The Tamano Smelter is a large scale coastal facility which started operations in 1972 employing the FSFE process. The FSFE is a Outokumpu type flash smelting furnace to which electrodes have been added to the settler and the up-take is equipped with a water-cooled jacket. With respect to hearth maintenance and the elimination of boiler trouble, this type is superior to the conventional type flash smelting furnace.
In the initial start-up, the Tamano Smelter was producing 101, 000 tons of anodes a year, and through the introduction of a two step oxygen enrichment, process production has been increased to the present 196, 000 tons per year. During this period the two so called oil shocks of 1973 and 1979 resulted in a dramatic rise in energy cost. To cope with this an energy saving program was instituted to reduce production costs.
This paper focuses on the energy savings associated with the flash smelting furnace. First, the water-cooled up-take was replaced by a boiler from which waste heat could be recovered, and secondly, the fuel was changed from heavy oil to coke. In addition, the fuel change resulted in an auxiliary benefit. Through the development of a FSFE operational technology called carbon monoxide concentration control, the special qualities of coke could be utilized and the charging of the electrodes in the settler was eliminated.

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Although the Kamioka Mine faced a crisis in the past several years, it has regained its competitiveness and profitability by streamlining the operation. The management set the followings to double its productivity as their challenging goals:
(1) Increasing the production capacity from 3, 500 to 4, 000 tonnes per day
(2) Developing a highly productive mining system-Super Mechanized Cut & Fill method
(3) Streamlining the administrative and service departments
As a result, the following achivements have been made over the past four years
(1) Doubled the labour productivity to 45 tonnes per man shift
(2) 32 percent decrease in the operating cost
(3) The ratio of net profit to net sales has increased to 38 percent.
This paper describes the achievements of the management that revived the international competitiveness of the Kamioka Mine.

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A series of fire experiments have been carried out, using a 1/6 scale model gallery lined with three-piece timber sets in order to investigate the effect of some practical conditions such as ignition intensity, air velocity and fuel load density on spread characteristics of mine fires.
The results of the investigation are summarized as follows;
(1) The characteristics of timber fire spread are greatly affected by ignition intensity. Fire along timber sets loading 25 kg/m³ of fuel density is able to spread leeward in case ignition intensity is more than 60 kWh/m³ and develops into fuel-rich type when intensity exceeds 480 kWh/m³.
(2) Timber fire shows oxygen-rich type combustion when the air velocity is 0.5 m/s to 1.0 m/s. Fire is intensified as air velocity increases and a phenomenon of fuel-rich type is observed in which most oxygen is consumed when the air velocity is between 2.0 m/s and 5.0 m/s.
(3) Timber sets are revealed to be most combustible in case fuel load density is 20 kg/m³ to 40 kg/m³ and fire is intensified with the increase of fuel load density in this region. Timber lined zones in which fuel load density is less than 10 kg/m³ can be regarded as quasi-non-combustible zones because no fire spread was observed.
(4) Fire in a timbered gallery can be classified into four groups, i. e., fuel-rich, oxygen-rich, oxygen-poor and fuel-poor by the relation of air velocity to fuel load density. A new calculating method using basic equations on combustion conditions during fire spread is proposed by which fire spread rate and length of fire zone can be estimated on the basis of fuel-air ratio and other factors.

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An electric conductivity method was applied to the measurements of local concentrations of spherical particles in slurry.
A probe, equipped with two ringlet electrodes on its surface, was utilized for measuring the resistivity of water and slurry.
An AC source was used to supply current to the electrode circuit and this was effective in eliminating the accumulation of scales and bubbles which gave rise to instability on the electrode surface.
Since the resistivity increment due to solids was expressed as the relative resistivity divided by that of water, the effects of water resistivity fluctuation and position relative to the pipe wall were eliminated.
Probe calibration carried out both in fluidized tests and in flow tests through a vertical downward pipe showed dependence on particle size.
The data obtained by the two methods indicated different tendencies; the fluidized tests were plotted as straight lines and the flow tests were plotted as curved lines on log-log representations.
Since the discharge concentration calculated using the calibration curves from the fluidized tests showed lower values in the high concentration region, the calibration curves obtained from the flow tests were used for concentration measurement.
The curves were well represented by a modified version of Maxwell's equation including compensated terms for particle size and concentration.
The accuracy of the calculated discharge concentration in a non-conductive horizontal pipe and in a conductive vertical pipe was 7.1% in the worst case.
Although the application of this method was limited to particles with narrow size distributions, a consistent picture of solid concentration profiles could be presented.

