Leaking tailings dam could harm the Tambo River and Gippsland Lakes

Thursday, February 26, 2015

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Leaking tailings dam 7 million tonnes of toxic wasteIn February 2006, having spent around $7 million of taxpayers' money trying to fix up an unstable tailings dam abandoned by a failed copper and zinc mining enterprise, the Department of Primary Industries was moved to ask the Register of Geographic Names to call the dam 'Lake St Barbara'.

Ironically, in Spanish and Italian, the words Santa Barbara signify the powder magazine of a ship or fortress, and this is exactly what this tailing dam is - a ticking powder keg.

In the past few years a new company, Independence Group, applied to re-open and expand the old copper and zinc mine and the Lake St Barbara tailings dam. They plan to raise the dam wall to a height of 45 metres and store up to 7 million tonnes of toxic waste, around ten times the volume held by the original dam.

The mining operation now has federal government approval and, shortly before last year's Victorian election, then state planning minister Matthew Guy gave his approval. He famously confused the name of the mine and, in his assessment, claimed that no objections had been raised over the location of the tailings dam. That is fundamentally false.

The former planning minister and member for Bulleen also claimed that a post-closure trust fund of only $5.5 million would account for catastrophic failure of the dam. But the report he referenced for that estimate actually recommended a $264 million bond.

According to the environmental assessment, the toxic waste in the dam must remain covered by two metres of water for at least a thousand years, and that, frankly, is impossible.

For a start, an independent report by consulting and engineering company GHD has pointed out that the membrane used in the original dam (the industrial film used to keep the earth and rock wall impermeable) will only last for around 30 years. And the somewhat improved membrane planned for the dam wall extension has a lifetime of just 100-200 years. Neither of them can be replaced or repaired.

And in the lifetime of the dam there will inevitably be many ten-year droughts, which will evaporate the crucial protective water cover.

There's more: the GHD report listed 67 cases where important information from the company on how the tailings dam will be managed long-term was either missing or inadequate.

So, what happens if the mining company does its business and goes west like the last company, leaving a serious toxic legacy threatening the Tambo River and Gippsland Lakes for generations to come?

The Gippsland Environment Group (which has been leading this fight), the VNPA and others made strong written submissions and presentations to the investigative panel on the inadequacies of the dam and many other issues.

The saving grace is that the tailings dam (or Lake St Barbara if you're so inclined) remains technically outside the mining approvals so far. And that, we are quite sure, is where it should stay.

We implore Victoria's environment minister, planning minister and energy and resources minister to look very carefully at the long-term safety of Gippsland's waterways, and deny final approval for the Stockman Mine.

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