The deposits underlie boreal forest (technically the southern section of the taiga biome) and peat bogs (also called muskeg). One of the best places to see the land changes caused by mining is NASA's Earth Observatory World of Change story on the Athabasca. There is a slideshow of satellite images starting in 1984 through 2011, which allows you to see the changes in the terrain over time (plus an excellent writeup). I have the first and last of the images here, and added a couple of 2013 images taken from Google Earth.
|Image from 1984 - NASA|
|Image from 2011 - NASA|
|Image from 2013 - Google Maps|
|Image from 2013 again but with a wider field of view - Google. |
Note the new mine to the north that isn't visible in the other images.
Alberta has an interactive map up at http://osip.alberta.ca/map/ where you can click around and view project boundaries and the like. It links to project information too, but I found it pretty user unfriendly.
The Athabasca tar/oil sands oil is considered an 'unconventional' oil source - it isn't liquid that can be pumped out of the ground. Instead it is in the form of bitumen—a very thick and heavy form of oil (cyclo- or complex forms of hydrocarbon with >40 carbons), also called asphalt or in older texts asphaltum. Bitumen is practically solid to begin with and in the deposit it coats grains of sand and other minerals forming a deposit that bears more resemblance to coal than oil.
There are two ways that the bitumen is extracted. The first is open pit surface mining, like coal. Ground cover is removed, a pit is dug and oil sand is collected with draglines and bucket-wheel excavators or power shovel-and-truck operation. The processing is easier to understand if you watch this video ...
The second, which is used for deeper deposits, is called SAGD - Steam Assisted Gravity Drainage - where pairs of wells are drilled into the ground then have a horizontal leg though the formation. The upper well injects steam into the formation, heating the rock and causing the bitumen to start flowing down into the lower well, where it is pumped up. This type of extraction causes significantly less visible damage than surface mining. Again a video might help ...
Commercial production of oil from the Athabasca oil sands began in 1967, but didn't really swing into high gear until around 2003 as oil prices rose. This is actually visible in the NASA satellite images. Alberta contains about 173 billion barrels of economically recoverable oil, making the regions tar sands the world’s third-largest oil supply after Saudi Arabia and Venezuela. Approximately 35 billion barrels of it is surface mineable - the rest must be recovered using in situ methods like SAGD.
The environmental affects of all this activity are still playing out before our eyes, with the First Nation peoples being disproportionately impacted. Many First Nations have had to shift away from their traditional diets out of concerns over contamination and their land, air and water resources are being harmed.
A study released last month by the University of Manitoba found traditional foods, such as muskrat and moose, wild-caught in northern Alberta have higher-than-normal levels of pollutants, icluding heavy metals and polycyclic aromatic hydrocarbons, that the study associates with oil sands production. Researchers found arsenic levels were high enough in muskrat, duck and moose that they were of concern for young children. Mercury levels were also high for duck muscle, kidneys and livers as well as moose and muskrat kidneys.
A study released earlier this year suggests that the environmental health risks associated with the oil sands operations in Alberta’s Athabasca region have probably been significantly underestimated. And Canadian government research published earlier this year has confirmed that toxic chemicals from tar sands production are seeping into the Athabasca River.
And now this is were we link back to the Keystone Pipeline. The bitumen extracted from the oil sands is diluted/thinned with light hydrocarbons like benzene to make dilbit (diluted bitumen) so that it can flow (sludge?) through a pipeline. Dilbit is much more acidic than normal crude oil and contains much higher levels of heavy metals and other contaminants. Because of these properties, dilbit spills are already justifiably notorious for being difficult to impossible to clean up. You can get an idea of how bad dilbit is from this op-ed http://www.nytimes.com/2012/08/21/opinion/the-dangers-of-diluted-bitumen-oil.html.
So the primary worry here, that we were meant to be exploring in class last semester, is that the dilbit that would flow through the proposed Keystone XL Pipeline extension, right over an Ogallala Aquifer recharge zone, and that a spill there would be something that we don't know how to clean up effective, damaging the water supply for roughly one-fifth of the wheat, corn, cotton and cattle produced in the United States (not to mention all those people living in the High Plains).
So - this oil is still going to market. The question is how - via pipelines ? Railcars ? Trucks?
There is a lot more that could be said, but I am going to leave this here. If you have been listening to the news you know that several other water issues have been making headlines lately. Eek!