The quicksilver deposits in the Yamato metallogenic province in Japan are greatly controlled by the geological structure. They are of the vein type, filling up thrust like fault of NWSE direction in granodiorite and echelon fissures of NS trend in the foot wall of the sheared zone.
Seeing from the features of the brecciated ore, as well as from various mineral paragenesis, it appears to suggest the following facts.
(1) The following succession of mineralization is revealed:
Preeipitation→brecciation→Precipitation
This implies at least the two stages of mineralization.
(2) There had been the alternating change in chemical nature of the mineralizing solution.
(3) It might be taken consequently as showing the continuation of mineralization which is longer than being hither to inferred.
The cinnabar bearing liparite dyke found in Nara quicksilver mine may explain the relation between quicksilver deposits of this province and the young volcanic activity. In this instance, the details of paragenetic relation of cinnabar and the associated minerals in the. hydrothermal quicksilver deposits of south western Japan are seeked to be studied in relation with the young volcanic activity.

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Doyashiki deposits of the Hanaoka Mine, had been mined by Drift Caving method in the past day, but owing to several accidents by alluvial subsidence, ecessive ore production in the 2nd World War time and underground water floods at July 1947, these deposits had been in the crisis of desolation.
Several kinds improved mining method was adopted for our ore bodies which have various underground conditions.
Typical mining methods are as follows:
(1) Drift Caving
(2) Cut and Fill stoping by long blast holes
(3) Block Caving
(4) Semi-Squar set stoping
(5) Top Slicing by Kappe System.

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In the bituminous coal seams in Japan which have received strong metamophism with heat and pressure, much gas is occluded. The gas existence in the domestic coal seams have not only been influenced by the adjoining structure of strata, but have been influenced by the thermal and dynamical energies. It seemed the existence of gas in coal seams might have relation to the coalification speed as well as structure of coal formation. So, the artificial coalification method commenced by Bergius was used to make sure this fact experimentally.
In this paper, the Upper Nakago, Yumoto, Taiheiyo and Upper Taiheiyo coal were studied having connection with the gas existence in them .When the coalification grade was advanced under the various coalification speeds, the amount of evolved gas from coal were correlative with their coalification speed and was especially related to their heating history in making the high grade bituminous coal artificially.
Then, the difference between the compornent of gas which was produced in autoclave and that of the natural free gas in coal was studied about the Taiheiyo coal by mean of mass-spectroscopy.
The results of experiment showed that most of the hydrocarbon compornents of natural free gas was methane and others were trace of other hydrocarbon, ie. propylene, etc. But in the artificial coal gas, other hydrocarbons, ie. ethane, popane, etc. existed in higher rate in comparison with methane gas content.

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This Stuby has been investigated on the 6×7 ropes, diameter 22 mm, by corroding in the acid solution at laboratory and inspecting the changes of mechanical characteristics of wire ropes and rope wires caused by their corrosion.
As a result of this investigation it has been found, that the decreasing percentage of breaking loads has not a certain relation with the decreasing percentage of diameter but is nearly proportional to the spuare of decreasing percentage of clamped diameter of wire ropes.
It has been proved that: the proportional constants are in a range of 1.5-2.5, which depends on the kind of ropes and the condition, of corrosion, and the decreasing percentage of the breaking loads is nearly proportional to the decreasing percentage of the sectional area of wire ropes, the decreasing tendency of breaking loads is fairly slower than the decreasing tendency of elongation percentage and that of breaking energy.
The result obtained by testing the wires, which are taken from corroded wire ropes, showed that the decreasing tendency of diameter and breaking loads are slower than the decreasing tendency of number of torsions and that of bends.
Such a experiment is very few, so I think that the data obtained in this case will be a valuable reference one, when we need the investigation of corrosion on wire ropes used in practice.

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In magnetic separation, an exact relation between magnetic force acting on a mineral particle under a given field conditions and its definite magnetic susceptibility have a fundamental importance for practical applications of the process.
The writer theoretically induced the above mentioned relation concerning a spherical cubic and cylindrical mineral particles. These relations were formulated in the equation of (20), (32) and (36).
In the case of paramagnetic or diamagnetic mineral particles, the value of their susceptibility remains constant for a fairly wide range of magnetic field so their theoretical analysis of the relation is not so difficult. While in the case of ferromagnetics their susceptibility depends on the field strength furthermore the induced demagnetizing field make the relation more complex.
In this article, the writer reported the magnetic forces of paramagnetic and diamagnetic mineral particles of quartz, calcite, epidote, chalcopyrite, pyrite, rutile, ilmenite and zircon and determined the field intensities to attract these paramagnetics. These were calculated by the above equation. The results were illustrated in Table 1.

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Leaching reaction of chromite in H₂SO₄ with K₂Cr₂0₇ as an oxidizing agent was studied.
Since it was found that for the dissolution of chromite in H₂SO₄, the oxidation of ferrous iron in the ore to ferric state was an important factor, the extraction of Cr was restricted by the ratio of FeO content in the ore to the theoretical amount derived from Cr₂0₃ content. The FeO ratio of the high grade ore (Cr₂O₃ 43.95%, FeO 18.70%) was 90% and the low grade ore (Cr₂O₃ 37.41%, FeO 11.66%) was 66%. The extraction of Cr of the high grade ore was 94.5%, but with the low grade ore, it was only 46.1% under the same conditions as the high grade ore, due to the low FeO ratio.
An experimental equation on the rate of leaching was given by
y= α√θ—βθ
where y is the extraction of Cr, θ is the leaching time and α, β are constants. It was considered that the rate process would be the diffusion in particles.

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