ORIGIN Energy says it will cost more than $1 million and take several years to determine the cause of mysterious bubbling along the Condamine River.
Since attracting strong media interest earlier this year via a short video clip posted online, the bubbling has been a major focal point for opponents of the coal seam gas industry, who argue the seepages are evidence of the impacts of resource activity on the environment.
However, the State Government and Origin Energy told Queensland Country Life this week that while the exact cause of the seeps was still unknown, initial investigations had not established any link with CSG activity.
A spokesperson for the Department of Natural Resources and Mines said there was anecdotal evidence and historic groundwater records of gas seepages in the Condamine River and methane in groundwater bores reaching back for decades.
However, the spokesperson said the aim of ongoing testing was to identify the cause.
The government is conducting a multi-agency investigation into the occurrence of gas seeps in the Condamine River, which is independent to that being undertaken by Origin.
The spokesperson said the state LNG Enforcement Unit (LNGEU) was independently monitoring and assessing the Origin investigation, with a long-term investigation also under way to allow government experts to verify the information it received from the company.
"Sampling and analysis of seeping gas has been undertaken, and ongoing monitoring of seeps at four major locations has occur-red along the Condamine River as well as water bores within a 10km radius of the seeps," the spokesperson said.
"The investigation has completed its initial phase, with results suggesting that there is no safety risk or environmental harm in the immediate area of the seeps. A sustained focus will be on the verification of data generated from Origin's investigation, involving both field-based and desk-based checking of plans, methodologies and results."
Origin Energy believes the seepages are a naturally occurring event, after its surveying of more than 70km of the Condamine River, Charleys Creek and surrounding tributaries by canoe and on foot.
In a letter to surrounding landholders, Origin CSG regional manager Rob Hart said the company had identified five seep locations, all of which are located within a 5km section of the river, and at least one of which is thought to have been occurring for the past 30 to 40 years.
The company said any discrepancies between the number of government and Origin identified seepages being investigated was because two of the incidents were located together on the same property, so this could be described as the same seepage location.
"Since our investigations commenced, we have conducted fortnightly water and air sampling, weather and access permitting. These results have been provided to the Queensland Government LNG Enforcement Unit," he wrote in the letter.
"We have tested 21 water bores in the surrounding area and have found naturally occurring levels of gas present in 20, which is consistent with previous baseline monitoring activity.
"In some we have run a video camera down the bore hole to determine at what level gas may be entering."
