The difficulty of mining oil sands varies depending on the location of the oil sands. Oil sands deposits that are less than about 250 feet below the surface can be removed using conventional strip-mining methods. The strip-mining process includes removal of the overburden, excavation of the resource, and transportation to a processing facility. Nearly all mined bitumen is currently upgraded to synthetic crude oil. Oil sands extraction processes are generally divided into two categories: mining and in situ operations. Only 20% of Alberta's bitumen reserves are close enough to the surface to be mined. The remainder can only be feasibly extracted in-situ using steam. Although in-situ bitumen extraction traditionally had very low recovery rates,
