Mining Institute, Far Eastern Branch of RAS (Khabarovsk, Russia):

Alekseev V. S., Senior Researcher, Candidate of Engineering Sciences, alekseev.igd.khv@mail.ru
Seryy R. S., Senior Researcher, Candidate of Engineering Sciences
Sobolev A. A., Senior Researcher, Candidate of Engineering Sciences

An increasing number of placer deposits are being developed, with their sands containing significant amounts of fine and thin gold. The processing of such sands in sluice box-type devices inevitably causes excessive losses, which may only be reduced through the upgrades of respective obsolete process equipment or its replacement with advanced sluice boxes and processing facilities. When the processing equipment fails to meet the operating conditions, it demonstrates lower performance or gold losses reaching 40–50 %. The studies conducted for the initial sands and fine-grained tailings, in combination with the analysis of operation of a PGSh-50 type sluice box at the placer deposit on the Langeri River (Sakhalin region), allowed identifying the key factors leading to increased losses of fine gold. It has been established that the gold of the deposit rates as fine and very fine, its modal size does not correspond to the hydraulic size and, in hydromechanized sluicing, its losses exceed the standard values. Based on the results obtained, the sluice box was upgraded as follows: the perforated metal disseminating surface was replaced with polyurethane slotted screens; for the uniform and controlled supply of the undersize material, hoppers with a gate valve were installed on the shallow-filling sluice; polyurethane covers are used as collectors on the shallowfilling sluices. The upgrade enabled increasing the recovery of fine and thin gold by 20–26 % and reducing the overall losses by 5%.

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