Development of Coalbed Methane (CBM) has boomed in USA since late eighties. Many petroleum technologies has been applied for recovering the CBM economically. In spite of many efforts, not all the projects have succeeded, because of the differences of reservior properties between coal seam and conventional natural gas formation. This paper summarizes the present technologies for developing the CBM and CBM related properties of coal seams. The followings are reported; world resource estimation of CBM, gas storage characteristics of coal seam, gas and water flow pattern in the coal seam, well drilling method, well completion method, stimuation methods, simulation technology and the related environmental problems.

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Generally information-cost functions of exploration techniques having low unit cost are low in limit information, while those having high unit cost are high in limit information. Consequently, information-cost functions of many techniques intersect each other.The most optimal combination of a low unit cost technique and a high unit cost one is realized by changing from the former to the latter when the information at which the difference of costs between both techniques are largest is obtained.If we use information-unit cost functions which are derivatives of information-cost functions, the optimal combination is represented as the trace where functions having the lowest unit cost at given information among all the functions are chained.

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In order to control airflow in ventilation network, a ventilation relation table is introduced in the study. Factor F_{m, n} in the table which was derived from macroscopic characteristics (Eq. 1) between a branch “m” and a branch “n” by computer simulation varying aerodynamic resistance of the branch “m”. Fm, nis composed of three or two digits (two digits: in case of monotonous relation) concerning to accumulated number of the pole (the hundredth digit), changeable range of airflow rate in branch “n” (the tenth digit) and degree “Nm, n” in Eq. 1 (the first digit).
Main results of the paper are as follows;
1) Macroscopic characteristic in airflow rate in two branches, “m” and “n”, is represented as one of the three relations; a) a line, b) a monotonous curve and c) a curve with poles.
2) It was shown that more than 96% of the branch combination had monotonous relationship of macroscopic characteristics in the Horonai Coal Mine, Japan.
3) Active/passive characteristic of a branch can be estimated from a dot pattern diagram showing macroscopic characteristics of all the branch combinations instead of digits in the branch relation table. Where the active characteristic of a branch “m” means total number of a branch with a pattern along mth row and passive characteristic of a branch “n” means total number of a branch with a pattern along n-th column.
4) Airflow rate in all the branches (191 branches) in a ventilation network of the Horonai can be monitored by 37 sensor branches with monotonous relationships of macroscopic characteristic.
5) When many coal faces work simultaneously and regulators are set in branches with a linear macroscopic characteristics relating to the coal faces, the sensitivity of airflow change in the faces due to open/close regulators can be given as inclination of the ventilation transition planes in Fig. 8.
6) It is more available to use a ventilation transition diagram using monotonous macroscopic characteristics between coal face and two branches with a regulator as candidacy branches to set a regulator are increased.

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This study was carried out to evaluate the size distribution of a rock heap by a simple method, which was considered to be available for the evaluation of the largest size of a rock in a rock fall. It was confirmed that both shape parameter m and scale parameter η in Weibull distribution of sampled material from a rock heap can be expressed by exponential equation of three dimensions. Applying this experimental equation on m and η, size distribution function of the whole heap was obtained, for which a heap was sliced into several blocks, a block was divided into some triangular columns and a column was sliced into several tens of minute triangles with small width. Weight of the material of each size in a minute triangle with small width was summed up to a triangular column, to a block and finally to the whole heap. Size distribution function was decided by summing up the weight in each size. It was proved from statistic test of significance that there was no difference among size distribution line of feed and that obtained from above mentioned method in 8 cases among the-tests of 10 times. This method is considered to be available for the estimation of the size distribution of a rock heap and for the evaluation of the largest size of fallen rocks.

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Low diffused spiral water jet cutting system in water has been developed. With this system, the 5 cmthick styrofoam was cut in water under the 2.94×10⁶ Pa (Case 1: 30 kgf/cm²) and 3.92×10⁶ Pa (Case 2:40 kgf/cm²) water pressures. The widths cut by spiral water jet were reduced by 26.5% from 3.4mm to 2.5mm in the case 1, and by 47.2% from 5.3mm to 2.8mm in the case 2, as compared to the conventional water jet.
The motivation behind this study is to clarify water jet cutting performance for narrow cutting from the fluid dynamics view pont.
The water jet cutting performance for narrow cutting is depended on the low jet diffusion. The essential approach for achieving the narrow cutting is to generate swirl with large free vortex region. This request can be achieved by the steep axial velocity distribution of spiral water jet.

