Kushiro Colliery operates with underground mining as one of the largest coal production in Japan, and supplies to power stations with about 25% demand of domestic steaming coal. The colliery produces about 80% raw coal by mechanized longwall mining introduced from 1967 which is composed of Drum Shearer, Shield Supports, A.F.C and Stage Loader.
The large scale production by longwall mining brought into various problems on the safety and productivity such as lower coal recovery ratio, deeper coal fields, and the rise of mining cost.
Kushiro Colliery have been developed new mining techniques accepted hard-ware and soft-ware to improve the coal recovery ratio and to suppress the deeper coal fields. At present, the colliery is strongly performing higher efficiency and safety of mine management by means of the reformation of working systems, the early construction of main roadways for new coal field and intensive transportations, and the completion of safety education.
Realization of various mining techniques have been pulled through the reduction of mining cost and managing inovation on the serious colliery management.

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The high appreciation of Japanese Yen since the second half of 1985 has adversely effected the profitability many metal mines in Japan.
Toyoha mine also has difficulties in returning a profit during the early stage of the highly appreciated Yen period.
To break through this crisis and to give the Toyoha operation a promising future, the following measures were executed.
(1) Implementation of an effective exploration program following a comprehensive geological study of potential ore bearing formations, and the rapid developments of mining access and associated infrastructure.
(2) Technical developments for the improvement of mining, milling and flotation operations.
(3) Rationalization of the administrative and service sections.
Over a five years long period, the following results have been attained, and Toyoha Mines Co., Ltd. has survived.
(1) An increase in the mineable ore reserve by 5 million tonnes in conjunction with an increase in the grade by a factor of 1.2.
(2) Total productivity increased by a factor of 1.6.(Underground productivity also increased by a factor of 1.8)
(3) A 24% decrease in the total operating cost.(including yearly wage increases)
(4) The ratio of “profit before tax” to “sales” increased to 27.2%.vThis paper details both the measures for improving the operating efficiency and the achievements of every section within Toyoha Mines Co., Ltd.

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The Miike Coal Mine, the largest and oldest coal mine in Japan, has to cope with such problems, as the extension and deepening of mining areas. This mine has maintained a policy of giving priority to increasing coal production for many years. However, this mine, like other coal mines in Japan, is obliged to reduce production according to The 8th Coal Policy of the Japanese Government.
In this difficult economic environment the Miike Coal Mine has been making extensive efforts to rationalize mining operation by integrated mechanization.
The results of this rationalization are summarized as follows.
(1) The shift of production structure of 4.5 million tons (salable) from 3 pits comprising 10 coal faces, to 2.5 million tons from 1 pit comprising 2 coal faces.
(2) Improving of overall productivity from 106.3 tons/man.month in 1986 to 127.3 tons/man.month in 1989.
(3) Production cost savings of 10%.
(4) Improving of safety from an accident rate of 35/million workers in 1986 to 26/million workers in 1989.

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Four kinds of copper concentrate of different compositions were oxidized in N₂-O₂ gas stream. The dependence of the desulphurization reactions on oxygen partial pressure and wall temperature was examined. X-ray diffraction pattern analysis of the cinders showed that copper concentrate was thermally decomposed, and the FeS formed simultaneously was oxidized to Fe₂O₄. The non-isothermal oxidation of copper concentrate particles was described using an unreacted core model of copper concentrate covered with an outer product layer of magnetite. The frequency factor k₀ of the interfacial reaction rate constant was determined so as to fit the calculated desulphurization curve to the observed curve. It was found that the k₀ value significantly decreased with an increase of p_O2. Moreover, k₀ for CuFeS₂ was larger and it decreased with the amount of FeS₂ contained in the copper concentrate.

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The effect of gelatin as an additive on the electrodeposition of copper in acidic copper sulfate solution was studied by impedance measurement. The crystal orientation of the deposits were investigated by X-ray diffraction (XRD) and the morphology by scanning electron microscopy was explained relating to it. Gelatin is a polarizer due to the adsorption on the electrode surface and it inhibits the growth and so iet the nucleation rate faster. Fine crystal structure were observed when gelatin was added to the solution. When current density is 560A·Em^-2, the addition of gelatin has specific influence on the orientation of Cu deposits and the deposits has a (200) preferred orientation structure, but the preferred orinetation of (200) disappears if gelatin were added too much.

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Zinc leaves electrodeposited at the zinc-sulfate solution/n-hexyl acetate interface at various applied potentials were investigated electrochemically and metallographically. Two types of zinc leaves, spoke-like and filmy deposits, were observed at the interface; spoke-like deposits grew at higher applied potentials, i.e., at higher current densities, and filmy deposits at lower applied potentials, i.e., at lower current densities. The filmy deposit consisted of two layers: one on the organic liquid side was lustered and dense, the other on the aqueous solution side was dark-grey and composed of aggregate of fine spokes. The thickness of the layer on the organic liquid side was about 1 μm and that on the aqueous solution side was about 30 μm at an applied potential of 0.5 V. As the applied potential became higher, the layer thickness increased.

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In response to the progress of electronic equipment/appliances/instruments, there is a strong demand for the batteries of higher capacity, ligter weight and smaller size.
In order to fulfill this requirement, new materials for the higher performance batteries have been actively researched and developed.
Conductive polymers have been marked as promising candidates to satisfy for the demand.
Polyaniline is now being expected as an attractive conductive polymer in its chemical and thermal stability along with the ease of production process of controllable electrolysis.
The shape of the polyaniline prepared changed with the kind and concentration of the electrolyte and with the current densities applied.
The discharge capacity was also related to the shape: especially fibrous polyaniline with the capacity above 100Ah/kg was better than others.
All the polyanilines synthesized by the eletrolysis showed high coulombic efficiencies above 90%.

