On the driest continent on earth, water is our most precious resource. Despite this, the current mining boom is putting at risk our drinking water catchments, our underground water resources, and our rivers and wetlands.
Sydney Drinking Water Catchment
There are five major drinking water catchments that are managed specially to provide clean drinking water to over 4 million people in Sydney, the Blue Mountains and the Illawarra. Large parts of the catchments have been gazetted as Special Areas designed to exclude public access and protect the quality and quantity of water to the city. Unauthorised access to Special Areas can lead to fines of up to $44,000.
These rules, however, do not prevent mining in these sensitive sites and there are 8 underground coal mines currently operating within the Sydney drinking water catchments. Over the last 20 years, longwall mining in the catchments has led to major land subsidence which in turn has caused cracking and draining of rivers, creek beds and undergrounds aquifers, cliff falls, draining of swamps, fish kills, methane gas bubbling to the surface of creeks and rivers, and iron oxide pollution, as well as the discharge of polluted mine water into local creek systems. Despite these known impacts, which were confirmed by an official inquiry, mining is still occurring immediately adjoining creeks and rivers in the catchment causing methane vents and creek fracturing.
One of the worst examples of damage from longwall mining in the Sydney catchment is the Waratah Rivulet, which previously provided 30% of drinking water to the Sutherland Shire. The once pristine Rivulet was cracked, drained and dewatered for almost its entire length and polluted with iron oxide after longwall mining in 2007. This video tells the story.
Another worst case example is the mysterious drying up of Thirlmere Lakes, a World Heritage listed lake system, after longwall mining approximately 700m away within a Special Area of the Warragamba Catchment. An independent study has concluded that coal mining is likely to have played a substantial role, although the NSW Government has conducted a questionable inquiry which tries to avoid that conclusion.
Despite this appalling damage, longwall mines continue to expand with a number of new longwall mining panels underway and new underground coal mines proposed for the Sydney drinking water catchments. The catchments now face a second threat in the form of proposals for extensive coal seam gas mining. Coal seam gas exploration licences have been granted over the whole or part of five drinking water catchments and an approval for drilling of coal seam gas wells by Apex Energy has been granted within a Special Area. Extraordinary as it seems, and despite promises to the contrary, Sydney's drinking water catchment which is vital to the health and wellbeing of 4.3 million people is not safe from the rapacious mining boom and its impacts.
Fitzroy River Catchment, Queensland
Rural drinking water catchments are not safe either. The Fitzroy River in Central Queensland is the water supply for the regional centre of Rockhampton and one of the major coastal estuaries which flows in to the Great Barrier Reef. However, there are over 30 coal mines within the Fitzroy River Basin which frequently discharge wastewater into the system and an escalating coal seam gas industry which is seeking to discharge even more.
In 2008, billions of litres of untreated water from an open-cut coal pit which was flooded after heavy rain at the Ensham mine, near Emerald, was discharged into the Nogoa River, a tributary of the Fitzroy River. Downstream water quality testing showed increasing salinity and sodium levels that were a threat to townships like Blackwater, Tieri, Bluff and Middlemount that were reliant on the river for drinking water supplies, and a danger to the health of the aquatic ecosystem.
The same problems occurred again during the floods of 2010, but on a grander scale with a larger number of mines affected. Many of the mines still have contaminated water on site, with at least 281 billion litres of contaminated water reported to be sitting in 16 different mines within the Fitzroy River Basin.
A number of mines have been fined for breaching discharge permits with releases into the Basin. Salinity levels within the Fitzroy River increased between June 2011 and February 2012 and Rockhampton Regional Council has asked for legislation to require treatment of water by mining companies before it is discharged. Despite this, the Queensland Government has recently passed legislation making it easier for mines to discharge contaminated water under 'emergency' provisions.
Other impacts of open-cut coal mining on water resources in the catchment include the loss and depressurisation of aquifers, consumption of surface water for washing and dust suppression, creeks being mined and 'replaced' with artificial channels, and the creation of final pit voids which fill with groundwater and accumulate salt and toxins and can lead to acid mine drainage.
Condamine River
The National Water Commission has stated that coal seam gas mining risks having 'significant, long-term and adverse impacts' on water resources and called for caution in its implementation. Some of the threats identified by the NWC include depressurisation and contamination of aquifers, land subsidence, reduction of surface flows in connected systems, management challenges surrounding large volumes of waste water, alterations of water quality and impacts on the health of wetlands and rivers.
Australia Pacific LNG have approval to discharge up to 20 million litres of treated coal seam gas wastewater each day into the Condamine River. Even after treatment, tests show that this water includes chemicals such as boron, silver, chlorine, copper, cyanide and zinc at concentrations that would be toxic to aquatic organisms.
