from "National Geographic"-- Alberta Tar Sands

Nowhere on Earth is more earth being moved these days than in the Athabasca Valley. To extract each barrel of oil from a surface mine,
the industry must first cut down the forest, then remove an average of two tons of peat and dirt that lie above the oil sands layer, then two
tons of the sand itself. It must heat several barrels of water to strip the bitumen from the sand and upgrade it, and afterward it discharges
contaminated water into tailings ponds like the one near Mildred Lake. They now cover around 50 square miles. Last April some 500 migrating ducks mistook one of those ponds, at a newer Syncrude mine north of Fort McKay, for a hospitable stopover, landed on its oily surface, and died...