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A little more about tar sands by Joella

Posted by cachaca80 - 3 July 2010 at 8:18pm - 6 Comments

Tar sands, a brief introduction:Canada’s tar sand mining has been named ‘the most destructive project on Earth’ but what are tar sands and why are they so destructive? What follows is a short explanation of what tar sands are and a little insight into why they are so destructive.Tar sands are a combination of clay, sand, water and bitumen, which is a sticky tar like form of petroleum, which must be separated from the clay and sand before it can be ‘upgraded’ to form synthetic crude oil¹. Most of the world’s oil is in the form of tar sands, the two biggest reserves are in Canada and Venezuela. In Canada most of the tar sand reserves are located within three main deposits in northern Alberta; the largest is the Athabasca tar sands and the two smaller deposits are known as the Cold Lake and Peace River deposits. Together these deposits cover an area of land roughly the size of England (around 54,000 sq miles)². Most of the worlds tar sands are not recoverable, however in Canada commercial tar sand mining has been active since 1967 with the opening of the Great Canadian Oil sands (now Suncor Energy)³, however due to the recent economic conditions and the rising price of crude oil the interest in producing oil from the tar sands in Canada has increased⁴. The production of crude oil from tar sands is more complex than the recovery of oil from conventional oil wells. Without going into too much detail the tar sand oil recovery process includes extraction and separation procedures to separate the bitumen from the clay, sand and water and then additional ‘upgrading’ of the separated bitumen before it can be refined⁴, the bitumen also often requires dilution with lighter hydrocarbons to make it transportable by pipe. The process of extracting crude oil from tar sands not only requires the input of a lot of energy, it is destructive and is a major source of pollution. It appears that throughout the process of tar sand mining destruction and pollution occurs. In the Athabasca tar sands the bitumen deposits are shallow enough to allow surface mining to be used to extract it. Typically there is around 1-3 meter layer of muskeg (peat bog) at the surface with up to 75 meters of clay and barren sand underneath, the underlying tar sands are around 40-60 meters deep and lie on top of a layer of relatively flay limestone². Surface mining destroys the entire landscape, the whole top layer of earth is removed along with any vegetation or wildlife that was living in it, this process appears to literally kill the landscape in order to recover the oil underneath⁵. The land being removed is primarily boreal forest, Canada is home to half of the boreal forest left in the world. Tar sand operators were granted licences on the basis that they would return the land back to the condition it was before mining started, however it has been admitted by a number of companies that it is almost impossible to artificially return boreal forest to the condition they found it in⁶. Even if it was possible it is unlikely the biodiversity that once existed would return. As if the destruction of a huge area of natural beauty and its wildlife is not enough, tar sand mining has other detrimental effects which harm both the environment and human health. Between 2 to 5 barrels of water are used to produce each barrel of crude oil from tar sand surface mining. This water is primarily drawn from the Athabasca River and is seriously lowering the water level of the river⁷. The planning of more tar sand mines means that even more water will be drawn from the river in the future. Water is mixed with chemicals in the extraction and separation process and despite some efforts to recycle almost all of the water used becomes contaminated and ends up in tailing ponds⁸. These tailing ponds are often adjacent to the river the water originally came from and therefore pose an enormous threat of contaminating the freshwater supply and poisoning wildlife. In fact the water that is in the tailing ponds are acutely poisonous to aquatic life and wildlife that comes in contact with it. There are also worries that water from these ponds may leach out over time, the result of which would be disastrous⁶. These tailing ponds are so big that many of them can be seen from space. Greenhouse gas emissions from the tar sand production process are three times those of conventional oil production⁷ making the tar sands one of the fastest growing sources of greenhouse gas emission in Canada¹⁰. The increase in tar sand production means that the total emissions are expected to continue to rise⁸ and may double by 2015. Not only is tar sand mining producing more greenhouse gases than conventional oil production, the destruction of the Boreal forest is also reducing the carbon storage these forested areas provide⁶. The production process also burns as much natural gas each day as is needed to heat four million homes. As part of the Kyoto protocol Canada had a target to reduce its greenhouse gas emissions by 6% from the 1990 levels by 2012, unfortunately in 2006 Canada’s greenhouse emissions were already 27% higher than the 1990 levels. With the number of barrels of oil being produced by tar sand set to increase and as the average amount of CO2 released in the production of one barrel of oil by tar sands is around 85.5kg it appears that the gap between Canada’s GHG emissions and targets will continue to increase⁶. The local and indigenous communities have also been affected by the tar sands projects. The Canadian first nation indigenous people who live downstream from the tar sands are worried about the water quality of the river and the level of toxins in the fish. There have also been a number of unusual incidences of cancer within the Fort Chipewyan community which is being looked into by the Canadian health authority⁶.

Surface mining is not the only method used to extract tar sand from the ground, in the cases where the bitumen is too deep to use surface mining some form of in situ recovery is used. This is often similar to conventional oil wells however due to the stickiness of the bitumen it will not flow under normal conditions and a process involving steam is used. This however uses even more water and energy than surface mining does meaning that in situ mining just adds to the problems of surface mining⁶. This has been just a brief introduction into the process used in tar sand mining and the environmental impacts they have. It appears that calling tar sand mining ‘the most destructive project on earth’ may not be that far from the truth. The impact tar sand mining has on not only the surrounding environment but the world is hugely destructive. From polluting the air, water and land to having enormous implications on greenhouse gas emissions, tar sand mining has a lot to answer for. To some producing oil from Canada’s tar sands may seem like a quick fix to the potential oil shortage however if we sit down and look at the facts it should become clear that the environmental costs of tar sand oil production is far too high. References – 1. http://en.wikipedia.org/wiki/Tar_sands#Environmental_issues 2. http://www.moneyweek.com/investments/commodities/are-canadian-tar-sands-the-answer-to-our-oil-needs.aspx 3. http://www.oilsandsdiscovery.com/oil_sands_story/mining.html 4. http://ostseis.anl.gov/guide/tarsands/index.cfm 5. http://www.americanprogress.org/issues/2010/06/tar_sands.html 6. http://www.andrewnikiforuk.com/Dirty_Oil_PDFs/Scraping_barrell.pdf 7. http://www.tarsandswatch.org/tags/water-depletion 8. http://www.neb.gc.ca/clf-nsi/rnrgynfmtn/nrgyrprt/lsnd/pprtntsndchllngs20152006/pprtntsndchllngs20152006-eng.pdf 9. http://www.tarsandswatch.org/tags/global-warming 10. http://www.greenpeace.org/canada/en/campaigns/climate-and-energy/solutions/political-solutions/kyoto/what-we-do/nanticoke/the-problem/international-negotiations/cop14mop4/canada_tarsands/