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A pre-feasibility study of the Kloof Eastern Boundary Area project, Kloof Gold MineGhoussias, Konstandinos January 2003 (has links)
Thesis ((M.Sc.) Engin))--University of the Witwatersrand, Faculty of Engineering & the Built Environment, School of Mining Engineering, 2003. / The ore reserves of the Kloof Sub Vertical Shaft operations are coming to
an end and as such, the Eastern Boundary Area mining operations, which
will extract the Ventersdorp Contact Reef ("VCR"), must be commissioned
to replace the diminishing reserves. Although feasibility studies have been
carried out on the eastern portion of the Kloof Gold Mine lease area, none
have been undertaken to investigate the potential benefits of including the
new mineral rights recently acquired from JCI. This project report is a prefeasibility
study into the potential value to Kloof of accessing and
extracting the resources of the Eastern Boundary Area.
This project report shows, using DCF analysis, that the Eastern Boundary
Area has potential to economically generate the additional reserves that will
be required to supplement Kloof s diminishing Three Shaft reserves. An
NPV and IRR are calculated for the project, the results of which support the
commissioning of further investigative work in order to obtain a better
understanding of the orebody and to generate results that are more accurate. Despite its popularity, traditional DCF analysis has fundamental
shortcomings, as do the commonly associated measures of NPV and IRR.
This project report identifies and reviews these shortfalls and comments on
methods to overcome these as far as practically possible.
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The effects of lightning in shallow coal mines: an engineering study.Geldenhuys, Hendrik Jacobus. January 1995 (has links)
A thesis submitted to the Faculty of Engineering, University of the Witwatersrand,
in fulfilment of the requirements for the degree of Doctor of Philosophy in
Electrical Engineering. / Lightning causes electrical shocks to people, the premature ignition of
explosives, and the ignition of methane underground in coal mines. This
study examines this problem using a theoretical study and the results of an
extensive measurement programme that was conducted in several coal mines.
The work that has been done, particularly in South Africa, is also reviewed.
Two mechanisms are responsible for the penetration of lightning surge
currents into the underground workings. A direct strike to the service
structures leading into a shaft is one of the two mechanisms, and the second
is that resulting from lightning strikes to the strata above the underground
workings.
The frequency and amplitude with which such surges can be expected is
quantified using the theoretical study. This model correlates well with the
observed frequencies of the empirical studies.
The sensitivity of methane to lightning-type sparks is investigated. Currents
as low as 10 rnA have been proved to be capable of igniting methane. The
sensitivity of conventional detonators is also investigated. The thesis
proposes a generalised test which can be applied to both the low-impedance
protection method and a high-impedance protection method. The test
methodologies have been generalised to make provision for any new
innovative detonators that may be used by the industry.
A risk evaluation of mines is developed which allows a mine to be
categorised according to the likelihood of lightning causing an accident in a
mine.
The South African Recommended Practice for avoiding such accidents is also
reviewed. / Andrew Chakane 2018
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The geology of the Lily Syncline and portion of the Eureka Syncline between Sheba Siding and Louw's Creek Station, Barberton Mountain LandAnhaeusser, C R (Carl Robert) 16 September 2014 (has links)
No description available.
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Evaluation of productivity trends in the South African coal mining industryDu Toit, Anthea January 2017 (has links)
A research report submitted to the Faculty of Engineering and the Built
Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the
requirements for the degree of Master of Science in Engineering, 2017 / Productivity is an important topic within the mining industry and advances
in productivity open up opportunities to make the best possible use of
South Africa’s mineral wealth. The report uses publicly available data to
assess trends in productivity in the SA coal mining industry since the
1980s and to compare SA’s performance with that of the US and Australia.
