The progressing depletion of conventional oil sources has lead to a raise of unconventional sources of oil, in particular deposits of oil mixed with anorganic sediments called tar sands or oil sands. Canada has one of the largest such deposits in northern Alberta called the Athabasca oil sands. Large scale mining of these deposits started in the late 1960s and here i assembled a timeline of satellite images illustrating the vast increase in the scope of mining there in recent years.

Mining of tar sands is connected to significant environmental risks. It consumes large amounts of energy and water to extract oil from these deposits and produces a lot of heavily polluted wastewater that is collected in huge ponds you can see in the images above.