Centennial Coal has agreed to delay seismic testing in Lake Macquarie next week after an outcry from environmentalists and fishers and calls from MP Greg Piper to delay the work.
Environmental group Save Our Coast and the Greens reacted with anger when they learned late this week that Centennial was poised to start surveying four square kilometres of the lake floor between Wangi Wangi Point, Swansea, Pulbah Island and Murrays Beach from Monday.
Mr Piper wrote to Environment Minister Matt Kean and Planning Minister Rob Stokes on Friday afternoon calling for their "urgent intervention" to stop the survey until more is known about its impacts on marine life.
The Newcastle Herald understands a senior Centennial Coal executive contacted Mr Piper late on Friday and agreed to delay the survey by a week.
A review of environmental factors (REF) prepared for Centennial last year by environmental consultants GHD says the survey will involve firing pulses from a seismic "sparker" at up to 227 decibels, well above the noise level which can cause permanent physical damage to dolphins and sea lions and affect the behaviour of turtles and other marine animals.
"Sound pressure levels (SPL) for the survey will typically be 216 dB ... with maximum levels ranging up to 227dB," the report says.
"There is extensive evidence that marine species can be impacted by the intense broadband pulses produced by seismic airguns.
"Seismic survey and drilling are expected to generate noise thresholds that give potential to cause a temporary or permanent hearing shift in animals."
The report refers to South Australian government "underwater noise piling guidelines" which say noise levels above 198 decibels can "cause direct physical damage to [dolphin] physiology".
The report goes on to conclude that "overall, no significant impact is considered likely" on the seal, dugong, turtle and bird species covered by relevant fisheries and biodiversity legislation.
Centennial Coal said on Friday that the consultant's report "unfortunately contains several inaccuracies" and the survey work would have "no environmental impacts below the surface to marine life".
"The technology being deployed is similar to a sonar depth finder on a boat," the company said in a statement.
"The seismic survey is not using the air gun blasting technique. It is using a sparker survey, which is a low-impact pulse generated by an electric spark commonly used in sensitive environments.
"227dB in the air has a significantly reduced profile in water due to pressure and attenuation."
The GHD report does not make a distinction between potentially damaging noise and the noise emitted by the sparker device.
Centennial said it carried out similar survey work in 2009 and 2010 "to confirm the location of the lake floor" and maintain a safe distance between the lake's water and mine workings.
Its survey activities are covered by its 2013 mining lease. They were discussed in October at one of the company's six-monthly community consultation group meetings.
The REF says the "Myuna Rockhead Exploration Programme" will provide an "interpretation of geological structures in future areas" of Myuna Colliery, which extends under the lake.
It says the seismic survey will be completed in two two-week blocks.
Mr Piper told the Newcastle Herald that "like most of the community" he was unaware of the survey work until late this week. His office had taken hundreds of calls on Friday from concerned residents.
"On that basis alone I think the work should be deferred until the community can be properly informed about what is being done and the processes involved," he said.
"There is clearly a lot of angst in the community, and in my mind I think it would be wise to delay the start of testing and allow everyone to get their heads around the facts."
In his letter to Mr Kean and Mr Stokes, Mr Piper wrote that "while there is some conjecture around the extent of those impacts, I am not confident that the type of seismic testing being undertaken is without risk or without consequence for marine life and ecosystems".
"I must note that Centennial has all the appropriate consents to do the mapping, but I would certainly question whether that process is as rigorous as it should be and ask you to note that this approval was granted many years ago at a time when we knew much less than we do now about seismic mapping," he wrote.
"I am very concerned at the process which has allowed this to proceed without any input from the community or the likes of myself.
"As someone who has been significantly involved in the remediation of the lake over many decades, I cannot possibly support this type of process to proceed with so many questions remaining unanswered."
Save Our Coast representative Natasha Deen, Lake Macquarie fishing shop owner Jason Nunn and Lake Munmorah resident Gary Blashke met with Centennial Coal and a representative for Mr Piper on Friday afternoon to discuss the survey.
Dr Deen said on Friday evening that she was delighted the company had postponed the testing.
She said the delay would give Save Our Coast time to work with the Environmental Defenders Office on strategies for permanently halting the work.
"Destructive and damaging seismic blasting within beautiful Lake Macquarie has been suddenly imposed on us by Centennial Coal without community awareness, without adequate community consultation or concern for the fragile ecosystem," Dr Deen said.
"Just as we were celebrating a win over Advent Energy cancelling seismic testing offshore, now our dolphins, seals, turtles and all other animals within the lake are at risk."
Mr Nunn said the mining company had faced a "huge public outcry" if it had started seismic testing on Monday.
"The councillors, members and the fishers weren't consulted. Who have they consulted?" he said.
"Two thousand juvenile flathead get released in and around the test areas. How is this loud noise going to impact on that, and the entire fragile estuary?"
He said Lake Macquarie was well known as a haven for juvenile green sea turtles, dolphins and seals.
"Last time they did seismic testing the ocean became like a desert, and that was at 100 metres. Imagine the damage done at 11 metres in shallow water?"
Lake Macquarie City Council said it had not been part of the approval process for the proposed survey.
"We acknowledge the concerns within the community about the adequacy of consultation by Centennial Coal prior to the survey being approved and the potential impact to sea animals and the marine environment," a council spokesperson said.
The council said it had been notified recently by Centennial that it planned to start mapping the lake floor and drilling boreholes "to investigate the continuity and quality of the coal seam".
It had asked for more details on the approval process and arranged for Centennial to brief council staff.
The GHD report says the drilling will take place from a 20-tonne jack-up barge over four 16-week periods over the next five years. The drilling would comprise 60 surface-to-seam boreholes.
Greens MP Abigail Boyd said the drilling and seismic testing were poised to begin without "proper consultation or notice".
"The lake is already contaminated by lead and zinc, caused largely by the coal industry, which has already impacted on fishing quotas," she said.
"By disturbing the lake sediment, this proposal risks spreading the impacts of that contamination further.
"All this for the sake of digging out more coal by an industry determined to put short-term profits over the long-term needs of the community and our environment.
"Instead of propping up a dying industry and destroying our lake, we should be leading the way and reaping the economic benefits of a just transition to 100 per cent renewable energy."
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