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Occupational exposure to radon in a South African platinum mine / M. Schoonhoven.Schoonhoven, Martin January 2012 (has links)
Background: The Platinum mining operations in South Africa mining platinum containing ore from areas where variable amounts of uranium are found, leading to the possibility of occupational exposure to the radioactive disintegration products of Uranium-238 and in particular the gas Radon-222. No scientific data is available for occupational exposure to Radon-222 in South African platinum mining operations. Objective: To determine the risk of occupational exposure to the radioactive disintegration products of naturally occurring Radon-222 gas in a South African platinum mine. Design: Quantitative sampling (personal and static) to establish baseline data on exposure to radioactive disintegration products of naturally occurring Radon-222 gas in a underground South African platinum mine. Setting: The Bafokeng Rasimone platinum mine located 30 km North West of Rustenburg in the Bushveld complex in the North West Province of South Africa. Study subjects: One hundred and seventy four potentially highest exposed underground employees and one hundred and twelve static underground samples were sampled. Method: Personal and area samples were taken on selected employees and in locations using RGM samplers using CR-39 plastic as a detection medium. Employees were selected to sample the highest exposed occupations and static samples were located to sample returning air from levels underneath the sampling point before it is exhausted to the above ground atmosphere. After analysis by an accredited laboratory, the results were converted to exposure following the National Council on Radiation Protection-78 methodology. Main outcome measures: Quantify the relative risks of potentially highest exposed employee`s exposure to the radioactive disintegration products of naturally occurring Radon-222 gas in underground working areas in milliSievert per year. Results: The mean reference background exposure averaged 0.6168 mSv/a with underground personal exposure averaging 0.6808 mSv/a, and underground static exposure averaging 0.8726 mSv/a. These values are substantially below the 50 mSv/a Occupational Exposure Limit, and only pose a slightly elevated risk for the development of lung cancer above the normal back-ground exposure. Mining Team leaders and rock drill operators were identified as the potentially highest exposed employees due to the close proximity to the working face, large amounts of time spent close to the working face and the lower ventilation volumes at the working face, with Team leaders having the highest exposure of the sampled occupations with a average of 1.16 mSv/a. Conclusions: Occupational exposure to radioactive disintegration products of naturally occurring Radon-222 gas in the underground air of a South African platinum mine does not pose a significant risk to the health of employees working in the platinum mine. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.
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Development of a dynamic centrifugal compressor selector for large compressed air networks in the mining industry / Johan Venter.Venter, Johan January 2012 (has links)
Various commercial software packages are available for simulating compressed air
network operations. However, none of these software packages are able to
dynamically prioritise compressor selection on large compressed air networks in the
mining industry.
In this dissertation, a dynamic compressor selector (DCS) will be developed that will
actively and continuously monitor system demand. The software will ensure that the
most suitable compressors, based on efficiency and position in the compressed air
network, are always in operation. The study will be conducted at a platinum mine.
Compressed air flow and pressure requirements will be maintained without
compromising mine safety procedures. Significant energy savings will be realised.
DCS will receive shaft pressure profiles from each of the shafts’ surface compressed
air control valves. These parameters will be used to calculate and predict the
compressed air demand. All pipe friction losses and leaks will be taken into account
to determine the end-point pressure losses at different flow rates. DCS will then
prioritise the compressors of the compressed air network based on the overall
system requirement.
This software combines the benefits of supply-side and demand-side management.
Potential energy savings with DCS were proven and compressor cycling reduced. A
DCS user-friendly interface was created to easily set up any mine’s compressed air
network. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013
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Occupational exposure to radon in a South African platinum mine / M. Schoonhoven.Schoonhoven, Martin January 2012 (has links)
Background: The Platinum mining operations in South Africa mining platinum containing ore from areas where variable amounts of uranium are found, leading to the possibility of occupational exposure to the radioactive disintegration products of Uranium-238 and in particular the gas Radon-222. No scientific data is available for occupational exposure to Radon-222 in South African platinum mining operations. Objective: To determine the risk of occupational exposure to the radioactive disintegration products of naturally occurring Radon-222 gas in a South African platinum mine. Design: Quantitative sampling (personal and static) to establish baseline data on exposure to radioactive disintegration products of naturally occurring Radon-222 gas in a underground South African platinum mine. Setting: The Bafokeng Rasimone platinum mine located 30 km North West of Rustenburg in the Bushveld complex in the North West Province of South Africa. Study subjects: One hundred and seventy four potentially highest exposed underground employees and one hundred and twelve static underground samples were sampled. Method: Personal and area samples were taken on selected employees and in locations using RGM samplers using CR-39 plastic as a detection medium. Employees were selected to sample the highest exposed occupations and static samples were located to sample returning air from levels underneath the sampling point before it is exhausted to the above ground atmosphere. After analysis by an accredited laboratory, the results were converted to exposure following the National Council on Radiation Protection-78 methodology. Main outcome measures: Quantify the relative risks of potentially highest exposed employee`s exposure to the radioactive disintegration products of naturally occurring Radon-222 gas in underground working areas in milliSievert per year. Results: The mean reference background exposure averaged 0.6168 mSv/a with underground personal exposure averaging 0.6808 mSv/a, and underground static exposure averaging 0.8726 mSv/a. These values are substantially below the 50 mSv/a Occupational Exposure Limit, and only pose a slightly elevated risk for the development of lung cancer above the normal back-ground exposure. Mining Team leaders and rock drill operators were identified as the potentially highest exposed employees due to the close proximity to the working face, large amounts of time spent close to the working face and the lower ventilation volumes at the working face, with Team leaders having the highest exposure of the sampled occupations with a average of 1.16 mSv/a. Conclusions: Occupational exposure to radioactive disintegration products of naturally occurring Radon-222 gas in the underground air of a South African platinum mine does not pose a significant risk to the health of employees working in the platinum mine. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.
