The thesis contains work aimed at improving the copper transport-efficiency shown by the commercial phenolic oxime reagents which are surveyed in chapter 1. New solvent extractants based on ligands which are diacids and can thus form neutral complexes with divalent copper that have a 1:1 ligand to metal stoichiometry, instead of the 2:1 stoichiometry shown by conventional reagents, are reported. The design, preparation and copper(II) extraction capabilities of a series of 3-substituted 2-hydroxy-5-alkyl-benzaldehyde-octanoylhydrazones are described in chapter 2. Chapter 3 considers the complex tautomerism of series of 3-alkyl-4-(2’hydroxy-5’-alkylphenylenamine)-pyrazol-5-ones and their ability to extract copper(II). The addition of certain non-chelating neutral auxiliary ligands is shown in chapter 4 to enhance copper(II) loading by both hydrazone and pyrazolone ligands. Addition of 2-ethylhexanal oxime in a 3:1 ratio, results in enhancement of copper(II) extraction for all ligands tested and the formation of 1:1:1 ligand to copper(II) to 2-ethylhexanal oxime complexes is indicated by EPR spectroscopy. Addition of 3-ⁱpropyl-2-pyrazol-5-one to the 3-nitro- and 3-hydro- substituted hydrazone ligands in a 1:1 ratio, produces a similar effect. Hydrogen bonding fro the auxiliary ligands to the phenolate pyrazolonato and/or hydrazonato oxygen atoms is proposed in these ternary complexes. Inter-ligand hydrogen-bonding is also proposed in most of the binary complexes discussed in chapters 2 and 3 and it is suggested that rational design of new simple extractants for base metals should exploit this feature in enhancing both strength and selectivity of new reagents.

Sewage sludge and colliery spoil can be used in the reclamation of contaminated land. Heavy metals may be present in both spoil and sludge at higher than background levels. The decomposition of sewage sludge produces soluble organic molecules which can form complexes with heavy metals. The object of this thesis was to discover if authigenic metals in colliery spoil would be mobilised as a result of the presence of organic matter derived from sewage sludge. A laboratory experiment was conducted using 24 PVC columns (length 50 cm, diameter 6 cm) filled with colliery spoil (weight 1.8 kg) from the Dechmont Bing near Glasgow, Scotland. This spoil (acid-extractable metal concentrations in mg kg<SUP>-1</SUP>: zinc 426, lead 259, copper 60, nickel 42, cadmium 1.8, chromium 22, barium 307, magnesium 3400) has been used to reclaim the contaminated site of the nearby, former Hallside Steelworks. A rural sewage sludge (metal concentrations on dry matter basis in my kg<SUP>-1</SUP>:<SUP> </SUP>zinc 275, lead 70, copper 165, nickel 12, cadmium 2.2, chromium 12.7) was applied to 16 of the columns at the rate of 300 tonnes per hectare. The columns were irrigated with synthetic rainwater over a period of 15 months at a rate of 900 mm per annum. The leachate was analysed for heavy metals (Zn, Pb, Cu, Ni, Cd, Cr) pH and organic carbon. The concentration of zinc, and also of barium and magnesium, was higher in the leachate from sewage sludge-amended spoil columns (maximum enhancement; zinc 54 μg 1<SUP>-1</SUP>, barium 145 μg 1<SUP>-1 </SUP>and magnesium 108 μg 1<SUP>-1</SUP>) and the pH was lower. The concentration of organic carbon was not directly related to metal concentrations. The results show that the application of sludge to land can lead to enhanced metal levels in drainage water, and that the source of the metals may be authigenic. It was also found that heavy metals can be transported as adsorbed species on fine sediments.

In this work, Monte Carlo computer simulations are used to study hydrocarbon molecules (linear, branched and cyclic) within the pores of four different porous material: three zeolites (silicalite-1, AIPO₄-5 and ITQ-22) and one mesopore (MCM-41). The three zeolites have different compositions and pore structures and include an extremely well known and widely used structure (silicalite-1), a recently synthesised zeolite with a complex pore structure (ITQ-22) and a zeolite with a simple, one dimensional pore structure (AIPO₄-5). The mesopore, MCM-41, has pores which are an order of magnitude larger than the zeolites and can therefore accommodate many more hydrocarbons within its porous network. The adsorption characteristics of the three hydrocarbons in the zeolites are simulated and compared with the available experimental data. Binary and ternary mixtures of the hydrocarbons are also studied and the temperature dependence of the selectivity of each zeolite is discussed and an explanation given for any reversal in selectivity at high temperature. Ideal Adsorption Solution Theory is used to predict the behaviour of mixtures in zeolites and the results of the theory are compared with the simulations. A new computational model for MCM-41 is introduced and used to study the adsorption of hydrocarbons within its pores. The results are compared with experiments (where possible) and the structure of the adsorbed molecules is investigated. Possible refinements to the model are proposed and their effect on the adsorption properties discussed.

