Akabira Colliery has been opend since 1938. The mine has many minable coal seams and is recentry extracting six seams, of them. The seams incline steeply toward syncline axis which runs across the central part of the mine from south to north. The mine has continued to product annualy washing coal from 1Mt to 2Mt since 1960's on a condition that there were mining trouble and safty caused by many faults and a lot of methane gas flow.
In 1986, a change of coal situation that a demand of domestic coal took a sudden turn for the decrease because on an amendment of coal policy in Japan made Akabira Colliery determine to improve the basic structure of mining and safty. As the result, the structure of ventilation and transportation was simplified and made more efficient. And mining inside the shaft saftypillar has become a necessity. Heavy mechanised mining system replaced manual one. Akabira Colliery has become a new mine and come to be able to continue production in spite of severe situiation of domestic coal. Since the shaft is apt to be influenced or possibly damaged by ground movements, the prediction of shaft behavior due to mining, the monitoring of shaft deformations, and the repair of shaft damage should be executed as precisely as possible.
This report shows experience of a drastic remodeling of mining structure and safty one which was carried out at Akabira Colliery from 1986 to 1994.

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Consideration was made on the chemical species of cobalt ions in aqueous solution, which are necessary for reproducing experiments on the hydrolysis of cobalt nitrate and on the neutralizaion of cobalt nitrate solution with sodium hydroxide. Model analysis based on the chemical equilibria among these species was carried out, to obtain concentrations of these species as a function of the concentrations of cobalt nitrate for the hydrolysis experiment and of the concentrations of sodium hydroxide for the neutralization experiment. A general feature of the data both on the hydrolysis of cobalt nitrate and the neutralization can qualitatively be reproduced, by assuming chemical species of Co²⁺, CoOH⁺, Co (OH) ₂, Co(OH) ₃^-, Co(OH) ₄^2- and Co₂0H³⁺. A quantitative agreement between data and calculations, however, is not satisfactory, which suggests the necessity to further take into account of the existence of polynuclear complex ions of cobalt in the aqueous solution.

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Phase changes during the solidification of Bi-Pb-Sr-Ca-Cu-O melt were studied. Under solidification processes with constant cooling rates of 0.001-10°C/s, Bi₂Sr₂Ca₂Cu₃O_x (2223) is not formed but Bi₂Sr₂Ca₂Cu₃O_x (2212) and Bi₂Sr₂CuO_x (2201) are observed. The time-temperature-transformation (TTT) diagram in the solidification of the melt is proposed based on the results of X-ray diffraction (XRD) analysis. A high-Tc superconductor phase of 2223 is formed through the isothermal treatment at 850°C fora, ove 150ks.The analyses of XRD and scanning electron micrograph (SEM) with energy dispersive X-ray (EDX) suggest that 2201 needles are crystallized at the interface between (Ca, Sr) ₂CuO₃ crystals and melt, and the part of 2201 crystals transforms to 2212 and 2223 crystals by the diffusion of Ca, Sr, and Cu ions.

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Water-miscibility of some glycol ethers, alkyl phosphates, and TBPO has been determinedin a temperature range of 278-333 K. Solubility isotherms and phase relations have been measured for the ternary systems, salt-water-organic liquid. TMP, TEP, and TEGBE are miscible with water in the temperature range. TBPO, EGBE and DEGHE are partially water-miscible and have LCST of 286 K, 322 K and 298 K respectively.
Mutual solubility of the solvent mixtures is sensitive to salt concentration; salt effect enlarges miscibility gaps in the partially miscible systems; TMP-water mixture with sulfate shows a lower consolute temperature. Salts are concentrated into a water-rich phase or crystallized in a homogeneous region, depending on the composition of solutions.
Characteristics of these mixtures may be applicable to the processes for purification of waste water, or recovery of metals from dilute solutions. The organic liquid used can be recovered by a small change in temperature or salting-out process from the aqueous solutions. The watermiscible solvents are also separated from solutions by extraction with another organic liquid having temperature-sensitive mutual solubility.

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This paper proposes a computer model of ore pile for scooping task planning. Ore pile has irregular shape which changes during scooping operation. For the effective task planning in the autonomous scooping system, it would be required to predict the change of pile shape due to gravity flow of rock, initiated by scooping.
The proposed model is composed of column elements which simplify the structure and shorten the processing time. The working place is tessellated into sections which are bases of the columns. The hight of a column represents the hight of ore at the center of corresponding section. However, the size of each section and the unit hight of column are not coincident with particle size of ore. The model represents the shape, mass and falling behavior of the pile under the assumption which simplifies the falling motion of ore particles.
The small scale experiment of scooping in laboratory shows that the predicted shape and the measured shape after each scooping are consistent with each other, and the predicted and measured scooped volume at each scooping are agree very well. The proposed model has sufficient accuracy and performance for the scooping task planning.

