Modification 4 Longwall 317 and 318 Modification

I would like to thank the NSW government for their commitment to receiving and considering submissions to projects that have large and ongoing impacts to our local areas. I strongly object to the Metropolitan Mine Modification 4 proposed by Metropolitan Coal, a wholly owned subsidiary of Peabody Energy Australia Pty Ltd and the expansion and continued mining of coal from within the water catchment in Woronora Dam and near the Royal National Park. I currently live in Towradgi and am fortunate enough to have grown up in the Illawarra close to Maddens Plains, the Royal National Park and Woronora. I have often visited the Illawarra escarpment and Royal National Park for work as well as leisure and greatly appreciate the natural beauty and biodiversity of these places as well as their cultural value. I deeply care about protecting the environment and communities in this area where we rely on the Woronora Reservoir for drinking water.

The current application proposes to expand the existing Longwall 317 and create an additional Longwall (318) further west into the catchment as well as first workings mining to the west and further prolong the life of the coal mine and extraction of coal. These developments jeopardise the safety of the water catchment with the potential of pollution, water loss or disruption of supply to all people reliant on Woronora Reservoir for water. Woronora is a critical part of Sydney's drinking water supply and to risk this to expand fossil fuel extraction is reckless.

Besides drinking water the mining expansions could damage vulnerable ecosystems that support the network of biodiversity in area. Harming ecosystems high in the catchment has obvious negative effects for all downstream ecosystems and so can flow on far further than just the proposed expansion. The mine expansion will also have indirect impacts on all ecosystems by prolonging the use and amount of greenhouse gas emissions. As long as carbon dioxide and methane are being released into the atmosphere climate change impacts will continue to grow and worsen causing stress to all environments and potentially increasing bushfire risk, drought and/or storm damage locally. With a net zero target for 2050 it is far from prudent to be approving and facilitating more coal mining, especially with so many other risks involved.

The modifications proposed, particularly additional Longwall (318) and first workings, are in land as yet not owned by the company which makes them likely set up for further mining opportunities that maybe uncovered. The modification is projected to produce a total of 10.703 Mt CO2 -e in emissions, which may be under reported (see https://www.climatecouncil.org.au/resources/australias-methane-challenge-fossil-fuels-agriculture-waste/). This will only further prolong the life of the coal mine, greenhouse case emissions and line the pockets of a foreign corporation that is inadequately taxed.

We need to begin developing a just transition away from fossil fuels and fossil fuel industry, supporting workers and communities to reskill and find work in alternative industries, rather than putting all our futures at risk from climate change and most directly the safety of drinking water for Sydney and surrounds, the biodiversity of those natural areas and the cultural value of the Illawarra escarpment.

For the reasons above, I strongly object to Modification 4 Longwall 317 and 318 Modification of the Metropolitan Mine. I urge the Minister to reject this proposal in order to protect our water, environment, and climate.

I am writing on behalf of members of the Shire Climate Action Network (ShireCAN), based in the Sutherland Shire, Sydney, to object to Modification 4 – Longwalls 317 and 318, Metropolitan Colliery. I will be outlining the key areas of concern as to why this submission is an objection in the attachment below.

I support the mine extension

Re Peabody’s Metropolitan Coal Mine Extension.

Good day, I fully support the motion proposed by Councillor Deidre Stuart OBJECTING to Peabody Coal’s proposed extension 4 – Longwall 317 and 318.
Clean water is essential for survival, and no wise or prudent government would sign off on a project that carries such a large, ongoing risk to the Northern Illawarra and Sydney water catchments.
Indeed, it’s profoundly irresponsible to consider such an option, bearing in mind that any reassurances from Peabody re potential contamination and/or environmental subsidence and the consequent drying out of surface ecosystems (that also exacerbate bushfire risk) remain invalid – because no such reassurances or guarantees can be made.
Coal is on the way out, sustainable technologies are the future, yet Peabody still seeks to pursue major industrial works with an undeniably high risk factor to a water catchment essential to the lives of millions, and all for a dying resource?
No-one with a shred of common sense or judiciousness would countenance it.
AGL, Australia’s biggest coal generator, recently proclaimed that its rapidly growing battery storage portfolio would emerge as a major cash cow as the country’s main grid transitions from baseload to renewables and flexible capacity, highlighting the major changes in the sector and a clear roadmap to the future.
A road map that needs to be built around accountable and sensible ecological decisions that produce more robust, resilient and stable environmental conditions, thereby also supporting the urgent need to adequately prepare for the ongoing effects of climate disruption, which remains a serious and pertinent issue to the country as a whole.
Thing is – without a healthy environment we’ve got Buckley’s of coping with, let alone competently managing, the rapidly escalating impacts and costs of climate change.
Business as usual just doesn’t cut it anymore folks, and you can bet the grandkids and coming generations will have plenty to say about the decisions we all make now.
It’s time to show our accountability, and our smarts.
Yours sincerely, Anne Quinlivan.