It is found that between 1980 and 2003, productivity growth in the SA coal
mining sector was primarily driven by capital deepening. However,
productivity growth has been negative from 2004 onwards, despite
continued capital deepening. Possible explanations include resource
depletion, investment lags, deteriorating worker quality, increased
complexity, more stringent safety regulations and adverse labour market
conditions. The report highlights skills development and investment in
innovation as possible ways of addressing declining productivity
performance in the SA coal mining sector and recommends improvements
to the availability of data for productivity research purposes. / CK2018
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Educational data mining (EDM) in a South African University: a longitudinal study of factors that affect the academic performance of computer science I studentsMashiloane, Lebogang 22 January 2016 (has links)
Degree of Master of Science by research only:
A Dissertation submitted to the Faculty of Science, University of
the Witwatersrand, Johannesburg, in fulfilment of the
requirements for the degree of Master of Science.
Signed on September 10, 2015 in Johannesburg / The past few years have seen an increase in the number of first year students registering in the School
of Computer Science at Wits University. These students come from different backgrounds both academically
and socially. As do many other institutions, Wits University collects and stores vast amounts of
data about the students they enrol and teach. However this data is not always used after being stored. The
area of Educational Data Mining (EDM) focuses on using this stored data to find trends and patterns that
could enhance the knowledge about the student’s behavior, their academic performance and the learning
environment.
This longitudinal study focuses on the application of EDM techniques to obtain a better understanding
of some of the factors that influence the academic performance of first year computer science students
at the University of the Witwatersrand. Knowledge obtained using these techniques could assist in increasing
the number of students who complete their studies successfully and identifying students who
are at risk of failing and ensuring that early intervention processes can be put into place. A modified
version of the CRISP-DM (CRoss-Industry Standard Process for Data Mining) was used, with three data
mining techniques, namely: Classification, Clustering and Association Rule Mining. Three algorithms
were compared in the first two techniques while only one algorithm was used in the Association Rule
Mining. For the classification technique, the three algorithms that were compared were the J48 Classifier,
Decision Table and Na¨ıve Bayes algorithm. The clustering algorithms used included the Simple
K-means, Expectation Maximization (EM) and the Farthest First algorithm. Finally, the Predictive Apriori
algorithm was selected as the Association Rule Mining technique.
Historical Computer Science I data, from 2006 to 2011, was used as the training data. This set of data
was used to find relationships within the data that could assist with predictive modeling. For each of the
selected techniques a model was created using the training data set. These models were incorporated in
a tool, the Success or Failure Determiner (SOFD), that was created specifically as part of this research.
Thereafter, the test data set was put through the SOFD tool in the testing phase. Test data sets usually
contain a variable whose value is predicted using the models built during the training phase. The 2012
Computer Science I data instances were used during the testing phase. The investigations brought forth
both expected and interesting results. A good relationship was found between academic performance in
Computer Science and three of the factors investigated: Mathematics I, mid-year mark and the module
perceived to be the most difficult in the course. The relationship between Mathematics and Computer
Science was expected, However, the other two factors (mid-year mark and most difficult module) are
new, and may need to be further investigated in other courses or in future studies. An interesting finding
from the Mathematics investigation was the better relationship between Computer Science and Algebra
rather than Calculus. Using these three factors to predict Computer Science performance could assist
in improving throughput and retention rates by identifying students at risk of failing, before they write
their final examinations. The Association Rule Mining technique assisted in identifying the selection of
courses that could yield the best academic performance overall, in first year. This finding is important,
since the information obtained could be used during the registration process to assist students in making
the correct decisions when selecting the courses they would like to do. The overall results show that using
data mining techniques and historical data collected atWits University about first year Computer Science
(CS-1) students can assist in obtaining meaningful information and knowledge, from which a better unii
derstanding of present and future generations of CS-1 students can be derived, and solutions found to
some of the academic problems and challenges facing them. Additionally this can assist in obtaining a
better understanding of the students and factors that influence their academic performance. This study
can be extended to include more courses withinWits University and other higher educational institutions.
