Steel-fiber-reinforced mortar (SFRM) or concrete (SFRC) is one of the future promising composite materials. SFRM can be sprayed easily and quickly on the wall of tunnel or gateway. Sprayed SFRM is especially suitable to today's rapid excavation by a tunnel boring machine, a boom header or a continuous miner.
In this study, uniaxial compression tests were performed controlling strain rate in air-dried condition. It was found that steel-fibers did not affect the peak strength and the pre-failure characteristics such as Young's modulus and Poisson's ratio.
It is well known that a sprayed steel fiber is oriented parallel to the sprayed surface. When load was applied in the fiber oriented direction, no apparent effect of steel fibers was observed even in the post-failure region. When load was applied perpendicular to the fiber oriented direction, on the contrary, ductility and residual strength in the post-failure region considerably increased. An empirical equation was proposed to estimate the residual strength. Also, energy required to break a SFRM sample was obtained and discussed.

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Right now button bits are widely used in rock drilling. Considerable effort has been expended by manufactures to increase performance and durability of the button bits. However, most of them were conducted on try and error basis mainly because high level acceleration and vibration in rock drilling prevented accurate sensing and fundamental data collection concerning button bit performance.
In this study, static penetration testing was carried out to clarify the performance of worn bits. Preliminary test was conducted on Sanjome andesite as a sample rock, and then Niihari sandstone was tested with one new bit and three worn bits. The testing results can be summarized as follows;
1. Penetration rate decreases linearly with height loss of face chips. Slopes of penetration curve both inloading and unloading portions linearly increase with height loss of face chips. Specific energy, or energy required for unit excavated volume, also linearly increases with height loss of face chips.
2. Linear relations also exist against height loss and gauge loss of side chips. For example, penetration rate decreases linearly with height loss/gauge loss of side chips.

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Basically, the pipe jacking system involving the pushing or thrusting of the drivage machine through concrete pipes ahead of jacks. The method utilizes the mud slurry which is formed around the pipes for stability of surrounding soil. However, it is not well understood the behavior of the soil and mud slurry around the pipes. From this point of view, this paper discusses the seepage behavior of the mud slurry on soil around the pipes by means of laboratory tests and 2-D Eulerian Lagragian analysis.
The results of this research are summerized as follows;
1) It can be applied to the seepage behavior of the mud slurry by using 2-D Eulerian Lagragian analysis.
2) Large slurry permeation zone tends to form thick mud screen around the pipe.
3) The mud screen between the soil and the pipe is easily formed by high density mud slurry and high slurry pressure.
4) Once the mud screen was formed, the thickness of the mud screen increased gradually because it behaves like a filter paper under pressure.
5) Thick mud screen prevents the mud slurry from permeating into the soil.

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The present paper describes the result of an application of the authors proposed method for optimizing a mine ventilation system to an actual mine. Practical methods for the optimization considering airflow distribution, energy consumption and other parameters are discussed. Also, an existence condition of an roadway which shows the cost saving character when the resistance is decreased by the excavation of an new roadway parallel to it or enlarging the sectional area of it is examined.
The results are summarized as follows:
(1) The application of an actual mine shows that the proposed method is practicable and gives effective methods for saving ventilation cost.
(2) The effectiveness of the decrease in roadway resistance as an method for the saving of ventilation cost depends on the airflow rate, total cost and the time that the roadway is to be utilized.

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coal mines, by using smell detectors in our laboratory. From the results of measurements, it is clear that there are significant differences between measured data from each different type of smell sensor for coal, rubber of belt conveyer, oil and wood.
In order to discern the source of combustion gases, we developed and tested a distinction system using a neural network system. From the results of the tests, the neural network system enables the identification of the source of gases, whether it would be coal, wood, oil and rubber of belt conveyer.