The operation injected 324 million directly into the NSW economy last year. It employs a local work force that is 400 strong and part of ongoing skills development program in the area.

Sydney’s water supply is too precious and vital to allow any additional longwall coal mining or other underground mining anywhere near our water storage. We are all aware of the damage done to sections of some of the Warragamba inflows due to cracking as a result of mine subsidence , I have family in lithgow who have seen sinkholes near their house, and the risks cannot be justified. The extension of the longwall propsed is purely for commercial gain; between underground and open pit coal mining anywhere near, our state is being plundered. Additionally, fossil fuels are responsible for much of climate change we are experiencing, and it is worsening. Please do not all the proposal to proceed, water storage is an essential, profits can be made in other ways and other areas

This project will support local jobs and will allow more investments in the local conservation.

I support this project to secure ongoing employment for the Illawarra local region workforce. I also believe that coal production is essential to support the NSW and Australian economy with coal that is used for steel making for Australian housing and government infrastructure projects.

The mining company supports a large number of local workforce and uses local suppliers where possible. The company invests in local conservation as well as investment in local sporting and education programs.

In addition to supporting the local community for over a century, the Metropolitan Mine is a key source of steelmaking coal in the Illawarra region, essential for the efficient and stable production of Australia's only operating integrated blast furnace steel making facility. Without Metropolitan steelmaking coal, Australia's national security is affected through the detrimental impact to our ability to produce our own high quality steel for advanced technological applications. The alternative is a high-risk strategy to rely on foreign trade partners, like China.

I object strongly to this proposal for risky underground mining in our drinking catchment.
. This company is known to have breached the law before.
. Previous underground mining such as under Therlmere Lakes has proven disastrous for not only water supply for humans but to the environment and species which depend on continuous lifesaving water.
. The extension of coal mining must be seen as criminal when the disastrous climate effects of extending the burning of fossil fuels is so clear around this planet.
. Our children and theirs deserve responsible decision making, and that means no coal mine extensions.
What is needed is introduction of laws which rapidly reduce the dangers of climate chaos and that includes no new coal.

I object to the proposed modification of longwalls 317 and 318. I am a resident of the southern edge of Sutherland Shire. I have maintained a close watch on the steady expansion of Metropolitan mine and am well versed in the controversial impacts that this mine has had on the local environment and its associated threat to our water supply. I have personally witnessed the evidence of coal waste from spread all the way down the Hacking River to Audley - which the mine was finally prosecuted by the EPA. I am aware of the subsidence impact from earlier longwalls on the Waratah Creek and Eastern Tributary. I fear similar impacts will occur on Honeysuckle Creek tributary. The critical upland swamps hove already suffered from earlier longwalls and despite claims that LW 317 & 318 will minimize swamp impacts, the maps provided do indicate mining will be in close proximity to swamps. Indeed, Metropolitan in their summary of impacts admit at least 6 upland swamps will have a risk of greater than negligible impact. It appears to me that Metropolitan are asking to continue to impact the environment to the similar extent to that experienced from their previous LW mining. I do not believe it is acceptable to continue to impact on the environment and our valuable water sources on the grounds that the damage witnessed from previous mining was allowed.