Keywords. Educational Data Mining, CRISP-DM, Classification, Clustering, Association Rule Mining,
J48 Classifier, Decision Table, Na¨ıve Bayes, Simple K-means, Expectation Maximization, Farthest
First, Predictive Apriori
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Rib Cutting Resue Stoping, improvement on stoping rates and reduction in waste dilution compared with other known resue stoping methods on a Free State gold mineScholtz, Alwyn January 2018 (has links)
Mining of the Basal Reef at Jeanette Mine, is typically complicated due to an overlaying Khaki Shale (shale) that has unfavourable rock engineering properties. Shale has always been either left underground or mined as part of the orebody. The first approach can only be applied in areas where the quartzite beam (directly above the Basal Reef and below the shale) is of sufficient thickness to support the shale in the hanging wall. This method is known as undercutting. Alternatively, open stoping can be applied in areas where the shale and the Basal Reef is extracted concurrently and sent to the mill as diluted ore.
Alternatively, a resue stoping method can be considered in areas where undercutting cannot be done, due to a thin quartzite middling. Resue stoping involves stowing or packing of the shale into the mined-out area and is not included as part of the hoisted rock. In the past, resue stoping was done by hand packing, which is unsuitable for a modern mine. As such, two mechanised resue stoping methods can be considered, namely; Longhole Resue Stoping and Rib Cutting Resue Stoping.
Rib Cutting Resue Stoping utilises a continuous miner (“CM”) to remove the shale in a first pass, extract the reef during a second pass and backfilling the mined-out rib with shale. The use of a CM will significantly improve the extraction/mining rate, sidewall stability, backfill placement, dilution and overall safety.
Longhole Resue Stoping utilises strike drives from where longholes are drilled into the shale and the reef in an up-dip direction moving on retreat. The shale is blasted with sufficient force into the mined-out area behind it, compacting it. The reef will be loaded by Load Haul Dumper (“LHD”) or dozer.
It was determined that Rib Cutting Resue Stoping is more effective than Longhole Resue Stoping due to a higher extraction rate, lower dilution, reef loss reduction and improved shale sidewall stability. The operating angles and equipment height limits the application to only 51% of the available reef at Jeanette mine with favourable dip and thickness. Longhole Stoping can navigate hard rock, shale and increased dip angles; it can be applied to 91% of the available ore deposit.
Longhole Resue Stoping and Rib Cutting Resue Stoping should both be considered as suitable stoping methods for Jeanette. / Thesis is submitted in partial fulfilment for the degree of Master of Science in Engineering to the Faculty of Engineering and the Built Environment, School of Mining Engineering, 2018 / XL2019
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Quantitative aspects of mining induced seismicity in a part of the Welkom Goldfield /cRicardo Isidro Loureiro Ferreira.Ferreira, Ricardo Isidro Loureiro. January 1997 (has links)
A dissertation submitted to the Faculty of Science, University of the
Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of
Master of Science in Geophysics . / Rockbursts continue to be one of the more high profile and problematic worker
hazards in the South African gold mining industry. Recent advances in the technology
of seismic monitoring systems and seismic data analysis and interpretation methods
hold considerable promise towards improving the success rate of rockburst control
measures. This study tests different methods for the evaluation of the response of
geological structures to mining induced stress changes.
A small part of Western Holdings Gold Mine in the Welkom goldfield -- the Postma
Area -- offers a challenge because of its geological complexity, accessibility and high
incidence of seismicity. The sensitivity of the local network to ground motions in this
area of interest and the expected spatial location accuracy is established and deemed
adequate for a detailed investigation of seismic activity. The local mining geometry,
geology and methods of mining are discussed. The fractured state of the rock mass
observed in situ, close to the stope faces, is in agreement with the results of numerical
elastic modelling and the high stresses inferred seismically. Almost immediately after
the incidence of a large event (ML 3.7) which occurred close to one end of a dyke, an
increased rate of seismic activity became apparent at another part of the same dyke,
some 250 m to the east. A change in the state of seismic stress, before and after the
large event, points to a transfer of stress along this geological discontinuity.
