Extreme Oil
Photo of oil refinery
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Interactive Feature: Lean how to extract oil from tar sands and what tar sand is made of.
Oil Sands Excavation Extraction Tar Sand


Nearly a century ago, a Canadian engineer named Sidney Ells suggested on-site extraction using hot water for some of the oil sands. In 1929, Dr. Karl Clark, a chemist with the Alberta Research Council, patented an improvement on Ells' idea, separating the sand and bitumen by using steam, hot water, and other elements. For oil-sand deposits more than 75 meters (250 feet) beneath the surface, steam injection is used to extract the bitumen, which is then pumped to the earth's surface for further processing.

Yet most extraction is done away from the tar sands. Oil sand is piped into a large tank (see figure at right), which filters out the bitumen by allowing the various parts to settle in the tank according to weight: The heavy sand moves to the bottom; brackish water (called middlings) finds the middle area; and the bitumen floats to the top. From that point, the bitumen is further treated before distribution.

Chart shows Bitumen Froth, Middlings, and Sand
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