The thesis takes the form of a collection of publications and patents concerning gold extraction which were presented over a period of 18 years while employed at the Anglo American Research Laboratories.

In general, as the uniaxial compressive strength of rock samples is tested, the uniaxial strength of the rock decreases with increasing sample size until a strength is reached beyond which no further decrease in strength is observed for further increases in size. The size at which this occurs was termed the critical size by Bieniawski (1968) and the corresponding strength the critical strength. Once these values are obtained no significant changes in strength may be expected as a result of further volume changes. For the purposes of pillar design, this strength should be adjusted to account for other factors that affect pillar strength, the main factors being the width to height ratio (w/h) effect, jointing and contact conditions. Further test work on Merensky Reef was required to clarify the: 1. Values of it’s critical size and strength 2. Effect of the w/h on it’s strength 3. Effect of the frictional contacts between the reef and the surrounding rock on the reefs uniaxial strength. These results could then be integrated into a holistic pillar design methodology to improve current pillar designing practices. These effects were examined through the laboratory testing of samples originating from Amandelbult Platinum mine. A critical strength of approximately 110 MPa was obtained for samples with diameters, 130 - 250 mm (w/h =1). Increasing the frictional contacts between sample and loading platens was found to increase the sample's strength. A marked difference was found between the insitu and laboratory contact friction angles for Merensky Reef. The insitu contact friction angle was found to be approximately 2.5 times larger then the laboratory contact friction angle. The uniaxial strength increased linearly with increasing w/h ratios up to a w/h ratio of 6. For w/h ratios greater then 6 the strength continued to increased with increasing w/h ratios, but no curve could be acceptably fitted to the data to describe this trend. The results of this study can be applied to mine pillar design in the Bushveld Igneous complex. / Dissertation (MEng (Mining Engineering))--University of Pretoria, 2007. / Mining Engineering / unrestricted

Dissertation submitted in compliance with the requirements for the Master's Diploma in Technology: Electrical Engineering (Light Current), Technikon Natal, 1987. / In the gold mining industry, one of the significant physical properties of the mineral slurry is its density and it is important to be able to measure this parameter in most processes. There are many techniques for determining the density of fluids, but because of the hostile, abrasive nature of mineral slurry, very few of these are suitable, This dissertation describes the deveiopment, construction and testing of a portable, ultrasonic, density measuring instrument. The instrument uses an ultrasonic transducer as the primary measuring element, and system operation is based on the fact that the driving impedance of the transducer varies with changes in the physical properties, and hence the characteristic impedance, of the surrounding medium into which the ultrasonic energy is being transferred. The technique may a-Lao be used to measure the relative concentrations of two liquids in a mixture or emulsion, provided that the characteristic impedances of the liquids are sufficiently dissimilar. The electronic circuitry is fairly straightforward, consisting essentially of an oscillator, driving circuit for the transducer and a voltage monitor to provide a d.c. voltage proportional to the impedance of the transducer, and hence to the density of the surrounding medium. Most of the research has been concentrated on the probe design, as the type of transducer, the type and thickness of facing material and the method of construction all contribute to the sensitivity of the instrument. A design of probe assembly has been developed that may be used for both slurry density measurement and the measurement of the ratio of aqueous to organic liquids in emulsion. / M

