The tar sand mines in Alberta, source of the oil that may one day flow all the way from Canada to Texas through the Keystone XL Pipeline, are growing by enormous leaps and bounds. This superb series of satellite pictures, brought to you by National Geographic, tells the whole story.
When the first mine opened alongside the pristine Athabasca River in 1967, oil extracted from oil sands (also known as tar sands) was too expensive to compete with liquid crude. But now, with oil prices hovering at about $100 US per barrel, the costly and environmentally taxing process of pulling bitumen out of the clay mixture makes it economically feasible.
Processing, transporting and refining the oil is very energy intensive, however, producing 15% to 80% more carbon emissions than average petroleum products over their life cycle. The photos show the growth of huge piles of tailings leaching all manner of goo into the Athabasca River.
The sands hold an estimated 1.75 trillion barrels of oil, the second-largest known deposit of oil in the world after the deposits in Saudi Arabia. The Alberta deposit is being developed by a host of international oil companies, though ConocoPhillips holds the largest stake.