A thin mixture of water and fine, insoluble materials suitable for pumping as a liquid. Pipelines are the cheapest and most efficient means of moving materials long distances. In Arizona, the Black Mesa slurry pipeline carries eight tons of powdered coal per minute to the electrical power plant near Page on Powell Reservoir. A much longer pipeline has been proposed for shipping subbituminous coal in Wyoming to Midwestern cities. Water supply is a crucial factor in these arid regions lying in the Rocky Mountain rain shadow zone.