The charging of particulate materials due to contact with the inside surface of a pipeline wall (triboelectrification) during pneumatic conveying is common in bulk solids handling equipment. Electrostatic discharge from particulate materials in a transport line can lead to fire and explosion hazards. Conversely, the phenomenon of electrostatic charge can be utilized to measure particle flow. At present there is only a very limited amount of experimental data available to describe the triboelectric charging properties of particulate materials under known flow conditions. This paper reports work undertaken to investigate the electrostatic charging properties of olivine sand. A purpose-built rip has been developed to observe such charging tendencies for a range of suspension densities, conveying velocities and test materials. Tests involved the indirect observation and recording of charge on the particles at specific locations within the test pipeline.