My name is Cherrida Hardaker and I am a 79 year old great grandmother living in the Illawarra. I am writing to tell you that I most strongly object to the proposed Metropolitan Coal Mine modification 4 Longwall 317 and 318 Modification (MP08_0149-Mod-4 ‘Modification’).
I most vividly remember the Peabody mine and the coal sludge they inflicted on a tributary of the Hacking River in the Royal National Park not that long ago. This isn’t a ‘Not in my backyard’ submission even though it is in my local government area. This mine and its emissions have implications at a global scale. That is why, even if I wasn’t a resident of the Illawarra, I would still strongly object to the modification for reasons listed in this submission.
Objection to the Modification Proposal
The Metropolitan Coal Mine is an existing underground coal mine located in Helensburgh, and is owned by Peabody Energy Australia Pty Ltd. It currently operates under Project Approval 08_0149 which relates to Longwalls 20-27, 301-317, granted in 2009. The proposed MP08_0149-Mod-4 (the Modification) seeks to:
 expand on the existing approved area by extending the already approved Longwall 317 to the north;
 add an additional Longwall 318 to the west;
 add First Workings mining also to the west; and
 relocate an approved but not yet constructed ventilation shaft (#4) approximately 3 km to the west.
The Metropolitan mining lease sits entirely within the Wollongong Local Government Area (LGA), and the proposed expansion Modification also is within Wollongong LGA’s borders. The Modification proposes to expand mining significantly beyond their Mining Lease boundaries. The Modification (i.e. the expanded underground mining areas and proposed site for the relocated ventilation shaft) is located on land zoned in the Wollongong LEP as C2 (Environmental Conservation).
The Metropolitan Coal Mine mines under the legislated Woronora Special Area of the Greater Sydney Drinking Water Catchment (GSDWC). Special areas are areas recognised as having very high water, water infrastructure and ecological values, and are ‘protected’ under the law. Hefty fines apply to members of the general public who enter without appropriate permission. The Modification proposes to expand further into and further undermine the Woronora Special Area.
The proposed additional Longwall 318 would undermine the large upland swamp (# 106). Under NSW legislation, upland swamps are an endangered ecological community type, and their occurrence contributes to the very high water and ecological values of the Woronora Special Area. Upland swamps help capture water and release it slowly to their surroundings. Longwall mining by Peabody at Metropolitan has already destroyed and damaged other upland swamps through fracturing and subsidence of the geological strata under the swamps. Once the rocks and clays and other geological layers that hold water (under the swamp) are broken up, then when rain falls, the water flows through the swamp rather than being held by it. The swamps dry out: wetland species (plants and animals) die, and peat dries and becomes fuel for fires.
Furthermore, the fracturing and subsidence of the ground caused by underground longwall coal mining allows for methane-rich gases released hundreds of metres underground at the cut coal seams to percolate up and be released into the atmosphere. Whereas upland swamps are natural fire barriers, desiccated upland swamps can increase fire risk. On top of this, the water that would have been retained by the swamps and moved through surface water systems, instead percolates through the fissures and fractures and becomes polluted with heavy metals before it finds its way either down into mine voids and/or out into the wider environment.
I object to this Modification proposal on the following grounds:
 Climate change impacts from both projected and unaccounted-for greenhouse gas (GHG) emissions:
o This Modification will lead to yet more projected GHG emissions – Scopes 1, 2 and 3 as outlined in the proposal. Given experience to date of coal mining in Australia, these projected emissions will significantly under-estimate the Scope 1 fugitive methane emissions during the life of the mine and during decommissioning.
o This Modification will lead to GHG emissions that are not accounted for in the proposal. Methane-rich GHG emissions will likely continue for decades, if not centuries, well beyond the mining and decommissioning period – directly from the disrupted landscape and via unsealable infrastructure such as adits and shaft vents. Even if the company follows through with their stated decommissioning and removes the shaft-vent above-ground structures in a timely way and plugs the shaft with reject, there is still no way to reseal the landscape. The use of polyurethane/grout or other materials attempting to repair and plug cracks and repair rock platforms, simply does not work. High-pressure coal seam gases escaping from deep underground will find their way out through other weak spots or openings in the mining-disrupted landscape.
o The Bulli Coal Seam which Metropolitan mines is notoriously gassy. Metropolitan is NSW’s fifth highest emitting coal mine with a very poor track record of GHG abatement. Its Scope 1 emissions in FY24 were at their highest level since the Safeguard Mechanism was introduced in 2016 (at almost 700,000 t CO2-e). Furthermore 80% of Scope 1 in FY24 was methane (554,603 t CO2-e).
o According to the NSW Net Zero Emissions Dashboard, NSW is not on track to meet its 2030 GHG emissions reduction target. Since April 2025, NSW DPHI has approved new coal projects that will very likely be responsible for ~24% of the projected 2030 overshoot. NSW is in an even worse position related to its 2035 target. Approving this Modification will only make meeting NSW emissions targets more difficult. Moreover, experts (e.g. Climate Council, CSIRO, Ember etc) argue that during the next decade the world needs to urgently cut fossil fuel methane emissions – due to the methane’s high warming potency and short lifespan in the atmosphere – while we find ways to reduce carbon dioxide emissions. However, keeping our world within 1.5oC warming now seems already out of reach.
o The Illawarra is already experiencing the beginnings of climate chaos – with seven natural disasters declared since July 2019. Many in our community have been impacted directly by flooding, wind, heat and smoke. In the same time period, the Illawarra Emergency Operations Committee was activated more than 12 times. Our council is still carrying costs from these events. Our community is wearing rising costs resulting from climate change – including higher insurance premiums and rising food costs.
 Further negative impacts on the quantity and quality of water in the GSDWC: this is inconsistent with the neutral or beneficial requirement in the EP&A Act. Metropolitan has already caused very significant damages in the Woronora Special Area (e.g. as discussed in the Independent Expert Panel on Mining in the Catchment reports) – much more than was predicted at the proposal stages, with impacts on water quantity and quality. An extensive literature demonstrates that longwall coal mining busts up the geological strata as evidenced by subsidence, hogging, tilting, fractures, cracks and the like – and this damages the landscape with impacts on water flows and water quality. Moreover, Peabody has released polluted waste material into a waterway which flows through the Royal National Park on numerous occasions through 2022, in January, July, August, September, October, November, and December. In January 2023 the NSW Environment Protection Authority (EPA) reported yet another spill of “grey, turbid water with possible coal material present.” In March 2023 the NSW EPA reviewed the mine’s license to pollute and tightened some conditions, but this has failed to prevent further damage to the park. In August 2023, the embankment of the mine site next to the adjacent creek collapsed, coal waste material again spilled into the creek, and from there into the Hacking River, which flows through the heart and length of the Royal National Park. Throughout these incidents no effective emergency management procedures were put in place to stop the coal waste polluting the Hacking River and Royal National Park.
 Potential destruction of Aboriginal cultural heritage through damages to sites and to the cultural landscape – occurring across an estimated study area of 455 hectares. The proposal indicates that a total of 29 cultural heritage sites were identified in a survey of just 9% of the area. Consulted Aboriginal parties argue that cultural heritage sites should be considered wholistically and all have high cultural significance even though the Niche assessment did not identify any as having high scientific significance. The report notes potential fracturing of exposed sandstone at grinding groove sites and potential for rockfalls at overhang sites. 25 of the 29 confirmed Aboriginal heritage sites located in the Modification area could experience subsidence-driven ground movement, potentially leading to loss of cultural value.
 Damage or destruction of fragile ecosystems, including specifically to the upland swamp 106.
 Impacts on our biodiversity and species that result from: 1. Geological impacts and altered hydrogeology caused by ground subsidence and fracturing from underground longwall mining; and 2. Direct land, ecosystem and water disturbances associated with surface infrastructure such as shaft vents and sealing of roads and heavy vehicle movements – extending beyond the current impacted Mining Lease zone. Australia is already in a biodiversity and species extinction crisis.