Using two time-lapse surveys over an underground gas storage reservoir in St. Illiers la Ville, in France, I demonstrate the potential for multichannel transient electromagnetic (MTEM) data to detect the presence and movement of hydrocarbons in the earth through a new approach to the acquisition and processing of the data. I introduce a new pre-processing methodology for noise reduction and deconvolution of the system response to recover the impulse response of the earth. The thesis is divided into three parts: overview of electromagnetic methods, modelling, and processing of MTEM data. I carried out a comprehensive review of all electromagnetic (EM) methods in relation to hydrocarbon exploration. Of all these, the MTEM method provides the best resolution, detectability and spatial coverage of resistive targets. In the MTEM method a transient current is injected into the ground through a grounded dipole source and measurements of induced voltages at many receiver sites form the data for analysis. 1-D modelling indicates that the in-line component of the electric field is most sensitive to a buried resistor. The response of the cross-line component is about two orders of magnitude smaller, while the magnetic field is not sensitive to the resistor at all. Modelling the St. Illiers la Ville data shows that the response of the reservoir occurs between about 3 and 15ms, and at offsets greater than about 750m. I modelled in-line electric field data to test the application of a resistivity analysis using a seismic refraction analogy. The analysis was applied after transforming the data to a wave-like non-diffusive domain in log-time. The results indicate that the approach works only for a two-layer model and breaks down if the resistive layer is thin, typically less than a few hundred metres. The new MTEM data processing methodology includes improved noise reduction through the application of a dip filter, and deconvolution for the system response each time the source is fired. This enables the impulse response of the earth to be recovered. Processing of two MTEM datasets from St Iliers la Ville reveals both the presence of the gas in the reservoir and the movement of the gas between the two surveys.

This thesis concerns the design and evaluation of the properties of new types of metal extractants for use in the mining industries. Current reagents and industrial solvent extraction processes are discussed in Chapter 1. Chapter 2 addresses the improvement in mass transport using the diacidic imine ligand, 4-<i>t-</i>butyl-2-{[(<i>E</i>)-5-<i>t</i>-butyl-2-hydroxy-phenylimino]methyl}-phenol (1). This prototype ligand is shown to form complexes with nickel in the desired 1 : 1 ligand to metal ratio. X-ray structure determination of crystals of the nickel complex obtained by slow evaporation of a methanol solution shows this to be a tetranuclear complex [Ni₄(1-2H)₄(MeOH)₄], with interesting magnetic properties. The strength of 1 as an extractant for nickel into chloroform was found to be too low (pH_1/2 ca. 6.7) to be used commercially for recovery from mixed Ni(II)/Fe(III) feeds. However, it is potentially much more practicable for the recovery of copper (pH_1/2 ca. 3). EPR experiments support formation of dinuclear Cu(II) complexes [Cu₂(1-2H)₂], in chloroform with μ-phenoxy bridges between the Cu(II) ions. Addition of 3-<i>iso</i>-propyl-2-pyrazol-5-one to chloroform solutions of 1 results in extraction of Cu(II) as the mononuclear ternary complex [Cu(1-2H)(3-<i>iso</i>-propyl-2-pyrazole-5-one)] with a useful reduction of the pH_1/2 value to ca. 1.6. Modification of 1 by substitution <i>ortho</i> to the hydroxyl group on one or both aromatic rings of either a <i>N-</i>piperidinomethyl or bis(<i>n</i>-hexyl)aminomethyl group to generate potential metal <i>salt</i> extractants is discussed in chapter 3. Solvent extraction experiments have shown that the piperidinomethyl-substituted ligand, 4-<i>t</i>-butyl-2-{[<i>(E)</i>-5-<i>t-</i>butyl-2-hydroxy-phenylimino]-methyl}-6-piperidinyl-phenol (5), extracts <i>both </i>Cu(II) cations and sulfate counter anions in a pH range which is applicable to processing high tenor feeds from pressure leaching of sulfidic ores. Loading data are consistent with the formation of a 2 : 2 : 1 assembly, [Cu₂(5-H)₂(SO₄)], and with the sulfate ion being located within the inner coordination sphere of the Cu(II) centre.