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Persistent organic pollutants (POPs) associated with a platinum mine in the Limpopo Province, South Africa / Ilse JordaanJordaan, Ilse January 2005 (has links)
South Africa ratified the Stockholm Convention (SC), which became legally binding on 17
May 2004. This Convention targets 12 particularly toxic persistent organic pollutants (POPs)
for virtual elimination. The Convention also requires parties to reduce the release of
organochlorine pesticides and the intentionally- and unintentionally-produced POPs such as
dioxins, furans and polychlorinated biphenyls (PCBs) (referred to as dioxin-like chemicals).
Dioxins are a heterogeneous mixture of chlorinated dibenzo-p-dioxins and dibenzofurans
(PCDD/Fs) congeners. These substances were never intentionally produced but are produced
as by-products of industrial processes (such as metallurgical processes and bleaching of paper
pulp). They can also be formed during natural processes such as volcanic eruptions and forest
fires. The largest contributor to releases of PCDD/Fs in the environment is incomplete
combustion from waste incinerators leading to the unintentional production of these
compounds. Polychlorinated biphenyls (PCBs) are used in transformers and capacitors, but
can also be formed unintentionally during industrial and thermal processes. Dioxin-like
chemicals (PCDD/Fs and/or PCBs) are classified as persistent because of the following
characteristics: lipophilicity and hydrophobicity; resistance to photolytic, chemical and
biological degradation and they are able to travel long distances. As South Africa is a semiarid
region, POPs will be less prone to travel here because these substances favour colder
regions with high soil organic matter.
Fish, predatory birds, mammals (including humans) absorb high concentrations of POPs
through the process of bio-concentration, leading to bio-accumulation of these substances in
the fatty tissue. PCDD/Fs occur as unwanted trace contaminants in air, water, land, in
residues and products (such as consumer goods e.g. paper and textiles). The distribution of
these chemicals into various matrices is problematic since they cause damage to the
environment and human health. These chemicals pose a threat to human health when found
in high concentrations that may lead to acute hepatoxicity and dermal toxicity (chloracne).
Long-term exposure to low concentrations of these substances might lead to chronic effects
such as reproductive problems and carcinogenicity.
Since ferrous and non-ferrous metal production is a source of dioxin-like chemicals, a
platinum mine in the Limpopo Province, South Africa, was selected for this investigation.
The aim of the study was to determine if there are dioxin-like chemicals associated with
platinum mining and processing, and if the H4IIE reporter gene bio-assay could be used to
semi-quantify and assess the potencies of the complex environmental and process samples by
determining their Toxic Equivalency Quotients (TEQ). The implications of the sources to the
formation of dioxin-like chemicals regarding the SC were investigated and recommendations
were made to improve this study.
Samples were collected from tailings dams, woodchips, a dumpsite and slag from the smelter
at Union Section. Samples were extracted with the Soxhlet apparatus using hexane as
solvent. The percentage total organic carbon (%TOC) was determined for each sample to
normalise the data. The method used was the Walkley-Black method.
In determining the TEQ of each sample, the H4IIE luc cell line was used. The cells of the
H4IIE luc line are genetically modified rat hepatoma cells stably transfected with a luciferase
firefly gene. The luciferase gene is activated by the presence of dioxin-like compounds and
the concentration of the enzyme is measured as relative light units (RLUs). The amount of
RLUs is directly proportional to the dioxin load in the extract. This method is rapid, cost and
time-effective in determining the TEQ when compared to chemical analysis.
