The contents of the fly ash hopper are pneumatically conveyed to a fly ash storage silo. The silo is emptied onto trucks that then haul the material off for use in other applications. Fly ash derived from burning coal creates a very dusty environment and tends to stick, creating build-up inside the silo. Fly ash silos are typically very large to allow continuous flow from the hoppers. Density and dielectric constant of fly ash is low. Users need to continuously monitor the amount of fly ash inside the silo so that it can be emptied on time, maintained, and cleaned when necessary.