This paper describes a study on the states of stress and deformation around the bottom of a circular vertical shaft by means of analysis of finite element method.
The problem is solved by the application of non-linear stress analysis considering the ground as the media under conditions of plane strain and axisymmetric strain.
In this analysis, the authors assume that the ground has a non-linear stress-strain relationship which is derived by using Mohr's yield criterion modified by Griffith's theory of fracture.
From the calculating results, the extents of loose range in the ground around the shaft are, moreover, investigated for two kinds of strength of the material of ground.

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In this paper, the authors report a testing method of torsion of rock substance. The test piece for the torsion test is prepared by the following procedure. A boring core of rock sample is glued to steel end-pieces by means of an alignment jig. As drying out thl glue, the section of rock cylinder is reduced by 20-30% over three quaters of its length using the grinding lathe, so that the centre line of the reduced section (effective section) of rock cylinder might coincide the centre line of the steel end-pieces. This procedure is applied to furnish the test piece for the uniaxial tension test of rock substance.
The angle of torsion is measured with the double mirrors double reflecting type optical lever, the advantage of which is the insensivity to the rotation of the test piece.
The modulus of rigidity measured by the torsion test mentioned above is compared with ones calculated from Young's modulus and Poisson's ratio measured by the uniaxial compression and tension test. It is revealed that the modulus of rigidity obtained from the torsion test is smaller than one obtained from the uniaxial compression test and greater than one obtained from the uniaxial tension test.

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The equation of motion for solid material in hydraulic transportation was expressed as
T=F+G
and, it was described in the 1st Report that thrust (T) was given as
T=n_s C_D0γω/2g (ν_m-ν_s) 2a_s
C_D0=drag coefficient of particle alone
The authors examined experimentally and theoretically variation of drag coefficient by increase in the mixture rate.
As a result, in order to calculate the drag coefficient, the authors formed a clear definition of terminal velocity (ν_f) of particle group.
ν_f=ν_f0 (1-3/2q)
ν_f0=√4(ρ-1)gds/3C_D
C_D=drag coefficient of particle group
According as mixture rate of particle group increases, the drag coefficient (C_D) multiplies in the case of rock and water mixture, but does not multiply in the case of coal and water one.

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In the previous paper, the buckling of a pipe due to its own weight was examined with various lengths, diameters and materials.
Otherwise, the buckling of the pipe supported at the upper end was investigated theoretically and experimentally in this report.
Considering the above condition, the differential equation of the deflection curve of the buckled pipe is showed (1) and this solution is obtained as follows, (2) or (3) where N2=holizontal reaction force R₂=vertical reactionforce n, a₁, a₂=constants
As the equation (3) was suitable for our experimental condition, the deflection of the buckled pipe was calculated by using the equation (3), and authors could obtain satisfactory results that the upper expression was fitted for the above mentioned condition.

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The kinetics for the copper ion adsorption on sphalerites of various iron contents was studied by measuring the adsorption of copper ion in the presence of oxygen and in the oxygen-free circumstances.
The relations between the copper ion adsorption rate and the agitation rate were characterized by a straight line in the log-log plot. With the increase of iron contents in sphalerite, the copper ion adsorption rate on sphalerite decreased in the case where oxygen was sufficiently dissolved in the copper ion solution and the pH was high enough.
The reaction rate of the copper ion adsorption on sphalerite changed from the rate of the parabolic function to the rate of the exponential function with the increase of iron contents in sphalerite. As a result, in the abovestated conditions, it was surmised that the kinetics for the copper ion adsorption on sphalerites of various iron contents was considerably complex. The kinetics for the copper ion adsorption on pyrrhotite was explained by the protective film theory.
From the above results, it may be considered that the dissolved oxygen in the pulp is one of the important factors for the copper activation of sphalerite.

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At Uchinotai Mill of Kosaka Mine, Cu-Pb bulk concentrate is floated, depressing Zn and Fe by sulphurous acid. Formerly, Pb was floated from the bulk concentrate by sodium cyanide to depress Cu minerals. But this method, as known well, was not always economical because of soluble loss of valuable metals and high operating cost. Recently, as a result of laboratory flotation tests using relatively pure galena and chalcopyrite, it was found that pulp heating was an effective means to depress galena, and float chalcopyrite. Flotation tests from Cu-Pb bulk concentrate (16.7% Cu, 13.7% Pb) showed that after pulp heating up to about 70°C for several minutes Cu concentrate was floated without additional reagents. Tailing became Pb concentrate.
By repeating these laboratory and continuous flotation tests, we decided that this method could be applied to practice. So the new flowsheet of Cu-Pb separation has been introduced at Uchinotai Mill since Nov. 1968.
Operation is now going on favorably.

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Thermodynamics of copper mattes in Cu₂S-PbS system and copper saturated-mattes in Cu₂S-PbS-Cu system were studied in the temperature range from 1, 150°C to 1, 250°C.
The vapor pressures of PbS or Pb in these mattes of various compositions were measured by the dew point method and the thermodynamic functions were calculated from this experimental data.
In Cu₂S-PbS system, the activity curve of PbS deviates positively from Raoult's law in the mole fraction range of PbS from 0 to 0.3, negatively from Raoult's law in the mole fraction range of PbS from 0.3 to 1 and the activity curve of Cu₂S deviates positively from Raoult's law. The values of activity coefficient, γ are 0.3-3.0 for PbS and 1.0-1.4 for Cu₂S.
By using these activity data, free energy change, enthalpy and entropy change of mixing, and chemical potentials of PbS, Cu₂S in Cu₂S-PbS system were obtained. In Cu₂S-PbS-Cu system, the activity curve of Pb deviates from Raoult's law and activity coefficient was found to be 1.4-3.7 at 1, 200°C
The distribution of Pb into two liquid phases, matte phase and metal phase, in Cu₂S-PbS-Cu system was measured by chemical analysis of these phases and were shown by distribution coefficient L_Pb (L_Pb=Pb wt% in matte/Pb wt% in metal) or L'_Pb (L'_Pb=Pb mol% in matte/Pb mol% in metal). The value of Lpb or L'pb was 3.8 and 9.6 at 1, 200°C.

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Purification of zirconium tetrachloride by sublimation process, reduction of zirconium tetrachloride with magnesium and separation of magnesium chloride from zirconium by vacuum distillation were studied.
The results obtained were as follows;
(1) Sublimation conditions:
Innerpressure of sublimation furnace 1.1-1.5kg/cm²
Temperature of sublimation furnace (lower zone) 300-600°C
Temperature of sublimation furnace (upper zone) 200-300°C
Sublimation time 100-120hr/batch/
(1 batch ZrCl₄: about 2.7t)
(2) Impurities can be effectively removed from zirconium tetrachloride by means of once sublimation: Iron removed about 92%, Aluminium about 85%, Titanium about 90/0, Silicon about 83%.
(3) Reduction conditions:
Innerpressure of reduction furnace 1.1-1.8kg/cm²
Temperature of reduction furnace (lower zone) 780-920°C
Temperature of reduction furnace (upper zone) 360-600°C
Reduction time48hr /batch
(1 batch Zr: 0.7-0.8t)
(4) Vacuum distillation conditions:
Temperature of vacuum distillation 940-980°C
Vacuum 10^-4-10^-6mmHg
Distillation time 50/-60hr/batch
(1 batch Zr: 0.7-0.8t)

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