Native gold ores

The technological loss of Au on gravitational separation of Au-bearing ores of Bamskoe deposit (Baikal district, Russia)

N.S. Rudashevsky, Yu.L. Kretser

1. Sample 53 – Au gravitational concentrate, Au ~60 ppm
2. Sample 43 – tailings from gravitational processing, Au 2 ppm.

Au and Ag minerals in heavy concentrate of the sample 53; SEM images (BIE)

Au — native gold, PTZ — petzite, HS — hessite, PY — pyrite, AIK — aikinite, GN — galena, CT — calcite


Grain sizes of gold minerals of different technological products of Au-bearing ores, Bamskoe deposit (Baikal district, Russia)

a and b - histograms, c and d - lognormal probability plots


Grains of Au minerals from heavy concentrate of tailings after gravitational processing (1-19), SEM image (BIE).

Au — native gold, PTZ — petzite, HS — hessite, PY — pyrite, Q — quartz, PO — pyrrhotite, TiO2 — rutile.


Native-gold-PGM heavy concentrate (HS-concentrate of native gold + PGM=97.6%), received by HS-concentration of the “black sand” sample (Sotajoki, Lapland. b — detail of a).


Matrix mineral phases of the "black sand" sample

ILM — ilmenite, MT — magnetite, MNZ — monazite, ZRN — zircon, ALM — almandine, WT — ferrowolframite, PL — plagioclase, Q — quartz.


Grains of native gold in the sample of "black sand";

a-h — volume grains; i-k — polished sections of gold grains (AuI and AuII — different generations of native gold).


Sperrylite crystals separated from heavy concentrate of the "black sand" sample by hand

c-d — polished section from crystals (SP — sperrylite, BT — biotite, PO — pyrrhotite).


Different shape of crystals and grains of sperrylite (a-l) in the "black sand" sample.

SP — sperrylite, MC — mica.


Different PGMs (apart from sperrylite) from the "black sand" sample.

a-b — grains of Pt-Fe alloy, c — grain of isomertieite, d-i — grains of cooperite (e — detail of d; h — detail of g); MLN — inclusion of malanite.