Study on migration of gold particles in technogenic sands of placer deposits

Abstract

Technogenic placers are characterized by a chaotic distribution of gold and other valuable components, which restricts their industrial mining for gold. The development of an effective mining method for technogenic placers is therefore of great national economic importance. The study is aimed at creating a new type of technogenic placer deposits with high gold grade zones, to be formed through the preferred vertical migration of high-density particles under the influence of natural and industrial factors. The resulting enriched zone shall have higher gold grades as compared to the original technogenic mass, with a thickness equal to 45–60 % of the thickness of the technogenic placer. This will reduce the volume of sand to be washed and significantly cut the related operating costs. This technology will allow mining technogenic placer deposits that have been previously considered unprofitable. The study is aimed at finding the optimal parameters of rock mass cyclic flooding and drainage that would ensure the most intensive migration of gold particles, as well as at assessing the effect of rock mass grain-size distribution on the intensity of gold migration. The data obtained facilitate a significant expansion in the theoretical knowledge on gold particle migration and identification of migration intensity patterns for various gold particle sizes, depending on the seepage flow parameters and mining and geological characteristics of the rock mass in respective technogenic placers.The work was carried out with the financial support of Government of the Khabarovsk Territory under the program «On the provisionof grants in the form of subsidie s from the regional budget for the implementation of projects in the field of scientific research in the direction of natural, technical, humanitarian and social sciences».The research was carried out using the resources of the Center for Collective Use of Scientific Equipment «Center for Processing and Storing Scientific Data of the Far Eastern Branch of the Russian Academy of Sciences», funded by the Ministry of Science and Higher Education of the Russian Federation under project No. 075-15-2021-663.Experimental studies, sample preparation, determination of gold content were carried out on the basis of the Center for Collective Use «Center for Research of Mineral Raw Materials» of the Khabarovsk Federal Research Center of the Far Eastern Branch of RAS.