加拿大的西部阿尔伯塔省一个重要、但长时间不被人注意的资源是油沙——藏在地下含着丰富石油的沙子。不同的是,石油在地下呈液体状,可以用机器直接抽取。油沙却是固体状的,要像挖煤那样挖掘和开采,之后还要通过特殊的方式把其中含的油提炼出来,成本高代价大。在油价低于每桶30美元 An important, but unnoticed, resource in Alberta, western Canada, is oil sands - hidden in oil-rich sand beneath the earth. The difference is that the oil is liquid in the ground, you can use the machine to extract directly. Oil sands are solid, digging and mining like digging coal, and then refining the oil contained therein in a special way at high cost. In oil prices below 30 dollars a barrel