Recycling of shredder residues(SR) has been started in 1992 and was expanded the capacity in 2000 by charging them directly into two reverberatory furnaces which we have used for copper concentrates smelting since 1965. Directly charging SR into the reverberatory furnaces was so unique operation that a lot of technical problems arose after the expansion, such as dust troubles in boilers and electrostatic precipitators, corrosion of boiler tubes, damage to refractory of the furnaces and etc. SR treatment has increased due to overcoming such troubles, the amount of SR treatment reaches at 140,000 t per year in 2004 and Onahama Smelter and Refinery is one of the largest plants to treat SR in Japan.

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Fiber reinforced concrete (FRC) or mortar (FRM) is one of the future promising composite materials and suits, for example, today's rapid excavation by a tunnel boring machine, a boom header or a continuous miner. It is well known that FRC or FRM is improved in toughness and crack resistance mainly by the pullout resistance of fibers. Though some pullout tests have been published, fundamental data concerning pullout resistance are still insufficient and pullout process of fibers is not clear.
In this study, pullout test was conducted pulling a single PET or polypropylene fiber out of the mortar sample at a constant displacement rate by a servo-controlled testing machine. The maximum pullout resistance of PET / polypropylene fiber was considerably lower than that of steel fiber. The displacement at the peak value was larger than that of steel fiber. The coefficient of variation of the maximum pullout resistance was smaller than that of steel fiber. After the peak pullout resistance, pullout resistance-displacement curve was decreasing linearly with displacement though undulations synchronized with the indent interval were observed.

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Steel wire, which gives a pre-stress to ground and steel bar such as a rock bolt, are generally used in order to support rock. In this study, we introduce a new type support instead of the former one, like a rock bolt and cable bolt. We call spiral bar the bar that give torsion to the steel plate. It is easy to use the spiral bar like rock bolt, since it has high pullout resistance from ground. If axial force acts on the spiral bar, inner force will arise in borehole because of the spiral shape when grouting or a filling material fixes it. The behavior in the case that the spiral bar receives external axial force was investigated experimentally. And the 3-D numerical analysis was then performed by the finite difference method. A simple equation to estimate axial resistance of arbitrary sized spiral bar with self-enhancement function is proposed. The result of estimation is agreement with one of the experiments and numerical analysis.

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A borehole meter with a built-in laser displacement sensor has been developed for measurements of stress change and deformation in rock. The fundamental principle of the instrument is to rotate the laser displacement sensor sequentially around a borehole axis and measure the distance from the borehole center to the wall of the borehole for each rotation angle. It has the following features:
1. Measurements can be made without contact way and its principle of measurement is simple.
2. Resolution is high and the range of measurement is wide.
3. Reliability is high because of many measuring points.
4. The geometry of cross-sectional plane in a borehole can be evaluated.
5. Measurements can be made at different depths in the borehole.
The applicability of a borehole meter was investigated through the laboratory tests in the block models with a broken zone or a discontinuity around a borehole.
As a result, the borehole meter was found to be available to the measurement in a situation where the broken zone or discontinuity exists. This means that the versatile monitoring can be performed at any depth of a single borehole in-situ rock mass with only one borehole meter.

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Contaminant transport phenomena in an aquifer are mainly affected by the advection of groundwater, diffusion and adsorption to the soils. The adsorptive effect has usually been expressed as the retardation factor in numerical mass transport models. The retardation coefficient was treated constant in previous many studies on the assumption that adsorption equilibrium was linear. However, nonlinear adsorption equilibrium has also been reported in soil-contaminant interactions. The adsorption depends on the concentration of contaminant in the nonlinear equilibrium, so that the retardation coefficient needs to adopt the concentration dependency in the case of relatively large adsorptive effects.
This paper expresses the difference of retardation factor using nonlinear adsorption and linear one for the contaminant transport phenomena in the aquifer using a one-dimensional advection-diffusion model. The numerical analysis was conducted under the assumption of the square-pulse response measurement at the output in a column experiment.
The analysis showed the rejoins of the model parameters that nonlinear adsorption was unable to approximate the linear adsorption equilibrium. We need to evaluate the contaminant transport phenomena using nonlinear in that region.

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Weathering of arsenopyrite is a main cause of arsenic ions in acid mine drainage, and establishing the mechanism of arsenopyrite dissolution is important to design and develop methods for suppressing the dissolution. However, the factors affecting the oxidation state of arsenic formed by arsenopyrite dissolution are not established.
This study investigated the effect of Fe(II) and Fe(III) concentrations as well as the presence of dissolved oxygen on the oxidation states of arsenic ions formed from arsenopyrite in sulfuric acid solutions by a shaking-flask method. Dissolved oxygen or Fe(III) was required as oxidant for dissolving arsenopyrite. When only Fe(III) was present as the oxidant, arsenic extracted from arsenopyrite was As(III). In the presence of dissolved oxygen, both As(III) and As(V) were formed and the concentrations of these ions were varied depending on the solution composition: As(V) was dominant when Fe(II) or Fe(III) were not added, and As(III) was dominant with high concentrations of Fe(III) and Fe(II). It was also found that under aerobic conditions arsenopyrite acts as a catalyst for the oxidation of As(III) to As(V), and that Fe(II) and Fe(III) inhibit the As(III) oxidation. Based on the results, the mechanism for arsenopyrite dissolution and the oxidation state of extracted arsenic are discussed.

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The removal of As(V) from wastewater containing low concentration of As(V) was investigated by addition of Fe(III), Al or Pb salts. Results show wastewater that contains 5 mg/dm³ As(V) is reduced below the regulated concentration of Japanese effluent standard (0.1 mg/dm³) when treated at pH 4.5∼7.5 with the addition of 50 mg/dm³ Fe(III) salts and at pH 6∼8 with the addition of 20 mg/dm³ Al salts. Successful removal of 3.75 mg/dm³ As(V) in wastewater is also possible when treated at pH 7∼11 with the addition of 20.7 mg/dm³ Pb salts, subsequently reducing Pb concentration below the regulated concentration of Japanese effluent standard (0.1 mg/dm³).
Chemical equilibrium calculation which considering the formation of arsenic salts with Fe(III), Al or Pb hardly explains the experimental results. Furthermore, as the concentration of As(V) increases, the isoelectric point (IEP) of precipitations after the removal of As(V) by Fe(III), Al or Pb shifted to acidic pH. It is surmised that As(V) is removed by adsorption on the surface of ferric, aluminum or lead hydroxide.
Solid/liquid separation from these As(V) removal experiments using a column bed method packed with fibrous ferro-nickel slag was also investigated. Ferric, aluminum or lead hydroxide particles adsorbing dilute As(V) that have several hundred nm in sizes, are thinly dispersed and can perform rapid solid/liquid separation (2.5mm/sec).

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