Variation of longitudinal wave velocity with respect to water content was measured for quartz diorites by using ultrasonic pulse method, and the result is illustrated in Fig. 1. The difference between the dry and saturated longitudinal wave velocities increases with increasing porosity. In this paper, we examine quantitatively the effects of saturation on longitudinal wave velocity of quartz diorites.
Walsh's equations for bulk and shear moduli are adopted to evaluate the longitudinal wave velocities of dry and saturated rocks, and applied to the explanation of velocity increase in saturation condition.
The examples of comparison between the observed velocities and the computed results are given in Tables 1-3. It is clearly seen from these tables that the water content in cracks increases greatly the longitudinal wave velocity. Therefore the increase in longitudinal wave velocity due to saturation of pores occurs when the pores are in the form of cracks, and the increase amount of velocity in saturation condition can be explained by crack model based on Walsh's expression.
The velocity variation due to saturation is also calculated by assuming equations (11) and (12), and the comparison of computed curves and observed values is shown in Fig. 5.

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Multiple regression method (eq.(1)), in order to relate characteristic X-ray intensities (I) with ore grade (X) or pulp density (X), were applied to the data obtained by six channel fluorescent X-ray analyser in Kuroko flotation plant (ore feed rate: 500kg/h) in our institute.X=a₁I_Sb+a₂I_Pb+a₃I_Zn+a₄I_Cu+a₅I_Fe+a₆…(1) where a₁-a₆; coefficients P_b, Z_n, C_u, F_e and pulp densities were analysed by this method usingfollowing flotation pulp. 1 flotation feed, 2 rougher concentrate, 3 rougher tailing, 4 scavenger concentrate, 5 final tailing
The same coefficients of eq.(1) were used to the pulp 1, 3, 5 above-described, because ore grades and pulp densities do not differ each other.
Peculiar coefficients of eq.(1) were used to the pulp 2 and 4 respectively since their pulp densities were too low.
As a result of these procedure, the calculated values by eq.(1) showed sufficient accuracy for process analysis.

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As a first stage of the explanation of the optimum ball filling for vibratory reduction a fundamental conception was applied to vertical and declined oscillation of lying fixed cylindrical container, where two-dimensional ball movements and their two-dimensionally maximum throw orbits were refered to besides following assumptions:
(1) The maximum grinding effect may be expected if every realizable ball movement under given oscillating condition can be reproduced without any hindrance.
(2) The possibility of the ball movements in a container should be controlled by the mobility of the balls originated from the highest layer of the ball mass, which is to be regulated by the dimensions of the container considered as well as by the amount of the ball exist.
Two boundary conditions regarding to the throw time of the balls from the highest layer let assume the existence of two kinds of optimum ball filling in accordance with two kinds of interaction between grinding bodies.
As these two kinds of interaction should not be realized alone in the practical grinding process it is proper to regard some fillingsgrade between two boundary values based on the above two boundary conditions newly as an optimum fillingsgrade. It depends on the oscillating condition to be given and on the strength properties of the grinding material whose kind of interaction should be preferred in each case.
In the present instance the optimum ball filling for vertical oscillation was discussed both theoretically and experimentally, when a certain deduction was drawn also for declined oscillation.

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In order to find out a new use of pyrite, its utilization for the paving material was investigated.
In this report, the results obtained by some fundamental tests are mainly described. These are summarized as follows:
(1) The adhesiveness of asphalt to pyrite and the preventive effect due to adhered film against the oxidation of pyrite.
a) The adhesiveness of asphalt to pyrite is better than that of asphalt to the common paving aggregates such as andesite and limestone. This phenomenon is based on the differences in chemical affinity between asphalt and these materials.
b) The oxidation of pyrite is depressed by asphalt coating.
(2) The physical and chemical stabilities of the bituminous mixture containing pyrite.
a) The physical stability (Marshall stability) of the bituminous mixture containing pyrite is superior to that of the mixture consisting only of the common materials (limestone, river sand and powdered limestone). This tendency must be closely related to the article (1)-a).
b) Within the scope of the present investigation, the chemical stability of the bituminous mixture containing pyrite did not cause a situation which clashes with the standards of waste water provided in the Water Pollution Control Law. Part of the above results may be based on the effect of limestone mixed together with pyrite.
c) Accordingly, as a trial for practical application, constructing and examining'a test road mixed with pyrite are considered to be significant.

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The leaching of zinc blende concentrate by aqueous solution without the roasting process has become major interest as one method of zinc hydrometallurgy.
The study on the leaching mechanism of zinc blende has been carried on by means of varying the experimental factors i.e the leaching agent, the leaching time, the leaching temperature, the oxygen partial pressure and the agitation speed.
The summary of the experimental results is shown below;
(1) On the leaching by sulphuric acid solution, the leaching rate of zinc is under 85%(175°C, 1 hr., O₂pressure 30kg/cm², 50g/lH₂SO₄), but that of iron is over 90%.
(2) The blowing of oxygen into the H₂SO₄leaching solution under atmospheric pressure, produces elemental sulphur from H₂S generated by the leaching reaction.
(3) When the concentrate is leached by ammonia solution under high pressure, the main reaction is represented by the equation ZnS+4NH₃+20₂→Zn(NH₃)₄SO₄and the following subreaction occurs. ZnS+(NH₄)₂SO₄+20₂→Z
nSO₄·(NH₄)₂SO₄
(4) This leaching reaction is controlled by chemical reaction on the surface of the ore at low temperature range (55-100°C), and at high temperature (100-120°C), it is slightly shifted from chemical-control to diffusion-control. The activation energy of leaching is respectively 12.6kcal/mol. and 5.26kcal/mol.
(5) The leaching rate of zinc is about 95% under the following conditions; O₂pressure 10kg/cm², 3mol/l NH 3.1mol/l (NH₄) ₂SO₄. 175°C. 2 hours.

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