The purpose of the study is to investigate the influence of flooding on underground coal mines.
Two case studies were investigated the shallow underground Klibarchan coal mine and the
deep underground Usutu mine. Kilbarchan colliery is located 10 km south of Newcastle in
KwaZulu/Natal. It comprises two underground sections, called Roy Point and Kilbarchan. Usutu
colliery is situated just 8 km outside the town of Ermelo in Mpumalanga, close to Camden power
station on the N2 road to Piet Retief. The geology of both studies lies within the Karoo Group,
Ecca subgroup in the Vryheid formation. Higher precipitation at Usutu and Kilbarchan occurs in
the summer months, while Kilbarchan has a higher annual rainfall of 864 mm/a compared to
Usutuâs 705 mm/a.
The water levels at both mines yielded interesting findings. Usutu mine is compartmentalized
with walls in the underground. These walls are so strong that they function as âlow pressureâ
seals resulting in compartmentalized underground, withstanding the huge pressures created by
the recharged groundwater. This causes water levels to differ in the underground. Water levels
at Kilbarchan mine vary in depth, but when plotted in metres above mean sea level (mamsl)
they plot in a straight line. Regional recharge at Usutu was calculated as 5.7 % and 11.3 % at
Kilbarchan. Recharge is influenced by what type of mining activity was practised in that specific
area. It was concluded that recharge on opencast is between 15 to 20%, the stooped area
between 10-15% and in an underground shallow mine it could be as high as 10%.
Mining activity ceased in 1992 at Kilbarchan. Pumping is a common practice at flooded
underground mines, because the mine needs to be filled with water on an ongoing basis. This
prevents sulphate generation and the water quality from deteriorating. Pumping at Usutu is well
managed and flushing started to occur in the underground with the electric conductivity
improving over time. Pumping at Kilbarchan is poorly managed and over pumped. The electric
conductivity over time, is not improving indicating that oxygen infiltrates the system when too
much pumping occurs. Bord-and-pillar mining followed by stooping has been the main mining
method. At Usutu mining activity ceased in the late 1980 and then the mine was flooded.
It is finally there is concluded that an underground should be flooded as quickly as possible and
then managed well. Shallow underground mines have a higher potential of contamination,
because of a shorter residence time. The depth of mining, topography, mining methods, water
levels, exposure to oxygen, rainfall, recharge, residence time and pumping have an influence on
the effects of a flooded coal mine.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-05312013-124333 |
| Date | 31 May 2013 |
| Creators | van Zyl, Nicolaas Lessing |
| 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-05312013-124333/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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