800px-Syncrude_mildred_lake_plantThe Athabasca Sands (also known colloquially as the although there is no actual tar) are large deposits of bitumen, or extremely heavy crude , located in northeastern , – roughly centered around the boomtown of . These sands, hosted in the McMurray Formation, consist of a mixture of crude bitumen (a semi-solid form of crude ), silica sand, clay minerals, and water. The Athabasca deposit is the largest reservoir of crude bitumen in the world and the largest of three major sands deposits in , along with the nearby Peace River and Cold Lake deposits. Together, these sand deposits lie under 141,000 square kilometres (54,000 sq mi) of sparsely populated boreal forest and muskeg (peat bogs) and contain about 1.7 trillion barrels of bitumen in-place, comparable in magnitude to the world’s total proven reserves of conventional petroleum.

With modern non-conventional production technology, at least 10% of these deposits, or about 170 billion barrels were considered to be economically recoverable at 2006 prices, making ’s total reserves the second largest in the world, after Saudi Arabia’s. The Athabasca deposit is the only large sands reservoir in the world which is suitable for large-scale surface , although most of it can only be produced using more recently developed in-situ technology.

Read on about the environmental impact of oil/tar sands