to manage AMD risks. Given the massive scale of waste rock now being mined in the Pilbara alone, this is a daunting engineering challenge. But where is the government or industry data on the proportion of mine wastes prone to AMD risks? Simple—nowhere, not even collected. No data, no problem.

Of course, if you visit intensive mining regions like the Hunter Valley, the Pilbara, Kalgoorlie or the Latrobe Valley, there are many other critical issues associated with mine wastes. These include dusts, surface water risks from saline water discharges, or even discharge of fresh waters changing the hydrology of creeks, let alone the aesthetic impacts from the creation of entirely new mountain ranges. As waste rock dumps are built, they can fill valleys or obscure them from view, leading to significant social impacts and risks such as soil erosion and AMD seepage.

In my experience of visiting many mining communities around Australia, ranging from locals next to a single mine to large communities with intense industrial scale mining (and now coal seam gas) smothering their region, it is mine waste which is the Achilles heel of modern mining. If someone was to run focus groups on mining, I wholeheartedly believe that it would convincingly show that mine waste is a core environmental concern for those familiar with the mega-industrial scale of modern mining. It is also this mega-massive scale of modern mining which brings with it mega-massive environmental risks which need to be carefully assessed, monitored and managed.

In my mind, visiting small, sometimes rehabilitated sites twenty years after they were cleaned up is important—has the rehabilitation worked, and if not, why not? If we can’t even get the rehabilitation right on smaller polluting mines, why then should we believe that similar engineering techniques on larger mines, sometimes a thousand times bigger in mine waste terms than their nineteenth to mid-twentieth century cousins, would work any better? Where is the industry and government evidence of assessing mine rehabilitation performance five, ten or twenty years after rehabilitation?

Given that sulfidic mine wastes can cause AMD pollution for centuries to millennia, why aren’t we factoring in such thinking when approving new mines? Why wasn’t this used as a great moral and scientific justification for the (inept attempt at a) mining tax?

Let’s do some simple maths. Assume engineers can provide a rock solid, rolled gold guarantee that they can successfully rehabilitate mine wastes say 95 per cent of the time—and by success I mean with no future risks whatsoever. Now think of the 5 per cent we fail to rehabilitate or that needs ongoing monitoring and maintenance—this is 5 per cent of billions of tonnes growing exponentially annually. This means as much mine waste as was mined at Mt Morgan over a century being produced every year. Imagine this building up across the landscape and affecting rivers and groundwater and you can begin to understand why so many informed locals and communities are concerned about the sheer scale of modern mine wastes. Let alone the fact that no intelligent engineer could ever seriously provide a 95 per cent or higher guarantee on perfect mine waste rehabilitation.

The Bougainville and Ok Tedi copper-gold mines in Papua New Guinea have each dumped about a billion tonnes of tailings and waste rock into rivers (or are allowing such wastes to erode into rivers). While these are truly infamous mines for the severe human and environmental impacts they have caused, the Ertsberg-Grasberg mine in Indonesia has reached a massive total of some 1.4 billion tonnes of tailings dumped to the Ajkwa River, as well as some 4 billion tonnes of waste rock—a single mine with more mine waste than Australia’s entire copper sector. It is worth pointing out that Rio Tinto states it will not operate mines using riverine tailings dumping (they may have learnt their lesson from Bougainville), it only owns about 9 per cent of Grasberg (Freeport McMoRan is the 82 per cent owner and operator) and is therefore not responsible for riverine tailings dumping there—how convenient for Rio.

Finally, let’s think of some of the other pollution impacts from mining such as carbon dioxide pollution from coal (and coal seam gas) or high level nuclear waste from uranium. If you look at Australia’s coal exports in 2012, these alone are responsible for some 800 Mt of greenhouse gas emissions—nearly double Australia’s emissions. Unfortunately, it was Australian-origin uranium in every reactor at Fukushima at the time of the nuclear meltdowns in March 2011—not something the Australian uranium industry should be proud of, especially given the fact that thirty years of uranium sales to Japan were probably only worth a few billion dollars while the financial costs of cleanup alone to Japanese taxpayers is amounting to hundreds of billions of dollars (excluding social and other economic costs). A related issue is the radioactivity found in almost every rare earth (RE) deposit, due mainly to thorium but sometimes uranium too. When poorly managed, the radioactive wastes from RE mining and processing can cause significant public health and environmental impacts, just ask Malaysians about the former Bukit Merah RE refinery and you’ll understand why they are so concerned about Lynas Corp’s Kuantan RE refinery recently built and opened (after protracted court cases bought by the local community to stop the facility).

Summary Thoughts

The Australian mining industry has grown dramatically in the past sixty years to be a major export-driven industry. Based on our extensive mineral resource base, almost all commodities could be expected to have a bright future, but one of the major issues and constraints which already faces the industry and will increasingly dominate public debate is mine wastes and their management. In fact, such issues were already documented by German scholar Georgius Agricola in his famous 1556 book De Re Metallica:

… the strongest argument of the detractors is that the fields are devastated by mining operations … Further, when the ores are washed, the water which has been used poisons the brooks and streams, and either destroys the fish or drives them away. … Thus it is said, it is clear to all that there is greater detriment from mining than the value of the metals which the mining produces.

Increasingly, the Australian mining industry will be forced to address mine waste either by regulation or by social opposition. In the digital age of the internet, it is even easier to document mine waste impacts, or for industry and government to make monitoring and rehabilitation data publicly available and even incorporate it into mapping systems (like they do for geoscience and mineral exploration already). Although acid and metalliferous drainage risks and impacts are already substantial, based on infamous sites such as Mt Morgan, Redbank and others, the scale of the problem is growing exponentially.

Just because we have billions of tonnes of coal resources does not mean we have to mine them and produce mega-billions of tonnes of mine wastes (and greenhouse gas emissions). Sure, the world will need iron ore for steel, copper for electricity, rare earths and a variety of minerals and metals to meet reasonable needs and demands, but not at the mindless expense of communities, their local environments and the planet’s climate stability.

After all, in looking at the modern mining debate, IT’S ABOUT THE IMPACTS STUPID.

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