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It is known that the addition of silver ions enhances the bacterial leaching of chalcopyrite. This paper evaluates the influence of several factors, such as initial pH, silver concentration, the kind of silver compounds added, and the procedure of silver addition, on the catalytic effect of silver ions in bacterial leaching of chalcopyrite flotation concentrate using Thiobacillus ferrooxidans. To avoid the inhibition of growth of T. ferrooxidans by silver ions, the inoculation was carried out after 90 minutes of silver addition as silver sulfate solution. The leaching rate of copper at the initial stage of experiments increased with increase in initial silver concentration. The increase in the yield of copper leaching leveled off after the bacterial leaching of about 15 days, but adding silver ions again activated the leaching of copper. The highest leaching rate and the recovery of copper were obtained in the experiment carried out at the initial pH of 1.3. The catalytic effect of silver ions was not observed at the initial pH of 1.0. When silver ions were added after 10 days of inoculation, higher yield of copper leaching was obtained compared to the experiment with the silver addition at the beginning. The addition of silver sulfide powder also accelerated the bacterial leaching of chalcopyrite.

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Alternating Magnetic field generates in the separation area by rotating alternatively arranged magnetic poles of permanent magnet fixed on hexagonal iron pillar. Magnetic flux is concentrated by an iron pole piece of Fe-Nd-B type permanent magnet. Feed sample passes through the separation area vertically to the direction of magnet rotation. Eddy-current-induced force on metal plate increases as the value of conductivity divided by density becomes large. As metal plate size decreases, the larger number of magnet rotation is needed.
If the ratio of conductivity per density is enough large, nonmagnetic metals can be separated with each other. Also by controlling the rotation speed of magnet, metal plates withdifferent size can be classified.

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The causes of re-oxidation of zinc vapor during the Injection Smelting Process was investigated in this paper. The various effects were studied by using an experimental furnace with a temperature distribution simulated the actual furnace.
The oxidation of zinc vapor was remarkably increased at the concentration ratios of CO₂/CO gases greater than 0.7. The limiting concentration of initial CO₂ gas, which caused the sudden increase of the oxidation of zinc vapor, was 16 to 20 vol %. The higher zinc concentration and the greater difference of temperature between the oxidation zone and the smelting zone also accelerates the oxidation of zinc vapor. The addition of moisture in the atmosphere promoted the oxidation, but the increase of the gas flow rate did not.
It was clarified that the slags, such as fayalite slag or fly ash enhance the oxidation, but the dusts, such as coke or dross does not. If the dispersion of powders of slags and fly ash can be prevented, the oxidation of zinc vapor will be also supressed.

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The kinetics of re-oxidation of zinc vapor during the Injection Smelting Process was investigated in this study. The equation for the oxidation rate was obtained as a function of partial pressures of zinc vapor, CO and CO₂ gases.
The oxidation velocity accelerated with an increase in concentration ratios of CO₂/CO gases, that is, with an increase in concentration of initial CO₂ gas. The higher zinc concentration and the greater difference of temperature between the oxidation zone and the smelting zone promoted the oxidation rate. Dusts such as FeO, Fe₂O₃, coke and fly ash also accelerated the oxidation rate.
The re-oxidation product, zinc oxide were easily deposited on the silica wool or silica reactor tube. Deposited crystals of zinc oxide were hexagonal pyramid or prism shape. The particle size decreased to fine powder with an increase in concentration of zinc vapor. But it became progressively greater with an increase in the concentration ratio of CO₂/CO. The compositions of deposited zinc oxide on FeO, Fe₂O₃ or coke were complex oxide such as ZnO·Fe₂O₃ or (Zn, Ca, Al, Si, Mg) O.

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The fine particles of yttrium oxide containing europium are very important for the fabrication of red phosphor. In this study, the synthesis of the fine monodispersed particles containing yttrium and europium from the homogeneous solution using urea as a precipitant generator was investigated. The obtained precipitates are considered to be amorphous basic carbonate. The ratio of yttrium to europium in the precipitate could be controlled by adjusting the concentration of the starting materials in the initial solution. The yields of metal ions were more than 99%, irrespective of the ratio of yttrium to europium. The particles of the precipitates were very spherical and dispersed, and the size distribution of the particles was narrow. The average sizes of particles changed from 100nm to 300nm continuously with increase in yttrium ratio. The dried powder converted to cubic oxide by calcination at above about 600°C, and the calcined composite powder showed specific emission at 611nm. This emission is particular to Y₂O₃: Eu type phosphor.

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