The attenuation characteristics of elastic waves by strata can be estimated using the inverse filter techniques from the reflected waves on seismograms. The procedures to get the attenuation characteristics are as follows:
1) Extract the isolated reflected waveforms from each interface of strata on reflection seismograms.
2) Caluculate the cross correlation function between the waveform at the n-th interface and the output waveform after applying the whitening deconvolution filter to the waveform at the n-th interface. This cross correlation function corresponds to the waveform of minimum phase which has the same amplitudespectrum as the waveform at the n-th interface.
3) Design the inverse filter for the waveform of minimum phase by solving the Wiener's normal equation.
4) Convolve the inverse filter with the waveform at the (n+1)-th interface for getting the attenuation characteristics of elastic waves by the n-th layer.
The present procedures are applied to the synthetic reflection seismograms and the actual VSP data.

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In the previous report (3rd report), slaking which reflects one of water-durability of rock was clarified.
The present paper describes the results of measurements of swelling which causes slaking and several discussions of the factors which influence slaking and swelling.
The results are summarized as follows:
1) All shales show a swelling phenomenon and the value of volumetric swelling strain of shales saturated at 75% R. H.(25°C) is between 2 and 12%.
2) Considerable anisotropic swelling is observed in shales.
3) The value of volumetric swelling strain is proportional to the montmorillonite content.
4) Slaking mechanism may be explained by swelling of montmorillonite and reduction of capillary tensions with increased water.

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To obtain the fundamental data on suppressive effect of nitrogen injection against spontanious combustion in coal mines, some extinguishing experiments were carried out by using intermediate scale model coal seams in a test gallery. The results obtained through experiments and discussion are summerized as follows:
(1) The upper limit of oxygen concentration in sealing area to suppress smoldering combustion of coal was about 5% in case of the early heating stage, and under 1% in case of its growing stage.
(2) Temperatures in model coal seams during the nitrogen injection dropped rapidly according with the decrease rate of oxygen concentration, and so early extinguishment can be expected in case of lower oxygen concentration in sealing area.
(3) Gas composition in sealing area has some relation with temperatures in coal seams under suppression process of combustion.

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Recently, application of the air lift pump for lifting manganese nodules have been the subject of interest.
The purpose of this study is to make clear the complex behavior of solid particles in the vertical three phase pipe flow and to collect useful data for design of air lift pump. The experiments were performed using the transparent acrylic pipe of 30mm in diameter and 5m in height, and three different sized colored glass spheres of 1.46, 5.16 and 12.5mm in diameter as the solid particles. The two kinds of flow patterns, i.e., the slug flow and the froth flow were observed in this experiments.
The results obtained are summarized as follows:
(1) The solid particles are lifted and transported in the water slug flow or in the thin water film surrounding the air slug flow.
(2) The lifted quantity of solid particles per unit time increases with increasing the immersion ratio and decreasing diameter of the solid particle.
(3) The experimental pump performance for three phase flow agrees well with the calculated result by the Usami's method.
(4) Among three phases in flow, the mean rising velocity of air is the fastest, and that of solid particles is the slowest. The local rising velocity of solid particle is almost constantin the water slug and decelerated in the air slug flow part and then accelerated rapidly as soon as the solid particle enter into the water slug flow.
(5) The static pressure fluctuation increases with increasing the air flow rate.

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Experimental and theoretical studies have been performed for improvement of hydraulic breaker used in the fields of mining and engineering works. In the previous paper, a mathematical model of the hydraulic breaker was constructed to evaluate the performance, and the analytic solution was derived from the state-space equation.
In this paper, a method of design is developed by introducing a design index of the hydraulic breaker, which is closely related to the performance. The design index which can be determined without calculating each performance value corresponds to a coefficient of the forced term in the solution for a piston displacement. Crosssectional area of the rear chamber and percussion speed of the piston correlate to each other. On each crosssectional area of the rear chamber of the piston, envelopes with respect to the design index and the percussion speed of the piston are obtained. It is also indicated that the hydraulic breaker should be designed to make the design index as small as possible.

