Numerical modelling of gold transport and deposition
Date
2015-06-29
Authors
James, Christophe Stephen
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A pair of mathemat .cal model? are preje. id : >r .. ir
lating the hydraulic transport and depc it.on of go .
in fluvial systems such as existed durL.g the formation
of Witwatersrand reefs. The first model describe
transverse distribution of suspended p rtic oxer
plain areas adjacent to channels whii th* eccr :
describes the longitudinal distribution within i channel.
These models enable the distr ibut ion patte-r
gold deposits to be related deterministically
channel geometry and the hydraulic 1: • :
ing during reef formation.
The gold now present in the reefs v. , * ransported
mainly in suspension. This is confirmed by showing that
the hydraulic conditions required to mobilize the
largest quartz particles in a typica- reel samp.e are
easily capable of suspending typical gold particles.
Deposition patterns of gold are therefore closely
related to the distribution of gold particles in
suspension, which car be described iy the diffusion
analogy.
The transverse movement of suspended particles from a
channel over an adjacent inundated plain is described
by a --vo-dimensi x-nal elliptic partial differential
equation which accounts for transport by diffusion and
convection in the vertical ind transverse directions.
This equation is solved in finite difference form for
steady, longitudinally uniform flow conditions.
The transverse model is verified by comparing predicted
and measured distributions c ‘ fine sand deposits in a
laboratory flume with a compound section. The model is
applied to hypothetical situations to determine which
factors have the greatest influence on the extent and
variation of plain deposits. Several gold distributions
Description
A thesis submitted to the Faculty of Engineer vng,
University of the Witwatersrand, Johannesburg for the
degree of Doctor of Philosophy.
Johannesburg, 1984