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Li-bearing tosudite has a regularly interstratified structure consisting of chlorite and smectite layers. Hydrothermal treatment of unground and ground Li-tosudite was carried out under 150°C to 250°C in a distilled water and various concentrations of NaOH solutions, and the reacted products were examined by XRD, ethylene gricol treatment and methylene blue absorption capacity.
The final reacted products obtained from the both of unground and ground Li-tosudite were mainly analcime, and swelled Li-tosudite was also formed as a by-product. The formation temperature of analcime using ground Li-tosudite was low compared with that using unground Li-tosudite, and its temperature was also related to concentration of NaOH solution. The analcime formation temperature become low with increasing NaOH concentration in the both cases of unground and ground Li-tosudite.
Heterogeneous substitution of interlayer cation (Na⁺) was considered to be occurred on the basis of different features of XRD profile after ethylene gricol treatment and under various relative humidity states.
The interlayer structure of Li-tosudite was altered into complex interlayer structure of swelled Li-tosudite, and analcime was readily obtained as a final product from the unground Li-tosudite compared with the ground Li-tosudite. These facts suggest that the reacted products of hydrothermal treatment reflect an original crystal structure of the starting material.

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The mechanism of sphalerite depression in hot flotation (Pb flotation) and the flotation behavior of sphalerite activated with copper in the subsequent Zn flotation have been investigated.
In single mineral flotation at pH 6 using potassium diethyl dithiophosphate as a collector, the floatability of sphalerite did not depend on pulp temperature (25 and 60°C). In the flotation of sphalerite and pyrite mixture at 60°, the flotation recovery of sphalerite was significantly decreased as the mixing ratio of pyrite increased. However it was only slightly decreased at 25°.
The reaction product on sphalerite surface after conditioning in the pyrite suspension or ferrous sulfate solution at pH 6 and 60°Cwas identified as a basic iron sulfate by means of X-ray photoelectron spectroscopy and diffuse reflectance infrared fourier transform spectroscopy. Collector adsorption did not depend on the pulp temperature and the presence of pyrite.
From the above results, it is concluded that sphalerite depression was caused by deposition of hydrophilic basic iron sulfate on the surface, which was formed by oxidation and hydrolysis reactions of ferrous ions dissolved from pyrite surface.
After hot flotation, sphalerite was activated by copper ion and easily floated by using potassium amyl xanthate as a collector. Collector adsorption on the sphalerite after hot flotation was increased by copper activation, but the collector adsorption samples with and without copper activation did not differ so much to explain the difference in the floatability.
Accordingly, the different floatability of copper-activated and unactivated sphalerite may be explained by the difference in collector adsorption mechanism, i. e. hydrophobization. Namely, in the case of copperactivated sphalerite, it is supposed that hydrophobicity of potassium amyl xanthate overcomes that of basic iron sulfate which has been deposited on the surface during after hot flotation, resulting in enhanced floatability.

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Removal of 12 organic compounds containing chloro-chemicals from an aqueous solution has been carried out using solvent sublation. The removal mechanism of solvent sublation was studied, from which the calculated value for removal was obtaind to compare with the experimental results.
The removal rate of organic compounds is strongly concerned with the physical and chemical properties of their compounds, such as solubility, vapor pressure, surface tension and distribution coefficient between the aqueous and organic phase. The experimental removal rate is evaluated and discussed concerning the physical and chemical properties of the compounds to be removed. A model for the removal mechanism is constracted by considering several terms such as adsorption on bubble, entrainment with boundary layer of bubble, vaporization to bubble and mass transfer to the organic solvent in the upper part of column. The calculated value is in good agreement with the experimental results. According to the removal model, contribution percentage of the above terms is estimated and then it is clarified which terms are significant for the removal of the organic compounds with different chemical properties.

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A fundamental study was carried out to improve the temperature profile in a sintering machine of ISP by blowing gases of different composition and flow rate through a pellet column held at 550°C in an electric furnace. Considerably different temperature profiles were obtained with gases of the same composition but at different flow rates. Gases containing SO₂and O₂can react with green pellets and, therefore, a counterflow-type operation is suggested to enlarge the high temperature region in the sintering machine which may decrease the percentage of recycled sinter fines.

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