Roadheader was developed as a heading machine of coal mine in 1 9 6 6 in Japan, following to other countries. At first, it cut coal seams. And it has been improved to cut more severe strata. In Japan there was a big market for digging tunnels in the field of civil engineerings. Roadheader has been widely used for a heading machine of tunnels in Japan. The specification to be attained for tunneling was slightly different from that of coal mine. To improve cutting abilities, a big cuttinng force and a machine stability is most important. But increase of cutting force is restricted by a machine weight. Because it is inevitable for a selecting cutting system to receive a reaction force by a friction of machine weight. In future Roadheader will become a more powerful and useful machine.

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RTK-GPS (Real Time Kinematic-Global Positioning System) was applied to topographic survey in open-cut mines. The operation of the survey involves great difficulties, such as obstacles caused by local topography and electromagnetic noises interfering with micro-wave from GPS-satellites. Therefore, the survey was carried out under conditions when a good GPS-satellite constellation was formed in the sky, limited by local topography in each working face. A clear data link between two GPS-receivers on the working face was also important. In a field experiment at an operating open-cut mine, about 190 points were surveyed in about 5 hours on two successive days. Repeatability was estimated to be about ± 6 cm in coordinates obtained by the RTK-GPS. Topographic changes by operation were well pointed out by examining plotted RTK-GPS surveyed points on the topographic map surveyed by the traditional method. Consistency in coordinates was estimated to be about ± 9 cm between traditional local coordinates and those obtained by the RTK-GPS. Usefulness of the RTK-GPS was clearly demonstrated by examining actual field data acquired in operating open-cut mines. Rapid and precise measurement by the RTK-GPS is more suitable than the traditional optical surveying method for monitoring the topographic change in working face and for providing digital topographic data required for computer systems.

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Mineral processing plants show a lot of difficulties as control objects. As they involve many variables, non-linearity and large disturbances, they can hardly be mathematically modeled, which is required for application of deterministic control theories. It is therefore hard to control those plants by the conventional, especially linear control algorithms. The authors have therefore conducted a series of studies on feasibility of the fuzzy logic control in mineral processing. As a result, the fuzzy logic control yielded sufficient control performances. Usually a trial and error method, however, must have been practiced in fuzzy logic control design to optimize the controller parameters, such as scaling factors, fuzzy rule tables and so on. The authors intended in this paper to develop a way to automate a part of the above procedure by applying the genetic algorithm to optimize the scaling factors. The genetic algorithm is a unique optimum-seeking method that comes from an evolution process, and has recently been highlighted in different engineering areas. It is the algorithm to search the optimal value by mapping the search space structure into the dynamics of the evolution of the living beings. The target control system for this study is concentration control system based on actual resources processing plant. From the results of the computer simulations, it has been demonstrated that this system can determine the fuzzy controller scaling factors automatically, and can be an effective method for a control system design of mineral processing plants.

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Aragonite-type calcium carbonate was synthesized from calcined scallop shell using carbonates of orthorohombic structure (such as SrCO3) as seeds, by bubbling CO2 at ambient temperature. The products were examined by FTIR, SEM, EPMA, and XRD. The addition of SrCO3 increased aragonite content in the products, but BaCO3 and PbCO3 did not play the role of seed crystals due to the difference of their lattice parameters to those of aragonite, whereas lattice parameters of SrCO3 are the most similar to them. With increasing SrCO3 -addition, formation of aragonite was accelerated to a limit in the amount. Light calcium carbonate rich in aragonite was formed in agglegates consisting of needle-like crystals with large specific surface areas.

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Aragonite-type light calcium carbonate was synthesized from calcined scallop shell at ambient temperature in the aqueous system with Mg2+ ions under the CO2 bubbling for 4 hours. The important factors to obtain high purity of aragonite were the mole ratio of Ca2+/ Mg2+, flow rate of CO2 , reaction time, pH and temperature. Under the optimum condition, the purity of aragonite in products was determined to be more than 99.4 (w/w) %, by XRD and FTIR analyses. The specific surface area was obtained to be 5-8 m2 g-1 by the BET method, and the morphology was characterized in wisker with several micrometers in length by SEM.

