Water released from former mine site at Mt Morgan
A CONTROLLED release of water from an abandoned mine site at Mt Morgan has been carried out after continued heavy rain in Central Queensland.
Abandoned Mine Lands Program officers from the Department of Natural Resources and Mines today conducted a controlled release of up to 300 megalitres of water into the Dee River system.
Queensland Commissioner for Mine Safety and Health Stewart Bell said the controlled water release was necessary to minimise any risk of an uncontrolled discharge of untreated water from the former mine's open cut pit into the Dee River.
"Approximately 400mm of rain has already fallen on the Mount Morgan mine site and over 600mm in the upper Dee River catchment," Mr Bell said.
"That's more rainfall than was recorded on the site than during the 2010-11 wet season.
"As a result, the water level in the open cut pit has risen 1.2m over the past 24 hours and is currently 370mm below the spillway.
"With additional heavy rainfall expected, a controlled water release is the only practical option to maintain site safety and minimise potential environmental impacts."
Mr Bell said the controlled water release had been timed to occur when there were strong natural flows in the Dee River to dilute the water and minimise any potential environmental impacts.
"The Dee River continues to flow strongly and this presents favourable conditions to achieve dilution of any untreated water downstream of the mine site," he said.
"As Mount Morgan is close to the top of the catchment, under existing flow conditions we will be able to achieve a dilution rate of approximately 100 litres of clean river water mixed with every litre of untreated mine water within 20km downstream.
"The department has conducted similar controlled water releases at the former Mount Morgan Mine in the past with no significant decline in river water quality.
"Three large evaporators working at the Mount Morgan Mine site to lower pit water levels are in automatic mode.
"Seepage capture and return systems other than the central Mundic Gully system have been turned off to minimise water re-entering the mine pit."