Laboratory tests were performed to investigate the effects of sonic energy on the selective removal of ash-forming minerals from Illinois No. 6 coal. The net effect of exposure to sonic energy was elucidated by using wet-sieved narrowly sized coal samples free of undersize material loosely clinging to particle surfaces. A 10-kHz near-field array processor, configured for continuous rinsing of coal in the presence of sonic waves, was used. Results for sonically treated, then wet-sieved coal and the initial wet-sieved sample showed ash content removals ranging from 11.6 to 31.3% by weight, as a result of exposure to pulsed sonic energy for a 50-second total time of sonic treatment. Calculated recoveries of heating value ranged from 97.6 to as high as 99.8%, depending on the particle size of coal treated. Ash content of the sonically dislodged undersize material ranged from 55.0 to 86.9% by weight. Exposure to sonic energy also enhanced the floatability of Illinois No. 6 coal. Lower ash-content float fractions resulted from sonic pretreatment of the coal feed, compared to float fractions of wet-sieved coal not exposed to sonic energy. Separate tests with specific gravity fractions of Illinois No. 6 coal have shown that exposure to sonic energy promotes separation of coal-mineral composite particles.