In late May 2012, the Condamine River was found bubbling 'like a spa bath' near the Queensland country town of Chinchilla. A gas metre registered high levels of methane coming from the river. The bubbling was occurring in an area where coal seam gas wells are located in close proximity to the River. Whilst the gas company concerned, Origin Energy, blithely described the bubbling as a 'natural' phenomenon, landholders in the area have never heard of or encountered gas leakages on this scale previously, and Dr Gavin Mudd from Monash University School of Engineering stated that it was feasible that de-watering of the coal seam had enabled methane gas to escape to the surface.
Evidence of methane migration as a result of coal seam gas mining has also been provided by a local landholder who has been able to set his water bore on fire after drilling took place nearby, and an old coal exploration drillhole at Daandine, near Dalby, which has recently caught fire after coal seam gas mining in the vicinity. There is also a large body of evidence indicating that methane migration is a relatively frequent occurrence near unconventional gasfields in America.
Dawson River, Floodplains and Wetlands
The beautiful Dawson River in central Queensland, and its floodplains and wetlands, are under enormous threat from coal and coal seam gas mining. The Dawson starts in the foothills of the Carnarvon Range and flows east through Taroom and then north towards Moura. It is a major tributary of the Fitzroy River, which is the main water supply for Rockhampton.
The Dawson faces multiple heavy threats - a proposal for an enormous dam to supply water for coal mines, the current and planned discharge of treated wastewater from coal seam gas mining into the river and its tributaries, and a large number of planned open-cut coal mines and gasfields in catchment areas including 6 open-cut coal mines proposed near Taroom. At risk is the quality of drinking water supply to Rockhampton and other regional centres, the integrity of the nationally important Palm Creek wetlands, the survival of active Great Artesian Basin spring wetlands, and the future of an important river system.
The proposed Nathan Dam, if approved, will flood 72km of the Dawson River and cover 32,000 acres of land - which is more than twice the size of Sydney Harbour. It will hold 888 billion litres of water and flood all the way back up to the township of Taroom. It will inundate 22 unique and nationally significant springs of the Great Artesian Basin, known as Boggomosses, which include one of only two known population sites for the critically endangered Boggomoss Snail. The Dam will effectively destroy the Dawson River as a major intact river system, drowning highly productive floodplains along with some 8,250 acres of vegetation which forms a riverine corridor that is habitat for 216 different animal species.
The discharge of treated coal seam gas wastewater into the Dawson River and its tributaries will cause changes to water quality and natural flows, and coal seam gas mining itself in catchments and adjoining creeks also poses a substantial risk. Under threat are the nationally important Robinson and Palm Tree Creek Wetlands - a chain of more than 200 lakes, swamps and wetlands stretching across 100,000 acres along the floodplains and waterways of the Robinson and Palm Tree Creeks. The Wetlands form a kind of oasis - supporting extensive growth of palms and providing habitat for many waterbirds including Magpie Geese and Cotton Pygmy-Geese. They area located approximately 15km north-west of Taroom and flow east into the Dawson River - falling within the expansion area now sought by Santos for drilling of 6,100 new coal seam gas wells.
Great Artesian Basin
The Great Artesian Basin (GAB) covers 22% of Australia and is the only reliable source of water across its overlying arid and semi-arid areas. In addition to water, significant unconventional gas resources are held within some of its aquifers or in older, deeper rocks.
Gas extraction requires drilling into GAB aquifers or right through the Basin. This creates a risk of inter-aquifer leakage via the gas well. Water quality can be impaired if water from different aquifers mixes or if it is contaminated by gas or drilling fluids. It is extremely difficult and expensive to reverse such damage. The greater the number of gas wells, the higher the risk.
Coal seam gas extraction requires the removal of some of the water in the coal seam to reduce pressure and allow the gas to flow. Environmental Impact Studies make it clear that pressure and water levels in adjoining aquifers will fall. Recovery to pre-coal seam gas extraction levels will take decades or centuries. This means negative impacts on other water users and their businesses. Water Group advice to Environment Minister Burke stated there is also likely to be “a significant impact” on threatened species dependent on GAB springs.
Pressure is an extremely important and valuable resource in the GAB. Hundreds of millions of dollars have been spent by governments and landholders on the Great Artesian Basin Sustainability Initiative to save water and restore the pressure lost from uncontrolled bores. Coal seam gas extraction threatens to undermine the achievements of GABSI to date. Some landholders have decided not to rehabilitate their bores as the benefits will be cancelled by coal seam gas developments.
There are also large coal deposits in the GAB area and dozens of new mines are proposed. Open cut and underground mining cut through aquifers, interrupting the movement of groundwater and also require dewatering of coal seams. These activities have major impacts on groundwater resources and groundwater dependent ecosystems such as GAB springs.
More information about extractive industries and the GAB can be found here.
