Faculty of Engineering and the Built Environment, School of Mining / Inhaling excessive amounts of respirable coal dust will lead to work-related lung disease commonly known as Coal Worker’s Pneumoconiosis (CWP) or black lung. Prevention and control of CWP requires accurate knowledge of the dose-response relationship to set-up and review occupational exposure limits (OELs), which do not exist in SA. Due to historical reasons, poor emphasis of occupational health on the mines resulted in inadequate exposure data in SA. The new Mine Health and Safety Act (1996) overcame the deficiencies of the past and require quantifying the dust exposure and efficiency of dust control measures, and continuous risk assessments for dust exposure. The current method of exposure assessment is expressed using an Air Quality Index (AQI) which is the ratio of the measured dust level and OEL of coal dust. The difficulties with the usage of AQI are poor descriptions of dust problem areas and its magnitude, poor quality of the data leading to “no dust problem situation” and failure to extract information on ‘dose in milligram’ to relate them to the disease rate. Gravimetric size-selective dust sampling was introduced for the first time in 1990 in SA. Due to the lack of critically important coal dust exposure data available, this thesis has set out to examine several critical exposure related parameters and determine dust levels underground. This research study had the objective of the development of a pragmatic diagnostic tool (method) called the Dust Exposure Level Index (DELI) to evaluate the exposure of workers. The DELI incorporates a set of controllable parameters and influential areas and prioritises them to manage and reduce the worker exposure. The DELI model was to provide critical information as an index, i.e., to show whether the environment is dusty, border line or relatively free of dust and effectiveness of administrative and engineering dust control measures. The research work in this thesis has led to very explicit conclusions, which were based on extensive dust measurements in various coal mines over a five year period. Conclusions obtained for the various sets of controllable parameters used in the DELI model are as follows: 1. A previous analysis of the dust data during 1990 indicated that the dust levels have increased with mechanisation. The contamination of coal dust samples due to stone dusting can result in high dust levels giving a “false” indication of the efficiencies of the dust-control systems. 2. The dust exposure levels during coal cutting indicated that a worker positioned inside the cabin of a CM during the cutting of a 24 m coal block is at a higher dust exposure risk than the worker when cutting a 12 m coal block. Also, the miner who is operating in a heading is exposed to higher dust exposure risk than in a split. 3. The analyses of measured real-time dust data showed a clear relationship between the average dust levels and the frequency of occurrence of “peak” dust levels. The study demonstrated a clear method of using real-time dust data for assessing exposure. 4. The average measured section intake dust level was 0.80 mg/m3 and 60 % of the collected data exceeded the 0.5 mg/m3 limit indicating that this is a base dust level to which the worker is exposed without carrying out any additional work in the section. 5. The average measured section return dust level was greater than 2.0 mg/m3 indicating the high exposure levels of workers, and ineffectiveness of the ventilation and dustcontrol systems. 6. The results of this research study indicated that there is no conclusive relationship between the rate of coal production and respirable dust levels. Also, the type of dust control system used has pronounced effect on dust levels in the sections. The capture efficiency of any dust control system is not one hundred percent at any given time. During any cutting process for a given time and dust control type, part of the escaped respirable dust is added to the coal face atmosphere through air re-circulation. Therefore, respirable dust levels can be expected to increase with time during the shift, even at constant production levels. 7. A limited number of particle size analyses have indicated that there is no clear relationship between the dust concentration in mg/m3 and total surface area (m2) of the respirable dust sample. 8. For the first time, a clear delineation of coal types (semi-bituminous and semianthracite) that possess the most inherent respirable dust generation potential (IRDGP) was possible (p = 0.000). Also, there was no conclusive relationship (p = 0.373) between different semi-bituminous coal seams (1, 2, 4 and 5) and IRDGP. 9. The laboratory roll-crusher test results of South African coal types indicated that average inherent silica for the test coals was 3.54 %. The DELI model took into account, the merits of personal exposure data in exposure assessment, but the limitations and quality of data one obtains in the South African situation overweighed use of the fixed-point sampling. The “limits of acceptability” used in DELI are based upon acceptable guidelines prescribed by the authorities such as National Institute of Occupational Safety and Health (NIOSH), Mine Safety and Health Administration (MSHA), South African Department of Minerals and Energy Affairs (DME) and latest information on epidemiological studies. The DELI model gives the visual “colour” coding and descriptive categories for easy interpretation and understanding of exposed dust level to uneducated workforce. This type of DELI index representation gives a clear and concise picture of the mine or various section dust conditions. The DELI model exposure assessment technique gives accurate feedback because it was based on latest recommended size-selective sampling methods and instrument and vast amount of measured data, which was not previously available. The application of the developed DELI model for exposure assessment and its comparison with AQI were evaluated for coal mine dust data. The study demonstrated that the DELI model is a practical diagnostic tool that gives a fair reflection and information on dust levels and is an exposure assessment tool for the coal mining industry that will assist in reduction of CWP in South Africa.

In modern China, air pollution has become an essential environmental problem. Over the last 2 years, the air pollution problem, as measured by PM 2.5 (particulate matter) is getting worse. My report aims to carry out a longitudinal data analysis of the air quality index (AQI) in 3 main economic zones in China. Longitudinal data, or repeated measures data, can be viewed as multilevel data with repeated measurements nested within individuals. I arrive at some conclusions about why the 3 areas have different AQI, mainly attributed to factors like population, GDP, temperature, humidity, and other factors like whether the area is inland or by the sea. The residual variance is partitioned into a between-zone component (the variance of the zone-level residuals) and a within-zone component (the variance of the city-level residuals). The zone residuals represent unobserved zone characteristics that affect AQI. In this report, the model building is mainly according to the sequence described by West et al (2007) with respect to the bottom-up procedures and the reference by Singer, J. D., & Willett, J. B (2003) which includes the non-linear situations. This report also compares the quartic curve model with piecewise growth model with respect to this data. The final model I reached is a piece wise model with time-level and zone-level predictors and also with temperature by time interactions. / text

Heart and Minds concept is one of the most overlooked approaches of the counterinsurgency. This is surprising especially because the classic coercive strategies are struggling with producing sufficient outcomes. In fact it is quite the opposite in practice and they fail to supress the insurgency ultimately. Hearts and Minds strategy is based on assumption that if the government is able to gain public support the insurgents will lose vital resource for their fight and they will collapse eventually. In this thesis I am going to explore the potential the Hearts and Minds strategy has and demonstrate its strengths and weaknesses. There are five cases of insurgency to be examined in which the Hearts and Minds has been used successfully or unsuccessfully. The first case is the Emergency in British Malaya. Gerard Templer is considered as an author of the Hearts and Minds phrase, therefore his administration of Malaya should be examined I believe. Second case is the FARC insurgency in Colombia. Third case is the Zapatistas movement in Mexico. Fourth case is the US invasion into Iraq in 2003. Last case is the 2012 Tuaregs uprising in Mali and subsequent development. It is clear from the findings that Hearts and minds has its place among the COIN approaches. Even though it is not best suited for all...

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