Utilization of the deep and large underground space. especially, geological disposal of nuclear waste might be increasing in future. Typical results of space safety assessments make it clear that there can be no good scientific reason for trancating analyses at more than 10,000 year's interval. The most important technical tasks concern the development and deployment of suitable science and technology for implementing safe underground facilities. Experiences worldwide has shown that the most controversial technical tasks, however, are the formulation of appropriate safety requirement together with criteria for demonstrating compliance with these requirements, and the preparation of comprehensive and transparent case study that demonstrates repository safety. It must be clear to all interested parties exactly how the engineered and geologic barriers work in concert in a robust manner to provide the safety. The qualitative arguments that support our understanding of large-term behavior of a repository must be explained. One of the first and must critical phases of field development is reliable geological interpretation and precise geological characterization. Geological interpretation and precise characterization and safety assessments, make it clear that there could be scientific analysis by stages on the scale of island arc, wide and middle regions. Of course, near field analysis and future assessment is most important to take precise data and to analysis them. This paper, discuss on the geological characteization of the Kinki District for the case study.

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Simulation of rock behaviour going back to the past is proposed in this paper. Usually computer simulation is carried out solving partial differential equations as time goes by, that is, starting at tA and ending at tB with tA < tB. In the proposed method, computer simulation is performed from tB to tA. Analytical consideration may suggests that solution ascending time is similarly possible as that descending time. Numerical solution ascending time, however, has some difficulties because information of initial state is gradually dispersing as time goes by, therefore, very small difference of initial values at tB results in very large difference of solutions at tA. The difficulties in numerical simulation are discussed in this paper. For demonstrating and evaluating the feature of the proposed method, relaxation of rock stress is selected as an example case. A selected site is peripheral of Beijing, China where 100 million years ago a large rock mass was intruded and considered to cause large rock stress around the site. Supposing that rock stress continuously relaxed up to the present, a simulation back to the past is carried out obtaining material constants, then, simulation on to the future starting at the present is also carried out to estimate the creep strain after 10 thousand years. In the proposed method, only a model at the present is necessary. In the conventional simulation, however, requires modeling at the past which is considered to be more difficult and time consuming than modeling at the present. As stated in this paper, the proposed method has some difficulty in numerical solution, however, we considered this method is one of the promising methods to examine the long-term rock behaviour.

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Forcing auxiliry ventilation with an auxiliary fan and a duct is widely employed at heading faces in mines in order to maintain the required safety levels of, particularly combustible gases such as methane, and dust concentration, temperature and humidity. However, it is not necessarily easy to design the optimum ventilation method in given situations, mainly because of the complexity of airflow created in the working place. In other words, there remain many problems that must be solved while many related studies have been reported. One of the major problems is the distribution of gas concentration at a heading place. From this point of view, the authors carried out in-situ measurement of methane gas distribution by a high-resolution gas measuring apparatus and the numerical analysis of the distribution by means of CFD. The results of the measurement present more detailed patterns of gas distribution in the working place and it is also shown that the simulation method employed in this project can be utilized for prediction of the airflow and the gas distribution at the heading in a practically satisfactory accuracy.

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The particles in water form regular stripes of clusters when a standing wave is generated in a tube. With increasing particle concentration, the particles are moved up to the upper part of the tube by lift force and make massive clusters. The lift force is resulted from the dissipation of the wave. The first purpose of this paper is to measure the total dissipation of low frequency ultrasonic wave transmitted in water containing polystyrene beads. The dissipation rate is approximately proportional to the volumetric concentration of the particles. The second purpose is to simulate the cluster formation with the method superposing Oseen's flow flied of each sphere moving at low Reynolds number. The simulations of five and three settling particles resemble the relative position of particles observed in the experiments. Simulations of the cluster result in similar formation of clusters obtained in the experiments. However, the velocity of a particle cloud moving in the same direction is overestimated by this method.

