Australasian, European, Canadian and American geo-environmental specialists
have long been involved with pit lake studies in the physical processes and
dynamics as well as the geochemical aspects of these mitigation methods and
events. The use of pit flooding as an environmental post-closure option has
however been studied and used to a limited extent in Southern Africa and Africa to
a whole, with some recorded cases mostly being by accident rather than a
planned mitigation. This document is a written paper on a hydrogeochemical
investigation on the feasibility of flooding an open pit platinum mine in the
Bushveld Igneous Complex as a post-closure mitigation option.
Various data sets and sources were compiled and processed and served as input
data into a hydrogeochemical model of the expected impacts on the conceptual
meromictic pit lake environment. Weathering and speciation models allowed the
evaluation of the current system with thermodynamic and chemical reaction
processes leading to the hydrochemical composition of the groundwater as we
observe it in the field. Furthermore transient mixing simulations between
groundwater, surface water and rain water was allowed to occur under various
reducing and evaporative conditions. The modelled lake chemistry was then
evaluated against recreational, agricultural and domestic water use standards to
investigate the feasibility of the lake to be used post-closure.
Final recommendations and mitigation methods were proposed with the flooding
of the open pit as a post-closure option declared feasible. A final deliverable of
the study was a system thinking and modelling template for hydrogeochemical
modelling in various scenarios to guide other scientist through the process of
modelling fluid-rock, fluid-waste and fluid-fluid interaction.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-07162013-153548 |
| Date | 16 July 2013 |
| Creators | van Coller, André Abel |
| Contributors | Dr PD Vermeulen |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-07162013-153548/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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