A report from Canada's The Globe and Mail on Wednesday looks at what the tar sands industry foresees as the future of its toxic old mine pits -- recreational lakes -- a plan the newspaper describes as an "ecological gamble."
The proposed plan is to fill 30 of the mines after tar sands extraction is over, and fill them with water, a less costly option than filling them with earth, covering up "toxic effluent" at the bottom.
These lakes will cover "100 square kilometers as part of a series of artificial watersheds spreading over 2,500 square kilometers," the Globe and Mail says.
But even the report outlying the plan from CEMA, what the paper says is an industry-funded group, states that “scientific uncertainty is high” around the lakes, and there is a likely “potential for substantial negative and environmental and/or social impacts.”
From the Globe and Mail:
The report is also a striking look at how much remains unknown about lakes that will, in some cases, bury mine effluent called tailings. Those tailings are largely sand and clay, although they are laced with hydrocarbons, salts and naphthenic acids sufficiently toxic that they cannot be released into the environment. In an estimated 50 per cent of the end pit lakes currently contemplated, those tailings will be placed at the bottom of the pit, before being covered with a “cap” of fresh water mixed with dirty mine-processed water. The expectation is that the thicker tailings will remain on the bottom and solidify over the years, while biological processes will work to remediate the water above it. [...]
And the science is still out on whether they will work – or leave a toxic legacy, notes David Schindler, a respected scientist at the University of Alberta. No further end pit lakes should be approved, he said, until “we must have some assurance that they will eventually support a healthy ecosystem.” There is to date, he added, no “evidence to support their viability, or the ‘modeled’ results suggesting that outflow from the lakes will be non-toxic.”
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— 350 dot org (@350) October 3, 2012
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— Greenpeace Canada (@GreenpeaceCA) October 3, 2012
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— Council of Cdns, Vic (@cocvic) October 3, 2012