Composite mineral particles in a monolayer were X-ray radiographed with monochromatic beams at different incident energies. The digital radiographic images were subtracted according to the dual-energy (DE) principle, which is extended to multiple-energy (ME) for the purpose of this work. The subtraction allows the selective derivation of two images thicknesses, one for each mineralogical phase component. The integration of the thickness gives the volumetric content in the phase. Preliminary experimental results were compared to the grade obtained by micro-CT, showing good agreement. The possible developments related to the fast DE evaluation of particle grades are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.