Tar sands (also referred to as oil sands) are a combination of clay, sand, water, and bitumen, a heavy black viscous oil. Tar sands can be mined and processed to extract the oil-rich bitumen, which is then refined into oil. The bitumen in tar sands cannot be pumped from the ground in its natural state; instead tar sand deposits are mined, usually using strip mining or open pit techniques, or the oil is extracted by underground heating with additional upgrading.Oil sands represent as much as 66% of the world's total oil reserves, with at least 1.7 trillion barrels in the Canadian Athabasca tar sands and 1.8 trillion barrels in the Venezuelan Orinoco oil sands, compared to 1.75 trillion barrels of conventional oil, mostly located in Saudi Arabia and other Middle-Eastern countries.
Tar Sands Extraction and Processing[ii]
Tar sands deposits near the surface can be recovered by open pit mining techniques. New methods introduced in the 1990s considerably improved the efficiency of tar sands mining, thus reducing the cost. These systems use large hydraulic and electrically powered shovels to dig up tar sands and load them into enormous trucks that can carry up to 320 tons of tar sands per load. After mining, the tar sands are transported to an extraction plant, where a hot water process separates the bitumen from sand, water, and minerals. The separation takes place in separation cells. Hot water is added to the sand, and the resulting slurry is piped to the extraction plant where it is agitated. The combination of hot water and agitation releases bitumen from the oil sand, and causes tiny air bubbles to attach to the bitumen droplets, that float to the top of the separation vessel, where the bitumen can be skimmed off. Further processing removes residual water and solids. The bitumen is then transported and eventually upgraded into synthetic crude oil.
India, with increasing energy needs, has also announced plans to invest $1 billion in the Athabasca Tar sands in 2006. Four different Indian companies are involved in this investment.
Potential locations in India
As of Mar 2009, there are no data available regarding availability / reserves of tar sands in India
- Produces more greenhouse gases than normal refining of oil.
- Uses a lot of water.
- Tar sands development projects tend to be environmental disasters - these involve large-scale mining operations (and other 'extractive' operations) and could leave huge scars on the landscape long after the mine is played out.
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