Industrial minerals processing has some demanding flow measurement requirements, which have not been adequately met by traditional flowmeter technologies such as electromagnetic or Doppler flowmeters. A new flow measurement principle that overcomes many of the disadvantages of the traditional approaches has been discovered and been placed into practice in over 152 processing plants. This technology is based on the combination of an axial array of passive sensors wrapped around the outside of the process pipe and powerful array processing algorithms to accurately determine the volumetric flow rate of most fluids including gases, clean liquids, and slurries as well as liquids and slurries with entrained air. The principle of operation will be described, along with examples of its proven ability to provide accurate, reliable flow measurements in hydrocyclone/screen feed lines, and the presence of slurry containing magnetic ore such as magnetite.