As I was unable to fit the complete submission here I have added the whole submission as an attachment.

Supporting locals, with means of employment

Submission in support of the extension of Metropolitan Colliery
Our national, state and local economies rely heavily on coal mining which provides multiple benefits for all Australians.
The modification will generate a net economic benefit for NSW and for the Illawarra local community.
Coal is NSW’s most valuable export and is Australia’s second most valuable export.
Coking coal from coal mines in the Southern Coalfield has ideal qualities for steel production and it has fewer impurities, such as sulphur and phosphorus, than coal from countries in Asia. Australian coal contains less than 0.5 percent of sulphur, whereas Indonesia that has more than 2 percent sulphur content in its coal.
The coal mined by Metropolitan Colliery is high quality metallurgical (coking) coal, with about 10 percent of its product of thermal coal quality. Coking coal is essential to make steel with current technology.
It is vital that high quality metallurgical (coking) coal is produced locally to supply the Bluescope steel works and overseas industries. Local coal production minimises transport costs and ensures that high quality coke is produced. This assists Australia to maintain its competitive advantage compared with overseas producers.
The federal government’s ABS tables of multiplier effects show that more than three times as many indirect jobs are created for every person directly employed in a coal mine.
Australia and NSW need to focus on the positive aspects of coal mining and its many benefits so as not be distracted by ideologically driven anti-mining activists. Everyone should be proud of what coal mining is doing for NSW and Australia.
The report submitted demonstrates its comprehensive coverage of all environmental issues. The benefits from the continuation of this coal mine are immense.
Coal is literally building our future. Without it, we couldn’t make steel to build our homes, bridges, schools and hospitals.
For all these reasons I fully support the proposal.

