This paper treats a numerical analysis of behaviour of moving shock and contact discontinuities by an explosion of high-pressure gas in an underground space. Two situations are considered as the form of space. One is an abruptly wide-open duct. The other is an L-shaped duct with a sharp corner.
First, as soon as a shock front travelling straightforward by a sudden breakdown of diaphragm passes through sharply wide-open space, the shock front diffracts around an acute corner, and thereby a vortical structure is incipiently formed at the downstream region from the corner. The front of diffracted shock wave extends with keeping the self-similarity about a corner edge. Second, in the L-shaped duct, an outside part of the shock front is incident on the opposite wall and reflected from there and an inside part of the shock front diffracts around the corner. As a result, the reflected shock and the diffracted one interact with each other and the shocks with the threefold point are formed. The reflected shock, which does not interact with the diffracted one, interacts with the contact surface almost immovable at a little upstream side from the outside wall. Therefore, the gas near the outer corner remains in a high-pressure and high-temperature state by repeating the reflection as well as the transmission. However, these discontinuity waves become decayed as time goes by. The above-mentioned processes are discussed here from various points of view.

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This paper is concerned with a numerical analysis of behaviour of flow fields of a gas-solid particle two-phase fluid owing to an explosion of high-pressure dusty gas in an underground space.Asituation is considered where a high pressure gas is initially stored by a diaphragm in one closed end of a duct, and the other side of the diaphragm is open to a low-pressure gas. The gas-phase is treated as a continuum medium, and the particle-phase is treated as a discrete one. The particle cloud is divided into a large number of small subclouds. In each subcloud, the particles are approximated to have the same velocity and temperature. The particle flow field is obtained by following these individual subclouds separately in the whole computational domain.
As soon as the diaphragm is broken, a-shock wave propagates into the low-pressure gas region and a blast appearing behind the shock wave exerts local aerodynamic force on the suspending particles. It has been demonstrated that particles also are transported to the low-pressure gas region. As a result, it has been found that a dense region of particles is formed between the shock front and the contact surface, while a dilute gas-particle mixture is left in the upstream region of the contact surface.

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Deformation in roof rock was measured on an experimental tunnel in Matsumine mine. Two extensometers were installed in bore-holes drilled from an opening 15 meters above the experimental tunnel before its excavation. Therefore, the vertical displacement in the roof rock can be measured not only after, but also before the face passes under the measuring section.
The vertical displacement in roof rock consists of elastic part immediately after the blasting and time-dependent inelastic part. The inelastic displacement is considerably larger than elastic one. Total displacement and inelastic displacement in roof rock between two blastings increases with time following the power law, and the inelastic displacement rate decreases also following the power law. Through the measurement of such deformation behavior, it became clear that the rock mass around the experimental tunnel in Matsumine mine behaves as a visco-elastic body; a great part of the displacement is due to viscous or time-dependent behavior.

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Phase relations in the FeO-ZnO-ZnFe2O4-Fe3O4 system at 1, 100 K have been determined by the X-ray microanalysis and X-ray diffraction studies of the quenched samples. The results indicate that magnetite (Fe₃O₄) and zinc ferrite (ZnFe₂O₄) form a complete series of solid solutions in the Fe₃O₄-ZnFe₂O₄ system, while there is a miscibility gap in the FeO-ZnO system. Lattice constants for the Ze₃O₄-ZnFe₂O₄ spinel solid solutions in equilibrium with the Fe0-ZnO system exhibit positive deviations from Vegard's law.
The partial oxygen pressures were measured by an e.m.f. method using the stabilized zirconia solid electrolytes, the activities were obtained by applying the Gibbs-Duhem relations to the oxide phases. Activity of zinc oxide in the FeO-ZnO system coexisting with the Fe₃O₄-ZnFe₂O₄ solid solutions at 1, 100 K shows a considerable positive deviation from Raoult's law except that at ZnO-rich side it exhibits a slight positive deviation from Raoult's law in the range up to the solid solubility limit. The activity coefficients at infinite dilution, reFeo and γ⁰znO, at1, 100K were estimated at 4.7 and 0.9, respectively.Both the activities of magnetite and zinc ferrite in the Fe3O4-ZnFe₂O₄ solid solutions coexisting with the FeO-ZnO system at 1, 100 K show peculiar behavior. The activity of magnetite has a finite non-zero value in pure ZnFe₂0₄. The standard Gibbs energy of the reactions at 1.100 K were also obtained as follows:
ZnO (s) + 2/3Fe₃O₄ (s)+1/602 (g)=ZnFe₂0₄ (s), -59090±47J·mol^-1 (ZnFe₂O₄) and ZnO (s)+Fe₂O₃ (s)=ZnFe₂O₄ (s), -30160J·mol-1 (ZnFe₂O₄).

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Phase relations in the Fe₃O₄-ZnFe₂O₄-Fe₂O₃ system at 1, 100 K have been determined by the X-ray microanalysis and X-ray diffraction studies of the quenched samples. The results show that in the Fe₃0₄-ZnFe₂O₄ system magnetite (Fe₃0₄) and zinc ferrite (ZnFe₂O₄) form a complete series of solid solutions which is in equilibrium with the Fe₂O₃ that is practically pure.
The activities were measured by an e. m. f. method using the stabilized zirconia solid electrolytes. Both the activities of magnetite and zinc ferrite in the Fe₃O₄-ZnFe₂O₄ solid solutions coexisting with the Fe₂O₃ exhibit slightly positive deviations from Raoult's law at 1, 100 K. The activity coefficient at infinite dilution, γ⁰ZnFe2O4 at 1, 100 K was estimated at 2.2.
Lattice constants for the Fe₃O₄-ZnFe₂O₄ spinel solid solutions in equilibrium with the Fe₂O₃ obey Vegard's law. It was also found that the excess Gibbs energy of mixing in the Fe₃O₄-ZnFe₂O₄ solid solutions coexisting with the Fe₂0₃ at 1, 100 K showed small values. These two results are interrelated in the similar behavior, which suggest that activities are closely connected with crystal structures.

