The iron sand mining industry in Japan, dating from 1926, produced 1, 700, 000 tons of ore sand for the iron and steel industry in 1961.
The industry, however, being fraught with many problems yet to be sloved, such as the rise of production cost, the hesitant development of marcket prices, the materialization of the import from the Philippines etc., may fairly be said to be facing a turning point.
Some growth may be expected in the field of iron sand for blast furnace pig iron thanks to an increase in the out put of blast furnace pig iron the principal consumer of the material. But the major part of the consumer of the increased supply of iron sand is filled up by imports. Moreover much expectations cannot be placed on an increase in the consumption of iron sand for electric submerged furnqce. Accordlngly, consumption of domestic iron sand wili presumably be limited to around 1, 300, 000-1, 400, 000 tons per year.
To cope with this situation, it is prerequisite for the industry to pay utmost efforts to improve the constitution of the enterprises and to carry out managerical as well as technical rationalization.
Promotion of recovery of titanium from dressing waste is also one of the problems of vital importance wating for solution.

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This is a brief report on a testing strength of green crystalline schists sent from Sazare copper mine, Shikoku district.
Green crystalline schist is well laminated with the schistosity. Then the mechanical properties are characterized by the schistosity. Tensile strength by Brazilian method, compressive strength, and Young's modulus were measured on specimens of green crystalline schist prepared from boring cores which were cored in parallel and perpendicular to the schistosity.
Significant different values were recorded on the tensile strength concerning with the direction of specimen to the schistosity. And also, it was found from microscopic observations of specimens that these differences were due to their crystalline or structural natures.

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The production of coal, which can be won economically by underground mining, is limited. Therefore, we are obliged to give up some amounts of useful coal resources. For instance, such coal reserves in Tikuho coal field is estimated about one billion ton.
Then, the author propose to develope the new techniques which extract and utilize the coal in gaseous state by underground gasification.
Namely, we get high grade water gas by applying the combined method both with producer gas and water gas reactions to the underground coal seams, and then synthesize the final products (town gas or synthetic gasoline) by the Fischer-Tropsch process.

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In a pair of preceding papers, the authors discussed how the flotation process can be represented in terms of the Ist order kinetics, and showed what meaning can be attached to the flotation rate constant k₁ and its distributlon.
As an application of the theory thus developed, shis paper deals with a kinetic research about one of the practical flotation plants processing complex sulphide are in a commercial scale.
In this process study the authors take into account various particular groups of mineral particles to analyse their behaviours in the flotation system and to discuss their specific contribution to the overall performance of the flotation practice which might be effected.

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Anodic polarization curves of the compounds Cu₂S, Cu₂Se, Cu₂Te, Cu₃As, Ag₂S, Ag₂Se, Ag₂Te, AgCuSe, and NiO in copper sulfate-sulfuric acid solution were studied with the aid of the potentiostatic technique. Some anodic oxidation mechanisms of these compounds have been made clear. It is shown that the oxidation potentials of copper compounds are slightly more noble than that of copper, but the polarization curves of silver compounds are shifted considerably to the noble side. There is a possibility that copper arsenide dissolves at some electrolytic conditions of copper refining. Nickel oxide does not dissolve on account of passivity.

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