How do we define tar sands?

How do we define tar sands?
Oil sands, tar sands, crude bitumen, or more technically bituminous sands, are a type of unconventional heavy oil2. Source: Suncor Energy Inc. Available at:

How do we define tar sands? Where are they located? What are the environmental challenges? Let’s define tar sands and learn more about them.

Defining tar sands…

To begin with, tar sands, also known as oil sands, are a low quality form of oil1. Moreover, they are a resource, particularly abundant in Alberta, Canada and Venezuela, where heavy petroleum is mixed with sand, clay, and water2. In fact, this heavy form of petroleum is called ‘bitumen’.2

Additionally, bitumen is a thick molasses-like substance1. In general, it is made up of hydrocarbons similar to molecules found in liquid oil and used to produce gasoline and other petroleum products1. This bitumen allows a peanut butter-like consistency to tar sands3. In fact, bitumen has such a thick consistency, which makes it much more difficult to extract and transport compared to conventional crude oil3. Thus, bitumen does not flow easily. Instead, bitumen clings to the sand and clay and cannot be simply pumped out of the ground through wells like conventional oil4.  For this reason, oil sands are mined in two different ways depending on the depth of the deposit: open-pit and in situ mining4.

How are oil sands mined?

In brief, there are two methods of extracting tar sands, namely open-pit mining and in situ extraction4. Also, each technique depends on the depth of the deposit.

Basically, if tar sands are near the surface, they can be surface mined directly and transferred to an extraction plant where the bitumen will be removed from the sand, clay, and water4. This is open-pit surface mining. On the contrary, if tar sands are too deep for surface mining, the bitumen can be extracted in situ. Therefore, this occurs by injecting hot steam to lighten the bitumen and enable it to flow through a well to the surface4. This is in situ mining.

Where are they located?

For example, Alberta, Canada and Venezuela contain large depostis of oil sands4. Also, the largest deposits in the United States are located in eastern Utah4.

How do we define tar sands?
Oil sands located in northeastern Alberta.
Source: Alberta Geological Service. Available at:

What are the environmental costs?

Even though oil sands are an important energy resource5, they come hand-in-hand with environmental challenges. With this in mind, tar sands have a detrimental effect on climate change, water consumption and contamination, and wildlife6. As a matter of fact, the extraction process can poison rivers and water tables, kill wildlife, destroy ecosystems and increase greenhouse gas emissions7. Not only do oil sands produce more greenhouse gases than conventional crude oil, their extraction often involves the destruction of forests and peatlands.

In summary, the oil sands industries extracting bitumen and producing millions of gallons of synthetic crude oil each year are clearly threatening our planet. In other words, investment in more sustainable and green methods of energy production are vital to save our planet, or at the very least we have to be very strict on environmental impact7.


  1. Union of Concerned Scientists. (2020). What Are Tar Sands? [online] Available at:
  2. (2017). Definition: Tar Sands | Open Energy Information. [online] Available at:
  3. Oil, A. (2020). Oil Sands Products – Background – Alberta Oil Sands Products. [online] Available at:
  4. American Geosciences Institute. (2018). What are tar sands? [online] Available at:
  5. Natural Resources Canada (2014). Oil Sands: Economic contributions | Natural Resources Canada. [online] Available at: 
  6. (2018). Environmental impacts of oil sands – Energy Education. [online] Available at:
  7. Woynillowicz, D., Severson-Baker, C. and Raynolds, M. (2005). SANDS Fever Oil THE ENVIRONMENTAL IMPLICATIONS OF CANADA’S OIL SANDS RUSH. [online] Available at: http://large.stanford

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