The TEQ2o-valuesin the various samples, as determined with the H4IIE luc cell line, ranged
from 0.007 ngTEQ/kg to 54.06 ngTEQ/kg. Thermal processes at the smelter, sorption of
hydrophobic organic compounds (HOCs) to soil and tailings, and external sources such as
anthropogenic activities contributed to high TEQ2o-values. Climatic conditions, wind,
precipitation, and solubility of HOCs into surfactants lead to low TEQ20. The smelter at
Union Section had a very high TEQ20of 44.62 ngTEQ/kg compared to Impala Platinum mine
(5.15 ngTEQ/kg). This implies that workers at Union Section are possibly exposed to low
and high concentrations of dioxin-like chemicals. Long-term exposure to these compounds
could lead to bio-accumulation in the fatty tissue of the mine workers, leading to chronic
effects such as reproductive problems and cancer. The air emission of the furnace at the
smelter was 0.03 gTEQ/annum and the release of the PCDD/Fs into the slag was 0.60
gTEQ/annum. By effectively managing the smelter it is possible to reduce the TEQ.
The TEQ of each sample increased due to normalising the data. The normalised TEQ20
ranged from 0.94 ng TEQ/kg to 42497.48 ngTEQ/kg.
Dioxin-like chemicals are present on a platinum mine, but at varying quantities and the effects
of these compounds might be detrimental to the environment and the workers at the platinum
mine. Further analyses of the health impacts associated with the platinum mine are needed.
The H4IIE reporter gene bio-assay could be used to effectively determine the TEQ of each
sample. Although this investigation has identified the formation and presence of dioxin-like
chemicals at certain stages of mining and processing, not all of the processes were
investigated. Some of these processes have the potential to add, and even destroy, these
chemicals, affecting potential human exposure and amounts released to the environment.
This, however, requires further investigation.
The financial assistance of the National Research Foundation (NRF) towards this
research is hereby acknowledged. Opinions expressed and conclusions arrived at, are
those of the author and are not necessarily to be attributed to the NRF. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2006.
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The geometallurgical characterization of the Merensky Reef at Bafokeng Rasimone Platinum Mine, South AfricaSmith, Albertus Johannes Basson 08 October 2014 (has links)
Ph.D. (Geology) / Please refer to full text to view abstract
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A geological, petrological and mineralogical study of the UG3 chromitite seam at Modikwa Platinum Mine : significance to exploration and PGE resourcesMachumele, Nkateko Jones January 2014 (has links)
The UG3 at Modikwa Platinum Mine occurs as a platiniferous, planar chromitite seam. It is stratigraphically located in the Upper Critical Zone of the Eastern Bushveld Complex. Field work study comprise of underground mapping, sampling, surface mapping, borehole core logging, microprobing and microscopic investigations carried out at the Rhodes University. The UG3 at the Modikwa Platinum Mine is about 22cm thick chromitite seam underlain by a white fine grained anorthosite and overlain by a brown medium grained feldspathic pyroxenite. It is an incomplete cyclic unit consisting of chromite and feldspathic pyroxenite. The UG3 reef at the Modikwa Platinum Mine lease area represents a Platinum Group Metal resource of 300 million tons of ore at an in situ grade of 2.5g/t. Under the current market conditions the UG3 reef remains unprofitable to mine in an underground operation due to the operational cost involved. However, it has been illustrated that the UG3 chromitite seam can increase profit margins in an open pit operation provided it is mined together with the economic UG2 chromitite seam. The extraction of the UG3 as ore in the four Modikwa UG2 open pits would result in a combined operating cash profit of R330 million. The UG3 chromitite seam is platiniferous. The platinum-group minerals (PGM) range in size from less than 10μm to about 70μm. The PGMs are associated with sulphides and are both located in the interstitial silicates and are concentrated in the chromitite seam. The PGMs show a strong preference to contact boundaries of the silicate grains, the chromite grains and the sulphide phases. In some instances, they are enclosed within the chromite grains in association with sulphides. The general sulphide assemblage comprises pentlandite and chalcopyrite whereas, the PGMs assemblage comprises cooperite, ferroplatinum, laurite, FeRhS and PtRhS.
