Although he'll be returning with a wealth of original insight and photographs (see his coverage of North Dakota's oil boom), we've put together a basic primer on the oil sands.
What are oil sands?
Oil sands are a naturally occurring mixture of sand, clay, water and bitumen.
Layers of oil sand sit hundreds of feet beneath the soil, which must be stripped away in order to reach the deposits.
Where are oil sands found?
Oil sands can be found in many places around the world, but the largest deposits are in Venezuela and Alberta, Canada.
There are 175 billion barrels of proven oil reserves in Canada, second only to Saudi Arabia and Venezuela. Of that number, 170 billion barrels come from Alberta's oil sands, which are found in three main deposits: Athabasca, Peace River and Cold Lake.
