Short History of damage to Macarthurs rivers - Georges, Bargo, Cataract and Nepean

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

• In 1994 the Bargo river bed cracked.
• In 1996 the Cataract river bed cracked and the water disappeared, methane/ethane gas escaped and iron oxide bacterial pollution started.
• In 2000, Jutts Crossing on the Georges River at Appin cracked and the water in the rock pools disappeared.
• In 2001, further up the Georges river cracked and rock falls were reported.
• In 2001 the Douglas Park bridge moved as a result of the mining.
• In 2001 the Broughton Pass Dam sustained cracking.
• In 2002 Marhnyes Hole in the Georges River cracked and water disappeared.

Cataract river disappeared into cracks

• In the mid 90's much of the Cataract River flow disappeared into the cracks in the river bed and methane and ethane gasses were expelled from the cracks, measuring up to 20 litres per second in some areas.
• Once lit, the heat from the gas was sufficient to BBQ sausages, as TV reports showed at the time. It also smelt and was responsible for increases in the soil temperatures measured at 40 degrees on two house block size areas.
• Here all the vegetation died.

Broughton Pass dam wall cracked

• The dam wall of Broughtons Pass has cracked in four places and leaks across half its face.
• The pump house adjoining the weir was also damaged.
• The Nepean tunnel and the Upper Canal are also cracked.
• The extent of water loss from these is unknown. Monitoring by the DMR and the SCA is inadequate (TEC submission to Dendrobium COI, p. 7).

Catchment area suffering cumulative damage

The TEC submission points out that the damaged Broughtons Pass Weir controls 20% of Sydney's water supply and in this condition the weir could fail during a minor earthquake or a major flood

So, to conclude, the whole catchment area and its precious water is suffering cumulative damage and loss.

No government body seems capable of addressing the problem in a holistic way. The mining approvals and environmental impact statements address each proposal in isolation. Rivers SOS wants some more responsible process to be put into place, but meanwhile we will continue to campaign for our 1 km safety zone around rivers.

The councils have water inspectors patrolling the streets... Who patrols & controls mines and commercial water use?

Longwall mining-induced fault reactivation and delayed subsidence
ground movement in British coalfields

Donnelly, L.J.; Culshaw, Martin; Bell, F. 2008 Longwall mining-induced fault reactivation and delayed subsidence ground movement in British coalfields. Quarterly Journal of Engineering Geology and Hydrogeology, 41 (3). 301-314. 10.1144/1470-9236/07-215

Natural Environment Research Council - British Geological Survey

Abstract / Summary

Faults located in areas undergoing mining subsidence during the longwall extraction of coal seams may undergo reactivation. This has been observed and documented throughout the UK (and in other major coalfields around the world) over the past 150 years.

Subsidence-induced fault reactivation may cause moderate to severe damage to foundations, houses, buildings, structures and underground services, as well as damage to agricultural land through disruption of drainage and alteration of the gradient.

Monitoring of faults, as they are affected by undermining, has resulted in a better understanding of fault reactivation mechanisms and of the various styles of fault reactivation, in different geological and mining settings.

The duration of fault reaction is difficult to determine because of the lack of observational data. However, trough subsidence following longwall extraction of coal is rapid, often being completed within weeks to months.

This is commonly followed, shortly afterwards, by a period of delayed subsidence known as residual subsidence, which in the British Coal Measures rarely accounts for more than 10% of the total subsidence. In many circumstances, where faults are not present, residual subsidence is complete within 4 months, although several cases have been recorded where subsidence effects were still being observed more than 2 years after mining had finished.

Generally, it is accepted that fault reactivation sometimes may extend over the period of residual subsidence. In parts of the abandoned or partially active coalfields in the UK, relatively smaller ground movements have been observed in the vicinity of fault outcrops many years after mining has ceased. The reasons for this are not fully understood. None the less, prolonged periods of fault reactivation may have an important effect on land use and construction.

The objectives of this paper are to consider fault reactivation and, in particular, to document examples of post-mining ground movements around fault outcrops and to discuss possible causal mechanisms. Features associated with these movements include increases in elevation of the ground surface and deformation (e.g. subsidence, grabens, scarps or steps, fissures, compression and tension) of the ground surface in the vicinity of faults. These features, in turn, may be associated with groundwater or mine water rebound.