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Characteristics and mineralisation of platinum-group elements (PGE) in the upper group 2 chromitite (UG2) and merensky reefs at the Buffelshoek farm , Two rivers platinum mine: implications for platinum-group elements recoveryPheeha, Lesetja Charles. January 2022 (has links)
Thesis (M.Sc. (Geology)) -- University of Limpopo, 2022 / The Two Rivers Platinum Mine (TRP) located in the Eastern Bushveld Igneous
Complex is currently exploiting platinum-group elements (PGE) in the Upper Group
2 chromitite (UG2) Reef at the Dwarsrivier Farm. TRP has acquired a new prospect
(at the Buffelshoek Farm) and is currently planning to mine the UG2 Reef and
potentially also the Merensky Reef (MR). Three drill-cores which intersected the UG2
Reef and MR at the Buffelshoek Farm made available by TRP were sampled for
mineralogical studies using complementary techniques including reflected light
microscopy, mineral liberation analyser and electron microprobe. The platinum
group minerals (PGM) which host the PGE exhibit variability in their flotation rates
and consequently variable PGE recoveries that is mostly attributed to the not so well
understood PGM distributions and characteristics.
The purpose of the study was to investigate the PGE process mineralogical
characteristics such as the PGM phases, their modal abundances and mineral
associations, as well as the grain size distributions within the UG2 Reef and MR at
the Buffelshoek Farm. The observed PGM phases are broadly grouped into PGE
sulphides, PGE arsenides, PGE bismuth-tellurides, PGE antimonides and PGE
alloys. The PGM phases are largely dominated by PGE-sulphides (average of 80%)
in the UG2 Reef and PGE-arsenides (average of 39%) in the MR. Although the UG2
Reef and MR are mineralogically different, the PGM observed are similar in
composition, but vary in their proportions. The PGM are mostly associated with base
metal sulphides typically, pentlandite in the UG2 Reef and silicates, which are
dominated by amphiboles in the MR. The PGM grain sizes generally range between
2 and 22 microns in the UG2 Reef and range between 2 and 32 microns in the MR.
The concentrations of platinum are the highest in both the UG2 Reef and MR, and
with the platinum largely deported in PGE-sulphides (about 69 - 84.9%) in the UG2
Reef and PGE-arsenides in the MR. Palladium is mostly deported in the PGE sulphides (about 52.3 - 69.2%) in the UG2 Reef and mostly deported in PGE
antimonides (about 43%) and PGE bismuth-tellurides (about 37%) in the MR.
Rhodium (Rh) is entirely deported in the PGE sulphides in the UG2 Reef and
deported in PGE sulphides (about 86.5%) and PGE bismuth-tellurides (about 13.5%)
in the MR. Expected recoveries of PGM ranges from 76 to 89% for PGE sulphides
and arsenides in the UG2 Reef and 61.3% in the MR, which is considered good.
PGE bismuth-tellurides, PGE antimonides and PGE alloys are expected to be
variably to poorly recovered, requiring suitable reagents to be well recovered both in
the UG2 Reef and MR. / Faculty of Science and Agriculture Research Division
Geological Society of South Africa
North West University's School of Geo- and Spatial Science
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Evaluation of environmental compliance with solid waste management practices from mining activities : a case study of Marula Platinum MineManyekwane, Dikeledi, Lethabo January 2019 (has links)
Thesis (M. Sc.(Geography)) -- University of Limpopo, 2019 / Global production of Platinum Group Metals (PGMs) is dominated by South Africa due to
its large economic resources base in the Bushveld Igneous Complex (BIC). PGMs are
used in a wide range of high technology applications worldwide including medicinal,
industrial and commercial purposes, and its contribution to the Gross Domestic Product
(GDP) and creating jobs for many. In an area where mining activities dominate, there are
likely to be problems that need effective environmental management approaches, which
can be facilitated through legislations. Marula Platinum Mine (MPM) is located in Limpopo
province BIC which has the second largest number of mining productivity in South Africa.
Environmental legislations have been put in place by the South African government in
order to avoid or minimise the footprints caused by PGM mining.
This study looked at environmental compliance with solid waste management practices
by Marula Platinum Mine (MPM) as guided by Mineral and Petroleum and Resource
Development Act (MPRDA) and National Environmental Management Act (NEMA) as
well as the environmental impacts of MPM in the surrounding communities. Both primary
(questionnaires, field observations and key informant interviews) and secondary (NEMA,
MPRDA, journals, reports, pamphlets, internet and books) data was used to address the
objectives of the study. Descriptive method and Statistical Package for Social Sciences
(SPSS) version 25 were used for the analysis of data. The key research results revealed
that MPM was compliant with 65% and 21% partially compliant with solid waste
management practices. Only 14% of information on solid waste management practices
could not be accessed because MPM is still operational. MPM had also had negative
footprints on the surrounding villages such as dust generation and cracks on walls and
floors on houses of community members, strikes and increase in the usage of substance
abuse.
Recommendations of the study are that MPM should address challenges that hinder
environmental compliance so as to be 100% compliant with MPRDA and NEMA
regulations. MPM should also provide other mitigation measures for blasting of explosives
to reduce dust generation and problems of cracks on houses of surrounding village
members.
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