The Global Positioning System (GPS) is an innovative surveying system using artificial satellites currently under development by the US Department of Defense. This system has the potential to measure the ground movements of an extensive area. This report outlines GPS and describes the accuracy of GPS surveying. Several case studies about applications of GPS to displacement measurements, such as monitoring subsidence due to groundwater withdrawal, displacements of high cut slopes, crustal deformation, etc., are introduced. It can be concluded that GPS has great potential and will be extremely useful for measuring ground displacements in various rock engineering projects.

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Almost all the mining areas of Toyoha Mine are in hot rock and the areas in initial rock temperatures greater than 373K are not a few. Especially, the initial temperature of the new deposit which is recently discovered and named Shinano Vein partly reachs 433K.
In order to perform effective expansion of ventilation system for development of Shinano Vein under such condition, the authors carried out numerical analyses for prediction of underground climate. They set their main aim that they can decrease the inlet air temperatures of the airways going to the deposit as much as possible. They carried out prediction calculations for the models corresponding to current ventilation network and also carried out in-situ measurement of underground climate in the current condition, and they adjusted the values of the airway parameters so as to fit the calculated distributions of temperature, humidity and rate of flow in main frame come near to the measured ones. Then, they set up several plans for expansion of ventilation system, which can be performed in consideration of initial condition of rock and economical effect, and they determined the most suitable plan from the viewpoint of underground cooling by comparison of the temperatures, humidities and rates of flow, which are calculated from the planned models.

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The effect of the organic phases on the recovery of fine quartz particles by liquid-liquid extraction at various pH has been investigated using dodecylamine acetate (DAA) as a collector. Three kinds of organic solvents, n-butanol, methyl isobutyl ketone (MIBK) and iso-octane, were used as the oil phase in the present study. The interactions between the oil droplets and the quartz surface under different conditions of pH and DAA concentration have been examined through the related studies on the oil/water interfacial tension, contact angle and interfacial free energy for oil droplets to contact at the quartz surface in water. Good correlation was obtained between the percentage of quartz recovery and these variables. The recovery depends not only upon pH and collector concentration, but upon the properties of oil phase.

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The phase diagram of the Cu₂S-SnS system by the DTA method proved to be of simple eutectic type without a solid solution, and the eutectic point and the eutectic temperature were determined as 55 mol% Cu₂S-45 mol% SnS and 490°, respectively.
Also, vapour pressures of SnS of pure SnS, the Cu₂S-SnS and FeS-SnS systems were measured by means of the transportation method within a temperature range from 900 to 1, 100°, and activities of SnS in the two binary systems were calculated therefrom.
The activities of Cu₂S and SnS in the Cu₂S-SnS system exhibited a negative departure from the ideal behavior, but they were little changed by differences in temperature.
On the other hand, the activity of FeS and SnS in the FeS-SnS system deviated slightly positively from Raoult's law. This system could be regarded as a regular solution, and the following equation relating the Raoultian activity coefficient of SnS with composition and temperature has been obtained: ln_γSnS=438 (1-_χSnS) ²/T.
The activity coefficients at the infinite dilution of the components in the Cu₂S-SnS and FeS-SnS systems at 1, 100° were estimated as γ°_SnS=0.29, γ°_Cu2S=SnS=0.039 (Cu₂S-SnS system) andγ°_SnS=γ°_FeS=1.38 (FeS-SnS system), respectively.

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Bacterial leaching tests of pyrite with Thiobacillus ferrooxidans were performed, and leaching solutions and pyrite surfaces were analyzed during the tests.
The leaching of pyrite mainly proceeded according to the indirect bacterial leaching mechanism. The main reactions in this mechanism, i. e. the enzymatic oxidation of ferrous iron and sulfur by T ferrooxidans and the chemical oxidation of pyrite by ferric iron, accelerated when the number of the bacteria increased logarithmi-cally. With the rapid increase in the concentrations of ferric iron and sulfate in the leaching solutions, insoluble sulfate compounds were precipitated on pyrite. The redox-potential (Eh) was dependent on the mole ratio [Fe³⁺]/[Fe²⁺] int he leachings olutions. The redox-potentiailn creasedi n the activep hase of bacteria nd decreased in the latter inactive phase. It indicates that Eh can be a measure of the activity of T. ferrooxidans in the leaching process as reported by others. In the latter inactive phase, the insolubel sulfate compound formed on pyrite was shown to be jarosite by FTIR and XPS.

