Mineral exploration and mining is emerging as the greatest threat to the protection of the Tarkine. The Tarkine is facing a new threat from mining with new mines proposed for development over the next 3-5 years. Early successes in this campaign have seen off mine proposals at Keith River, Riley Creek and Nelson Bay River, but Venture Minerals are intending to press ahead with their proposed tin mine in the rainforest at Mount Lindsay.
Added to this is the massive interest in mineral exploration in the Tarkine rising from the China metals boom. There are currently 38 exploration licenses granted over the Tarkine. Exploration activities such as drilling, geophysical surveys and pit tests have a substantial impact on the Tarkine through clearing, roading and introduction of contaminants.
The TNC has significant concerns these impacts, and have called on the Environment Minister Tony Burke to immediately apply a National Heritage Listing to the Tarkine.
Whilst the old pioneers and old mining sites have been a significant part of the fabric of Tasmania’s west coast, mining has have a significant environmental impact – especially if it occurs in remote and untouched regions. Mining can have a significant destructive environmental impact not just at the mine site, but it also has the potential to lead to serious downstream impacts due to mineral runoff and impacts on river systems. The runoff from the old Mt Bischoff tin mine, for example, still contaminates the upper 30 km of the Arthur River, causing a virtual Dead Zone (Mercury 2003) due to the high levels of toxic metals that leach into the river system. The runoff from the Savage River Mine has also had a significant impact on the Savage River system since it was started several decades ago, though recent owners have invested in limited clean-up operations. At Luina, the acid mine leachate from tin mining has resulted in an acidic, orange sulphurous discharge that is poisoning the Whyte River.
The environmental problems that can be associated with mineral exploration include; increased fire risk, local disturbance to native vegetation, rubbish left behind, and disease, which can be transported via equipment and personnel. (PLUC 1997c) Mineral exploration can also lead to contamination of watercourses through spills, and impacts on ground water.
Early stages of mineral exploration, including aerial reconnaissance, surveys and mapping and stream sampling, cause little environmental disturbance. However, the later stages of exploration, which involve cutting of grid lines, and drilling at certain sites, involves the clearing and disturbance of vegetation and the construction of access tracks for drilling equipment (PWS 2001). In the Tarkine in particular, myrtle wilt is another issue that arises with mineral exploration, with the disturbance associated with mineral exploration having the potential to exacerbate myrtle wilt disease.
Erosion can be a major problem at drill sites, with tracks established for mineral exploration having the potential to become eroded, and the drill sites involving the stripping of vegetation and the removal of topsoil. Because Western Tasmania has such a high rainfall, these sites have the potential to actively erode. (PWS 2001) Drilling water and additives used at drill sites have the potential to cause erosion and possible contamination of any adjacent watercourses. In Tasmania, it is not uncommon for drill holes to intersect ground water under pressure, which will flow water onto the ground surface. Such flows may cause local long-term erosion. Some more intensive activities such as trenching and closely spaced drilling, track construction and line clearing, if carried out near rivers or streams, have the potential to significantly disturb river environments. (Environment Australia 1998). Some 58 exploration licences have been granted over the Tarkine, by 27 different companies.
Mining has a destructive impact on a restricted area, the size of which depends on whether the mine is open cut or underground. However, mining can be expected to have off-site impacts as well, which can often be more significant than the mine site itself.
There is a well-documented history in Australia of past mining activities having caused significant ecological damage, which persists in some rivers and streams, particularly where the river or river valley has been dredged or tailings have been discharged. The potential still exists for operating mines to result in water pollution, which even at low concentrations can exert chronic effects. Such effects include failure of organisms to reproduce (Lake 1992).
Whilst mining and on-site mineral processing operations are usually confined to relatively small areas, waterborne and airborne emissions have the potential to affect environments distant to the operation. The emissions which occur during the operating life of the mine, have the potential to continue to affect the environment long after mine closure; e.g. contamination from the Mt Bischoff tin mine (Waratah) continues to have significant impact on the upper reaches of the Arthur River, several decades after closure of the mine itself.
Waste rock is one of the major contributors to mining damage through visual damage to the landscape, but also through contribution to acid mine drainage. The way that waste materials are disposed of during a mining operation can therefore have a significant impact on the environmental impacts of the mine. Waste rock can contribute to acid mine drainage during the operational life of the mine and also after closure of the mine. Rock has the ability to produce Acid Mine Drainage (AMD) if it contains sulphides. Siltation and acid-mine drainage have major impacts on water quality, due to erosion of exposed surfaces, the flow of pumped mine water, and through natural rain water movement through stockpiles and mine workings. AMD has been the subject of much research and detailed investigation (TCM, 1992; Minerals Council of Australia, 1995), and it remains one of the major environmental issues associated with mines which operate in geological conditions which generate acid water. This includes most of the major West coast mines in Tasmania. Open-cut mines, including quarries, will always have a high impact on landforms, flora and fauna.
There are a number of vegetation types that careful attention needs to be paid to in terms of the impacts of mining and mineral exploration on Tasmanias West coast. These include, Epacris glabella and Micrantheum serpentinum. These species are associated with the occurrence of serpentinite and endemic to the West coast, suggesting that they are vulnerable to direct disturbance associated with mineral exploration on this particular geological substrate (Askey-Doran et al 1992).
What about existing mining?
Currently limited mining occurs within the Tarkine, at Savage River Iron Ore Mine, which is currently managed by Grange Resources, and the Corinna Silica Mine managed by Tasmanian Advanced Minerals. The declaration of a Tarkine National Park will have NO impact on these current mining operations, as current leases are cut out of the Park proposal.
Outside the Tarkine on the west coast of Tasmania there is the Hellyer Mine (Bass Metals) and Rosebery Mine (MMG), Henty Mine (Unity Mining), Renison (Bluestone), Avebury (MMG), and Mt Lyell (Vedanta). None of these mines would be affected by a Tarkine National Park.