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The tower mill is a new type of pulverizer specially conceived for a fine grinding of minerals. Its efficiency of the fine grinding largely depends on the structure of the cyclones. In this paper, to investigate influence of the cyclone structure on fine grinding, the weight, particle diameter of the products as well as the electric consumption were examined using 10 different structures of the cyclone and a limestone sample. The experimental results are summarized as follows: (1) The different structure of the single and twin cyclones have no influence on the pulverized products. (2) In the case of cyclone with spiral ribbons, the weight of cyclone products increased, the maximum and 50% particle diameters of the products became smaller than the other cyclones. (3) In the case of cyclone with the spiral ribbons of every 44mm pitch, the weight of cyclone products increased, and the 50 % particle diameters of products were coarser than that for the other spiral cyclone, and the electric consumption of blower decreased. (4) The cyclone have no influence on the maximum size and the 50 % particle diameters of products in the classifying column. (5) The 50 % particle diameters was proportional to the maximum particle size of the tower mill products in any case of cyclone.

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Authors have been studying the development of a new method of waste water treatment by hetero flocculation with fluorite as a solid flocculant, and further investigations on flocculation phenomena were made using quartz and fluorite particles which are negatively and positively charged respectively in distilled water.In this study magnetic stirrer and ultrasonic wave were used to clarify the influence of the method of sample preparation on quartz and fluorite particles, which contained large and small proportion of fine particles respectively, and their mixtures. It was found that quartz particles prepared with ultrasonic wave existed under the condition of primary particles in any proportion of fine particles at all pH range, while clusters of fine particles could be observed in using magnetic stirrer. When fluorite particles containing high proportion of fine particles were prepared with magnetic stirrer, the similar phenomena could be seen at pH < 10 and the number of homo-flocculated flocs decreased in comparing with that of ultrasonic wave at pH > 10 . In case of the mixture of quartz and fluorite particles containing large proportion of fine particles, the number of hetero-flocculated flocs increased enlarging the maximum size of floc at pH range of 3 - 10 when ultrasonic wave was used. And it was noticed that hetero-flocculation did not occur between clusters of fine particles and fine particles.

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This paper shows that ferrous ions are more useful for leaching chalcopyrite than oxidant ferric ions in sulfuric acid solutions in air at ambient temperatures. Leaching experiments and dissolved oxygen consumption measurements were carried out with a very pure chalcopyrite and 0.001 ∼ 1 mol dm-3 sulfuric acid containing 0 ∼ 0.1 mol dm-3 ferrous or ferric ions at 303 K. Chalcopyrite oxidation with dissolved oxygen was promoted by ferrous ions and was suppressed by ferric ions. As a result, the amount of extracted copper was higher with ferrous ions than with ferric ions in air. During the ferrous promoted chalcopyrite leaching, extracted copper ions catalyzed oxidation of ferrous ions to ferric ions which suppressed copper extraction. This result indicates that higher leaching rates can be achieved by reducing the ferric ions formed during the leaching.

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Restoration of contaminated soils to environmentally acceptable condition is important. Contaminants are primarily concentrated in the fine-grained soil fraction (i. e., silt and clay) and are not strongly retained on the coarse-grained particles (i. e. sand). Various methods currently used have advantages and limitations in remediating contaminants in soils. In fact, most successful in-situ remediation technologies are restricted to soils with relatively high hydraulic conductivities (silt and sand) and can not be used for fine-grained deposits. One of the newer techniques in soil remediation is a method based on electrokinetic phenomena in soils. Electrokinetic soil remediation is an effective in-situ separation and removal technique used for extraction of heavy metals and some organic compounds from fine-grained soils. The technology uses electricity to affect chemical concentrations and water flow through the pores of soils. However, the effect of the soil properties such as tortousity, permeability and pH on the distribution behavior of pollutants are not elucidated. Therefore, in the present study, the effect of the soil properties on the distributions of weak acids (acetic acid and phenol) in the electrokinetic processing of fine-grained soils are investigated. An analytical model, based on the Nernst-Planck equations, is presented to evaluate the effect of soil properties on the distributions of pH and weak acids and the results obtained in this study are summarized as follows: The distribution behaviors of acetic acid and phenol in close to the cathode are significantly different. The movement rate of acetic acid and phenol toward the cathode are faster with a decrease in the initial pH of soil and it is proportional to the acidification rate of soil. Soil properties such as tortousity and permeability significantly affect the remediation progress.

