For the purpose of advanced utilization of serpentinite, amorphous silica was prepared by acid leaching of serpentinite from Hidaka district, Kochi Pref.A high purity silica (SiO₂ content>99.5%) was obtained by 6N-HCl treatment at 100°C for 12 hrs.The microtexture of the silica retained the morphology of the original serpentine (chrysotile).Each fibrous aggregate consisted of fibers with about 0.07μm in diameter.Specific surface area varied from 5m²/g for the original material up to 400m²/g for the acid leached material containing 10%MgO.The surface area of amorphous silica maintained 150m²/g in the heating temperature range from R. T. to 800°C, and decreased to 40m²/g at 1, 000°C.
To evaluate the potential of the amorphous silica for industrial uses, syntheses of some siliceous materials were tried by using the amorphous silica as a source of silica.As a result, ZSM-5 zeolite, calcium silicate hydrate, silicon carbide and fluor-mica with well crystallinity were prepared for relatively short duration. Hence, it was found that the amorphous silica obtained by acid leaching of serpentinite, because of its high SiO₂ content, large specific area and high reactivity, was a very useful material for industrial applications.

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The Base Friction Method (BFM) is used to simulate the movement of continuous strata and it gives useful means to observe the process of roof falls. The Modified Base Friction Method (MBFM) was developed to simulate the movement of jointed rock mass by applying the horizontal force by using springs to BFM. As a model material for simulating the jointed rocks, sugar pieces were used. The process of roof collapse was photographed.
The relationship between the roof fall height and the initial span length of roof was measured by varying the arrangement of sugar pieces and the horizontal force. Three collapse stages were observed with the increase of the initial span length. These are, (1) Stable Stage in which no fall occurs, (2) Regular Collapse Stage in which the falls cause only the steplike collapsed surface and (3) Irregular Collapse Stage in which the falls do not cause steplike collapsed surface.

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The conical-ended borehole technique is presented to measure the threedimensional state of stress in a rock mass with a high accuracy and low costs by the stress relief method, and the optimum shape of the bottom surface is discussed as well as the gauge arrangement. It is shown how the stress tensor can be determined from the strains on the conical bottom surface of a single borehole, and how the error of stress determined can be evaluated theoretically. The sensitivity and the practicality of the present method are discussed, comparing the conventional methods of in situ stress measurement.
The axisymmetrical arrangement of cross gauges on a measuring circle with equal spaces of rotating angle, shown in Fig. 5, is suggested and the sensitivity of the present method is clarified to depend on the vertical angel:ω of the conical bottom surface, theradius:γ₀ 0f the measuring circle, the number:η of the strain gauges, and the Poisson's ratio:ν of rock. The smaller the vertical angle, the higher the accuracy in the stress tensor determination. Simultaneously, the accuracy improves with increase of γ₀ and η. From such an analysis of the sensitivity and the subsequent discussion on the measuring procedure in practice, the conical bottom of ω=60 degrees and the measuring circle of γ₀ equals to a half of the borehole radius are concluded to be convenient for the over-coring operation having a diameter equals to that of the conical-ended borehole. The observation equation to be used in practice is presented, and from the time and the costs involved it is concluded that the present method is a promising method.

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Elution of gold, silver or cobalt were eluted from five species of marine algal powder and two species of fresh-water algal powder previously adsorbed each metal ion was studied. The effect of pH on the elution was significant for all algal powder.
Cobalt was eluted from algal powder by suspending and stirring the algal powder in aqueous solution of low pH, but elution reagent was necessary for the elution of gold.
Equillibrium of the adsorption and elution of cobalt with algal powder was considered regarding pH and metal ion concentration of the solution.

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In order to clarify the effect of water spray for cooling fire fumes in underground open fires, a numerical simulation was carried out, using a proposed model of water droplets heated and evaporated in the hot fire gases. By means of this simulation the cooling effects of water spray were analyzed and clarified in practical conditions, and the requirements of water spray zones for underground open fires were determined. The results showed that a good agreement with those obtained by the fire experiments using a full-scale test gallery. The conclusions of the required water quantity, the spraying duration and the total quantity of water to be stored in situ have been adopted as the fundamentals for a guide line of water spray zones for suppression of fire spread in coal mines by the Industrial Location and Environmental Protection Bureau in MITI.

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The contents of manganese, water and sulfate ion, O/Mn mole ratio and BET specific surface area have been determined for the manganese dioxide produced by ozone oxidation in acidified sulfate solutions. The manganese dioxide was formed under the following ozonation conditions: the sulfuric acid concentration of the solution, 0.25 to 5.0mol/l and the temperature, 25.0 to 80.0°C, and the ozone partial pressure, 2.8×10^-2 atm.
The water content of the manganese dioxide was considerably reduced with a rise in the ozonation temperature and increased with an increase in the acid concentration.
The O/Mn mole ratio or x in MnO_X was almost constant at a high value around 1.98 over an acid concentration range up to 5.0mol/l and increased very marginally with a rising ozonation temperature.
Similar features were determined in the chemical analyses for the manganese dioxide formed in solutions of similar composition to the electrolyte solution for zinc electrowinning.

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This paper describes experimental results of water vapor adsorption of coal and numerical simulations relating to the spontaneous combustion of coal in a low temperature range. The calculation model using a thermal model as the physical effect of water vapor adsorption in addition to the oxidation due to the equilibrium exposure time concept is proposed.
Coal specimens supplied by the Akabira Coal Mine, the Taiheiyo Coal Mine and the Genesee Coal Mine (Alberta, Canada) were used for the water vapor adsorption experiments. The equilibrium moisture content of coal against relative humidity and unsteady water vapor adsorption rate caused by the step change of relative humidity were measured at several temperatures. The new numerical model to express the water vapor adsorption rate is proposed.
The calculation models were successfully applied to the numerical simulations of spontaneous combustion in the spherical deposit of coal. The numerical model includes heat conduction, oxygen and water vapor diffusions in the coal deposit. Numerical results show that the water adsorption has an effect to accelerate rising coal temperature at the early stage (<200 hours), but also has an effect to restrain the rise of temperature over the long period.

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Kozeny-Carman's equation is used for the determination of the specific surface area of particles by gas permeametry. We found that using this equation the measured values of particle size under the same experimental conditions vary widely. After conducting many experiments, a scatter in measured values of specific surface area of particles was obtained. However, the obtained scatter of points is thought not to be due solely to experimental error, but they suggests that the value of K is not a constant but is infact variable. Using glass spheres of known density and specific surface area, we proceeded to calculate the value of K.
The sorted glass spheres were prepared by the following procedure. Toshiba glass beads (#GB741) were sieved using JIS standard screens (-420+350μm), decantated and nonspherical particles were removed using an inclined rotating circular plate. The mean particle diameter, specific surface area and density of the glass spheres are 362.5μm, 165.5cm²/cm³ and 2.50g/cm³, respectively. The experiments were repeated under the same conditions as follows:
Sectional area of the cylindrical cell A is 32.047cm², the coefficient of viscosity of the nitrogen gas at 20°C η is 1.766×10^-5Pa·s, and the weights of the glass spheres are 200, 430, 860 and 1, 290g.
The experimental results obtained are as follows
(1) The values of Kozeny constant K obtained by the reverse calculation technique vary widely, and the distribution curves of the values of K are shown as normal distributions.
(2) In the case where the weight of the glass spheres is 200, 430, 860 and 1, 290g, the mean values of the constant K are found to be 4.478±0.3234, 4.584±0.1844, 4.602±0.1168 and 4.58±0.0883 and the number of repetitions are 210, 90, 90 and 80 times, respectively.

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