Submission in support of the extension of Metropolitan Colliery
Coal is NSW’s most valuable export and is Australia’s second most valuable export.
Our national, state and local economies rely heavily on coal mining which provides multiple benefits for all Australians.
The modification will generate a net economic benefit for NSW and for the Illawarra local community.
Coking coal from coal mines in the Southern Coalfield has ideal qualities for steel production and it has fewer impurities, such as sulphur and phosphorus, than coal from countries in Asia. Australian coal contains less than 0.5 percent of sulphur, whereas Indonesia that has more than 2 percent sulphur content in its coal.
The coal mined by Metropolitan Colliery is high quality metallurgical (coking) coal, with about 10 percent of its product of thermal coal quality. Coking coal is essential to make steel with current technology.
It is vital that high quality metallurgical (coking) coal is produced locally to supply the Bluescope steel works and overseas industries. Local coal production minimises transport costs and ensures that high quality coke is produced. This assists Australia to maintain its competitive advantage compared with overseas producers.
The federal government’s ABS tables of multiplier effects show that more than three times as many indirect jobs are created for every person directly employed in a coal mine.
Australia and NSW need to focus on the positive aspects of coal mining and its many benefits so as not be distracted by ideologically driven anti-mining activists. Everyone should be proud of what coal mining is doing for NSW and Australia.
Coal is literally building our future. Without it, we couldn’t make steel to build our homes, bridges, schools and hospitals.
The report submitted demonstrates its comprehensive coverage of all environmental issues. The benefits from the continuation of this coal mine are immense.
For all of these reasons I fully support the proposal.

To whom it may concern,
I am writing to express my extreme anguish at the proposed extension of the Metropolitan Coal mining operation. The proposal is disgraceful, as is the whole mining operation. The operation should never have been approved in the first place but the least that can be done now is to disallow any further mining activities. The mine threatens the Sydney drinking water catchment and biodiversity in the Royal National Park and Woronora Plateau. It also threatens the cultural heritage of our precious Royal National Park, Australia's oldest.
The mining operations have already polluted the Hacking River and the Royal National Park more broadly, so how any further developments are even considered beggars belief. When the general public is not even allowed to walk inside the catchment area the proposed mine would site under, or risk severe fines, how is longwall mining that threatens the very groundwater we, and broader biological values, in the Sydney region rely on even conceivable?
I hope my strong opposition is listened to and that common sense prevails.

Dear Assessment Officer,

I write to strongly oppose the proposed expansion of the Metropolitan Colliery into the northern area beneath the Woronora Reservoir and its catchment. This proposal poses unacceptable risks to Sydney’s drinking water security and to the integrity of surrounding protected ecosystems, and it should be refused on both environmental and public interest grounds.

1. History of Environmental Harm at Metropolitan Colliery

Peabody’s Metropolitan Colliery has an established track record of environmental damage in the Illawarra and adjacent Royal National Park:

Pollution incidents: In 2022 and 2023, the mine discharged coal waste into Camp Gully Creek and the Hacking River. The NSW Environment Protection Authority (EPA) prosecuted Peabody, resulting in penalties and enforceable undertakings totalling $3.6 million [NSW EPA, 2025]. These events directly polluted waterways within Royal National Park.

Ongoing failures of containment: In August 2023, an embankment collapse released further coal waste downstream, prompting EPA clean-up and prevention notices [NSW EPA, 2023].

This is not an isolated event but a pattern of operational failure and environmental harm.

2. Damage to Local Waterways and Drinking Water Supply

Independent panels and government reviews have repeatedly documented damage caused by longwall mining from the Metropolitan Colliery to streams that flow into the Woronora Reservoir:

Subsidence-induced fracturing and water loss: Pools along the Eastern Tributary cracked and drained following longwall mining, requiring repeated grouting interventions to attempt to restore flow [NSW DPE, “Sydney Metro Mining Panel Reports,” 2019–2022].

Iron oxide contamination: Mining-related fractures have altered flow pathways, causing iron oxide “staining” and degraded water quality in tributaries [NSW DPE Independent Panel, 2020].

Catchment function reduced: The Independent Expert Panel for Mining in the Catchment (IEPMC) found that mining has reduced surface water availability and increased the risk of leakage into subsurface pathways in the Special Areas that feed Woronora Reservoir [IEPMC Annual Report, 2022].

Any extension beneath the reservoir itself risks catastrophic and irreversible impacts on one of Sydney’s key drinking water supplies.

3. Impacts on Royal National Park and Sensitive Species

The mine’s discharges and hydrological alterations extend into the Royal National Park, a protected biodiversity refuge:

Platypus habitat degradation: Platypuses (Ornithorhynchus anatinus), recently confirmed in the Hacking River catchment, depend on clean, reliable streamflow. Coal fines, sedimentation, and altered hydrology directly threaten their habitat [University of NSW Platypus Survey, 2020].

