In-principle approval has been given for 10 longwall mines that will pass directly beneath Woronora Reservoir. Longwall mines have already caused serious damage in the Woronora ‘Special Area’ catchment – WaterNSW has noted the impact of the mines LW23-27, with ‘Unexpectedly high levels of surface cracking (along the creek and at pool / rockbars) and consequent drying of a large proportion of pools.’ Swamps that filter and clean our water have also shown signs of drying out – with groundwater levels ‘not having recovered many years after completion of mining.’ (p.B4, B5). Water security is a matter that goes beyond politics – no matter what your political leanings or position on coal. Woronora is a critical public asset that is simply too important to jeopardise. So many people we’ve spoken to are horrified that mining is even being contemplated under a drinking water catchment, let alone that it has got to this point. In 2014 the NSW Chief Scientist found Sydney alone among major cities permitted longwall coal mining under publicly owned water catchment.
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Over 10,700 people signed our petition calling for this mining to be stopped in 2020. An additional 25 environmental conservation organisations and local community groups signed another statement calling for the permits to be rescinded.
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Under state legislation, hard copy petitions with more than 10,000 signatures must be debated in State parliament. A week prior to the scheduled debate Planning Minister Rob Stokes ignored community opposition and granted final approval for three of the next longwall mine tunnels. Two of these, LW306 and LW307, are currently being worked, and both run directly under the reservoir. Both Liberal politicians and the Labor opposition spoke in favour of allowing this mining under our water supply to continue.
Eastern Tributary, Waratah Rivulet July 2019 (photo: Kaye Osborn)
The photo here is the Eastern Tributary of the Waratah Rivulet – a major stream running into Woronora Reservoir. It was taken in July 2019, and shows heavy iron oxidising bacteria growth and iron oxyhydroxide floc contamination. Water in this area is supposed to be pristine, filtered through natural streams and swamps. It’s changed to this rust colour because it drained underground through cracks caused by subsidence from the mining, and has come out again contaminated. “An issue which particularly concerns WaterNSW is that it is anticipated that any additional increases in iron, manganese and possibly aluminum and other species dissolved from undermined catchments will impact on raw water quality delivered to Sydney Water and other customers…metals transported to reservoirs in particulate and/or dissolved forms are more likely to be precipitated and build up in the lake sediments over time.” WaterNSW Submission to the recent Independent Expert Panel looking into mining in the catchment – see p.24
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The petition to protect our water supply was started in good faith in the hope that the democratic process would allow community voices to be heard. We do not believe the parliamentary debate applied proper scrutiny to this matter, and do not accept the government’s assurances that the damage occurring in the Woronora Reservoir catchment is insignificant. Our statement here has a longer account of the debate, our response to it, and questions we would like our politicians to answer…
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In addition to the concerns expressed by WaterNSW, over 20 independent scientists have questioned the ‘science’ that has been applied to justify the mining. They have called for this mining to be suspended “until the cumulative impacts and consequences of mining to date can be reliably assessed and quantified.” They have noted the government’s “dependence on assessment reports prepared by consultants selected and funded by mining companies”, and stated that “such reports cannot be regarded as independent”. None of this was mentioned in the debate. Waratah Rivulet is a significant tributary leading to Woronora dam – the image above shows a streambed that has cracked due to mining related subsidence – compressive forces have caused “upsidence” where the creek bed bulges upwards. All surface flow has been lost. Image credit: Julie Sheppard – National Parks Association of NSW Macarthur Branch. The National Parks Association of NSW and Sutherland Shire Environment Centre are among a coalition of groups who have been raising concerns about the impact of mining since 2007 – http://riverssos.org.au/mining-in-nsw/waratah-rivulet/
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Cumulative impacts could have serious negative consequences for reservoir water quality
The Woronora Reservoir catchment is classified as a ‘Special Area’ – permission is required to enter. Fines for entering without permission can be up to $44,000. Photos you see on this page were taken on the few occasions permission was granted. People are not normally allowed into the area in case they cause damage, or pollute the water. The only people who appear to be allowed in the area work for the mining company, Peabody. The Wororona ‘Special Area’ is covered with larger rivulets, streams and swamps. Swamps play a critical role in filtering and purifying our water. In the mine plan map here, the swamps are depicted in brown. A recent independent expert panel looking into mining in the catchment has noted that damage to swamps from mining can be irreversible. Their report states mining should not be allowed on the presumption that remediating swamps is possible. Subsidence from longwall coal mining can create a network of cracks and fissures, tilting rock strata, draining creeks and drying out of swampland. If the water does reemerge from subsidence cracking it can be leached through with chemical contaminants including iron, aluminium and manganese, lithium, strontium, barium, titanium, zinc and nickel. Apparently even trace amounts of zinc and nickel are toxic. The final report by the independent Expert Panel looking into mining in this area also stated that water returning to the surface from mine workings can ‘leach metals’ and this ‘needs increased attention in mining proposals, especially in the Special Areas where ‘cumulative impacts could have serious negative consequences for reservoir water quality‘. See pp.vi-vii Water quality in the Greater Sydney catchment has already been impacted by coal-mining activity: a recent freedom of information request found sludge accumulating on the bottom of Cataract and Cordeaux dams has resulted in elevated levels of iron that have exceeded acceptable limits more than 90 times in three years. Whether such contaminants are accumulating on the floor of the Woronora reservoir is unknown.
