Mineralogical distribution of trace platinum-group elements in the disseminated sulphide ores of Noril'sk 1 layered intrusion

Abstract

The mineralogical distribution of Pd, Rh and Ru was determined in three small samples of disseminated ore from the layered Medevezhiy Ruchei Ni–Cu–platinum-group element mine, Noril'sk 1 layered intrusion, Siberia. The three samples were taken from a cross-section of the deposit ranging from the uppermost part of the picrite horizon (chill zone) through the main picrite horizon to the lower taxitic gabbro dolerites. Different microanalytical techniques were used to determine the major- and trace-element species as well as the abundance of major, minor and trace minerals. The results indicate that Pd is concentrated mostly in pentlandite and less in the platinum-group minerals (PGM). In the uppermost part of the picrite horizon about 67% of the Pd occurs in pentlandite, whereas only 30% occurs in the PGM. About two-thirds of the Rh is found in pyrrhotite; the second carrier of importance for Rh is pentlandite. The Ru distribution is more variable between the three samples, but about one-third of the Ru is carried by pentlandite, the remainder being distributed in variable amounts in pyrrhotite, chalcopyrite and pyrite. Knowledge of the platinumgroup element distribution is important for economic evaluation of the mineralization and for efficient metal recovery.