A quantitative analysis of recorded seismicity indicates spatial and temporal variations
in the state of stress and strain throughout the rock mass surrounding Mining
excavations. The elastic stress modelling performed routinely by rock mechanics
engineers in the deep gold mines is, by itself, incapable of catering for the rheological
nature of the rock mass, but taken together with independent seismic evaluations of a
fault orthogonal to a highly stressed dyke it is shown that both methods are mutually
complementary and can enhance the assessment of the seismic instability of the
structures. A back-analysis is conducted on ten large seismic events (ML 2.5) to
identify precursors. These show that the timely recognition of high gradients in
physical seismic parameters pertaining to strain rate and stress in time and space
immediately prior to major seismic events is a real and practical possibility, as such
constituting an early warning mechanism. The fore-warning of a large event is best
served by an analysis of seismicity over the short term (weeks or days) through
time-history variations and/or contouring of various seismic parameters, although
long-term seismic responses (months or weeks) characterise specific patterns and
trends which are useful in the forecast. / AC 2018
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The evaluation of employee assistance programmes in the coal mines within the Nkangala region.Lekgothoana, Josiah Patrick. January 2013 (has links)
M. Tech. Human Resources Management / It is important to acknowledge that employees need to be physically and mentally healthy in order to be productive, thus boosting the profitability of the organisation. According to resources, employee assistance programmes have the potential of enhancing the profitability of the company by reducing absenteeism, staff turnover, tardiness, accidents and medical claims. The problem statement of this study involves the uncertainty about the perceptions of the employees in the coal mines within the Nkangala region about the outsourced employee assistance programmes. It is only one coal mining company and an Employee Assistance Programmes service provider that granted permission to conduct the research at their organisations. This research project aims to evaluate the perceptions of the employees of the coal mine within the Nkangala region in South Africa, about the outsourced employee assistance programmes. The objectives of the study are to determine if the perceptions of demographic groups differ and also to determine if there are relationships between the theoretically envisaged subscales or dimensions.
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Factors that sustain small and medium enterprises at Impala Platinum Mine in Rustenburg.Hlahane, Dawid. January 2013 (has links)
M. Tech. Business Administration / The aim of this research it to investigate factors that can sustain T1 category small and medium enterprises (SMEs) that provides service at Impala Platinum Mine in Rustenburg. The population for the study was 53 SMEs owners/directors, convenient sampling was used and a sample of 26 percent responded to the questionnaire.
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The development and application of a 3D geotechnical model for mining optimisation Sandsloot open pit platinum mine South Africa.Bye, Alan Russell. January 2003 (has links)
Detailed geological knowledge is often a major unknown factor in open pit mining and design, and
therefore poses a significant risk in the mining venture. As the knowledge of the geology improves
so the risk of unforeseen conditions reduces and therefore safety and productivity can be increased.
Historically, geotechnical methods and information have predominantly been used exclusively for
pit slope optimisation. This research documents the procedures and developments undertaken to
compile a comprehensive geotechnical database, and the application of the geotechnical data to
open pit mining, beneficiation and planning. The utilisation of the geotechnical information has
been enhanced through the novel development and application of a computerised, 3D geotechnical
model.
Sandsloot open pit was developed to extract the Platreef pyroxenite orebody, which is hosted within
the Northern Limb of the Bushveld Complex. Sandsloot is currently the world's largest open pit
exploiting Platinum Group Metals. Interaction of the basic magma with the footwall sediments of
the Transvaal Supergroup and varying degrees of assimilation has resulted in a unique suite of
hybrid rock types. These various rock types provide significant engineering geological challenges.
Geology and the detailed understanding of its properties are fundamental to the optimal design and
successful operation of any mine. Extensive fieldwork was conducted to collect geotechnical
information, both from exploration boreholes and in-pit mining faces. Over a 5-year period,
geotechnical data were collected from 29,213 m of exploration core and 6,873 m of exposed
mining faces. Extensive field and laboratory testing was undertaken in order to define the complete
set of geotechnical properties for each rock type in the Sandsloot mining area.
