It has been predicted and circulated that the future energy supply will fall inwith a critical shortage. Many countries in the world which have a certain coal reserves reconsider to utilize coal as an indispensable energy resources until the practical atomic reactors come into full operation, while in Japan it is not deemed so important to make up the balance between energy demand and surrnly
Under such a situation in Japan as all the attention and effort are paid mainly to secure crude oil resources, the writer did einphasize the importance of role of coal in reviewing it economically and politically.
Standing upon the above mentioned view points, the writer reviewed the energy situation in Japan and U. S. A., and referred to reserves and distribution in the world, and evaluated the position of coal as energy resources, and also he described the present situation and the future problem of Japanese coal industries referring to British coal energy policy, and finally concluded that the future enegy should depend more on coal resources and the urgent energy policy should be established.

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During and after the 2nd World War the Uranium had been secured as the strategicmaterial. After the 1st international conference for the peaceful uses of Atomic Power in Geneva the n umber of nuclear power generating station has been gradually increasing and the Uranium, has become as the energy resources.
By the long term forcast until 2, 000 year it will be needed to capture 1.5 million tons of uranium additionally in the free world.
Japan must endeavor to secure uranium as nuclear fuel resources not only by the long term purchase contracts but also by the autonomous exploitation in some overseas countries.

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In the area of 250 (east to west) by 200km (north to south) in Rio Negro Province, Argentina, numerous fissure-filling fluorite veins of epithermal type can be found. The wallrocks of these deposits are various. They are rhyolite, rhyolitic tuff and pyroclastic flow, dacite, granite, mica-schist, etc. However, the feature of the wallrock alteration in these deposits are quite similar to each other.
Frequently, innumerable rock fragments are cemented with fluorite and quartz in fractured zones. Veins, having a width of 1-3m and an extension of 200-500m along tree strike, are not uncommon. In these veins quartz, barite, sericite, calcite, and gypsum are closely associated with fluorite. In some deposits, small amounts of galena, sphalerite, chalcopyrite, and pyrite are recognized, occasionally, nacrite, montmorillonite, and stilbite are also found.
Filling temperatures of liquid inclusions in fluorite specimens were studied with the heating stage attached to the microscope, and it was revealed that the measured values are in a range from 90°C to 210°C with 95% of probability. Any relations were not recognized among the filling temperature, the mineral assemblage, and the wallrocks in these deposits.
It is suggested that fluorite precipitated when the temperature of the ore-forming solution decreased to 90-210°C, following the crystallization of higher temperatureminerals, and that montmorillonite, calcite, and gypsum were formed in later stage with decreasing temperature of the solution, Furthermore, it is considered that the chemical nature of the hydrothermal solution which formed these fluorite deposits varied between weakly acidic and weakly alkaline.

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In this second report, the change of velocity of sonic wave (P-wave) in the same specimen subjected to pulsating compressive or tensile stress is investigated in detail and wide range.
The distinct change of P-wave velocity in the loading direction, in unstressed condition, is not observed after applying pulsating tensile load. When pulsating compressive load is applied, the velocity in Sanjomeandesite decreases by 20%, the velocity in sandy-tuff and other rocks decrease by about 5%, while the velocity in granite shows a tendency to increase by about 5%.
The change of velocity of P-wave measured in the loading direction, in loaded state, is investigated also with respect to the magnitude of stress level and repetation of loading. The results are obtained as follows:(i) There is no change of velocity in granite due to the repetation of compressive loading.
(ii) There is no change of velocity in other porous rocks, under compressive load more than 50% Sc, due to the repetation of loading. However, under compressive load below 50% Sc, there is a remarkable change of velocity due to the repetation of loading.
The velocity of P-wave in granite under uniaxial compressive stress, increases by about 30%, and this remarkable result could be explained by the closing of cracks, considering with the shape of stress-strain curve. Velocities in other porous rocks increase by about 5% when they are compressed uniaxially.

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The width ratio of rib pillars to openings is an important factor to be taken into consideration on designing large stapes. The present paper describes how to determine it on the assumption that the maximum stress in pillars at such a stage that full plastic deformation has occurred over the portions of stress concentration, should not exceed the allowable compressive strength of pillars.
First the pillar stresses were analyzed both by two-dimensional and three-dimensional ways, on the results of which some modifications were made by considering the results of model experiments. Then Eqs.(10) and (11) derived from the results obtained were proposed for use in determining the maximum stress.
The applicability of this method was proved by the governmental committee on mine safety, with the result that if allowable stress is estimated at one-third of the core strength, these equations to determine the maximum stress can be applied.

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Tests were conducted to study the minimum currents to ignite methane by electricsparks generated at the voltages lower than 100V in AC circuits. Three types of spark generator were used in the tests.
The minimum igniting current at a fixed voltage depends on the self-inductance of the transformer used in the circuit, and the current indicated somewhat decreasing tendency with decreasing self-inductance. The spark generators of both German and English type showed better performances than hand-operating type, and the least igniting currents were obtained by German type at lower voltages than 10V, and by English type at higher voltages than 10V. When an electrostatic capacitance of about 100PF is connected in parallel to the inductance in the load circuit, the minimum igniting current decreases with increase of inductance.
When electric sparks are generated by repeating on-off operation of either line of the resistances connected in parallel in AC circuit, the lower resistance is easier to ignite methane.

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The on-stream real time analysis technique of flotation pulp will play the most important role in the control of the process where the main disturbance is the variation in feed pulp nature.
In order to investigate the fundainental problems encountered in “Kuroko” pulp analysis, a series of experiments has been done with a prototype analyzer. Several results obtained are as follows:
1) The correction for pulp density change is substantial. A monitor, a metallic block placed behind the sample cell, is used as a pulp density senser. The fluorescent X-ray through the pulp can be used as a pulp density indicator.
2) A down flow type cell with a specially designed head tank is satisfactorily used as a sample cell.
3) A metallic block for monitor should be selected carefully. For example, cadmium can not be used to analyze zinc because some of the characteristic X-rays are very similar to each other.
4) An example of pulp density correction equation for a specific grade pulp has been presented.
5) Even at a constant pulp density, the matrix effect on the X-ray intensity is significant, therefore it is recommended to make a different calibration equation for a different composition pulp.

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Effects of impurities, such as Ge, Co and In, on the potential dependence of the interfacial impedance at the solid zinc-acidic zinc sulfate solution were measured with an impedance bridge under the presence of the d.c. potentiostatic polarization.
The results obtained are as follows:
1) When 0.1mg/l Ge or 1-10mg/l Co is contained in the above mentioned electrolyte, marked increases in the interfacial capacitance and decreases in the interfacial resistance are observed over the range from the potential of zinc corrosion to that of zinc deposition.
2) The addition of 10mg/l In does not have influence on both the polarization curve and the impedance potential relation, which are similar to the results for the pure electrolyte.
3) It has been found that the interfacial impedance is closely related to the critical current density of zinc deposition and decreases with the increase of impurity which has the tendency to raise the critical current density.

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