When a shaft is sunk by the well sinking method with air blowing, the edge point of the well sometimes meets a hard sedimented soil or a weathered tertiary rock. In these cases the power of detonating explosive is usually utilized to break such a soil or a rock under the cutting edge of the well.But the procedures employed in these blastings are mostly based on experience only and we know some wells sunk in the past had been broken by a blast due to the unsuitable amount of charge of explosives.
Now, the authors have carried out some fundamental investigations on the phenomena related to the underwater explosion in a shaft with the object of obtaining the useful data for the design of blasting operations to sink the shaft well more effectively and safely.
The main results obtained are as follows:
1) In the range of depth, about 200m from the water surface, the pressure pulse always propagates in water with the velocity of 1, 500m a second.The peak pressure decays with the exponent of 1.76 against the distance and it has nothing to do with the kind of explosives used.
2) Shinkiri dynamite, a gelatine dynamite, when sealed tightly in the pressure-proof vinyl tube, can be detonated in water with 200m from the water surface.
3) When we indicate the index of power of underwater explosion exhibited by Shinkiri dynamite as 100, the corresponding indices for Shoan dynamite, an ammonium nitrate dynamite, and the black powder can be represented as 62 and 48 respectively.
4) If we perform an underwater blasting at the depth of 200m, nearly twice much explosive is necessary to get the full crater compared with the amount needed near the water surface.

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To investigate the relation between early stage of spontaneous combustion and rank of coal. We examined 15 coal samples and get next conclusions.
(1) The temperature difference generated by oxidation of coal.Δθ_p is expressed for the coal rank by the equation (1). Where, C is carbon contents %, and a is a constant.
Δθ_p=ae_-0.217·σ.(1)
(2) The logarithm of the amount of oxygen consumed, carbon dioxide production and carbon monoxide production varies linearly with the logarithm of the time of oxidation, or expressed mathematically as follows:
X=ct^b(2)
where X=amount of oxygen consumed, carbon dioxide production or carbon monoxide production, cc in the oxidation reaction t=time in oxidation apparatus, hrs
c, b=constants
(3) CO₂/O₂ and CO/O₂ vary independent of coal rank. At the early stage of spontaneous combustion, we can't presume coal temperature by CO₂/O₂ and/or CO/O₂.
(4)The coal temperature θ°K when rate of temperature rise amounts to a fixed value, is expressed for the coal rank by the equation (3):
1/θ=a-3.6·C×10^-5
Where C=C%, a=constant

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In the present paper dealing with the copper ion activation for pyrite, extents of effects of activation and floatabililty were comparatively studied for six kinds of pyrite gotten from different five mines in Japan namely Hanaoka, Yanahara, Toyoha, Matsuo and Osarizawa. Also the mineralogical properties of these pyrites such as chemical, physical and crystallographic were investigated.
From the above experiments, it was shown that copper ion activated every pyrite tested as well as that of Yanahara mine. The extent of effect of activation, however, was somewhat different in the pyrites gotten from different localities. Relatively large degree of activation was found in the pyrites from Yanahara, Hanaoka and Toyoha.
It was also shown that there are some differences in floatability of the pyrites tested. The floatability of the pyrites from Toyoha and Osarizawa was lower than the other.
The results of these differences in activating property and floatability of the pyrites tested was considered in relation to the mineralogical properties, which seem to depend on the geological formation, but it was difficult to ascertain the relation between them.

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Pyrite has been said to have subtle behaviour and important influences on other minerals in flotation process of complex sulphide are “Kuroko”. It is known that pyrite itself has the delicate variations of crystal structure and of material properties including semiconductivity, oxidation nature, and some other chemical and physical characteristics. The study was carried out for the purpose of grasping heterogeneity of inner and surface structure of pyrite causing complicated flotation properties and elucidating the relation between the surface constitution and its flotation activity.
In this paper, pyrite samples from one of the typical Kuroko deposits, the Hanaoka mine in northern part of Japan, were studied from the viewpoints of both crystallographycal and surface topographical aspects. The results obtained are as follows:
1) X-ray diffraction analysis revealed some structural variation of samples whose atomic ratio S/Fe was 2.00-1.93, i. e. 2θ₃₁₁ (target: Co): 66.406-66.495, then d₃₁₁: 1.6334-1.6314Å, the relative intensities e. g. I₂₀₀/I₃₁₁ and I₂₁₀/II₃₁₁ increased with 2θ₃₁₁
2) The observation of the polished surface of samples with reflection microscope showed much variety and heterogeneity of surface appearance, e. g. grain size, and the distributions of pores and pits.
3) The surface stability was studied with phase-contrast microscope and electron microscope using twostage replica of the samples etched by HNO₃ (1+1) for 0.5, 1.0, and 3.0min.
It was made clear that each sample exhibited peculiar distribution of etching structures and the surface was composed of micro mosaic parts whose diameter was of the order of tens to one tenths μ. This fact would explain the heterogeneity of the oxidation property and the reactivity with reagents.
In order to detect the stability difference among different faces, the dominant faces of pyrite a {100}, e {210}, base face a {100} with secondary growth crystals and a {100} of the secondary growth face were etched with HNO₃ (1+1) for 0.5, 1.0, 3.0, and 30.0min., and were observed with electron microscope by the twostage replica method. The test showed that the stability of faces is lowered in the following order, e {210}>a {100}>base face{100}of secondary growth crystals>secondary growth cryStalline face{100}.On the faces of the last two many dislocation figures and peculiar crystalline growth steps were revealed, which means that those faces should be unstable and, therefore, show complex flotation behaviour.
5) The observation of the secondary electron figure with scanning electron microscope. enabled us to get direct information about the surface structure of fine pyrite particles which were significant in practical flotation.

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This investigation relates to a basic study on the separation of zirconium and hafnium, especially on the purification of hafnium for large production scale.
This results are as follows:
(1) By the use of sulfuric acid as an eluant, its suitable concentration for zirconium and hafnium separation is about 1.0 N. But fractional elution combined with 1.2N sulfuric acid is more effective for their separation than 1.0N. sulfuric acid only.
(2) When the flow rate of elution is 0.3-0.5ml/min/cm², good separation of two metals is given.
(3) The ion exchange columns consists of 1st column in which the zirconium and hafnium ions are loaded and 2nd column in which these two ions are separated. Good separation of two metals is obtained by the use of the connected columns.
(4) When a mixed solution as acetone-sulfuric acid or methyl ethyl ketone-sulfuric acid mixture is used for elution, more effective separation of two metals is obtained than sulfuric acid only.
(5) In the elution of the columns, a small amount of hafnium is always eluted with zirconium before the main peak of zirconium appeares. So, it is difficult to obtain hafnium free zirconium.

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The roasting of zincblende, pyrite, chalcopyrite, galena and Kuroko-complex sulfide ores of which main constituents are copper, lead, zinc and iron-was studied.
The thermogravimetric analysis and differential thermal analysis of these ores were measured in the air atmosphere and the chemical changes of these ores were investigated with the aid of infra-red spectroscopy and X-ray diffraction analysis. As a reslut of the measurements, it was found that the formation and decomposition of sulfates, which were difficult to discriminate by X-ray analysis because of their small contents, could be confirmed apparently by infra-red absorption spectroscopy. Moreover, sulfates and basic sulfates of copper, zinc, lead and iron showed respectively characteristic absorption band of infra-red spectrum, and was capable to discriminate these sulfate with one another.
The formation of copper ferrite, zinc ferrite and zinc silicate was also confirmed.

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