The phase relations in the system Cu-Fe-S, especially the one among chalcopyrite, cubanite and pyrrhotite, were studie at temperatures of 600°, 700° and 800°C by synthesis using the rigid silica glass tube method.The total composition of samples was selected as it ranges on the line which connects CuFeS₂ and FeS.Electron probe microanalysis was applied for the determination of the composition of synthetic products, especially for that of the phase boundaries of chalcopyrite and pyrrhotite solid solutions. The following results were obtained.(1) The complete solid solution between chalcopyrite and pyrrhotite would not be formed even above 800° at the present experimental condition, because the region of pyrrhotite solid solution extends to the sulfer-rich direction while that of chalcopyrite solid solution retreats to the copper-rich side at temperatures above 600°.(2) The most iron-rich end of the chalcopyrite solid solution shifts from the slightly iron-rich composition to the iron-poor one than cubanite when the tethperature of synthesis rises from 600° to 800°, though the boundary of the region was unable to determine precisely by EPMA.(3) Pyrrhotite can contain Cu approximately 2.5 wt.% at 600°C, 4% at 700°C and 6% at 800°C.(4) Some causes of error at the analysis of composition by EPMA are discussed briefly.

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The present paper describes the results of theoretical investigation into determining the stress in the rock unaffected by boreholes or drifts from the strains or deformations measured in those openings. It is pointed out that when the stress in the rock is determined from variations in borehole diameter or from strains on the bottom surfaces of boreholes, measurement should be made at least in three boreholes, while we can determine the stress in the rock from strains on the wall surface of at least either a boreholes or a drift, or from deformation of a borehole. For all cases the formulae to be used in practice for determining the absolute stress in the rock are presented and the accuracy in the stresses obtained by these formulae is discussed.

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The problems of hydraulic transportation in pipe were studied and discussed by many authors, but fundamental. study of movement and behavior of a single particle in pipe were not yet carried out in Japan.
The authors analysed this probleme experimentally referring to the experimental results of Smolyzuilev in Russia, and obtained many new relations between parameters of a single particle transportation in pipe, that is, relations between velocity of a particle, mean velocity of water in pipe, specific weight of particles, and size of particles and pipe etc. were obtained.
These relations reveal us characteristic of behavior of a single particle in water pipe.

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The author made some studies about the safety of induction radio's lines which are used in coal mines.
The carrier waves which have been taken up in this research are the kilocycles of between 100 and 250 per second.
Results obtained till now are following:
i) In the case of ignition against methane mixture.
a) Ignitions occur at the sparking power of 3.5VA, when the line is broken during the carrier wave is being transmitted.
b) Ignitions occur at the sparking power of 0.78VA, when the line is disconnected by an occident during the modulation wave is being transmitted in the cable.
c) Ignitions, occur at the sparking power of 9.8VA, when induction wire line is being earthed in some occidents.
ii) a) lgnition power may be 28.8VA, when the wire cables connecting to the detonators are earthed, that are placed paralell with the induction systam.
b) Detonators ignite when the power comes up to 33.8VA, at the terminal of the transmitter. This is the case when the current has been originated in the cable of connecting to the detonators by inductive action of the paralell placed trans mitten line.
c) The minimum electric power what is able to ignite methane mixture or detonators is affected by impedance of the terminals, frequencies of carrier waves and the length of the induction line.
It is necessary that these conditions must be satisfied in order to keep the safety from methane mixture or detonator ignition, if we use the induction lines in the underground of coal mine.
1) Frequencies of the carrier waves must be between 160 and, 200kc/s.
2) Impedance of the high frequency terminal is to be below 150Ω.
3) Out-put of the transmitters does not exceed 5VA.

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The activation of multivalent anions in the amine flotation of oxide minerals has been investigated by means of flotation tests and the measurements of ζ-potential.
Though rutile, zircon, ilmenite, hematite and corundum are activated by the addition of multivalent anions such as SO^2-₄, PO^3-₄, or (COO) ^2-₂in the acidic pH range, magnetite, feldspar and pyroxine are not activated. Quaetz is activated only in the case of addition of (COO) ^2-₂.
The ζ-potential of rutile, ilmenite, or hematite increases negatively with the concentration of these multivalent anions and changes from positive to negative values at the pH values lower than zero point of charge.
From the above experimental results, the activation is probably caused by the specific adsorption of multivalent anions on the surfaces of oxide minerals.

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We already reported some results obtained from a series of experiments on “Extraction of Nickel from Laterites or Garnierite ores by Segregation Process”, which were carried out in a laboratory scale.
Using a rotary kiln, flotation and magnetic separation, the segregation process has been done on a semi pilot plant.
Using a rotary kiln, flotation and magnetic separation, the segregation process has been done on a semi pilot plant.
The nickel concentrates have been obtained in 85-90% Ni recovery and 12-25% Ni content.
The high Ni concentrats could be graded up to 35-40% Ni by combined process of flotation and magnetic separation.

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