Garnierite in nickel deposits of the Urals

Oxide-silicate ore deposits containing approximately 10% of Ni reserves of Russia are located in the Sverdlovsk, Chelyabinsk, and Orenburg districts of the Urals. Garnierite is among the most important industrial minerals of supergene nickel deposits. We studied this mineral in metasomatites and ores of the Cheremshan, Sinar, Elov, Sakhara, and Buruktal deposits based on the chemical, thermal, and X-ray phase analysis data. It is shown for the first time that garnierites of the Ural province are composed of both exogenous and hydrothermal mineral associations. The spatial distribution of minerals suggests that the hydrothermal association is a lateral and vertical (depth) continuation of mineralization in the Uralian supergene deposits. This conclusion widens significantly the scope of prospecting for new mineralized sectors in old deposits and the possibility of discovery of new deposits.     

Platinum Group Metals and Gold in Supergene Nickel Ores of the Moa and Nikaro Deposits (Cuba)

Contents of PGE and Au in nickel oxide-silicate ores of the Moa and Nikaro deposits, as well as their reworking products in the Moa and Nikaro ore metallurgical plants, have been determined.     

Platinoids and Gold in Oxide–Silicate Nickel Ores of the Buruktal and Ufalei Deposits in the Urals

Contents of platinum group elements (PGE) and gold in oxide–silicate nickel ores of the Buruktal and Ufalei deposits are determined. Mineral phases of PGE and Au in ores of the Ufalei deposit are observed as native palladium, Pd-platinum, native platinum, and native gold (fineness 948).     

Distribution and Genesis of Platinum Group Minerals in Nickel Ores of the Sakhara and Elizavet Deposits in the Urals

Nickel and iron–cobalt ores from weathering crusts on ultramafic massifs in the Urals contain elevated PGE concentrations. Platinum group minerals first found in weathering crusts in Russia are primarily represented by Pt-palladium, native platinum, and compounds of Pd and Pt with Bi, Sb, and Te. Platinum group elements are characterized by a high differentiated mobility in the weathering profile. This is manifested by a difference in values of the PGE accumulation coefficient and a spatial separation of local accumulation zones of different PGE. This is also experimentally confirmed by different values of the PGE solubility in natural waters. An important factor of the formation of PGE-rich zones in weathering crusts at the Sakhara and Elizavet ore deposits is their substrate represented by the Sakhara and Uktus massifs of the Ural Platinum Belt. It is supposed that geochemical barriers for the PGE concentration in these weathering crusts were provided by the iron oxide zone and horizons enriched in manganese minerals.