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In the deposit regime in which a stationary bed of solids appears on the bottom of the pipe, the ratio of the in situ concentration q to the delivered concentration C and the slip velocity are the most important variables govering the mechanism of slurry flow. Many of the empirical and semi-theoretical studies that have produced the correlations for predicting the values of these variables were based upon data on the limited flow conditions. For this reason, serious disagreement among the correlations can be found at comparatively low velocities where the tendency of the particles to settle due to gravitational forces become sufficiently large so that, eventually, the deposit regime may occur.
The objective of this paper is to develop general correlations which contain no empirical constants determined from experimental data in pipes.After analysing the force due to particle-particle interactions in liquidsolid fluidised systems, we obtained the relationship between qand C as follows:
_??_
in which: V=mean velocity of slurry flow;V_t=terminal settling velocity of single particle; R_ep=particle Reynolds number;α, β=Swanson's shape factor of particles;n=index of Richardson-Zaki equation for hindered settling of particles.
Also, solving the above equation numerically by the method of bisection, it could be shown that the ratio q/C was plotted against the Froude number V²/[gD (δ-1)], with the ratio d/D as a parameter if the area index κ of the particles should be constant: in which: g=gravitational constant;δ=specific gravity of particles; d, D=diameter of particles and pipe respectively.Therefore, assuming q and C to be defined, slip velocity, i. e., the difference Vw-Vs in mean velocity between liquid phase and solid phase, can be determined by:(V_w-V_s)/V=(q-C)/[q (1-q)]
Finally, we concluded that the correlations derived theoretically would be applicable in the wide range of slurry flow conditions, since the universality of them was verified with data from the published literature.

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Adsorption isotherms of octylhydroxamate and the relationship between octylhydroxamate adsorbed and phosphate released have beenmeasured against monazite. These results have been compared to those against synthetic CePO₄and LaPO₄. Adsorption of hydroxamate on monazite takes as long as several daysto reach equilibrium. The maximum adsorption of hydroxamate on monazite occurs at pHabout 10. Hydroxamate adsorption on monazite is much higher thanon CePO₄or LaPO₄and forms multilayer. Monolayer adsorption ofhydroxamate on monazite is mainly due to substitution reaction with lattice phosphate ions and makes surface hydrophobic. On the other hand, multilayer adsorption may be caused by precipitationof rare-earth metal hydroxamates and other mechanisms, such as hydrophobic bonding or hydrogen bonding between hydroxamate molecules. Hydroxamate adsorption is enhanced at elevated temperature, but flotation recoveryis not. This may be explained by a reason that the increase oftemperature promotes multilayer adsorption of hydroxamate which donot contribute to surface hydrophobicity.

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The leaching of manganese nodules by sulfur-oxidizing bacteria was carried out using elemental sulfur as the substrate for bacteria in 9K medium (without FeSO₄).The effects of pH and of the concentrations of elemental sulfur and manganese nodules on the leaching were examined.
The results obtained are summarized as follows:
1) Cu, Ni, Mn and Co are extracted from manganese nodules by sulfurous acid and sulfuric acid formed during the growth of sulfur-oxidizing bacteria.
2) The dissolution of metal ions from manganese nodules increases as the concentration of elemental sulfur increases up to 1.0% at the concentration of 0.1% manganesenodule.
3) The adapted bacteria, precultivated in the presence of manganese nodules, reduce the induction period in the leaching process and increase the dissolution of Mn and Co.
4) The increase in the concentration of manganese nodules prolongs the inductionperiod.However, the dissolutio

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The rate-controlling step was examined for the reduction of zincsulfide in a coked briquette which was prepared from zinc sulfide concentrate, calcium oxide (or calcium carbonate) as a sulfur-scavenging agent, and coking coal as both a binder and a reducing agent.It has been found that the obtained data are best fitted byassuming the rate-controlling step of the reaction to be the diffusion of gases involved in the sulfur-scavenging reactions through pores in the solid calcium sulfide layer formed on the surf ce of a calcium oxide particle. From the temperature dependency of the reduction rate of zinc sulfide, the apparent activation energies of the diffusion were found to be 47.3 kcal/mol for the briquette prepared with calcium oxide and 28.5 kcal/mol for that prepared with calcium carbonate, respectively.The difference in the values has been supposedly attributed to the different sizes of pore diameters in the calcium sulfide layers.Though these activation energies seem too large for the pore diffusion of gases, no other rate-controlling step has been found which can better fit the data in the present study, can take into account the non-particulate shape of the carbon in the briquette, and can explain the difference between the effects of calcium oxide and calcium carbonate.

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Solubilities and phase relations were determined for the systemsNiSO₄-Na₂SO₄-H₂O-CH₃OH and CoSO₄-Na₂SO₄-H₂O-CH₃OH as part of a series of studies on the applicability of alcohol for crystallization.
Both systems were similar to each other in phase relations and solubilityisotherms. These systems contained two eutectic points separating three crystallization fields based on NiSO₄hydrate, Na₂SO₄hydrate and their double salt above 290K, and the fields of the double salts were sensitive to temperature. Thesolubilities of the sulfates decreased with increasing concentration of methanol, however, solvent effects of methanol on solubility were greater with sodium sulfate than with nickel or cobaltsulfate.
Applicability of the data to a hydrometallurgical process was mentioned briefly.

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