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In order to develop economical production methods for high purity silicon used in solar cells, thermodynamic properties of boron, the most difficult element to remove, in molten silicon were measured by equilibrating Si-B melts with solid BN and/or solid Si3N4 at 1,723 K and 1,773 K. Based on the results, (a) the free energy change for the nitrogen dissolution into molten silicon, (b) the activity coefficient of boron at infinite dilution referred to pure solid, and (c) the interaction parameters related to boron in molten silicon were determined to be: (a) 1/2 N2(g) = (mass %, H, in Si melt): Δ (b) (at 1,723 K) (at 1,773 K) (c) (at 1,723 K) (at 1,773 K) (at 1,723 K) (at 1,773 K), respectively, for 1,723 ∼ 1,773 K. Finally, the stability diagram of the Si-B-N system was established.

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The lanthanide metals lanthanum, praseodymium and neodymium containing 2,200, 2,600, 1,850 mass ppm oxygen, respectively, were deoxidized to 20-30 ppm level at 1,073 K by an electrochemical method. The metal to be deoxidized was used as the cathode in an electrolysis cell which consisted of a graphite anode and molten CaCl2 electrolyte. The calcium metal produced at the cathode by electrolysis effectively deoxidized the lanthanide metal. Calcium oxide produced by deoxidation, dissolved in the melt. The liberation of carbon monoxide/dioxide at the anode was found to prevent accumulation of oxygen in the melt. For a quantitative discussion of the limits of deoxidation achievable by this technique, a thermodynamic investigation of the lanthanide-oxygen (Ln-O ; Ln = La, Pr, Nd) solid solutions was conducted. The lanthanide metal, yttrium and titanium samples were immersed in calcium-saturated CaCl2 melt, containing a small quantity of dissolved CaO, at 1,093 K. The oxygen potential of the melt and the Ln-O solid solutions were obtained from the oxygen content of yttrium samples at equilibrium, and the known thermodynamic properties of yttrium-oxygen solid solution. The results were confirmed by using Y/Y2O3 equilibrium to control the oxygen potential of the molten salt reservoir. The oxygen affinity of the metals was found to decrease in the order : Y > Ti > Nd > Pr > La. The deoxidation results are consistent with the thermodynamic properties of the RE-O solid solutions.

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Amberlite XAD-4 is used for catching a very small amount of organic substances in the water. LIX84-I is indicated a good ability on the extraction of various metal elements, as known in the field of solvent extraction. In the present study, solvent impregnated resin (SIR) was devised by adsorbing LIX84-I to XAD-4, as a result, it would be having the metal extraction ability. The extraction properties of nickel, cobalt and copper were investigated by using the SIR. In the case of metal extraction by batch method, the extraction behavior of each metals using the SIR was similar to the solvent extraction using LIX84-I. Copper was selectively extracted at the pH of 3.0, nickel and cobalt were almost extracted at the pH of 9.0. As a result of using fine particle size of XAD-4 and high concentration of LIX84-I when the SIR was made, the nickel, cobalt and copper could be extracted at a more short time. In the case of column method, the SIR was enclosed in the column, metal solution was flowed from top of the column. The extraction curve of each metals were similar to the case of solvent extraction using LIX84-I and SIR batch method. As flow rate was rapid, the amount of saturated adsorption was increased. For giving back extracted metals to the water phase, stripping was carried out. In the solvent extraction using chemical reagents of LIX system, the stripping of cobalt was difficult, but in the solid-liquid extraction using the SIR, cobalt was stripped easier. It is considered that the cobalts in organic phase of SIR could not form stable Co-LIX complexes.

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