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In the temperature range between 600° and 965°, the progress of the reactions in NdF₃-Ca-CaCl₂ reaction system had been observed by use of a'hot thermocouple with a scoop' apparatus which was first introduced here for the direct visual observation of high temperature solid-solid or solid-liquid reactions. The direct visual observation with X-ray diffraction analysis revealed that in prior to reduction of NdF₃ a low melting liquid phase containing 0.8 wt.% of NdF₃ was primarily formed through the interaction of solid CaCl₂ at around 700°. The liquid was comprised of NdF₃, NdCl₃, CaCl₂, and CaClF. It clearly indicated that the reduction reaction of NdF₃ with Ca in Ca saturated Ca-CaCl₂ melt was a homogeneous liquid-liquid reaction and its reaction rate was fast. The Nd metal was produced as aggregates of each particulate because the reaction sites of NdF₃ are not confined at the NdF₃ surface but dispersed in the molten salt.

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A large amount of the so-called rhodan waste solution that includes ammonium thiocyanate and ammonium thiosulfate is produced by the treatment of coke oven gas at the iron and steel manufactures, and this solution is combusted without utilization. This report is a basic research for using the rhodan waste solution to remove copper from iron scrap. The effects of the concentration of thiocyanate, oxidizing agents, pH and a temperature on the dissolution of copper were studied. Both Cu (II) and oxygen gas are necessary for an effective dissolution of copper, and the value of pH in a solution must be kept at 9. The dissolution rate of copper increases proportionally with the concentration of thiocyanate at its lower concentration, In this case, the rate-determining step is assumed to be the chemical reaction on an anodic site of the surface of copper. At the higher concentration of thiocyanate, the dissolution rate of copper hardly depends on the concentration, but it depends on the concentration of Cu (II). In this case, the rate - determining step is assumed to be the diffusion of Cu (II) on the cathodic site of copper. The reactions are considered as follows: Cu+2SCN^-+Cu (NH₃) ₄²⁺ =2CuSCN (s) +4NH₃
CuSCN (s) +SCN^-=Cu (SCN) ₂^-
Cu (SCN) ₂^-+4NH₃+H⁺+1/2O₂=Cu (NH₃) ₄²⁺+2SCN^-+1/2H₂O

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The Tower Mill KD-2 is a modified version of the Tower Mill KD-1 developed for grinding limestone. In comparison with KD-1, this new equipment is performed with three clearly defined parts: comminuting, classifying and collecting. Furthermore the inside diameter of the column classifier was enlarged (to 780mm) to regulate of ground particle velocity and the comminuting cell provided with two tapers (slope at the bottom of comminuting part) of different size.
Experiments were carried out to investigate the taper effect on ground particle. As a result, weights of products and the 50% particle diameters were found higher using the small taper than the big one, but the maximum values of the diameter of the ground particles (Dmax) were similar.
In regard to D_max compared with the Tower Mill KD-1, the following have been established: 1) Pulverization of limestone under a flow rate lower than 0.06m/s is improved using the Tower Mill KD-2 and the minimum D_max value is founded to be a 15.5μm.
2) D_max values distribution above the estimated curve assumed by stokes's law indicate that it will be possible to produce finer particles by improving the classifying part.

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The waste water treatment in mineral processing involves to fasten the settling velocity of suspended fine particles by flocculation. Although this method is largely established as an engineering technique, clarification of some parameters would lead to the understanding of the process. With this purpose, further investigations were made using quartz particles (Q89) and fluorite particles (F91) which including 58.8% and 65.8% of -2.31μm particles respectively, are negatively and positively charged respectively in aqueous solution.
In the experiments conducted with mixture of minerals, variation of the pH value of the aqueous suspension containing equal quantities of quartz (Q89) and fluorite (F91) had led to the heteroflocculation of particles in a range of pH below 10. It was noticed that maxi: mum particle size of the heteroflocculation was 37.0-26.5μm. This size was about three times larger than in using quartz particles (Q84) and fluorite particles (F85) which included 32.4% and 40.4% of -2.31μm particles respectively. Besides, in the experiments using Q89 and F91, the maximum size of single particles taking part in the heteroflocculation process was found to be -54μm instead of -3.27μm as was observed in Q85 and F85.

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A method of hydrothermal treatment has been tested to refine low-grade Amakusa pottery stones in both size ranges from 2.36 to 4.75 and from 4.75 to 9.5mm in order to upgrade for pottery use. Hydrochloric acid, 0.14mol/l, with addition of aluminum chloride is proved effective to alter albite into kaolin mineral under the hydrothermal condition at 200°C. This improves in the refractoriness of the treated samples as much as the same grade of the common high-grade Amakusa pottery stone. The treatment contributes to whiteness by decreasing Fe₂O₃ content of the products.

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