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A new 2-D stress change monitoring probe was developed. The probe basically consists of a rigid steel bar and three pairs of hydraulic curved jacks.
It was clarified through numerical simulations and laboratory experiments that, by using the probe, not only 2-D stress change can be monitored but also in-situ Young's modulus and Poisson's ratio can be measured

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Experimental results for the penetration of conical bits into rocks have been obtained and compared to theoretical results derived from an existing bit penetration model which is similar to the one established by Dutta. The tests were made in sandstone, andesite and granite using seven indenters with apex angles in the range 60-150°. Moreover, the effect of mechanical anisotropy on bit penetration behaviour was examined using sandstone. For the smaller apex angles chipping was predominant whereas for the larger apex angles essentially only crushing occured.
Crater volume and force-penetration curves were measured, and the theoretical cutting efficiency and the ratio of volume to work were evaluated. Using those values of the mentione parameters, quantitative consistency between theory and experiment is obtained. Accordingly, the penetration model has the capability of predicting quantitatively the rock cutting and drilling behaviour.

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This paper describes the ultrasonic attenuations in gas mixtures of CO₂ and air to investigate the possibility of a CO₂ gas concentration monitor using with the ultrasonic attenuations. Three kinds of ultrasonic transducers (40, 215 and 500 kHz) were used for the measurements. Measurements of the attenuation per unit distance of each ultrasonic wave were carried out by varying the length of a test cell of 26 mm in diameter from 30mm to 150mm. From these fundamental results, the practical gas detection cells were designed and the detection method in order to monitor the CO₂ gas concentration was developed. Two 215 kHz ultrasonic transducers were installed on the both sides of the gas detection cell of 4 mm in diameter and 70 mm or 40mm long. The attenuation of 215 kHz ultrasonic is the largest of the three ultrasonics. The ultrasonic waves are sent intermittently from the transducer and are propagated through the cell. The sound pressure of the ultrasonic waves are detected by another transducer on the other side. The peak detected value of the sound pressure in the first receiving waves is decayed sharply by introducing CO₂ and air mixtures into the cell compared with air. The relationship between the peak detected value;P₁ and CO₂ concentration; C (%) is presented.
The summary of the measurements is as follows:
a) The peak detected value of the sound pressure;P₁ extremely decreases with increasing CO₂ concentration in a range of C=0-20%(Fig. 11).
b) The ratio between the peak detected value of gas mixtures and air P₁ may be treated to be independent of temperature (Fig. 13).
c) The peak detected value is comparatively influenced by adding water vapor into the gas mixtures (Fig. 14).

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This paper presents a new procedure for rock stress determination, which utilizes the strain change on a hemispherical borehole bottom surface during overcoring, and the limitation of the applicability of the hemispherical-ended borehole technique.
The observation equations using the strain coefficients analyzed by FEM at four stages during overcoring is formulated. It is clarified that a more accurate rock stress can be determined by the new procedure, comparing with the conventional one, and shown concretely that the investigation of the measurement quality can be easily carried out, analyzing the residuals between measured and theoretical strains during overcoring. Furthermore, to make clear the limitation of the applicability of the hemispherical-ended borehole technique, the relation between a rock stress state existing prior to boring and drilled direction of borehole for measurement, is analyzed taking notice of the induce stress on a hemispherical borehole bottom surface at two stages during overcoring. It is indicated that the drilled direction of a borehole for measurement may be chosen to minimize the induced stress on the borehole bottom surface during overcoring, when the borehole is drilled in arbitrary direction under a rock stress state existing prior to boring. Then, it is concluded that the investigation of the measurement quality and the calibration test of overcored rock are indispensable to determine rock stress by the hemispherical-ended borehole technique with a high reliability.

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The production of zirconia microspheres in a newly developed semi-continuous system of agglomeration in liquid was investigated. Semi-continuous agglomeration experiments were carried out using zirconia powder containing 2.6 mol% of Y₂O₃ (surface area=6.76m²/g, mean particle diameter=0.45μm), a paraffin type organic liquid as suspending media and four levels of bridging liquid additions, i. e. 0.095, 0.105, 0.115 and 0.125ml/g. Several runs were performed for each bridging liquid dosage. A decrease in the amount of bridging liquid prolongs agglomeration time and decreases the diameter of agglomerates. The sintered agglomerates produced by using different dosages of bridging liquid have sphericity, i. e. the ratio of the maximum length and breath diameter, ‹1.14, density› 5.93g/cm³, mean diameter of 282-701μm and narrow size distribution. The agglomeration time and properties of agglomerates obtained from several runs of the semi-continuous agglomerator exhibited good reproducibility. However, the semi-continuous agglomerator can be sensitive to even minor changes in bridging liquid dosage which affect the agglomeration time and the properties of agglomerates. Consequently, there is a great need to develop a reliable instrumentation method for on-line monitoring of the agglomeration process. Cognizant to this need, the possibility of using power consumption, temperature, pressure, laser attenuation and noise relative energy for on-line monitoring was investigated. It was concluded that on-line monitoring of the agglomerate growth during the process of agglomeration in liquid was possible by measuring the laser attenuation and noise relative energy.

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