On the Gracey group of claims, Unuk River, B.C., are mesothermal-type quartz veins; (1) with speoularite-gold mineralization, (2) with galena-pyrite-gold mineralization, and (3) with chalcopyrite-pyrite mineralization containing no precious metals. The veins outcrop in a band of Late Palaeozoic(?) andesite tuff, siltstone, argillite, and limestone bordered on the northeast and southwest by Triassic(?) diorite gneiss sills. The main body of Coast Range intrusives outcrops five miles southwest of the property, but several stocks are exposed about five miles east of the property. The regional-type metamorphism, and most of the folding and faulting of the bedded rocks on the property have been caused by orogeny associated with the Coast Range intrusives; but some recrystallization of andesite-tuff can be attributed to thermal metamorphism produoed by the adjacent diorite-gneiss sills. The vein-forming fluids are probably derived from Coast Range intrusive rather than the local sills. In the quartz-galena-pyrite veins anhedral gold fragments are associated with three soft minerals, possibly tellurides, which form inclusions in the galena. In the quartz-specularite-gold veins the gold has been deposited in disruptions between specularite 'cleavage' plates. Both classes of veins contain minor amounts of gold in or near fractures in the quartz. No veins contain both abundant specularite and abundant sulfides. The specularite probably has been deposited earlier than the sulfides but in the same period of mineralization. Specularite does not necessarily indicate hypothermal deposition, but it is usually one of the first minerals deposited from hydrothermal solutions. It is formed only under oxidizing conditions, and if exposed to later sulfide-bearing, and thus reducing, solutions, it tends to be reduced to magnetite or an iron-bearing sulfide. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This paper is a benefit-cost analysis of the coal development undertaken by Kaiser Resources Ltd. in the Crowsnest area of British Columbia. The benefit-cost analysis is undertaken from the "point of view" of residents living in the East Kootenay prior to the development. The analysis seeks to examine the production efficiency of the allocation of resources resulting from the project from the point of view of East Kootenay residents. The project will provide primary gross benefits in the form of payroll income to local labour. The social opportunity cost of the use of this local labour must be subtracted from payroll income to obtain the net primary benefit. The social opportunity cost of labour is the value of the marginal product of the labour in alternative employment. A secondary benefit will accrue to local factors in the form of an increase in local income through an expansion of service and retail industries. The expansion will result from the regional multiplier effect of the increase in payroll income in the East Kootenay. The general level of unemployment was high in the East Kootenay prior to the development, and I assume that sufficient local labour and facilities exist to supply the increase in demand for services without requiring importation of labour or capital. Income generated by the regional multiplier will therefore accrue to local factors, located in the East Kootenay prior to the development. Intangible benefits in the form of training in coal mining and an increase in the cultural activities of the community will also occur. The costs attributable to the project include the negative externality effect on wildlife and the deterioration of the quality of the environment in the East Kootenay. A decline of wildlife will decrease the value added by local labour in supplying services to non-resident and residents hunters. The consumers’ surplus obtained by residents from hunting will decline, since greater expenditures will be incurred elsewhere for the same or a lower quality of hunting. The tourist industry will also decline in the East Kootenay. The decrease in local value added due to a decline in the quality of hunting and tourism can be estimated. However, the cost to residents of the East Kootenay from deterioration of the quality of the environment cannot be estimated and the effect is denoted as an unmeasurable intangible cost. The cumulative present value of net measurable benefits at 9% is $l4,717.983. A decision concerning the desirability of the project cannot be made on the basis of this calculation alone. The unmeasurable intangible costs and benefits must also be taken into account. The community, using the relative valuations placed on increased regional income versus the quality of the environment as expressed in a political consensus, must decide how large the unmeasurable intangible costs and benefits are. The project is desirable when only measurable benefits and costs are considered. However, if the cumulative present value of net unmeasurable intangibles is negative and exceeds in magnitude the cumulative present value of net measurable benefits, the Kaiser project should be terminated. / Arts, Faculty of / Vancouver School of Economics / Graduate

Mining frontiers have rarely attracted the attention of geographers because of the transitory nature of settlement in such areas. However, a more stable pattern of settlement emerges if the area of study is broadened to include the supply centres for the mines and the transportation routes along which the supplies were carried. The permanent impact of mining on settlement occurred in these service centres and along the main transportation routes leading to the mines. This study examines the nature of the permanent impact on British Columbia of the gold rushes which occurred between I858 and 1866. These rushes established a new pattern of settlement which remained until the coming of the railway in 1885, and, later, they acted as guidelines in the development of settlement. The British Columbia frontier was part of a larger frontier which was opened in California in 1848 and spread northward and eastward in the ensuing twenty years. San Francisco early secured a dominant position as the manufacturing centre for this frontier area, and it retained this position throughout the period of the British Columbia gold rushes. As a result, British Columbia remained within San Francisco's hinterland from 1858 to 1885 and most of the gold mined was shipped to the San Francisco Mint to pay for manufactured goods. The main flow of gold arrived when the United States Government was in very great need of gold to hack its borrowing for the conduct of the Civil War. The determination of the Colonial Government of British Columbia to secure political autonomy in spite of economic dependence on the United States led to the construction of costly wagon roads from east to west across the mountain barrier of the Coast ranges. These roads funneled trade from the interior of the Province through the Lower Fraser Valley to New Westminster and Victoria and thus avoided the traditional Columbia fur trade supply routes which lay in United States Territory. The wagon roads inaugurated a new era of transportation, and determined the locations of all important subsequent transportation routes in the southwestern part of Mainland British Columbia. Land was a strong interest among those who arrived in the gold rushes, and, at times, this land interest rivalled their interest in gold. The group of settlements subsequently established in the Lower Fraser Valley formed the nuclei of many present day communities, and the system of land survey which guided some of these early settlements shaped subsequent patterns of transportation. In the Province as a whole the patterns of settlement established between 1858 and 1866 remained substantially the same until the coming of the railway in I885. With the coming of the railway the Province entered a new phase of economic development, but the broad lines of settlement which the gold rushes created remained dominant and today they are still evident in the spatial organization of economic activities. Gold initiated a pattern which was confirmed by the subsequent construction of the trans-continental railway, the growth of the forest industries, and the development of agriculture. / Arts, Faculty of / Geography, Department of / Graduate

