In order to clarify the fracture process of rock, the stress-strain behaviors associated with the fracture-initiation and propagation from an initial crack were simulated in thistudy by the Finite Element Method.
The results of this simulation indicated:
1) At the stress level of the characteristic point B, that was the point of the onset of dilatancy in the stress-volumetric strain curve, the fracture was initiated and propagated in the direction of the loading axis due to the tensile stress around the initial crack.
2) Beyond the stress level of the characteristic point C, that was the point of the onset of non-linear strain behavior in the stress-axial strain curve, the fracture was propagated as an extending crack due to the shear stress in the direction across to the loading axis.
It was found that the stress-strain behaviors obtained from uniaxial compression tests in the 1st report coincided with those from the above simulations.

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Lately coal mining operations have been carried out in deeper levels. As a result, high rock temperature has caused temperature increase of a working face. The improvement of coal mining productivity requires both theoretical analyses for the face temperature increment and appropriate cooling measures of working area.
A. H. proposed an theoretical equation to calculate a face temperature by solving a differential equation of enthalpy balance. His solution process, however, was not sound in view of mathematical analysis. Therefore authors improve the process and proposed a newly derived equation for the analysis of the face temperature. This paper showed that difference between differential humidity ratio of conventional equation (dw) and that of new one (dw) considerably increased with increment of the face temperature. Differential humidity ratio is an important factor to effect on the face temperature increase in the differential equation. This means that the error with conventional equation cannot be neglected if the temperature is high. The newly proposed equation can more accurately describe the temperature increase in the wide range of temperature. This paper also calculated two constants, modified heat transfer coefficient and specific oxidation heat, by substituting some measured data, temperatures and relative humidities at both inlet and outlet of the face etc. into this equation. These calculated values were reasonable comparing with many data measured before.
Furthermore, the newly derived equation was verified by simulations that describe the same heat transfer problem. The calculated temperature at outlet of the face by this equation was in good agreement with the simulated results, while the equation derived by didn't coincide with the simulated temperatures.

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Wire ropes are commonly terminated by a socket with alloy filling, and the inspection of broken wire inside the socket is virtually impossible. This paper describes an electromagnetic inspection method of wire rope terminals on the premise that the socket is of non-magnetic metal. A pair of magnetogalvanic sensors travel along one of the measuring tracks which have been laid out on surface of the socket, while the terminal part of the rope is longitudinally magnetized. The output trace of the sensor normally meanders due to the interior distribution of disassembled component wires, but a broken wire induces a distinct local change of the leakage magnetic flux at the nearby sensor track, which is recognizable when the trace is compared with the precedent one obtained on the same track.

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The continual depletion of the world's iron ore resources necessitates the treatment of increasingly lower grade and finer size ores. In this paper high gradient magnetic separation was discussed as one of the beneficiation methods of iron ores. At first the capture of each single sample and the separation of the artificial mixture of hematite and quartz were investigated by using a high gradient magnetic separator (SALA HGMS). Next a low grade iron ore from Tou-Anzan, China was treated with HGMS on the basis of the separation data for the artificial mixture. The results are as follows.
1) Hematite particles of -74+10μm could be captured at more than 95% weight recovery by using HGMS under the conditions of magnetic field intensity 3-5×10⁶/4πA/m, slurry flow rate 300m/h and pulp density 10%.
2) Fine hematite-quartz artificial mixture of -10μm could be separated at 62% total iron grade and 92-94% weight recovery in the mags by using selective flocculation pretreatment and HGMS. To promote the selective flocculation of hematite particles, sodium silicate of 1kg/t and starch of 0.3-0.5kg/t were added to the artificial mixture slurry and the slurry was agitated sufficiently.
3) Each size fraction of the iron ore from Tou-Anzan, China was treated with selective flocculation pretreatment and HGMS, however the positive effect of selective flocculation was not detected for -10μm size fraction. Though selective flocculation treatment for -10μm increased the iron recovery from 78% to 83%, it decreased the iron grade from 54% to 44%. Magnetization measurements and separation tests of the Tou-Anzan ore by using leaching in acidic solution or heating proved that the existance of a small amount of ferromagnetics such as metallic iron or magnetite locked with gangue minerals decreased the iron grade in the mags. In high gradient magnetic separation it is considered very important to grind iron ores without mixing metallic iron particles in consideration of the difficulty of ferromagnetics removal with conventional magnetic separators. Also it is very important to investigate the movement of ferromagnetics as well as quartz and hematite in selective flocculation conditions.

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Precipitation studies of the binary solutions containing Fe (III) and either divalent ion of Mn, Cu, Ni or Co have beend emonstrated with sodium hydroxide, sodium carbonate or calcium hydroxide as a precipitant to provide fundamental information for the recovery of valuable metals from the leach solution of manganese nodules. The Fe ion among five metal-ions precipi tated at the lowest pH range as a ferric hydroxide. Precipitation curve for each of Mn, Cu, Ni and Co ions was found in a range of lower pH than that estimated from the solubility product of the respective hydroxide. The marked coprecipitation of Mn ion with ferric hydroxide was observed in the presence of sodium hydroxide or calcium hydroxide as a precipitant. Sodium carbon ate precipitant provides the best results for Fe separation from either of Mn, Cu, Ni or Co ion with little effect of coprecipitation between these ions. The common ion effect is considered essential for an interpretation of the different behavior among three kinds of precipitants used in each of the binary solutions. The separation tests have been applied to the soluti ons leached from manganese nodule with sulfuric acid. The successful removal of Fe component using sodium carbonate was experimentally performed at a pH of 4.5 from the leach solutions containing Mn, Cu, Ni and Co ions as well as the successive separation of Cu component at pH6.7 from the Mn, Ni and Co ions.

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The solvent extraction of arsenic from spent copper electrolyte by tri-n-butyl phosphate (TBP) was studied in order to develop a new process for purification of spent copper electrolyte. The paper includes selection of a favorable extractant, the results of batch-wise, step-wise and continuous counter-current extraction tests to determine the optimum conditions. The optimum conditions for spent copper electrolyte are the extraction with undiluted TBP at O/A=2 and the stripping with water at O/A=5 at55°C, whereas thos6 for mother liquor from copper sulfate plants are nearly the same but O/A for the stripping should be less than 3. Under these conditions, more than 85% of arsenic can be successfully removed from both spent copper electrolyte and mother liquor.

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The thermodynamic properties such as activities in molten arsenic alloys and phase relations between speiss and metallic lead phases have been determined by the author and co-workers because of the importance of these properties to analyze the behavior of speiss in various metallurgical processes.
The activities of arsenic have been measured in molten Cu-As binary alloys at 1000°C, and in both Cu-SIAs and Fe-S-As ternary alloys at 1150°C by use of isopiestic method.
The activities of arsenic and copper in Cu-As system deviate remarkably from Raoult's law at 1000°C, and values are slightly smaller than those at 1150°C which have been reported by the author and co-worker. The activity coefficients of arsenic in dilute solutiOn at 1000°and1150°C are 6.8×10^-3 and 1.0×10^-2respectively. The free energy of formation of Cu₃ As was also obtained and is given by:
Δ^G°T/cal=-6, 200-6.35T (1273-1423K)
In Cu-S-As and Fe-S-As ternary systems, the activity of arsenic increases with increasing sulfur content, and activity coefficient of arsenic in matte phase is much larger than in speiss. Therefore, it is clear that arsenic will be effectively removed from matte before metallic copper is formed in copper process.
The activities of the other elements in the ternary systems were calculated from the activities of arsenic by using the Gibbs-Duhem ternary integration.

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