The lab and commercial tests have validated basic parameters of flow at locks of high capacity sluice box with riffles. The found relations between the Darcy coefficient, Reynolds numbers and Froude numbers allow obtaining balanced design and technology parameters for industrial sluice boxes of the type of PGSH-II-50.Placers are an important source of gold and other valuable minerals. It is currently achievable to enlarge gold extraction by involving gold placer waste dumps in production using advanced mining and processing technologies. The most wide-used equipment for gold extraction is sluice boxes (PGSh-30, PGSh-50 and PGSh-75) running in high capacity sluices to wash readily and moderate washable coarse gold. These sluices are only disadvantageous for high valuable mineral loss, especially if gold contains much clay. The main cause of the loss is irrational parameters of flow in the sluice boxes that are designed regardless, for instance, grade analysis of host rocks and screen analysis of gold. Solid to liquid ratio, inclination of the sluice boxes, etc. Also, it is required to take account of dominant size, fine or superfine, of gold in natural placers and spoil dumps.Theory of gravity gold washing allows reliable flow parameters in scrubbers [1][2][3][4][5], where sluice box feed definitely exclude sizes above 16-14 mm, while hydrohoist washing machine sluice admit sizes to 150 mm. with hard-washable gold, the loss in such sluices reaches 60% of the total output. This is explained by high variations in overflow, midflow and underflow velocities, as well as in vertical pulsed velocity, in the conditions of restrained movement of particles of different size rocks and metals.The settling process and place of different size and density particles depends on vertical distribution of average velocities of turbulent flow, which conditions the remoteness of the particles from sluice, on the one hand, and the particle settlement time, which is governed by ratio of the particle weight to the particle downward movement resistance, on the other hand. The downward movement resistance of particles depends on the vertical pulsed velocity of flow, that is expressed in terms of the flow average velocity [6][7][8]. Kinematics of the flow is connected with flow friction coefficient or Darcy coefficient, which depends on unevenness of an added artificial material, if any. So, mats and sheets placed in sluices are the increased roughness sources, and can work both as gold catchers and modifiers of the flow regime. At the same time, the Darcy coefficient is not the same at the same roughness but changes by Reynolds number and Froude number, and by S/L ratio in a suspended matter-carrying flow.Apparently, to calculate rational parameters of sluices, it is necessary to relate the changes in the Darcy coefficient by Reynolds number at different S/L ratio in the suspended matter-carrying flow given the sluices are equipped with grooved mats and sheets.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.