Pneumatic conveyors have been used for the transportation of solids for many decades. Their design is substantially empirical, and because they run with almost no instrumentation or control, large safety factors are employed to ensure long-term safe and reliable conveying under all envisaged conveying conditions. The resulting excessive conveying velocity leads to increased energy consumption, pipeline wear and solids breakdown. The aim of the work reported in this thesis was to develop an instrumentation and control system which provides minimum cost conveying for a variable solids feedrate and composition, in a lean phase vertical pneumatic conveyor. Incipient blockage of the pipeline is detected through measuring solids velocity by cross correlation of signals from electrodynamic transducers. This solids velocity measurement system is modelled, and laser techniques independently confirm the experimentally measured solids velocity and profile in the pipe. A model of the pneumatic conveyor is described which is used in the design of a feedback control scheme. By controlling the pilot plant to convey at minimum safe solids velocity, independently of any solids feedrate change, energy savings of up to 45% are shown to be possible.