a study was conducted to understand the adsorption of n-hydrocinnamoyl-n-phenylhydroxyl-amine (hcnpha) on the surfaces of various pure minerals: sphalerite, pyrite, galena, chalcopyrite and quartz. hcnpha is a member of the n-arylhydroxamic acids that are good base metal mineral collectors. hcnpha was selected because it was reported to give the most promising results as compared to other arylhydroxamic acids.