Sampling of soils and till are conventional methods of gold exploration in glaciated regions. However, the exact nature of the residence sites and behaviour of gold within soil and till are poorly known. A gold dispersion train extending from the Nickel Plate mine, Hedley, southwest British Columbia, was investigated in order to determine the distribution and behaviour of gold within soils developed from till. Three hundred and twelve soil, till and humus samples (representing LFH, A, B and C horizons) were collected from fifty-two soil pits and thirty-four roadcut locations within the dispersion train. Soil and till samples were sieved into four size fractions; the resultant -212 micron (-70 mesh) fraction of each sample was analysed for Au by FA-AAS. Humus samples were ground to -100 micron powder and analysed for Au by INAA. Based on the analytical results, each LFH, A, B and C horizon was subdivided into anomalous and background populations. Detailed size and density fraction analysis was carried out on soil profiles reflecting anomalous and background populations, and a mixed group of samples representing the overlap between both populations. Samples were sieved to six size fractions; three of the size fractions (-420+212, -212+106, -106+53 microns) were separated into two density fractions using methylene iodide and analysed for Au by FA-AAS. The Au content of the -53 micron fraction was analysed by FA-AAS and cyanide extraction - AAS. Results indicate that the Au content of soil profiles increase with depth while decreasing with distance from the minesite. Heavy mineral concentrates and the light mineral fraction Au abundances reveal that dilution by a factor of 3.5 occurs within the till over a distance of 800 metres. However, free gold within the heavy mineral fraction is both diluted and comminuted with distance. Recombination of size and density fractions indicate that the Au contents of each size fraction are equivalent; variation in Au abundance is not observed with a change in grain size. Seventy percent of the Au in the -53 micron fraction occurs as free gold. Chemical activity has not altered the composition of gold grains within the soil profiles. Compositional and morphological differences between gold grains are not indicative of glacial transport distance or location within the soil profile. Relative abundances of gold grains between sample locations can be used as an indicator of proximity to the minesite. The sampling medium with the best sample representivity and contrast between anomalous and background populations is the -53 micron (-270 mesh) fraction of the C horizon. Geochemical soil sampling programs in the vicinity of the Nickel Plate mine should collect a minimum mass of 370 grams of -2000 micron (-2 mm) soil fraction in order to obtain 30 grams of the -53 micron fraction. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This study reports the results of an investigation of the potential pollution hazard of a potash brine disposal pond located near Esterhazy, Saskatchewan. The most serious problems associated with the brine pond are the potential pollution of groundwater resources and the possible contamination of a nearby stream by groundwater discharge. The primary geologic feature is a glacial buried valley aquifer consisting of highly-permeable sands and gravels. A three dimensional electric analog model was constructed to simulate the steady state and transient groundwater flow systems in the buried valley aquifer. The steady state analysis enabled the author to calculate the convective travel times of the brine from the brine pond to the nearby creek. The transient analysis was used to assess the feasibility of reversing the hydraulic gradient in the buried valley aquifer. Steady state results indicate that the most serious potential pollution hazard is brine seepage onto the surface immediately east of the brine pond. At a distance of 5600 feet from the brine pond, this seepage will occur within 30 years; nearer to the brine pond, it will occur sooner. This type of brine seepage could enter the nearby stream as a result of surface drainage. Brine pollution by groundwater discharge directly into the creek will take between 640 to 1260 years, so this mechanism does not pose an immediate pollution hazard. Transient results indicate that low-rate injection wells (up to 50 IGPM) would not reverse the hydraulic gradient in the buried valley aquifer. Injection rates between 370 to 575 IGPM would be required, but fresh water supplies of this magnitude are not available. The design of future brine ponds should include seepage calculations in the initial phases of design instead of after the fact. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

M.Com. (Business Management) / Background Best cost country sourcing is a relatively new concept and not many organisations are utilising this specific process nor are they optimising this as their sourcing strategy. Best cost country sourcing is one of the most profound sourcing processes available, and it has the ability to increase an organisation’s efficiency and effectiveness if implemented correctly. Purpose The purpose of this study is to determine if best cost country sourcing should be used as an alternative to local sourcing. It includes aspects of the best cost country sourcing process as well as its risks and advantages. Research method The dissertation analyses the process of best cost country sourcing and the effect it has on an organisation’s sourcing strategy. To achieve this understanding it is necessary to do a qualitative investigation, which is the reason a qualitative research was used as the research methodology in this dissertation. Conclusion Pursuing the process of best cost country sourcing requires a lot of dedication and implementation time. It is a complicated process and no two situations will be alike. Each organisation would need to determine the advantages, risks and challenges which they will encounter with best cost country sourcing. Organisations would also need to determine the best cost countries, as well as the criteria they would need to use in selecting potential suppliers.

Mrs. D.C. Schoeman