Mine subsidence in the Upper Nepean Catchment

Longwall Mining links

Georges River Macarthur

General longwall mining

• longwall mining process - damage, cause and effects
• backstow - mining subsidence - backstow reduces surface damage, our politicians don't legislate for it
• Cataract river - Cataract river during the seventies
• Georges river dieing - Georges river greatly reduced water levels
• Iluka Creek - Iluka Swamp - Iluka Creek, Iluka Swamp, Georges River catchment
• Macarthurs rivers - Bargo, Georges, Cataract rivers - Broughton Pass Dam, Marhnes Hole, Appin
• Mine subsidence - mine subsidence in the Upper Nepean river catchment
• Georges River photographs - photographs of 7 km downstream of Freres Crossing
• Stokes Creek Wedderburn - Stokes Creek, Wedderburn, Georges River, Campbelltown
• Wedderburn - Wedderburns rivers, creeks and properties
• Wedderburn gorge - Wedderburn gorge, Georges River catchment, environmental damage
• Woolwash - The Woolwash junction with O'Hares creek Wedderburn - Minto
• O'Hares - Iluka - Georges River, O'Hares Creek, Dharawal State Recreation Area, Iluka Creek, Iluka Swamp, Maddens Creek.
• O'Hares - Wedderburn - Georges River, O'Hares Creek, Campbelltown, Wedderburn.
• Dharawal State Recreation Area - Georges River, O'Hares Creek, Darkes Forest.

• gr_punchbowl_kentlyn - Punchbowl Creek at the Basin Georges River NSW
• broken promises - longwall mining - deceit, denial and broken promises
• Cost clean coal - Clean coal, is it too costly to consider
• Longwall Mining - Global Climate Change, letter to Kevin Rudd, Prime minister Australia
• The hidden costs of clean coal - The environmental and human disaster of longwall mining - Multimedia from The Center for Public Integrity Washington DC. Video filmed in the mine and the effects above ground.
• BHP Billiton environmental damage - BHP Billiton, Fly river, Ok Tedi river, copper mines, Irian Jaya, Barrow Island, deforestation Indonesia, environmental damage, longwall mining
• BHP Billiton misinformation - BHP Billiton Illawarra Coal - Rio Tinto misinformation and the publics wrong impression of mining
• Politicians and approvals - These politicians approve longwall mining licences which pollutes our atmosphere, damages our rivers, water catchments and your homes
• Mine subsidence - longwall mining and its impact on water resources
• When longwall mining comes to your town - When longwall mining comes to your town, your home is in the hands of the mining company- from the US and applies here in Australia

Cumulative effects of mine subsidence in the whole of the Upper Nepean Catchment

• Wendy Bowman, President of Minewatch in the Hunter, has said that some Hunter valley farmers had to cease irrigating their crops because the river water had become too saline due to mining.
  
  
• While Rivers SOS aim is to campaign for the 1 km safety zone around rivers, our research has led us to be increasingly aware of the cumulative effects of mine subsidence in the whole of the Upper Nepean Catchment. This area has been extensively undermined and it is only in the last decade or so that the rising price of coal seems to have made mining which endangers rivers too tempting to avoid. (Minister Kerry Hickey, Mineral Resources, told a parliamentary committee on 30/3/05 that "estimated royalties for longwall mines in 2002/3 were $602 million" - the government as well as BHP Billiton is naturally eager for the rising level of profit).
  
  
• All research indicates that the degree of subsidence cannot be accurately predicted, but that it will be more severe in rugged, hilly terrain (river gorges).
  
  
• Water is not only lost to rivers through thousands of subsidence cracks; there are further problems of pollution caused by up welling ground water and methane gas in parts of the rivers.
  
  
• In the Cataract, loss of water quality was noted due to increased iron, aluminium and manganese, and changes to PH. Excessive growth of iron-oxidising bacteria caused both the lower Cataract and the upper Georges to turn red and soupy for long periods. Up welling ground water caused increased water temperature, lower dissolved oxygen, more acidic PH, and rises in iron, sodium and chloride.
  
  
• The dissolution of the bedrock gases into the water reduced the ability of the river to contain dissolved oxygen. Hundreds of fish skeletons were found, by an inspector in 1994, some up to 1 metre, killed by either the draining of the pools and lack of flow, and/or by the pollution of the water (Water & Sydney's Future, p.55; Interim Report of the Cataract River Task force, Dec. 1997,p.34).
  
  
• More generally, "in the shale geology of the metropolitan catchment and environs, the ground water is eco-toxic, containing dissolved salts, dissolved hydrogen sulphide which is toxic to aquatic life, low oxygen levels and elevated soluble iron levels." (Total Environment Centre & Colong Wilderness Foundation, Submission re Dendrobium to Commission of Inquiry,2003, p. 5).
  
  
• As well as the problem of upwelling ground water through subsidence cracks, there is the problem of salination caused by pump-outs from working mines. At present the Tower Colliery (renamed Douglas by BHP B) is pumping out 2.8 tonnes of salt per day into the Nepean via Allens Creek, according to documents we obtained recently through a Freedom of Information procedure.
  
  
• An internal EPA memo described this level of pollution as "unacceptable". But the EPA will not or cannot take any action to stop this. They have told the Environmental Defenders Office that they are satisfied that BHP Billiton is investigating desalination technology. This, the company's officers have said, could take two years or more. It is likely that the planned longwalls in the Nepean will also involve pumping out of volumes of salt, adding to the load already in the river.
  
  
• Thus the upper Nepean will be subjected to salination and pollution as well as probable loss of water and cliff falls.
  
  

While Rivers SOS aim is to campaign for the 1 km safety zone around rivers, our research has led us to be increasingly aware of the cumulative effects of mine subsidence in the whole of the Upper Nepean Catchment. This area has been extensively undermined and it is only in the last decade or so that the rising price of coal seems to have made mining which endangers rivers too tempting to avoid.

Minister Kerry Hickey, Mineral Resources, told a parliamentary committee on 30/3/05 that "estimated royalties for longwall mines in 2002/3 were $602 million" - the government as well as BHP Billiton is naturally eager for the rising level of profit.

Mining has damaged not only the lower Cataract, the upper Georges, and the Bargo; but also Stokes Creek, Wongawilli Creek, Ousedale Creek and an unnamed creek near Appin Colliery.

Other smaller, perhaps intermittently flowing, streams and creeks are likely to have been affected, and some hanging swamps are likely to be lost in the new Dendrobium mines on the Cordeaux dam (according to Olsen Environmental Consulting, in their submission to the Dendrobium COI).

The swamps act as water filters and are rich in biodiversity.( NSW Scientific Committee, p. 14) They occur in the headwaters of O'Hares Creek and the Woronora River, also in major tributaries of the Nepean.

This information is extracted from new South Wales Rivers in a State of Shock Web Site.