About micro- and nanoscale gold in the veil of gold-bearing territories (on the example of a mineralization site in the basin of the river Adamikha, Amur region)

The article identifies the problem of the need to take into account micro-(1 mm to 0.12 microns) and nanoscale (<0.12 microns) gold in placers and weathering crusts in order to increase the objectivity of their and eroded ore objects potential assesment. The results of technological studies of gold-bearing deluvial deposits in the valley of the Adamikha river basin (Amur region) are presented. A quantitative assessment of the content of micro-and nanogold by fractions of loose material was made. It was found that in the studied sample of such material (weighing 50 kg), the major part (78%) refers to native gold with a dimension of <0.12 microns. Including 0.1% is in concentrator minerals, and 3.5% of the fraction (<3 microns), probably colloidal, is in technical solutions of wet sieve. Moreover, 3/4 of the total amount (18% visible and 57% invisible) of gold is concentrated in the fraction (1-0.5 mm). It is established that, taking into account the free invisible gold, the resources of the precious metal of the object under study increase by 3.4 times. The possibility of a more objective quantitative assessment of the Au potential of promising areas, taking into account the content of fine gold, is shown. Possible ways of solving the problem of a more reliable assessment of geological reserves and estimation of forecast gold resources, taking into account the knowledge of the quantities of micro-and nanoscale fractions, are proposed. The authors believe that studies of the forms of allocation and distribution, including invisible (<0.12 microns) gold in placers and weathering crusts will contribute to a more correct assessment of the studied gold-bearing objects and territories with the possibility of increasing the real resource potential of the precious metal in the region.