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For the purpose of determining the amount of chemically dissolved lead in ISF slag, molten lead was equilibrated with molten slag containing several mass% of zinc in a magnesia crucible under partial pressures of zinc vapor and oxygen. The partial pressures were controlled by utilizing the equilibrium reaction between a CO-CO 2 gas mixture and Zn 2 SiO4 . From the results, the solubility of lead in the ISF slag was obtained as a function of the oxygen partial pressure and temperature as follows : The amount of chemically dissolved lead in the actual slag tapped at 1,523 K, for example, was calculated to be 0.10 - 0.26 mass% from available oxygen partial pressure data of the slag. Also, from the activity coefficient of zinc oxide in the slag, the equilibrium zinc vapor pressure from the actual slag at the hearth of the ISF was estimated to be 0.64 - 0.95 atm, which seems to meet the stable operating condition of the ISF.

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Thermodynamic properties of NaO0.5 - CO2 - SOν/2 slag (ν: valence of S) have been investigated by conducting the following experiments: (1) Redox equilibrium experiments to determine the sulfur valence in the slag. (2) Solubility measurements of CO2 in the slags. (3) Activity measurements of NaO0.5 under various partial pressures of CO2 . (4) Distribution equilibrium measurements of S between the slag and molten copper. Based on the results, the equilibrium distribution ratio of S between the slag and molten copper have been estimated as a function partial pressures of CO2 and of oxygen and the slag composition at 1523 K.

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Zinc sulfide is directly reduced to zinc gas with metallic iron. In such a reaction the sulfur is fixed as pyrrhotite, and then it would be expected that roasting and/or sintering zinc sulfide would not be required. From this point of view, reaction experiments of zinc sulfide reduction with metallic iron have been conducted under nitrogen stream in the temperature range of 1,180∼1,240 K. A shrinking unreacted-core model has been applied to analyze the reaction data, based on the observation of cross section of partially reacted sample. In the model, the following steps were considered: a chemical reaction, a diffusion of zinc gas away through the product layer, and a diffusion of zinc gas through gas film. Reaction rate constant kc and effective diffusivity De determined were expressed as follows: kc/mol·m-2·s-1 = exp {-124.9 × 103/(RT) + 6.386} De/m2·s-1 = exp (-58.57 × 103/T + 37.41) where R : gas constant (J·mol-1 ·K-1 ), T : temperature (K). The activation energy of the reaction was 125 kJ·mol-1 . The calculated reduction curves using the rate parameters obtained finely reproduced the experimental data. The reaction proceeds faster with increasing temperature. The reaction is controlled by the diffusion of zinc gas away through the product layer at a lower temperature, while at a higher temperature, both the diffusion of zinc gas away through the product layer and the chemical reaction determine the reaction. At temperature of only 60 K higher, the reaction rate of zinc sulfide with metallic iron under nitrogen stream was comparable with that under vacuum.

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Thermodynamic consideration of melting of copper based alloys with cerium and neodymium were carried out at 1,623 ∼ 1,773 K and 1,523 ∼ 1,775 K, respectively. Solubilities of cerium and carbon in liquid copper in the presence of C-CeC2 and those of neodymium and carbon in liquid copper in the presence of C-NdC2 were determined: Cerium solubility in liquid copper under C-CeC2 equilibrium was obtained as log (CCe /mass%) = 0.424 + 3.59 × 10-4 T (1,623 ∼ 1,773 K) Neodymium solubility in liquid copper under C-NdC2 equilibrium was obtained as log (CNd /mass%) = 0.492 + 3.15 × 10-4 T (1,523 ∼ 1,775 K) Based on the results of cerium and neodymium solubilities, activity coefficients of cerium and neodymium in liquid copper were calculated: logγCe = -0.035 - 3.81 × 10-4 T - 3.29 × 103/ T (1,623 ∼ 1,773 K) logγNe = -0.638 - 3.15 × 10-4 T - 4.98 × 103/ T (1,523 ∼ 1,775 K)

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