A leading environmental engineer says the issue of waste salt from the coal seam gas industry has been underestimated and the "preferred" industry plan "needs active management forever".
The Queensland government has just released the latest draft of its Coal Seam Gas Brine Management Action Plan.
It was estimated that over the next 20 to 30 years up to six million tonnes of waste salt would be produced by the Queensland coal seam gas industry (CSG), a significant reduction from the previously estimated 15 million tonnes.
But environmental engineer Professor Stuart Khan from the University Of New South Wales said it was still "really very significant".
"I think when people first start thinking about this problem they think about a truckload of salt, perhaps, that might be shipped out and disposed of somewhere safely," he said.
The Queensland government's plan for managing waste salt is based on analysis by the University of Queensland's Centre for Natural Gas which is partly funded by three of the largest gas companies operating in the state — Arrow Energy, Santos, and APLNG.
The information UQ has analysed was provided by the peak body for the petroleum and gas industry, The Australian Petroleum Production and Exploration Association (APPEA).
Managing salt 'forever'
To release coal seam gas, groundwater is pumped to the surface and separated. A lot of this water is very salty and cannot be used without being processed.
The salt is removed from the groundwater by either reverse osmosis plants or through plastic-lined evaporation ponds, and both processes create waste brine or salt.
Currently the "preferred" method of long term storage of the waste salt is to bury it in sealed landfill sites, which is called salt encapsulation.
"The problem is that sort of salt encapsulation requires ongoing management," Professor Khan said.
A spokesperson for the Queensland Department of Environment and Science (DES) said it continued to work with the industry, landholders, and environmental groups on a plan for the long-term storage of waste CSG salt.
The DES did not specifically address questions about the long-term cost of managing waste CSG salt and who would pay.
"While encapsulation of salt has been identified as the most viable long-term solution, salt encapsulation facilities are not currently used by the industry," the DES spokesperson said.
Third-generation cattle farmer Glen Beasley lives close to the We Kando waste facility near Chinchilla in southern Queensland, which has approvals to hold CSG salt.
He said he was worried because it was on the Condamine River catchment.
"The possibility of contamination from either overfill of the ponds or leakage into the water table, the potential there is serious," Mr Beasley said.
The ABC has contacted We Kando and understands it currently has no CSG waste salt on-site, and it has no short to medium-term plans to take any CSG waste salt.
Shay Dougall, a Chinchilla local who advocates for landholders dealing with coal seam gas development, said the biggest ongoing problem for many was the lack of transparency.
"I don't believe this has been publicly dealt with properly, I don't think enough information is been made available," she said.
"And if it was, the information that's been made available today shows that this is going to be a long-term problem that has no real solution to it."
