Determination of Precious Metals in Geological Samples from Four Gold Ore Deposits of the North-East of Russia

Compositions of rare mineral phases containing precious metals (PMs) in samples from Natalka, Pavlik, Vetrenskoe, and Degdekan gold ore deposits (North-East of Russia) are studied by scintillation atomic emission spectrometry (SAES) and electron probe microanalysis (scanning electron microscopy and electron probe X-ray microanalysis, SEM–EPMA). The SAES method found dozens and hundreds of particles carrying gold, silver, and all platinum-group elements as native metals, intermetallides and solid solutions, arsenides, antimonites, sulfoarsenides, tellurides, selenides, etc. The variety of the elemental compositions of PM species (mineral phases) found by SAES significantly exceeds the list of minerals found previously by SEM–EPMA because of different natures of optical and X-ray spectra. The sizes of PM particles calculated by the SAES method and measured by SEM–EPMA are similar. The SAES data on the total concentrations of PMs satisfactorily agree with the results of inductively coupled plasma mass spectrometry.