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Silicon nitride is one of the excellent candidates for the high temperature structural component. Then silicon nitride was joined to itself with Cr-N, Fe-V and Al-SiO₂ system by HIP (hot-isostatic-pressing) process. The structure of joining interface was analyzed by the SEM and EPMA, and the bond strength of the joint was measured by the three-point bending test. The results obtained are as follows: Silicon nitride encapsulated into the stainless steel pipe after coating Cy-N was bonded by HIP'ing at 1, 473K. The obvious boundary in the joining interfacial layer was not observed. In case of the capsule-free HIP'ing with N₂ gas, these silicon nitride specimens were bonded at 2, 123K. Using Fe-V, the high bending strength of joint was also obtained by the capsule-free HIP'ing with N₂ gas like the case of Cr-N joining. The joint with Al-SiO₂ system by the capsule-free HIP'ing with N₂ gas had the same strength at the elevated temperature such as 873K comparing to the room temperature, because the compound concerned with Si-Al-O-N was produced at the joining interface.

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The oxidation of manganous ion by ozone has been investigated in sulfate solutions under the following conditions: the initial concentration of manganous ion. 0.4to2.0g/l; pH, 1.0 to 7.0; temperature, 25.0 to 80.0°C ozone partial pressure, 7.1×10^-3 to 2.3×10^-2 atm.
1) The oxidation was found to be significantly promoted by an increase in an ozone partial pressure and a vigorous agitation.
2) The oxidation reaction followed a zero order at pH below 4.5, the rates being virtually constant down to low concentration of Mn²⁺. The final product was determined to be MnO₂ in this pH range.
3) The reaction was found to proceed at pH lower than 4.5 according to the relationship.
-d [Mn²⁺]/dt=κ[O₃ (aq)][H⁺] ^-0.12 exp (-5000 (cal/mol)/RT)(mol/l/min)
4) Mn₂O₃ as well as MnO₂ was considered to take part in ozone oxidation at pH above 5.0, where the rates slightly decreased as the reaction proceeded.
5) The oxidation was not remarkably promoted by a rise in temperature. A reduced reaction rate was observed at 80°C probably due to a reduced stability of ozone in the solution at elevated temperatures.

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Exit gas from a coke oven is treated to eliminate sulfur and cyanate with aqueous ammonia, and the waste solution from this process includes about 11% NH4SCN and about 9%(NH4) 2S203. The solution, however, is only disposed of after combustion. Fundamental researches were made on the utilization of the solution in dissolving metals or metal oxides.
The effects of concentration of thiocyanate, quantities of oxidizing agents, pH, and temperature on the dissolution of silver were studied.
The following have been concluded:
1. Fe (III) and oxygen gas are necessary to dissolve silver. The pH value of the solution must be below 3 for keeping a sufficient concentration of Fe (IlI).
2. Dissolution rate of silver is proportional to the concentration of thiocyanate at lower concentrations ofthiocyanate, but, at higher concentrations, it becomes constant independently of the concentration.
3. When the concentration of thiocyanate is high enough to make the dissolution rate of silver independent of the concentration, the dissolution rate increases almost proportionally to the increase in the concentration of Fe (III).
4. When the dissolution rate is almost proportional to the concentration of Fe (III), the rate-determining step is the diffusion of Fe (III) ions to the surface of silver particles.
5. When the rate is proportional to the concentration of thiocyanate, the rate-determining step is the chemical reaction of thiocyanate with silver on anodic sites on the surface of silver particles.
6. Overall reactions are considered as follows:
Ag+Fe (SCN) _b ^(b-3)-+a·SCN^--Ag (SCN) _a ^(a-1)-+Fe (SCN) _c ^(c-2)-+ (b-c)·SCN^-Fe (SCN) _c ^(c-2)-+ (b-c)·SCN^-+H⁺+1/4 O₂-Fe (SCN) _b ^(b-3)-+1/2H₂O

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Many factors which affects the anode passivation during electrolysis were discussed in this paper. These includes the amount of slime and slime adhesiveness. The internal factors which affects the amount of slime include the type, concentration and the form of impurities which exists in the anode. The external factors include the concentration of the dissolved oxygen and the impurity ions in electrolyte or the electrolytic condition such as current density.
The anode impurities showed different behaviour of dissolution state according to the various forms of existence and the varying chemical properties of these elements or compounds. The anode slimes are formed either by dissolving of these impurities in the electrolyte at the anode or by remaining on the anode surface. The amount of these slimes greatly affects the occurence of passivation.
It was clarified that the coexistence of oxygen together with elements such as S, As and Bi in anode affects the amount of slime, adhesiveness and therefore also affects passivation. The possibility of passivation increased markedly with increasing current density, dissolved oxygen, impurity ions, as well as the concentration of H₂SO₄.

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A TiN film has been deposited on austenite stainless steel and high speed steel in arc ion plating system.
Adhesion between the coating film and the substrate was measured by scratch tester, and internal stress of the coating film was determined by X-ray diffraction.
The result showed that adhesion depended on film thickness and substrate hardness and that compressive internal stress of TiN film tends to weaken adhesion between film and substrate.
Further, acoustic emission signals generated during scratch test was measured by the elastic wave measurement system connected to the scratch test equipment. The result showed that acoustic emission intensity linearly decreased with increasing compressive internal stress of coatings.
The analysis by scratch test connected to the elastic wave measurement system will be useful to estimate mechanical properties of thin solid films.

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