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A hydrometallurgical process, in which aqueous Cu (II) ammine solution is used as leachant, is proposed for the selective recovery of copper and iron from motor scrap. In this paper, the chemistry of the selective dissolution of copper with aqueous Cu (II) ammine solution is described, and some fundamental experiments have been carried out. Copper is dissolved easily with aqueous Cu (II) ammine solution, leaving iron as unattacked. Copper can be dissolved from the enamel coated copper wire which is treated by heating or shot blasting. These findings suggest that copper can be dissolved selectively from motor scrap with aqueous Cu (II) ammine solution after the removal of the enamel coat. The dissolution rate of copper increases with the increase in NH₃ concentration up to 7 kmol m^-3. The concentration of (NH₄)₂SO₄ affects the dissolution rate. The optimum (NH₄)₂SO₄ concentration exists corresponding to NH₃ concentration. The dissolution rate of copper is negligibly small in the Cu (II) ammine solution without (NH₄)₂SO₄. The dissolution of copper can be accelerated by the exposure of the leachant to the air, by which the Cu (I) produced by the dissolution reaction is oxidized to Cu (II).

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This paper reports experimental study of the static and dynamic coefficient of friction, μ_s and μ_d, using 1-in. transparent or translucent pipes of four different materials; glass, acrylic resin, vinyl chloride, and polyvinylidene fluoride. Four different sizes of sand from 0.86mm to 2.18mm and sliding velocities from 1cm/s to 12cm/s were investigated. To determine these coefficients of friction, original apparatus were built.
Friction tests were administered to measure angles of an inclined plane on which solid particles start sliding for As and to measure friction forces of the particles pulling along at constant speeds for pd. The results of these are compared with the coefficients of sliding friction between a submerged sliding bed of solids and a pipe wall for saltation flow in a test pipeline constructed of the same materials as those for the friction tests of μ_s and μ_d.
The variation of the coefficient f with transport conditions are also discussed.

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Landscape destruction after open-cut mining gives to the social impression. This paper presents the method to predict and evaluate landscape changes caused by open-cut mining. Landscape changes with the progression of mining are simulated by the use of digital terrain models, and that are shown on the computer graphic screen. Evaluation tests are conducted by using of photomontages composed of computer graphics and present appearance photographs. Two psychometrical evaluation methods, rating-scale method and selection method, are adopted to estimate the allowable scale of mined-out quarry from the viewpoint of landscape engineering.
In this study, two quarries are chosen as the examples of case study. From the results of evaluation tests, it is shown that the landscape impact of mined-out quarry is subjected to the height ratio against the background mountains and the apprarent height of mining slope. Especially, the apparent height of mining slope is a important factor for landscape evaluation. It becomes clear that the allowable limit of the apparent height of mining slop is about 0.037. This value is equal to the visual angle of 1°, at which an ordinary person can distinguish the object observed. The apparent height 0.037 is therefore the quantitative criterion for the allowable scale of mined-out quarry from the viewpoint of landscape conservation.

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Circular roadway or tunnel is the simplest analytical problem. To this problem, the elastic solution and further solutions based on the plastic theory and the viscoelastic theory have been proposed by early workers. However, the elastic and plastic solutions are unable to explain the time-dependent behaviour of underground roadway. Although linear viscoelastic models are considerably applied to simulate the time-dependent behaviour, the non-linear rheological phenonmena have been reported by the recent tests.
In this study, a non-linear rheological model has been applied to simulate the time-dependent behaviour of rock around circular roadway. It is found that the calculated convergence, failured region and distribution of stress around circular roadway are closely related to the shape of stress-strain curve, especially the descending curve in post-failure region.

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A new dust sampler (model LV-5E) was developed for measuring the mass concentration of dust in coal mine. This apparatus is smaller and lighter in weight than the usual model (LVS-10B) with explosion-proof construction, and has an inertial impactor to collect the respirable dust.
Dust collection tests with LV-5E impactor of jet hole of 3.65mm in diameter in the laboratory chamber polluted by Arizona road dust, coal dust and CaCO3 powder, show that the respirable dust values are equal to the values measured by standard apparatus, i.e., Lor -Volume Air Sampler, and LVS-10B.

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This study deals with flotation as a method for removing impurities, such as ceramic brick and unreacted graphite, from synthesized diamond. Firstly, a series of flotation tests was conducted on raw synthesized diamond in order to determine the optimum conditions for removing ceramic brick. When kerosene was used as a collector, it was found that the grade of diamond recovered in the froth was high within a pH range of 2 to 4. The recovery and grade of diamond concentrate were about 90% and 95%, respectively. Secondly, to assess the effectiveness of separating unreacted graphite from raw synthesized diamond, a series of tests was carried out using hydrocarbons of C6 to C8, such as cyclohexane, xylene, benzene and n-decane. It was recognized that any hydrocarbon reagent was effective in separating unreacted graphite from raw synthesized diamond in an alkaline region of around pH 11.

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