The Fukiya gypsum deposit occurs in pale green tuffs of rhyolitic composition of the Middle Miocene age. The deposit has two unit-body groups, each consisting of four overlapping, lenticular gypsum beds. The gypsum beds are concordant with stratification of wall rocks and have a direction of elongation parallel to the structural weak zone. The total vertical extent of the deposit reaches about 140m.
Each gypsum bed has one or more centers of mineralization, where the deposition of gypsum might have exceeded the sedimentation of pyroclastic materials.
The gypsum deposition was associated mainly with chloritization of tuffs ands sporadic dissemination of pyrite in the deposit accompanied the sericitization. Diagenetic montmorillonitization seems to have affected rocks of much lower formations than the gypsum horizon, but it is not recognized in the chlorite-sericite zone of the gypsum deposit. This might suggest the stability of the zone against the diagenetic alteration.

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The CO/O₂ def. ratio, CO content and alkene content are used for the indicators of spontaneous heating underground. Now, we discovered a new method of the ratio of alkanes.
The reliability of the new method was proved by laboratory experiments and on the site tests. When coal temperature rise slightly, the ratio of alkanes increase sensitively. Therefore, the ratio may become an excellent indicator of spontaneous combustion of coal.

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Concerning coal measure rocks containing high pressure gases, the flow of the gas caused by making a plane or cylindrical free face in the rocks was considered theoretically in the previous paper.
The authors have treated more acculate numerical analysis on the partial differential equations obtained for the subject. It is found that the flow of gas through the rocks is represented by simple equations, (13), (21) and (27). Using these equatios, the variation of the gas flow with time through the rocks is calculated for any pressure and permeability. In order to confirm the above analysis, the experiments were carried out on the unsteady flow of gas through the several kinds of porous media cosisted of a cement and sand. These experimental results agree fairly with the theoretical analysis.
These results could be useful for the design of gas drainage in coal mines and the extraction of natural gases in strata.

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In order to find out the methods for measuring the shear strength of rocks, the several tests, namely the direct shear, the uni-axial and the tri-axial test, have been undertaken on five kinds of rocks.
A summary of the results is shown below.
1) Based on the concept postulated by Griffith, the diameter of a maximum stress circle through S_t-point, which represents the uni-axial tensile strength on Mohr's diagram, is equal to 4S_t. Consequently, the Mohr's envelope is expressed in a common tangent drawing from 4S_t-stress circle to S_c-stress circle, which represents uni-axial compressive strength. In this case, the shear strength is approximately obtained from an intersection of τ-axis and the common tangent, and can be calculated by using the following equation: if Se>3S_t
S_s-5=S_c·S_t/2√S_t (S_c-3S_t)
2) The shear strength of rocks under the various normal pressure acting on the shearing plane is given by a single shear test-device, which can be arbitrarily adjusted the inclination angle of the shearing plane by setting a pair of rotary dies. Satisfactory results in this test are usually to be obtained with the inclination angle ranging from 15°to 45°. Moreover a zone which we shall call “failure zone”, represents the relationship between the shear strength and the normal pressure, is illustrated on τ-σ plane. It will be seen that the shear strength of rocks may be approximately estimated by the failure zone, because the failure zone approaches to a Mohr's envelope in the vicinity of τ-axis.
3) The shear strength by the double shear test is calculated larger than that by Mohr's envelope, because the normal stress acting on the shearing planes in the double shear test is compressive.

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X-ray fluorescence analysis requires comparatively large amounts of samples when conventional sample holders are used. However, in the laboratory, rapid and completely non-destructive quantitative analysis by using the X-ray fluorescence technique permits the use of small samples and results are as accurate and precise as those obtained when using the large amounts of samples.
For testing the use of small samples in the laboratory, samples were prepared by brequetting pure magnesium borate, cadmium sulfide and barium oxide. Two methods of exposing the surface areas to primary X-ray beams were then used. In the first method, the minimum amounts required for analysis of the pure chemical briquettes were 0.3g for magnesium borate, 1g for cadmium sulfide and 0.5g for barium oxide by exposing the entire surface to primary X-ray beams. It was found that a minimum sample of 1 g was needed, if the three chemicals were mixed with varying amounts of each in any one sample. Minimum weight of samples was inversely related to the total mass-absorption coefficient, rather than to the density or the thickness of the samples. The lower the total mass-absorption coefficient, the greater the amout of samples required.
In the second method, when various portions of the center surface area were masked before exposure to primary X-ray beams, it was found that the decreases in the fluorescent intensity ratio were less than 10% if the exposed area was greater than 60% of the standard surface area (11.3cm²).

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In order to obtain the fundamental data for the extraction of nickel from silicate ores, the synthesis of nickel olivine and the reduction of the olivine with hydrogen were studied. A comparison between the results for synthesized materials and those for ores was also revealed.
The results obtained are as follows:
1) The nickel-olivine shows the orthorhombic lattice which has the general formula (Mg_m/2Ni_n/2) ₂SiO₄, where m plus n equals two, and m and n are the integers from zero to two. Ni₂SiO₄ and Mg₂SiO₄ form a complete solid solution at any composition.
2) It is found that the reducibility of Ni₂SiO₄ decreases as the content of Mg₂SiO₄ in the mineral increases.
3) When garnierite is heated in the air, anhydrous nickel silicate, 3 (Mg, Ni) O·2Si0₂, is formed due to the release of the water of crystallization between 460°C and 700°C.
This silicate tends to crystallize at higher temperatures than 800°C, forming forsterite and Si0₂. Nickel oxide in the mineral forms then nickel orthosilicate, and a complete solid solution with forsterite as the synthesized olivine does.
4) The anhydrous nickel silicate is amorphous and reducible. In order to avoid the formation of unreducible compounds of nickel, (Mg_m/2Ni_n/2) ₂SiO₄, a regulated slow cooling of the ores from 460°C up to 800°C under hydrogen reducing atmosphere is preferable.

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