This paper is concerned with the studies on the physical and chemical properties of synthetic meta-silicic acid, barite, calcite and gypsum, and the relation between pH and geological environments in the case of natural mineral depositions. Furthermore on the basis of above experiments, it is discussed that the case of ferric hydroxide, calcite, gypsum and meta silicic acid are precipitated at the same solution system.
The followings became clear after examining the experimental results.
1) The crystallization of ferric hydroxide such as goethite and lepidocrosite is obstructed by the presence of meta-silicic acid, and the heterogeneous cohesion of the both materials is took place.
2) The most suitable condition for meta-silicic acid is about 1.0 pH.
3) High grade crystallization of calcite and gypsum are formed at the condition of the pH 8.0 to 8.3, 2.5 to 3.5 respectively.

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In case of underground storage of L. N. G. whose temperature is -162°C, we must consider a mechanical and thermal stresses.
A temperature distribution around openings is necessary for getting a thermal stress distribution. In this study, theoretical analysis for temperature distribution around underground openings in various thermal conditions The finite divided elements method is adopted for the analysis.

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The acoustic analyses of the impact sounds of the wall of underground drift, using a ball type hammer, have been studied by authors for detecting drummy rocks.
So the corresponding values to the area surrounded with an envelope of the filtered waveform in each band of the filters were adopted as the index of the sound-energy for analysis of the impact sound. The corresponding values above mentioned were then measured electronically using an integrator, which was trial manufactured in this study.
According to the results of the former investigations applied this method, the center frequencies of the suitable bands of one-third octave band pass filter were 400Hz, 500Hz and 630Hz respectively for detecting drummy rock in the mine drift.
In this study, the model tests concerning the positions of drummy rocks in the drift, the impact directions and the dimensions of drummy rocks are carried out for improvement of the precision on above method.
In the model test, the model drummy rock of 40cm×40cm×20cm is set into the cement mortar block of 150cm×150cm×90cm as shown in Fig.3. As the results of the analyses of the impact sounds produced by upward, sideward and doqn -ward impact using a ball type hammer, it is considered that the acoustic characteristics of the impact sounds are not influencedvery much to the differences of imnact directions.
Then, the downward impact sounds of the model drummy rocks of 15 kinds in dimensions from 36cm×30cm×15cm to 50cm×50cm×50cm at the quarry are analyzed.
Consequently, it is found that the center frequencies of the suitable bands for detecting the model drummy rocks are also 400Hz, 500Hz and 630Hz and that in the 400Hz band, the drummy rocks are able to detect up to the dimension of 50cm ×50cm×30cm.

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The application of the authors' method used the stability parameter (i. e. Eq.(1)) for predicting the lower critical Reynolds number is extended to include the flow of Herschel-Bulkley fluids in pipes and between parallel plates.
The theoretical equations for calculations of the lower critical Reynolds number for the Herschel-Bulkley fluids flow in pipes and between parallel plates were derived as Eqs.(10) and (22) respectively These equations are not confirmed byexperimental data but would appear suitable for the prediction of the lower critical Reynolds number, since the theoretical results used the authors' method for the flow of pseudo-plastic fluids and Bingham plastic fluids, which may be regarded as a special case of Herschel-Bulkley fluids, in pipes and between parallel plates showed good agreement with the experimental results.

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The extended Huckel molecular orbital method has been applied to the adsorption of ethylxanthate (EX^-) on Cu clusters of up to 13 atoms with (100) and (111) planes. The calculated values of the simulated Cu cluster are in good agreement with the empirical ones of copper metal in its electronodensities and band widths. The EX^- adsorption on copper is rather chemical than physical. Although EX^- outside a distance 4 Å from copper surface does not have any great effect on its atom populations or atomic bond pgpulation, all the above populations change as EX^- comes close to the Cu surface. These change is considerable at distances 2 Å and 3 Å from the Cu surface due to the strong mutual interaction between EX^- and Cu clusters. Electrons are in main transferred from the two sulfur atoms of EX^- to Cu clusters, and then the new bonds formed between two sulfur atoms and copper atoms play a great role for binding EX^- to the Cu surface with increasing their strength as the distance decreases. The main contribution to these bond is due to the 4sp orbitals of copper than due to the 3d orbitals of copper. Oxygen effect on chemisorption of EX^- on Cu clusters indicates that the adsorption system at low coverage of oxygen on Cu surface is more stable only to adsorb EX^- on the Cu surface and it becomes less stable at high coverage of oxygen on the Cu surface.

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The results of previous studies on the thermoelectric power measurement of 12 kinds of Pb concentrates and the potentialdependence of the oxidation rate of the same samples were in summary discussed to elucidate the correlation between the semiconducting property and the oxidation rate.
The oxidation in acidic suspension follows the quasi-first order kinetics. The reaction process is tentatively considered to consist of 4 steps:(1) the formation of a positive hole in the valence band by a jump of an electron from the valence band to an impurity level at the PbS surface, (2) the electron migrates through the solid-solution interface to combine with the acceptor (Fe³⁺) in the solution, (3) adsorption of Cl^-onto the surface, follovved by (4) two positive holes react with PbS to yield PbCl₂ and S^o.
For the concentrates with low Cu contents (Cu<1-2%), the rate below 0.35V (suspension potential) is represented by _??_where T_0.5, d_o,
E_m,
E_o, E^α*, k, T, and e_o are the half life time of the oxidation, the diameter of PbS particle, the suspension potential, a constant, the ionization energy for the thermoelectric power, the Boltzmann constant, the absolute temperature, and the charge of an electron, respectively. The second term in the right side corresponds to the step (2), i.e. the cathodic reduction of Fe3+, and the third term is considered to correlate with the step (1) and (4).
For a few concentrates contaminated with CuFeS₂ (Cu>2%), the thermoelectric power and the rate are closely concerned with the Cu content. It is found that the transfer coefficient (0.6 in above eq.) increases with an increase in Cu content.

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The mechanism of volatilization removing of Pb and Zn from electric furnace dust by reducing pellet process was clarified and the behavior of volatilization of Cl and F was studied. When the dust pellets without carbon were roasted in air or water vapor atmospher, Pb in the dust was changed to PbCl₂ by coexisting NaCl and was volatilized above 90% at 1000°C. Pb compound, Pb (OH) Cl in the dust was decomposed to PbO and PbCl₂ at lower temperature, then PbCl₂ was removed. But, when NaCl content, was a little, sintering phenomena of the pellets by decomposition products PbO were observed and the fraction of volatilization of Pb was reduced at 1000°C. Cl-bearing compound was completely removed at 1100°Cin either roasting atmospher, but Zn was showed the fraction of volatilization of less than 20%. On the reducing treatment of pellets with carbon, Pb, Cl and Zn were entirely volatilized from the pellets above 1000°C. Iron contents in the pellets roasted above 1100°C were greater than 55% and it makes clear to use these pellets as iron ore.

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