Justification of physicochemical geotechnologies for polymorphic gold placers

Gold placers currently being mined contain various forms of gold in productive sand, and many such forms are difficult to recover by gravity separation, for instance, fine, flake and encapsulated gold particles. In the Far East of Russia, some placers hold commercial concentrations of chemically bound gold in aleurite fraction in productive sand and in schlich minerals. Sluicing of sand with such forms of gold occurrence can bring gold losses up to 40–50%, and even the advance centrifugal concentrators prove unequal to the task. For this reason, in mining of polymorphic gold placers with high content of gold forms unrecoverable using gravity separation methods, it is required to include leaching processes, both as in-situ leach of productive sand and in combination with the conventional mining and processing techniques. Investigation of one of such polymorphic gold placers, with largely different occurrence conditions of productive sand–Bolshoi Delegennyakh–Neverny placer—with a view to estimating feasibility of physicochemical geotechnologies used the integrated mineralogical and geochemical analysis of original samples and sluice box tailings samples, including electron microscopy and the local X-ray spectral analysis. The analytical results are reported in this article. Moreover, the article offers a theoretical justification of parameters and modes for activation leaching of difficult-to-recover gold forms using non-cyanide solutions, and the results of the experimental research of activation percolation and agitation leaching of samples of the Bolshoi Delegennyakh–Neverny sand and sluice box tailings. From the evidence of the research, the mixed-type process flowsheets are proposed for processing the test placer gold, including gravity separation and sluicing of gold sand, with the further box and tank leaching of fine, flaky and encapsulated gold particles, in combination with the deep-level in-situ leaching. 

Sekisov A. G., Byankin M. A., Alekseev V. S., Rasskazova A. V. Justification of physicochemical geotechnologies for polymorphic gold placers. MIAB. Mining Inf. Anal. Bull. 2026;(9):5-20. [In Russ]. DOI: 10.25018/0236_1493_2026_9_0_5.

The study was supported by the Russian Science Foundation, Grant 
No. 24-17-20026, https://rscf.ru/project/24-17-20026/, and by the Ministry of Science and 
Education of the Khabarovsk Krai, Agreement No. 109S/2024. The research was performed using resources of the Shared Use Center for Minerals Research supported by the Ministry of Science and Higher Education of the Russian Federation, Agreement No. 075-15-2025-621. 

A.G. Sekisov¹, Dr. Sci. (Eng.), Deputy Director for Research, e-mail: sekisovag@mail.ru, ORCID ID: 0001-0001-5780-6150,
M.A. Byankin¹, Graduate Student, e-mail: maxbyanich@gmail.com, ORCID ID: 0009-0006-2632-585X,
V.S. Alekseev¹, Cand. Sci. (Eng.), Deputy Director for Research and Innovation, e-mail: alekseev.igd.khv@mail.ru, ORCID ID: 0000-0002-8248-105X,
A.V. Rasskazova¹, Cand. Sci. (Eng.), Leading Researcher, e-mail: annbot87@mail.ru, ORCID ID: 0000-0002-6998-8120,
¹ Institute of Mining of the Far Eastern Branch of the Russian Academy of Sciences, a separate division of the Khabarovsk Federal Research Center of the Far Eastern Branch of the Russian Academy of Sciences, Khabarovsk, Russia.

A.G. Sekisov, e-mail: sekisovag@mail.ru.

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