Bitumen is a naturally occurring viscous mixture, mainly of [[hydrocarbon]]s heavier than [[pentane]], that may contain [[sulphur]] compounds and that, in its natural occurring viscous state, is not recoverable at a commercial rate through a well. | Bitumen is a naturally occurring viscous mixture, mainly of [[hydrocarbon]]s heavier than [[pentane]], that may contain [[sulphur]] compounds and that, in its natural occurring viscous state, is not recoverable at a commercial rate through a well. |