Amphibian impacts: Following the 2022 pollution events, surveys recorded sick and debilitated green stream frogs (Litoria phyllochroa) in the Hacking River catchment, an alarming indicator of water quality stress [Sydney Morning Herald, reporting EPA investigations, 2023].

The expansion proposal places both aquatic ecosystems and iconic native species at further risk.

4. Wetlands and Upland Swamp Damage

Illawarra upland swamps, listed as an Endangered Ecological Community under NSW legislation, are vital to maintaining catchment hydrology. Scientific studies have found:

Longwall mining causes swamp cracking and accelerated drying, leading to irreversible ecological change [Young, A., “Swamp Impacts from Underground Mining,” IEPMC report, 2019].

These upland swamps act as natural sponges that regulate flow and filter water entering reservoirs. Damage to them reduces both yield and water quality for the Woronora system.

Expansion under the reservoir catchment would place additional upland swamps at risk of drying and degradation.

5. Conclusion

The Metropolitan Colliery has already demonstrated an inability to operate without causing serious environmental harm. Its track record includes:

Proven pollution offences and EPA prosecutions (Camp Gully Creek, Hacking River).

Subsidence and water loss from key tributaries to Woronora Reservoir.

Documented damage to Royal National Park waterways, affecting platypus and frog populations.

Ongoing destruction of endangered upland swamps.

In this context, permitting expansion under the Woronora Reservoir — a critical drinking water supply — is indefensible. I respectfully submit that the NSW Government must refuse this proposal to protect Sydney’s water security, preserve the ecological integrity of Royal National Park, and prevent further damage to endangered wetlands.

Yours sincerely,



Key References

NSW Environment Protection Authority (EPA), Peabody prosecuted for coal pollution into Royal National Park (2025).

NSW Department of Planning and Environment, Sydney Metropolitan Mining Panel Reports (2019–2022).

Independent Expert Panel for Mining in the Catchment (IEPMC), Annual Report 2022.

Young, A. (2019), Swamp Impacts from Underground Mining, IEPMC Technical Report.

University of NSW (2020), Platypus Surveys in the Hacking River Catchment.

I object to the proposal of digging tunnels underneath the water catchment area that supplies drinking water to Sydney. During a recent outbreak of contamination worronora water was mixes in with warragamba catchment to dilute and ensure safe drinking water. We will be unable to do this if damage to the dam bed and tributaries results in a net loss of drinking water. Peabody has historic offences against them when they released coal sludge into the pristine port hacking River damaging eco systems. While I believe that peabody think they can do it safely and follow the coal $$$ through that area, we must recall mining accidents in the past where an entire lake in the us drained into the mine killing many. We cannot risk loosing our drinking water. Perhaps on a wet august like today there is enough water falling out of the sky, but we have all lived through droughts in Sydney and mandated water rationing. With the growing population of Sydney and Wollongong, we cannot allow to risk this reckless greed to impact the very future of our city.

Good evening
I am writing to object to the proposal to expand the longwall mining in the Metropolitan mine at Helensburgh.
I am a long-term resident of the Sutherland Shire and have spent many years working at the Woronora Reservoir and I am concerned that an expansion of the longwall mining will affect the water quality in the dam which is a major source of drinking water for Helensburgh and the Sutherland Shire. Longwall mines have been shown to cause subsidence of land above the mining and this puts the upland swamps at risk of draining and subsequently drying out. In their natural condition the swamps store water during wet periods and gradually release this water into the downstream streams and into the dam. If the swamps are drained the runoff following rainfall will be more rapid leading to erosion and poor water quality in the dam making the water more difficult to treat to the standards required by Sydney Water. During times of low rainfall there will be less runoff from the surrounding land because the swamps will have been drained due to the subsidence and the water in the dam will not be replenished by slow release of water from the swamps. This change in stream flow will most likely have a major effect on the biodiversity in streams below the swamps as well as in the swamps themselves.
The impact of further mining will also release methane, which is a very powerful greenhouse gas, from the coal seams which will add to the impact of climate change.
Even though this is just one source of emission, the addition of more methane to the atmosphere reduces the chance of keeping the global temperature below 2 degrees centigrade and so increases the risk of increase in extreme weather events and the cost to society of repairing damage caused to infrastructure in addition to the disruption to peoples' lives.
Please do not allow this expansion to proceed.