(1) In the Outer zone of the southwestern Japan a large number of cupriferous pyrite deposits occurs in the Sambagawa-Mikabu complex. The writer believes that they belong to the replacement deposit genetically related to the intrusion of basic igneous rocks which was accompanied by folding and regional metamorphism. The deposit of the Ôkuki mine occurs in the schistose green rocks, mainly as saddle reefs in the overturned and plunged folds. The intruded basic rocks occur in the core of the fold. The ore bodies are controlled by the major fold, bedding schistosity, flow cleavage and lineation. The structural features of this deposit are very important from the prospecting of the ore bodies.
(2) The Yanahara mine is the largest pyrite deposit in Japan. Apparently it is composed of massive ore bodies. In the mining area, basic intrusive exists in the folded part of the Trias (?) system. It occurs at the core of the folding and plunges the direction of the folding axis. Along the boundary between clayslate and basic intrusive the ore bodies exist. The main ore bodies occur at the crest of the folding, swelling and pinching to the direction of the plunge of the anticlinal axis. From these facts, it is recognized that the deposit of the Yanahara mine is quite similar to the Ôkuki deposit.

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In this study we chiefly investigated concerning the characteristics of the stress waves in rocks when they were impacted by detonators and also compared the dynamic stress-strain relation with the static one.
Young's modulus for rocks obtained dynamically was about two or three times greater than that obtained statically. The dynamic strength of rocks was also greater than the static one, but its difference seemed to be not so great as to metals.
Moreover it was an interesting result that various shock effects appeared in accordance with the kind of rocks.

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In the previous paper, It has been discussed for relative tendencies of various coals to ignite spontaneously by means of characteristic rate of oxidation.
In this paper, exerminations were studied. for the rate of oxidation of coal and composition of gas which evolved from coal during low temperature oxidation, in oder to obtain informations on the spontaneous combustion under the ground.
In this methods, the constant volume of oxygen was supplied over the coal and heated gently under the constant speed around the vessel, the oxygen consumption ande volved gases were measured by the pressure difference in mercury height of open manometer in this equipment.
In these experiments, works have shown that ignition of coal occured when the rate of oxygen consumption reached maximum, and components of gas in this period which evolved. from coals in the vessel were CO, CO₂, in stage of oxidation and ignition, and then in early decomposition stage, the most part of gases were CH₄, C₂H₄, C₂H₆, etc. hydrocarbons, as results of mass spectrometry.

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The defect of this type of flotator is that of correlationship of aeration with the pump action of impellers and that of poor efficiency accordingly derived.
With the object of comparative study, the author selected the “JETAIR” type of impeller which is made ot jet from the outer circular edge, and examining the moving status of bubbles and measuring the pump efficiency and checking up the frother effects he came to the following conclusion:-
1) Part of jet-bubbles is observed rolled into the impeller according to back eddy. Consequently for the increase of the pump efficiency and for independence of the aeration action, preventive measures of this back eddy is necessary.
2) The uprising bubbles are readily broken up into minuter particles at rather slow rotating speeds, and that with less pattering.
3) The frother effects are to be rapidly increased with the increase of the rotating speed, but above the limit speed the increase of effects is seen decreasing.
4) By means of a bubble vane, the dispersion of bubbles can be uniformalized deriving the increase of the frother effects.

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The floatability of artificial oxides such as iron, copper or zinc oxide has been investigated by flotation test in connection with the process of their preparation.
The unexpectedly floatable property so as to form the armoured bubbles by the addition of frother or xanthate-type collector in the pulp is remarked upon the oxide formed by the thermal decomposition of metal salt or hydroxide in the range of temperature where its sintering or additive solid reaction begins to proceed. The artificial magnetite prepared at a low temperature by wet method exhibits also the aerophilic character. Then, the surface areas of oxides are measured by B. E. T. method using nitrogen gas adsorption data. From the experimental results it is considered that the strong floatability of artificial oxides is related with the change of the surface structure accompanied by the ionic migration.

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The general outline of the distillation process employed at Mikkaichi Zinc Smelter has been previously published in the December 1956 issue of this journal. A more detailed report is given here as the operating conditions at this smelter have since then become more stabilized.
At present 3 electric furnaces are installed with a total average monthly production of 1000 metric tons of spelter. Metal recovery from the concentrates averages 90%. The total consumption of coke is 720kg/t and electric power 3750kWh/t. There is further scope for improving these results to some extent.

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従来錫電解精錬においては珪弗酸硫酸塩混合浴, アルカリ塩浴などが用いられているが, それらの電着状態よ粗状, 粉状を呈し, 回収操作が煩雑である. 本研究はたまたま硫酸ソーダ配合の硫酸錫溶液を電解液とするとき, 極めて綴密平滑な肉厚の電着が得られることに注目して, この硫酸ソーダ配合電解液による錫電解縞鎌について, 数多くの電解試験の結果から, 適当な電解液組成および電解繰作諸条件を検討し, とくに陽極中の不紅物の新与動にっいて詳細に観察した。
その結果本電解液は現行のいずれの錫電解精錬におげるより回収能率のよい電着が得られ, また湯極不績物のPb, Feに対しとくに高い精製能率が得られることから, ブリキ屑や半田屑から画収される粗錫の粘製には好適であることが認められた。よつて基礎実験結果から勘案された新錫電解精錬操業法試案を提案し, これによつてブリキ回収錫を電解精製するやや規模を大にした電解試験をおこない, 本操業法の実用性を確めた。終りに本実験は前本学職負工学土大竹正雄氏が協力したことを明記する。

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