The geotechnical information relating to each borehole and facemap was stored in the Datamine®
software package. The information was collected in the form of rock mass rating (RMR), uniaxial
compressive strength (DCS), fracture frequency (FF/m) and rock quality designation (RQD). The
architecture of the database was developed along the principals used for generating an ore reserve
model.
One of the novel applications was the development of a computerized 3D, geotechnical model in
Datamine®. The geotechnical parameters, namely RMR, DCS, FF/m and RQD, were modelled for
each rock type, using geostatistics, to generate a 3D model. The data were interpolated between
exploration boreholes and exposed mining faces and the modelling was constrained using
wireframes separated by rock type. The result is a 3D model containing 15 m3 model blocks
populated with interpolated geotechnical information. The dimensions of the model blocks are
linked to the mining bench height of 15 m. The model can be queried to give predictions on rock
mass conditions for any planned mining area, as is the case with the ore reserve model, which
provides predictions on platinum grades.
The crux of the innovative research is the practical application of the 3D geotechnical model. This
was achieved through the development of both a fragmentation and a slope design model, which
read the interpolated geotechnical information. These models provided an engineering tool to optimise mining and milling perfonnance.
Rather than viewing the drill and blast department as an isolated cost centre and focussing on
minimising drill and blast costs, the application of the model concentrated on the fragmentation
requirements of the milling and mining business areas. Two hundred and thirty-eight blasts were
assessed to detennine the optimum fragmentation requirements for ore and waste. Based on the
study a mean fragmentation target of 150 mm was set for delivery to the crushing circuit and a
mean fragmentation of 230 mm was set for waste loading from the pit.
The mine operates autogenous mills, which are sensitive to the fragmentation profile delivered.
The harder zones occurring in the ore zone have a major impact on the plant's perfonnance. The
geotechnical parameters in the model were related to Lilly's Blastability Index, and in turn to
required explosive volumes and the associated drill and blast costs. Having defmed the
fragmentation targets, the Kuz-Ram equation was used in the fragmentation model to predict the
explosive volumes required to ensure consistent mining and milling perfonnance. The
geotechnical model is used to predict changes in geotechnical conditions and therefore the blasting
parameters can be adjusted in advance to ensure the milling and mining fragmentation
requirements are met. Through the application of the fragmentation model over an eighteen-month
period the loading and milling efficiencies improved by 8.5% and 8.8% respectively, resulting in
additional revenue ofR29 million for PPL.
Based on the mining rock mass rating (MRMR) values within the geotechnical model a stable slope
design model was created in order to calculate optimum inter-ramp angles. From a slope design
perspective the model was used to target data-deficient zones and highlight potentially weak rock
mass areas. As this can be viewed in 3D, the open pit slopes were designed to accommodate the
poor quality areas before they are excavated. It also follows that competent geotechnical zones can
be readily identified and the slope optimised accordingly.
Due to the detailed geotechnical infonnation being available in three dimensions, the open pit
slopes were designed based on a risk versus reward profile. As a significant geotechnical database
was available, more accurate and reliable designs were generated resulting in the overall slope
angle increasing by 3 degrees. This optimisation process will result in a revenue gain of R900
million over the life of the mine. The revenue and safety benefits associated with this design
methodology are substantial and have potential application to all open pit mining operations.
The research has enabled detailed geotechnical infonnation to be available in three dimensions.
This information can be readily accessed and interpreted, thus providing a powerful planning and
financial tool from which production optimisations, feasibility studies and planning initiatives can
be implemented. The development and application of a 3D geotechnical model has added a new
dimension to the constant strive for business improvement and reflects a novel and successful
approach towards the application of engineering geology at the Sandsloot mining operation. / Thesis (Ph.D.)-University of Natal, Durban, 2003.
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