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The Water NSW Act states a Function of WaterNSW is ‘to protect and enhance the quality and quantity of water in declared catchment areas’.
There is no ‘protecting’ and enhancing’ taking place at Woronora. According to WaterNSW mining in the Woronora Special Area catchment has resulted in ‘environmental consequences [that] have caused (or are likely to cause) breaches in conditions in the relevant development consents, including performance criteria to protect watercourses and Sydney’s drinking water catchment.’ They also say ‘that there are numerous deficiencies in the manner that analysis and modelling is currently being used to support mining applications in the catchment.’ See p.3
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Pool N
The video below shows ‘pool N’, which was a 150m long permanent pool of water, part of the Waratah Rivulet that flows into Woronora dam. It remained full during the 2006-7 Millennium drought. This video was taken in 2014 when it drained dry due to cracks in the bedrock. The Independent Expert Panel report clearly states that predictions by mining companies about the impact of mining on surface and groundwater has not proven reliable, and that predictions about the impact mining has in terms of consequences for watercourses ‘remains an incomplete process’. The report states this raises the question of the reliability of estimates of how much water is being diverted from the catchment. See p.v In addition to the danger of water being lost due to subsidence damage from current mining activity, the report also raises concerns about a ‘limited understanding’ of the extent to which water is entering old mine workings, and the danger of the ‘permanent diversion of catchment water into mine workings.’ It notes the potential for ‘perpetual water loss’ through entrances to mines that have not been ‘properly sealed’, and that water coming out from old mine entrances is likely to be contaminated and could ‘require treatment in perpetuity’.
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In July 2019 The Sydney Morning Herald published an article with video drone footage showing streams filled with horrible red and soupy green discoloured water: ‘Shocking’: Mining damage in Sydney’s catchment prompts calls for halt‘. In that article, Peter Turner, mining projects science officer for the National Parks Association, confirmed that “A lack of pre-mining data, limited monitoring, and inadequate catchment and reservoir water-balance modelling make it essentially impossible to reliably determine how much water was actually being lost.”
The Woronora Special Area catchment is a critical public asset, part of our water supply infrastructure. The Water NSW Act 2014 states WaterNSW has a statutory obligation ‘to protect and enhance the quality and quantity of water in declared catchment areas’. The Act also requires WaterNSW to act ‘in accordance with sound commercial principles’, and ‘to maximise the net worth of the State’s investment’. Our water supply ‘Special Area’ catchments were set up originally so that if one failed the others could stand in as reserves. In 1998, extreme rain and flooding filled the drought-affected Warragamba Dam in just a few days. This triggered the Cryptosporidium crisis. Woronora was not affected. In 2015 the desalination plant was damaged by a typhoon and took a few years to properly repair. Our ‘Special area’ catchments are meant to be protected for a reason
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The Independent Expert Panel for Mining in the Catchment
The final recommendations in the Independent Expert Panel report suggest mining underneath Woronora Reservoir be allowed to continue subject to increased monitoring. The original terms of reference for this review was very narrow and only focused on identifying how to “strengthen the assessment of the ongoing operation of approved mines” and “undertaking further scientific research”. The terms of reference ensured the report focused on monitoring, rather than the question of whether mining should be allowed at all. This made the final recommendations a foregone conclusion. We do not view continued mining with increased monitoring of increasing damage as a solution. Once mining induced subsidence cracking to the bedrock occurs it keeps happening. Movement in each longwall compounds already existing subsidence. Each successive tunnel will be impacted to an unknown extent by effects from previous adjacent longwalls. Impacts occur in an incremental manner across longwalls, and the final cumulative impact may take several years to be identified.
Subsidence can continue even 20 years after it first occurs – the damage is ongoing, and will get worse over time, even after the mining company has left. Another serious concern with the final recommendations of the Independent Expert Panel report is that it mentions the possibility of ‘offsets as compensation for the consequences of negative environmental impacts’. In other words, the Report appears to suggest the government could consider accepting payment for irreversible damage to Sydney’s water supply as a result of longwall coal mining. In the whole 400+ pages of the 2 volume report, there is only one innocuous picture of mining induced subsidence cracking.