Oil sands consist of clay, sand, and other minerals, coated in water and thick, viscous oil called bitumen (or asphalt).

油砂包含有粘土、沙子和其它矿物，由水和粘稠的沥青把它们混合在一起。

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Production of oil from tar sands bitumen produces between three and five times the greenhouse gas pollution of conventional oil production.

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Alberta, Canada is site of the world's largest extraction operations from oil sands, heavy earth laden with bitumen, a hydrocarbon-rich mineral.

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The pipelines that currently carry bitumen from the oil sands to refineries in the Midwest will reach maximum capacity in as little as four years.

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