It has completely failed to protect the integrity of the water catchment on the Illawarra Plateau, which is responsible for roughtly 20% of Sydney's water source.
The reason is that it has allowed the catchment to be undermined (quite literally), by the coal miners, and they have cracked the bed rock to the local streams.
That has allowed large quantities of water to leak from the stream beds into the mined areas below.
It has also allowed contamination of the remaining waters in the streams, with methane gas, and with mineral contamination.
"Burning gas" Photo: Daily Telegraph 9/7/97
Photo sourced from: http://groups.msn.com/nepeanactiongroup/shoebox.msnw?Page=2
According to the website of the "Nepean Action Group": -
"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.
In the mid 90's the Cataract River flow totally disappeared into the cracking in the river bed. Methane and ethane gasses were expelled from the ground measuring up to 20 litres per secondin some areas.
Sydney Water is currently releasing 2.5 million litres a day from Broughton Pass Weir into the Cataract to provide some environmental flow, as the cracking is still allowing most of this water to escape into the ground and mine below. Also BHP are using another 2 million litres a day to dilute pumpings from the other mines into the Georges River. That's 4.5 million litres a day!!!So now eight years later the water is still disappearing into the subsidence, just as gas is still escaping through the cracks, the fish are gone, the pools are sometimes still red with iron oxide matts and the rock falls continue. The flow into the Nepean from the lower Cataract is still polluted. There are still problems in the Georges, Bargo and other NSW
rivers. Tonnes of salts are being pumped into the rivers from the polluted mines."
Quoted from the Nepean Action Group website
Bargo River - before and after mining cracked the river bed - (1970-75) and 2005)
The Rivers SOS website has a "mine of information" about the river damage, and the whole disaster of allowing "Long Wall Mining" under these rivers. Have a look at the 4 pages of photographs in their "Gallery" pages (use the drop down menu).
I shall write more about the details of "Long Wall Mining", and why it is so damaging.