Usually, the interpretation of electrical anomalies in the electrical prospecting consists in solving the inverse potential problem. It is very difficult to solve the general problem of any resistivity distribution, and then certain simplifying assumptions are often made about the types of resistivity distributions which occur in practice. Within the limits imposed by these assumptions, the standard curves and master curves have been calculated by many geophysicists.
In this paper, the author intends to explain the interpretation method by analog computer which has been studied by the author and his assistants since 1954.
Many standard curves are obtained and the effects of topography and near-surface conditions are interpreted and the direct interpretation method are explained by using some electrical field surveys.

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Analytical consideration of rock pressure has been conducted by using several mechanical models which are first approximations to the behaviour of rock substances underground.
In this report, states of stress and strain around the round and horizontal tunnelwhich is excavated in the infinite body under hydro-static pressure, are discussed to the following five cases:
(1) Rock is pure elastic.
(2) Rock is represented by a combination of Maxwell's body for the deviatovic partand Hookean body for the invariant part of the stress and strain relation.
(3) In the 2nd model, Kelvin model is existed instead of the Hooke body and Burgers body is existed instead of the Maxwell body.
(4) Rock is pure elastic until the maximum difference of the principal stresses reaches a finite value, and after that, the behaviour of the state of stress and strain is followed with the formula |σγγ-σθθ|=k.
(5) Rook is pure elastic and plastic and the state of stress is followed with the formulaτ=C+σ tanψin the plastic region.

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A fundamental experiment on fracturing rocks by spherical chip cutter and amilled tooth cutter in relation to tunnel boring machine applicability was carried out, and following results wereobtained.
(1) The depth and the with of fractured groove increase with the pitch of the milled tooth cutter, while this result couldn't be apparently obtained from spherical chip cutter since the range of the pitch wasn't wide enough.
(2) The fractured volume decreases with the pitch.
(3) A larger traction force is required when the pitch is large and in this case the difference between the maximum value of traction force and the minimum one is also large.
(4) The relation of the depth to the width depends not on the pitch but the rock'sproperty.
(5) The moment which is yielded by friction between the cutter and its rotating axis has large influence on the friction force.

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室内における予備実験からつぎの結果が得られた。
界面活性剤の作用により
1) 石炭の低温酸化反応熱が減少する。
2) 自然発火所要時間が長くなる。
3) O₂消費量およびCO発生量が少なくなる。
この結果に基づき現場実験を行ない, 界面活性剤水溶液を炭層に注入するとCOの発生量が減少することが推定された。したがつて石炭を適当な界面活性剤水溶液で濡らすと自然発火を抑制するという考え方の正しいことが推定される。

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Comminution kinetics is sometimes treated by the integro-clifferential equation which is derived from the method of the mass balance. The treatment consists of characterizing the grinding process in terms of selection and breakage functions.
The selection function is defined as the function by weight of the particles of a given size x, which are broken per unit length of grinding.
It is investigated in this study that this selection function varies with the grinding time, though it has been usually assumed to be independent of the grinding time.
By using the ideas of chemical reaction of the first order, selection function at each time of grind is calculated from the experimental data in the presence of all other sizes.
As the results of the computer simulation it has been found that we can assimilate the grinding process more precisely by taking size distribution in a mill into selection function, that is, the probability of a particle being broken is influenced not only by the particle size but also by the amount of weight retained.
Comminution kinetics is also represented by the equations which treat the grinding rate of cumulative weight larger (or finer) as a function of cumulative weight. The authors have also studied the relationship between this kind of equations and the integro-differential equation.

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The present paper describes the results of experiments on the physical properties of the sintered pellet made of pyrite cinder.
The physical properties of the pellet as a blast furnace feed have a great effect on the out-put rate of the blast furnaces. Especially, reducibility is of the most importance, and it depends on gas permeability of the pellet. Reduction tests under compressive load on the pellet in a reducing gas stream were employed as a method of permeability measurement, i. e., a extent of pressure drop of the gas stream indicates the permeability of the pellet in this case.
The test pellet were made of pyrite cinder and magnetite iron ores or lime stone. The lime stone was added to increase the basicity (CaO/SiO₂) of the pellets.
The results obtained are as follows;
(1) The extent of the pressure drop was 500mmaq in the case of regular pellets, and 50mmaq for pellets having a basicity of 1. 3, furthermore, volatility of chlorides of non-ferrous metals was accelerated by increasing basicity.
(2) The non-ferrous metal contents of the sinterd pellets were less than 0.04% for copper and 0.03% for zinc, and sulphur content was less than 0.05%. Moreover, compressive strength of the sintered pellets was more than 300kg/pellet and the porosity of the sintered pellets was less than 20%.

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Large scale tests on the application of periodic reverse current in electrolytic refining of copper were carried out at the pilot plant of Hitachi Refinery. A thyrister rectifier with an output capacity of D. C. 13, 000A was installed for the tests to generate the periodic reverse current. High current density of 350-400 A/m² (effective) was applied under normal electrolytic conditions.
Under these conditions, an anode passivation and other abnormal phenomenon did not occur and the appearance and deposition of cathode was found to be satisfactory. From the tests, it was confirmed that the technique of periodic reverse current could be applied in the electrolysis in industrial scale.
The cathode copper obtained from thses pilot plant tests were melted and casted into wire bars. Any differences in electric conductivity was not found between these wire bars and those of cathode copper obtained from the usual operation under 200-250A/m² D. C.

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