Since temperature distribution on the surface of the earth have not been measured at any mineralized zone, the authors have studied the method of measuring the temperatures, especially on the suitable conditions. As the result of these experiments, it has become clear that an injection needle type thermometer, in which thermister is used as thermosensitive element, is suitable to be used in a bore hole, and also that a method to prevent the soil from droping into the bore hole is necessary to minimize errors. By several tests, it is confirmed that temperature distribution could be measured at an accuracy of about 0.5-1.0°C, and by field tests at Kunitomi Mine, Hokkaido, it is proved that the outcrop exists in a relatively higher temperature zone.

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We have been studying the properties of strain waves in rock produced by the detonation of explosives. Rately, we get some fundamental values of the shapes of strain waves on research tests in Tertiary tuffaceous sandstone at Okitsu, Chiba prefecture, by using a Brown tube oscillograph (6 elements).
1. A strain wave propagates into rock neighbouring the explosive charge with a velocity having higher speed than the sound velocity in rock.
2. The propagation speed falls gradually with the distance from, the detonation point and reaches to the sound velocity, which is 2500m/s in this sandstone.
3. Though the strain waves get out of shape easily by the circumstances, the general shapes are non-oscillating waves having 0.2-4.5ms duration and 1-4m wave length.
4. Strain values are 2×10^-4-0.05×10^-4 within 1-6m distances from the detonation source under this test conditions, i. e. in soft Tertiary tuffaceous sandstone, 25-50g conventional explosives, 35mmφ bore hole, etc.
Strain is inversely proportional to 1.5 power of the distance.

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This investigation was carried out for the purpose of obtaining materials for the layout of pillar working or of driving close parallel headings. The stress state in an elastic ground with six parallel openings, square in section, was analysed by means of photo-elastic experiments under the initial stress in one direction as well as in two directions. The results are as shown in Fig. 3 and 4. The conclusion to this research will be given in the 2nd report.

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Now, two methods are planned for hydraulic transportation of coal. One is to pass the coal through a pump and the other is to feed the coal into the delivery pipe of the pump.
We studied, concerned with the former method, on the variation of characteristics of pump under varying size of coal up to 15mm and concentration up to about 35% in weight percentage. A 3-in sand pump was used for these experiments.
When the concentration of coal increases, the pump head and efficiency decrease and the brake horse power increases. In the case of constant concentration and quantity of discharge, the larger the size of coal, the lower the pump head and efficiency and the greater the brake horse power. When the size of coal is large, slight increase of concentration brings on eminent decrease In pump efficiency.
In this paper the results on the degradation of coal at the hydraulic transportation are also described.

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We have examined the theory of grinding of the tower abrasion mill and obtained the value of the coefficient n to be 0.8 in the expression of the work of grinding.
E=C/n-1 (1/D₂^n-1-1/D₁^n-1)
from the grinding experiments of this mill.
We have proved also, that the above mentioned coefficient is obtained from the height of the machine.
h=p/γ where p: pressure of the grinding medium.
γ: specific gravity of the material of grinding and the diameter,
d=√4Q/πρp or d=√4Q/πhγ
where Q: weight of the grinding medium of this mill.

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The floatability of fluorite and quartz and the adsorption of dodecyl benzen sulphonate ion at those minerals-solution interfaces were measured as a function of collector concentration and pH, and the correlations of the floatability and the adsorption were discussed.
The results are as follows:
(1) The floatability of fluorite is remarkably influenced by the collector concentration and pH, On the other hand, the floatability of quartz is extremely low under the same flotation conditions, These results are shown in fig. 5 and 6.
(2) The adsorption of the collector ion on fluorite surface is remarkably influenced by the collector concentration and pH. Under the constant pH, the adsorption increases with the collector concentration and under the constant collector concentration, the adsorption increases with hydrogenion concentration. These results are shown in fig. 9 and 10.
(3) The surface coverage at the critical flotation conditions and the standard free energy change of the adsorption were calculated.

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Thermal decomposition products, FeS_1+x, were prepared by the decomposition of FeS₂ in the atmosphere of N₂, between 625°C and 900°C.
Thermomagnetic properties and the crystal structure of these thermal decomposition products were studied by the method of thermomagnetic analysis and X-ray. And the change of thermomagnetic properties of thermal decomposition products in vacuo or in air at the elevated temperature was discussed. Results obtained were summarized as follow:
1. The composition of thermal decomposition products varies with the decomposition temperature. Of such decomposition products, FeS_1.13 (prepared as 625°C) and FeS_1.11 (prepared at 650°C) were ferromagnetic and their ferromagnetic Curie point was found to be 295°C; FeS_1.09 (prepared at 675°C) and FeS_1.08 (prepared at 700°C) were antiferromagnetic and their antiferromagnetic Curie point was found to be about 220°C; FeS_1.06 (prepared at 750°C), FeS_1.05 (prepared at 800°C) and FeS_1.00 (prepared at 900°C) are paramagnetic. Crystal structure of these FeS_1+x belongs to hexagonal system whose axial ratio, c/a, is 1.66-1.68. Lattice parameter a, c and axial ratio decreases with increasing the content of sulfur in FeS_1+x. These results coincide with that of H. Haraldsen.
2. When antiferromagnetic or paramagnetic decomposition products are heated, their thermomagnetic properties change under heating conditions, such as oxygen partial pressure of the atmosphere, heating temperature, etc.: That is, thermomagnetic properties of antiferromagnetic samples remain unchanged when they are heated to about 300°C in vacuum sealed silica capsule, or in vacuo of 5×10^-5mmHg. However, when they are heated to the same temperature in vacuo of about 10^-3mmHg, or in air, it changes to ferromagnetic one whose Curie point is 295°C. Paramagnetic samples change also to ferromagnetic, and the formation of small amount of Fe₃O₄ was detected by X-ray measurement, when they are heated in air to about 430°C. By this change, latticeparameter or axial ratio of FeS_1+x change to that of ferromagnetic one. From these results, it may be concluded that such changes from antiferromagnetism or paramagnetism to ferromagnetism is due to the initial stage of oxidation of Fes_1+x, and that at the initial stage of oxidation, paramagnetic or antiferromagnetic FeS_1+x changes to ferromagnetic FeS_1+x whose composition is near the upper limit of solubility of sulfur.

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Methods of preparing Zn-Th alloy electrolytically followed by the vacuum distillation of alloy to get a pure Th have been studied. In electrolysis, graphite crucible with a capacity of 300g salt have been used as the anode and fused Zn as the cathode. Temperatures around 800°C have been found. preferable to 700°C in order to get a high content of Th in Zn cathode and it has been shown that the highest content of Th in the alloy without lowering the fluidity of the alloy is 15-20wt.%. The pure Th metal sponge can be produced by vacuum distillation of the alloy at 1000°C. It has been shown that this process is promising as a method of preparing pure Th metal sponge.

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