Whilst geophysical mapping has been long accepted as an integral part of surface prospecting, its use in mining operations is only recently gaining acceptance. In-mine geophysical applications include in-mine exploration, grade control, ore delineation, blast hole and stope design, and in-situ geotechnical rock mass characterization. It is reported in several recent case studies that the cost savings can be substantial. In the INCO nickel mines of Sudbury a saving of the order of C 20 million was estimated for one year. A similar order of magnitude savings is inferred in some of the mines in the Witwatersrand basin, in South Africa. Savings of the order of millions are envisaged at Nickel mines in Kambalda, Western Australia. The key to effective use of geophysics in mines, or anywhere for that matter, is knowledge of the relationship between local petrophysical properties (and petrophysical property contrasts) and the different geological or engineering entities (be they ore, alteration, structure or stress) to be mapped. The most outstanding physical property of the matrix/massive nickel sulfide ores at Kambalda is their extremely high conductivity. Hence the use of geophysics is biased strongly to electrical and electromagnetic methods and is focused on direct detection of ore. In contrast, application of geophysics in gold mines is rarely aimed directly at the ore because of lack of physical property/contrast associated with the ore waste rock. However some applications are described, where geophysical techniques have been successfully used in gold mining. The reported order of magnitude cost savings by using geophysics, the long term decrease in commodity prices, the depletion of open pittable mining resources (forcing higher cost and lower safety underground mining) and the increasing international competitiveness of the mining industry indicate that the prudent use of geophysics in underground mines will continue, if not increase. However it is realized that geophysics is not a panacea, but rather a useful tool in the continuous drive towards lower cost and greater safety mining practices.

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When fault exist in the formation, the local stresses in the shallow depth will be affected by presence of slip or displacement on fault and topography. If the trace of fault is not straight, the stress distribution near fault become more complicated. This feature is studied numerically using boundary element method. Related to this problem, a numerical procedure of 2 and 3 dimensional coupled fictitious stress method and displacement discontinuity method which takes joint element into consideration is adopted. A sinusoidal fault trace is used to modelize the non-straight strike-slip fault in 2 dimensions, while a sinusoidal fault plane buried in the middle of symmetrical valley is used as numerical model study in 3 dimensions. This model is then applied to the Mozumi Sukenobe fault as field case study. Our finding on local stress near fault is consistent with field measurement. If the far field stress is defined in proportion to depth, our finding also predicts that the applied far field stress in the Mozumi Sukenobe fault is in compression with σ_Ho oriented at -40゜ from fault strike and the magunitudes of far field stress components are σ_vo〓ρgh, σ_Ho〓0.74σ_vo and σ_ho〓0.5σ_vo.

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A proper testing method to examine tha effect of spacing on penetration depth has not been established up to now. In this study, a simple testing method was proposed in which a button chip was penetrated on flat surface of a sample rock, 25 times in five by five square pattern. When applied force was relatively small, solitary penetration holes on rock surface were made at pre-determined spacings or intervals. When higher force was applied, rock between holes was chipped away or broken completely and holes were connceted each other to produce a large excavated region covering all testing area. Through comprehensive testing schedule, followings were found ; 1. Required force to penetrate a certain depth is proportional to square root of the chip diameter. 2. For Sanjome andesite and Kimachi sandstone, penetration depth approximately follows an equation with three constants ‹a’, ‹n’ and ‹c’; (depth)=a(force)/(chip diameter)^0.5-b(spacing)sⁿ-c, where ‹n’ takes a value between 1.5～2.0. 3. For Inada granite, penetration depth follows and equation; (depth)=a(force)/{(chip diameter)^0.5(spacing)^0.5}-c.

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The paper describes a fundamental investigation on bit wear and cutting mechanism in rock cutting comparing with those in mortar and metal cuttings. Turning-operation (facing) test previously developed by the authors were modified and used in this study. Main modification was made to measure cutting forces in three orthogonal directions by a newly attached dynamo-meter. A series of laboratory tests were carried out. Forty-seven rock samples, two mortars and five metals (mild steel, cast iron, copper, brass, aluminum) were tested in the study. Five kinds of cutting bits/chips made from three kinds of WC, a cermet and a ceramic were used. A measurement of cutting force and bit wear were successfully performed and main results can be summarized as follows ; 1. Cuttings of rock is relatively small and granular. 2. Bit wear is evident in rock cuttings and small in metal cutting. 3. Cermet and ceramic bits are easily failed by chipping in rock cutting, indicating that potentially the proposed testing method can be applied to evaluate durability of bit material. 4. Cutting component of resultant tool force is comparatively large in rock cutting. 5. Ratio of forces, (cutting-component)/(thrust component), is almost the same for all samples. 6. The ratio does not change even if bit wear is proceeded.