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This paper reports on an acoustic emission method and a DC electric potential method, as the measure for evaluating the progression of cracks during the fatigue test, of curved steel wires under both tension and pulsating bending.
The cumulative count of the AE event and the electric potential ratio (potential/initial potential) those increase with growing of a crack are shown. Considering the relation between electric potential ratio and relative crack depth, the initiation and growing of a crack are also investigated.
The results are as follows.
(1) Crack initiation happens at about 40% of total lifetime.
(2) Crack grows rapidly in the last several minutes before failure.
(3) Increment ((ν-ν_o)/ν_o) of electric potential-ratio (ν/ν_o, νo: initial value) is approximately proportional to the three-halves power of the area of the fatigue fractured region in a specimen.

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The extractions of aluminium and gallium from sodium hydroxide solutions containing organic acid (citric; H₃Cit, tartaric; H₂Tar, succinic; H₂Suc and lactic; HLac) have been investigated by using a trioctylmethylammonium chloride (TOMAC; R₃R'NCl) in benzene.
The presence of organic acids in the aqueous phase increases the distribution ratio in the order; H₂Tar>H₃Cit>HLac>H₂Suc, corresponding to the order of those acid dissociation constants (K₁). The extraction curves are similar to each other, and the distribution ratios decrease monotoniously with increasing aqueous pH, although the order of extraction efficiency is Al>Ga. The complexes formed in the organic phase contain M/Tar/R3R'N with the molar ratio 1: 2: 1, indicating the stoichiometry R₃R'NM (Tar) 2, in which M denotes Al and Ga. Therefore, the following mechanisms are proposed for the extraction of aluminium and gallium:
M(OH)_4(a)^-+2H₂Tar_(a)=M(Tar)_2(a)^-+4H₂O_(a)(1)
HTar_(a)^-+R₃R'NCl_(o)=R₃R'NHTar_(o)+Cl_(a)^-(2)
M(Tar)_2(a)^-+R₃R'NHTar_(o)=R₃R'NM(Tar)_2(o)+HTar_(a)^-(3) where (a) and (o) represent aqueous and organic phases, respectively. These results are also confirmed by infrared spectral measurement of the extracts.
With increasing temperature, the distribution ratios slightly decrease for both metals.

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In order to recover valuable metals from steelmaking dust, molybdenum and chromium have been leached from the dust with water and NaOH solution at several temperatures. Some experiments for the utilization of these valuable metals leached have been tried by means of various treatment methods. The experimental results obtained are summarized as follows:
(1) When the steelmaking dust was leached with water, a neutral aqueous solution was changed to an alkali solution because of the dissolution of Na₂O contained in the dust and pH of a leaching solution showed an alkali value more than 11.5. The leaching degrees of molybdenum and chromium in this water leaching process exceeded 80 percentage at the temperature of 333 K.
(2) Molybdenum in the leaching solution was recovered in the form of molybdenum trisulfide powder by H₂S gas injection and chromium was recovered in the form of hydroxide precipitate.
(3) A systematic treatment diagram on the basis of the results obtained was proposed for recoveries of molybdenum and chromium from the steelmaking dust.
(4) By a vacuum heating process molybdenum disulfide was prepared from molybdenum trisulfide.

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The application of the anomalous X-ray scattering (AXS) technique has been tested for obtaining qualitative and quantitative powder diffraction analysis of a multi-component mixture having a relatively complicated chemical composition and containing two elements of nearly the same atomic number. The system selected for analysis consisted of three chemically different mixtures of Cu₂S and CaFe₂0₄. The differential intensity pattern obtained from the measurements at two energies, 8.955 keV and 8.680 keV, corresponding to 25 eV and 300 eV below the Cu K absorption edge (8.980 keV), enabled the isolation of the Bragg reflections of Cu₂S from the calcium ferrite matrix and provided information for the quantitative determination of the Cu₂S component. The results indicate that the AXS technique is promising in reducing the unsolved difficulties associated with the conventional X-ray powder diffraction method. The quantitative analysis of Cu₂S in industrial copper smelting slags was also carried out by this new method

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