A procedure by the finite difference method has been developed for estimating the heat flow from the wet surface of a mine airway into air.
This procedure makes it possible to estimate the temperature at any point in rock surrounding the wet surface of airway and to estimate both the temperature and humidity of air current at any time after the ventilation is started.
As a first step, the distributions of temperature in rock were calculated at the several periods of time up to 10 years from the beginning of ventilation.
The conclusions obtained are as follows:
1) The cooling rate of temperature at the wet surface of airway is higher than that at the dry surface of airway.Therefore, the surface temperature on the wet rock-wall of airway is lower than that on the dry rock-wall.
2) The surface temperature on the wet rock-wall of airway is lower than the temperature of air in case of more active water-vaporization from the rock-wall.
The estimation of the temperature and humidity of air current is to be dealt with in the next paper.

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The effects of roadway shape and weak floor on roadway closure were studied with scale model tests, using a sandplastermixture as model rock material.
In addition, the FEM analysis, taking a fracture criterion into consideration, was conducted to compare with thesetest results.
The results of model tests and the FEM analysis indicated the following conclusions:
(1) The thicker the weak floor becomes, or the more the applied pressure increases, the greater the roadway closurebecomes.
(2) When roadway has the weak floor, the formation of fracture zone in the floor promoted the roadway closure.
(3)Circular roadway deformed with less amount than arched and square ones.
(4) The results of FEM analysis coincided with the experimental results qualitatively.

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Mine fires not only bring serious losses on the mines as the result of burning off facilities, machinaries and materials, butalso inflict a bodily injury upon persons working underground or under certain circumstances, cause heavy casualties sufferingfrom heat, smoke and toxic gasses generated.
In underground mines, they usually adopt forced ventilation to keep safety and healthy working environment. If a minefire takes place somewhere underground, however, the pressure distribution in the ventilation network of the mine is disturbed, and in the worst case the direction of ventilation is reversed.
It is therefore definitely important to estimate the ventilation pressure change during a mine fire.
In this report, under some assumptions to simplify the mine fire phenomena (see Fig. 1), the authors derived the equation (see Eq. 23) to calculate total pressure drop in a mine roadway where combustion products flow in. And then compared valuescalculated by the Eq. 27 corresponding to the case ofθ=0 in the Eq. 23 with measured using the horizontal model duct.In result, it was proved that there was fairly good agreement between the calculated and observed values (see Fig. 5).

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As an investigation of the mechanism of water movement in rocks related with the problem of moisture pick-up byventilation air current, experiments of air drying of coal measure rocks were carried out and the characteristic curves ofdrying of the rocks were obtained.
The results are summarized as follows:
(1) When the initial water content is high, in other words, the porosity is large, the characteristic curves are similar tothose of such porous materials as small particles. Namely, in the first stage, the constant-rate period is observed and thenthe falling-rate period appears with decreasing water content, and this falling-rate period is mostly divided into the firstfalling-rate and the second falling-rate.
(2) When the initial water content is less than about 0.07, only the falling-rate period appears irrespective of kinds ofrocks. Then, the critical water content may be considered to be about 0.07 in the experimental condition.
(3) During the falling-rate period, the drying curves of sandstones are nearly linear, while those of shales are S-shapeconfigurations. This indicates that shales are more difficult to dry than sandstones, and the same conclusion is obtained fromcomparison of equilibrium water contents of these rocks.

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In this paper, the flow between the wall of tube and that of capsule freely suspended in a vertical tube with water canbe considered as the turbulent flow based on the Reynolds number range R>5×10⁵, where R=U_ml/ν, U_m is the superficialmean velocity of flow suspending capsule, l the length of capsule and ν the kinematic viscosity of the fluid.
The hydrodynamic analysis on the turbulent boundary layers around a solid capsule and an inner wall of tube is developedand the effects of capsule/pipe diameter ratio, capsule length/diameter ratio on the drag coefficient of capsule are introduced.
As described, in the previous paper, similar approach was executed. Then, a drag coefficient of capsule can be expressedtheoretically and experimentally by a function of characteristics number.

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In the former two reports the authors have developed a mathematical model of continuous flotation process with back-flow model describing the flow characteristics of flotation cells and with the first-order flotation reaction equation involving the discrete distribution of the rate constants.
In the present report the residence time distribution of the pulp was determined in different types of flotation cells in Shikama Concentrator in Kamioka, Mitsui Mining and Smelting Co. Ltd., to find out that the back-flow model could describe their flow characteristics adequately. The bulk flotation circuit of lead and zinc minerals in the plant was investigated under steady state conditions by the simulation model using the data of semi-batch flotation tests in the laboratory. The flotation behavior of the minerals could be approximated by this simulation fairly well. Thus the process model was proved to be valid for the simulation of a full-scale continuous flotation process of lead and zinc minerals.

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In the first report, we have described chemical and physical properties of high molecular alkylamine that is fundamentallyimportant to apply the solvent extraction to the sodium bicarbonate production.
NaCl+CO₂+H₂O+Am⇔NaHCO₃+AmHCl (Am: Amine)
Hydrochloric acid byproduced should be extracted and eliminated out of the reaction system by amine in order thatsodium bicarbonate may be produced according to the above equation. Therefore, the reaction equilibrium is determined bythe base strength of amine, and the combination of amine and diluent basic enough to extract hydrochloric acid in thestable pH region of sodium bicarbonate must be selected.
The relationship between absorbed carbon dioxide, produced sodium bicarbonate and amine hydrochloride in theabove reaction has been clarified and the amount of produced sodium bicarbonate has been measured in the various conditionswhere the kind of amine and diluent, the concentration of amine and sodium chloride, and reaction temperature are changed.Solubility of carbon dioxide to the various solvents used in this study is investigated, which' may influence the absorptionrate of carbon dioxide.

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Australian ilmenite was chlorinated in a fluidized bed to study the rate of reaction, selective chlorination between Feand TiO2 and behavior of the main impurities.
The rate of chlorination was dependent on temperature, particle diameter of ore and coke and chlorine partial pressure.The reaction mechanism was explained by an unreacted shrinking core model, which is based on the assumption that afterthe reaction proceeds to a certain extent, the solid particle consists of an unreacted core, surrounded by a reacted shell.
Calcined petroleum coke (coarse or fine), unreacted petroleum coke, coal coke, charcoal, anthracite and graphite werecompared as reducing agents. Calcined petroleum coke (fine) was found to be most desirable for the impurities-ash andvolatile elements-and reactivity. The selective chlorination was dependent on roasting temperature, reaction temperature, particle diameter of ore and coke to ore ratio. The selectivity was improved by higher roasting temperatures, lower reactiontemperatures, lower coke to ore ratio and smaller particle diameter
The major impurities contained in ilmenite were SiO₂, Al₂O₃, CaO, MgO and MnO. When the ilmenite ore was chlorinatedto XFe=0.9 at 880°C, SiO₂ was virtually unreacted and the fractions of reaction for other impurities were respectively;Al₂O₃ 30%, MgO 78%, CaO 58% and Mno 90%. Ilmenite ores from different supply sources-USSR (Irsha, Samotkansky, Kusha), S. Africa, U.S.A.(Florida, Tennessee), Australian west coast (Cable) and Malaysia were also tested. It was foundthat the unreacted shrinking core model was also applicable to the chlorination of these ores.

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