Abstract: Improved methods of screening particulate matter are disclosed. For example, aqueous mineral slurries containing at least 10 weight percent of finely divided mineral solids are mechanically size separated using vibratory screening and a self propelled recirculative rotating spray bar, prior to, and subsequent to various processing steps. The employment of the spray bar improves the screening process by preventing blinding of the screen, as well as increasing throughput. As a result this invention reduces screen residues and/or increases production rates significantly.