The movement and storage of solids is usually more expensive than the movement of liquids and gases, which can be easily pumped down a pipeline. The best equipment to use to move solids will depend on a number of factors:
1. The throughput
2. Length of travel
3. Change in elevation
4. Nature of the solids: size, bulk density, angle of repose, angle of wall friction, abrasiveness, corrosiveness, wet, or dry