油砂
Oil sand consists of a matrix of solid mineral material—quartz sand and clays, water, and the hydrocarbon, bitumen, which is the heaviest form of petroleum. According to the United Nations Institute for Training and Research, bitumen's normal viscosity is greater than 10 mPa s and its density is greater than 1000kg/m. Oil sands, before processing, comprise fine particles of silt and clay, that are 44 microns or less, and coarse particles of sand and rock, that are larger than 44 microns. Each grain of quartz sand, which is extremely abrasive and has an angular shapes, is "completely enveloped within bitumen". Each sand grain is surrounded by a thin film of water and bitumen covers the aqueous layer and the angular sand grain. The bitumen-and water-covered grains of quartz sand stick to one another. When untreated, the highly abrasive oil sands would damage pipelines, trucks, and all the equipment used in mining and operations. As well, the viscosity of bitumen changes with heat and cold. It is like molasses when warm, and will freeze when cold. Bitumen as a hydrocarbon, is considered to be a valuable energy resource. The more bitumen in an oil sands deposit, the more valuable it is. If a deposit contains less than 6% of bitumen it is not worth mining. The oil sands deposit has to have at least 18% of bitumen has to be economically viable.