Salty mine water released into CQ river ‘within the limits’
A mining company and the state's Environment Department on Wednesday denied that the release of salty water into a Central Queensland river would do environmental harm.
From March 18 to 21, Idemitsu Australia Resources released water from the Ensham mine near Emerald into the Nogoa River that was more than 1000 times saltier than the existing background levels, at a rate of 2,700L/s.
Ellie Smith from Lock the Gate Alliance said that no mine should be permitted to discharge "polluted" water into rivers, especially with such a salinity disparity.
"Instead, mining companies should be required to treat all waste water by reverse osmosis and re-use it on site where possible," she said.
"It's hard to believe this mine was flooding, given nearby Fairbairn Dam is still only at 21 per cent capacity.
"It instead appears as though Ensham has taken the opportunity, while the river is flowing, to release dirty, polluted water that has built up in its mine pits over time.
"This isn't acceptable, particularly when all this water eventually flows into the Great Barrier Reef."
A spokesman for Idemitsu Australia Resources said the release was conducted in full compliance with Ensham's Environmental Authority.
He said that authority "allows for mine water to be released into the Nogoa River subject to a range of science-based conditions that ensure no environmental harm is caused".
"Source water sampling conducted at the mine prior to the release confirmed that no heavy metals were present," he said.
An Environment Department spokesman said that in this case, the salinity was "within the limits" of the site's water quality conditions.
"The water quality limits ensure that environmental values are protected," he said.
"The department requires mines to monitor and report releases, and the department reviews the results and reports to ensure releases are compliant with the site's conditions.
"Like much of Queensland, catchments in the Central Queensland region have received significant rainfall over the past week meaning any discharge is heavily diluted."