This thesis describes the development of a novel tomographic imaging system which can measure the concentration and velocity profiles in two-phase oil/gas flows. Two-phase flow measurement is a problem of great strategic and commercial importance to the oil industry. For example, an oilwell seldom produces just oil; there is often a significant quantity of gas and/or water present and it is very important to know how much of each is being produced. Unfortunately, this turns out to be a very demanding: task, particularly when the components have significantly different densities as in oil/gas flows. The fundamental problem with oil/gas flow measurement is that the individual components can arrange themselves in many different ways. This results in many possible concentration and velocity distributions, which in turn, render conventional flow measurement techniques inadequate. The tomographic system overcomes these problems by explicitly deriving the component distributions at two adjacent planes along a pipeline. These two images of the component distributions are then cross correlated on a pixel-by-pixel basis to obtain the velocity profile of the gaseous component. Multiplying the component concentration and velocity profiles yields a measure of the volumetric gas flow rate. The component distributions are obtained using two tomographic capacitance imaging systems. The problems caused by their interference have been examined in detail and this includes extensive electrostatic simulation studies. The field interactions are shown to affect the effective distance between the sensors and this varies with radial position, resulting in an effective separation profile". Numerous component distribution and velocity profile measurements are presented which were obtained from a 3" multi-phase flow loop, with superficial oil velocities ranging from 0.1m/s to 0.8m/s. and superficial gas velocities ranging from 0.05m/s to 0.5m/s. Void fractions range from 5% to 55%. The system is based on a combination of transputer and digital signal processor hardware and can reconstruct images at 180 frames per second. Techniques for real-time image correlation are examined and these, in combination with a number of suggestions for future work, will facilitate the development of a novel, real-time, multi-phase flow measurement system

Severe slug flow is one of the most undesired multiphase flow regimes, due to the associated instability, which imposes major challenges to flow assurance in the oil and gas industry. This thesis presents a comprehensive analysis of the systematic approach to achieving stability and maximum production from an unstable riser-pipeline system. The development of a plant-wide model which comprises an improved simplified riser model (ISRM) required for severe slug controller design and control performance analysis is achieved. The ability of the ISRM to predict nonlinear stability of the unstable riser-pipeline is investi¬gated using an industrial riser and a 4 inch laboratory riser system. Its predic¬tion of the nonlinear stability showed close agreement with experimental and simulation results. Through controllability analysis of the unstable riser-pipeline system, which is focused on achieving the core operational targets of the riser-pipeline produc¬tion system, the maximum stable valve opening achievable with each controlled variable considered is predicted and confirmed through the simulation results. The potential to increase oil production through feedback control is presented by analysing the pressure production relationship using a pressure dependent dimensionless variable known as Production Gain Index (PGI). The performance analyses of three active slug controllers are presented to show that the ability of a slug controller to achieve closed loop stability at large valve opening can be assessed by the analysis of the H∞ norm of the comple¬mentary sensitivity function of the closed loop system, T(s) ∞. A slug controller which achieves the lowest value of the T(s) ∞, will achieve closed loop stability at a larger valve opening. Finally, the development of a new improved relay auto-tuned slug controller algorithm based on a perturbed first-order-plus dead-time (FOPDT) model of the riser system is achieved. Its performance showed that it has the ability to stabilise the riser system at a valve opening that is larger than that achieved with the original (conventional) algorithm with about 4% increase in production.

More than 100 mineralized localities have been found in the west Carbery area. The stratiform mineralisations are mainly hosted in the top of the predominantly,red coloured Devonian West Cork Sandstone Formation. "Major" sulphide-quartz veins are mainly, hosted in the base of the overlying Devonian Coomhola Formation where green-grey colour is dominant. Apart from the dominant copper sulphides, gold, native bismuth, and a large variety of Cu, Bi, Sb, As and Pb bearing sulphosalts have been found in the vein type mineralisations. Two metamorphic stages metamorphism) have (burial metamorphism and tectonic been recognized. Textures and compositions of phyllosilicates, carbonate compositions and reflectance of carbonaceous materials (graphite) have been used to estimate the metamorphic temperature. The estimated peak metamorphic temperature is 350±25°C and pressure is likely to be -2 kbar on regional geological evidence. Fluid inclusion study and ore mineralogy suggest that "major veins" formed at a temperature of about 300o C.- The trapping pressure obtained from Group 2 subgroup· B inclusions of Ballycurnmisk Veins is about 2 kbar and from other inclusions is < 1kbar. Stable isotope study suggests that vein forming fluids are typical metamorphic fluids. Sulphur from stratiform localities was probably bacterially reduced and sulphur in the "major veins" may be. metamorphically modified from the same ultimate source.

One of the unique features of the Kent Coalfield is that it is entirely concealed by newer rocks. The existence of a coalfield under southern England, being a direct link between those of South Wales, Somerset and Bristol in the west and the Ruhr, Belgium. and northern France in the east, was predicted by the geologist R. A. C. Godwin-Austen as early as 1856. It was, however, only the rapid increase in demand for Britain's coal in the last quarter of the nineteenth century that made it worth considering testing this hypothesis. The first boring was made in the years 1886-90, and although it discovered coal, this did not in itself prove the existence of a viable coalfield. This could be done only by incurring the heavy cost of boring systematically over a wide area. As the financial returns from such an undertaking were uncertain, it was not surprising that in the early years, around the turn of the century, a dominant role was played by speculators, who were able to induce numerous small investors to risk some of their savings in the expectation of high profits.

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