Canadian oil sands spill continues

New Scientist : Since May, toxic bitumen has been spurting uncontrollably from the ground at various locations at a major oil sands operation in Alberta. Canadian Natural Resources, one of the world’s largest crude oil and natural gas producers, still does not know what caused the spills. The company extracts bitumen by injecting steam at high pressure into deep underground reservoirs in the tar sands. The steam heats and liquefies the bitumen and creates cracks in the ground through which the bitumen can be pumped to the surface. Although the project had been certified safe by government regulators, it now appears that the region’s geological formations may have been weaker than thought and unable to handle the pressure from the steam. The spill could adversely affect plans for the Keystone XL pipeline , which would carry oil from this and other sites to refineries on the Gulf Coast of Texas.