The Prospecting Value of the Fractional Granulometric Analysis in the Study of Diamond-Bearing Placers

The article presents the novel data of fractional granulometric testing on the Syuzevskaya diamond placer located in the northern part of the Chikman-Nyar depression. The geological section was studied to a depth of 42,0 m. 18 samples weighing up to 200 kg each were taken, selected sectionally at two-meter intervals and graded into 10 granulometric classes on the gamma-Baturin scale. The obtained results have important search value: 1) the curve of the debris distribution by size is typical for the mature alluvium of the foothill river; 2) the paleo river alluvium is formed by a high dynamics flow and is fairly well sorted by size, which is a favorable sign for the concentration of large diamonds and indicates a slight dilution with non-diamond-bearing detrital material; 3) the presence of a typical mature alluvium in the paleovally indicates a long time of its existence, which is also a favorable search sign for industrial diamond placers. The methodology and results of the study can be used at various stages of the exploration cycle for placer minerals, including diamonds, all over the world.