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Victor Subbotin, Geological Institute, Kola Science Centre RAS (Russian Federation)
Alexey Korchagin, JSC PANA (Russian Federation)
Dmitry Gabov, JSC PANA (Russian Federation)
Evgeny Savchenko, Geological Institute, Kola Science Centre RAS (Russian Federation)
Egor Nozdrja, ÑJSC Fedorovo Resources (Russian Federation)
Sergey Mineev, UralPlatinum Holding Ltd. (Russian Federation)
Pavel Korchak, JSC PANA (Russian Federation)
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PGE-bearing mineralization of low-sulphide type (0,5-5% base metal sulphides) in different structural units of the Fedorovo-Pansky intrusion is confined to anorthosite, gabbro, taxitic gabbronorite, norite, pyroxenite and harzburgite of various stratigraphic levels of the rock sequence (Northern and Southern PGE reefs of the Western Pana block, and Layered Horizon of the Eastern Pana block) and to the zones of igneous breccia (Fedorova Tundra block). The detailed mineralogical research of the ore composition has revealed 48 PGE minerals and unnamed phases, and defined their relative abundances for each block. The chemical composition of the minerals has been analyzed at SEM/EDS and microanalyzer in a few hundreds of polished sections for each deposit. The size of the analyzed grains varies from 2-3 to 680 m.
All the blocks are characterized by the prevalence of Pd and Pt tellurides and sulphides, e.g. kotulskite, merenskyite-moncheite and vysotskite-braggite in the ore.
In the Fedorova Tundra and Northern PGE Reef, Pd and Pt tellurides predominate over Pd and Pt sulphides, and bismuthides and stannides, such as sobolevskite, michenerite, froodite, paolovite, atokite, rustenburgite, are quite common. The platinum-group arsenides are represented by sperrylite, stillwaterite, palladoarsenide, menshikovite, vincentite, and palladobismutharsenide.
The Eastern Pana block displays the prevalence of vysotskite and braggite over tellurides and a sharply increased role of arsenides (sperrylite, stillwaterite, palladoarsenide) in the zones of intense hydrothermal alteration of the primary ore. The main mineral of the Southern PGE Reef within the studied area is vysotskite. However, one can also find here keithconnite among common tellurides. In addition, palladium, hongshiite, skaergaardite, zvyagintsevite, vasilite, laflammeite, laurite, and cuprorhodsite are more frequently observed here in comparison to the other deposits of the intrusion.
The composition of the most unnamed phases found in the deposits of the Fedorovo-Pansky intrusion roughly corresponds to the following formulas: (Re,Cu,Pt)S2, (Pd,Ag)4S, Pd2-x(Bi,Pb)(S,Se), (Pd,Au)2+x(As,Sn), Pt5Te7, Pd3As0.5Te0.5, Pd5Ge2, and Pd3(Ge,Te).
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