The Queensland Resources Council (QRC) has pointed to acidic rainfall as a cause of high levels of acidity and heavy metals in two creeks downstream from the Lady Annie Mine, near Mount Isa.
The QRC, which represents the interests of mining companies, has told Queensland Country Life that rainfall is as likely to be a factor as flood-related spillage from the mine itself.
Citing a chemist with extensive experience in the North West, the QRC points out rainfall is naturally acidic.
"The North West province is heavily mineralised and rainwater is naturally acidic from dissolved carbon dioxide," QRC saays.
"The natural water may already contain high metal values, or become high in metals when excess rainwater
makes the river acidic, dissolving metals.
"Only by testing water up-stream can anyone suggest elevated metals came from the mine."
EPA testing of the Inca and Saga creeks 12km downstream from the mine following flooding that caused a waste dam at the mine to overflow, revealed that water in both creeks had a pH level of 3.3. The lower the pH, the more acidic. Acid rain typically has a pH of 5.6, according to the EPA.
QRC CEO Michael Roche says media reporting of the flood-related discharges has been sensationalist, and says it isn't responsible to label the event as an environmental disaster before water quality test results are known.
"In the context of an extraordinary weather event and the State election campaign, such commentary was clearly designed to promote a political viewpoint rather than a rational assessment of environmental harm," he says.
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