AbstractThis article is the second in a series of articles (cf. Sundborg 1967) dealing with fluvial sediments and fluvial morphology and accounting for results of field research, experimental investigations and theoretical analyses conducted at the Geomorphology Laboratory in Uppsala. Black sand deposits in the valley of the river Luleälv are studied, and the hydrodynamical sorting and enrichment of heavy minerals is discussed. Grain size analyses and mineralogical analyses of heavy mineral samples have been performed. The mineralogical composition is discussed in connexion with a brief account of the general geological environment. Water velocities and grain size distributions, especially favourable for the enrichment processes are stated.