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This paper describes applicability of fuzzy control to a bilinear (nonlinear) concentration regulation system, which is typically found in mineral processing, focusing on nonlinearity and deadtime. These bring difficulties in realizing control systems. To express plant characteristics in linguistic form, at first, the authors have carried out a series of plant operating simulations. Consequently, the key features in designing a fuzzy control system are pointed out. The results are summarized as follows: 1. Nonlinearity (a) The concept of gain-scheduling is indispensable, because the process gain and the time constant (mean residence time) depend on equilibrim points. (b) In order to deal with inverse -response which can be found at times, special control rules should be designed. 2. Normalized deadtime L/T (ratio of apparent deadtime to time constant) (a) As a number of cells becomes larger or back-mixing ratio becomes smaller, the ratio L/T becomes larger, where control gain cannot be set large enough. (b) The fact that the magnitude of inverse-response is well characterized by the ratio L/T can be utilized in designing a control system. The authors have designed a fuzzy control system for the bilinear plant, taking accounts of the points mentioned above. The control rules of the obtained fuzzy controller has a structure satisfying the above features of the term “Nonlinearity.” And, the output gain is set suitable for L/T. The fuzzy controller is better than that of conventional PID controller in that the former is applicable to wider ranges of process variable changes. In addition, the fuzzy controller is applicable to various deadtime with one rule table, because distinct relation exists between normalized deadtime L/T and magnitude of inverse-response.

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Room temperature grinding of a mixture of CaO and Fe₂O₃ (hematite) was conducted using a planetary ball mill to synthesize calcium ferrite (CaFe₂O₄ ; CF). It is found that poor crystalline CF phase can be crystallized mechanochemically in the mixture by the grinding for about 2 hours, and its crystallinity is improved in the prolonged grinding. Heat treatment of the short time ground mixture, in which the CF phase is not formed yet, at about 900 ～ 1, 200 K enables to assist the crystallization of CF. Dephosphorization from molten iron was examined at 1, 573 ～ 1, 595 K using three kinds of fluxes with and without the CF powder prepared by the grinding for 5 hours. The flux containing the CF powder shows effective dephosphorization characteristics, however, substituion of all components of CaF₂ and Fe₂O₃ for the CF powder is ineffective for the Dephosphorization.

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Precipitation stripping phenomena of samarium oxalate from samarium-loaded D2EHPA solution were studied with a conventional impeller. The effect of intensified mixing induced by ultrasonic irradiation was also examined. Morhological variation as well as size distribution of precipitated samarium oxalate were observed with processing factors such as pH value, C₂H₂O₄ concentration, samarium concentration and D2EHPA concentration under ultrasonic irradiation. The needle-like precipitate was identified as Sm₂(C₂O₄)₃・10H₂O by XRD. Its shape was not significantly influenced by C₂H₂O₄ concentration, samarium concentration and D2EHPA concentration. The average size of precipitates was 4μm at a rotational speed of impeller of 800 rpm. It decreased to 2μm at 1, 300 rpm. However, the size reduction effect caused by ultrasonic irradiation was not so evident as abserved in cobalt oxalate precipitation. Plate-like morphology appeared by the addition of HCl to aqueous phase.

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There has been a trend to switch from pyrometallurgy to hydrometallurgy in copper refining of copper sulphide ores since pyrometallurgy process needs a huge amount of energy and is harmful to the environment. In this study, focusing on the extraction selectivity of EHO (2-ethylhexanal oxime), which extracts Cu, Ni and Pd from chloride solution, the mechanism and behavior of Cu²⁺ extraction with EHO from the leached solution of copper sulphide ores with ferric chloride solution and stripping of copper with water were investigated in order to clarify the possibility of an environmentally friendly hydrometallurgical process. The EHO extracts Cu²⁺ selectively from the chloride solution and the extraction reaction is a solvation type as follows ; Cu²⁺_aq + 2Cl^-_aq + EHO_org〓CuCl₂・2EHO_org The extractant does not extract other metal ions such as Zn²⁺, Fe²⁺ and Fe³⁺, which are the main impurities in the leached solution. It was also found that the extraction is an exothermic reaction of ΔH=-130kJ/mol and the stripping reaction is endothermic with the reaction heat of ΔH=43kJ/mol.

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Zn electrodeposition behavior and the morphology of deposited Zn were studied in the electrowinning solution containing polymer additives such as gelatin and polyethylene glycol (PEG). The molecular weight of gelatin and PEG were determined by gel permeation chromatography. During Zn deposition, the cathode potential was shifted to less noble direction and polarization resistance was increased with increasing the concentration or the molecular weight of gelatin and PEG added to the electrolytic solution. However, when the molecular weight of these additives was increased to exceed 10⁴, the cathode was depolarized and polarization resistance was decreased with increasing their molecular weight. The crystal grain size and the intensity of (002) orientation index of deposited Zn became smaller when the concentration or the molecular weight of additives was increased.

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B₂O₃ has been used commonly as a flux to accelerate a solid state reaction on synthesis of long phosphorescent SrAl₂O : Eu²⁺, Dy³⁺ phosphor. In this paper, the effects of B₂O₃ on the crystal structure and the afterglow characteristics of the material have been evaluated. The synthesised phosphor exhibited a broad band emission spectra peaking at 520nm, and the spectrum peak showed little effect by the B₂O₃ contents. The maximum afterglow intensity of the SrAl₂O₄ : Eu²⁺, Dy³⁺ phosphor was obtained at the B₂O₃ content of 5%. Adding the B₂O₃ caused the uniform distortion to the crystal structure of the phosphor, and resulted in reducing the length of a and c axis and β angle of the SrAl₂O₄ crystal. The uniform distortion was accompanied with crystal defects which can trap the hole generated by the excitation of Eu²⁺ ions. The afterglow characteristics of the SrAl₂O₄ : Eu²⁺, Dy³⁺ phosphor was thus enhanced.

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