I was reading a post from a fellow who made the point that Canada's oil sands are the biggest (natural) oil spill in history, and therefore the surface mining operations are good because they are cleaning it up. Interesting point I hadn't considered before.
It's true that surface bitumen has been flowing into the Athabasca River for thousands of years. You can see it as you travel up and down the river. This probably isn't good for the aquatic life, although maybe biologists say otherwise, I don't know the concentration or if it is actually a problem.
Incidentally I don't work for the Koch brothers nor the oil sands lobby. But I'd be interested in knowing others' comments on this. Are the oil sands just a massive, natural oil spill? If so, should humans bother trying to clean it up? If so, how should we do it?