Pneumatic pipeline, also called pneumotransport or pneumatic conveying, is the use of air or another gas to transport powdered or granular solids through pipes. It is the counterpart of the slurry pipeline, using a gas instead of a liquid as the medium to transport solids. First used successfully in the 1860s for transporting lightweight materials such as wood shavings, sawdust, and waste papers, the technology of pneumotransport has steadily improved and found increasing use in the last 150 years. Currently, it is used widely in many industries to transport minerals, grain, flour, coal, sand, cement, solid wastes, and hundreds of other products. Due to the high energy intensiveness of pneumotransport, and the abrasion (wear) of the materials transported, such pipelines are for transport over short distances only, usually less than 1 km, most often only a few hundred meters or even shorter. Some of the longest pneumatic pipelines are used to transport cement in major construction projects in remote locations. For instance, in 1933, cement was transported pneumatically over a distance of 1.8 km at the construction site of the Hoover Dam in Nevada, U.S.A. Shortly thereafter, a 2.1-km pneumatic pipeline was built to transport cement in the construction of the Grand Coulee Dam in the State of Washington, U.S.A. The longest systems are used in mining where single pipelines of 3.5 km are reported to be in use in some German coal mines. These mines also feature an extensive network of pneumatic pipelines, with a total length of over 40 km of interconnected pipes. Pneumatic conveying is used most often at harbors, barge terminals, and rail terminals for loading or unloading bulk materials such as grain, cement, and fertilizer to or from ships, barges, and trains. It is also commonly used in chemical plants, paper plants, breweries, cement plants, and food processing plants. Because most such applications involve transportation over short distances only, the technology is often considered as a means for materials handling (conveying) rather than transportation. This explains why it is usually referred to as pneumatic conveying. The term conveying implies transportation over short distance.