Sumitomo Osaka Cement Co., Ltd., has developed and operated the Autonomous Mining Truck System (AMTS) for open-pit limestone mining in Shuhou Mine, Yamaguchi Pref., Japan. (the annual amount of products are 8 million metric tons, the total amount of products are 260 million metric tons) Epoch-making features of the AMTS are those it has the ability to control two mining trucks simultaneously, and it has the capability of operation on overlap areas with manned mining trucks. In addition, it has striking improvement when compared to the conventional system. This is the pioneering a trace control system in this country for mining trucks using Global Positioning System, and even if the case of changing hauling routes, it requires no replacement of the accessorial equipment on mining benches. From 1999, the AMTS joint development project with Shin Caterpillar Mitsubishi Ltd. (present; Caterpillar Japan Co., Ltd.) , has started by field tests with a CAT 775, 60 metric tons haul capacity in Shuho mine. Afterward the AMTS has been transferred to CAT789s, 180 metric tons haul capacity, and from 2007, it has been started to operate in the mining site. We worked on a construction of the AMTS under three severe concepts as follows. (1) The safety first, (2) Area overlap operation with manned mining trucks, (3) Investigating its convenience apply. In particular, for safely operation, we placed a priority on building the obstacle detection equipment that is required to be fit for variable situation in mining site, and it has been tuned well after much trial and error. Productivity of the AMTS performs about 70% as compared to manned operation, and some of haul labor saving have already been confirmed. Improvement works should make progress on utilization and productivity of the AMTS from now on.
Consumption of a certain metal in a country increases with time. However, this time-consumption relation is not linear in the long range. Furthermore, population and GDP of a country increases in a non-linear way. I attempted to estimate the trend of consumption per capita of a metal as a function of GDP per capita. If population and GDP per capita of a country can be estimated as a function of time, then, by using the same formula, consumption of a metal of a certain country can also be estimated as a function of time. Subsequently, it became necessary to find a suitable formula to describe these non-linear relations; and one which could be used safely in long range extrapolation. I finally found the formula, and named it Extended Logistic Curve. Using this formula, consumption per capita of a metal of a country, or a district, can be estimated as a function of time(t). The result of this study shows China surpassing America and the whole of Europe in the consumption of Lead and Zinc before 2010, and catching up with America in Cu consumption around 2030, with India 20 years behind China in this respect. The world demand for refined Copper is estimated to reach 22 million tons by 2020 and 34 million by 2050. For Lead, the figure is 8.5 million tons by 2020 and 10.8 million by 2050. Finally, the estimate for zinc is 11 million tons by 2020, and 14 million by 2050. A supply shortage and raised prices are expected in the future, especially for Copper and Zinc.
As part of the research and development program on geological disposal of high-level radioactive waste Japan Atomic Energy Agency is implementing the Horonobe URL Project. This paper shows the results obtained from the laboratory tests carried out to understand mechanical properties of Horonobe siliceous rocks for site characterization. Accordingly, the relationship among microscopic observation, sedimentary history and mechanical properties of Horonobe siliceous rocks was discussed in this paper. Such laboratory tests as uniaxial compression test, triaxial compression test, isotropic consolidation test were carried out. Uniaxial compression tests were carried out for specimen sampled at about 50 m interval of eleven deep boreholes more than 500 m deep from the ground surface. Triaxial compression tests including isotropic consolidation test were also carried out using cores of the boreholes. The triaxial tests were carried out under drained and undrained conditions since change in pore structure was expected for the sedimentary soft rocks with large effective porosity. Physical and mechanical properties showed significant variations along the burying depth due to dissolution of the minute porosity in diatom occured from increasing of overburden, temperature etc. The consolidated undrained and drained triaxial compression tests showed different behaviors of strain-softening, pore pressure and dilatancy between diatomaceous and siliceous mudstones. Stress-strain behavior changed from strain-softening to ductile behavior under high confining pressure and pore pressure increased gradually even after peak strength for diatomaceous mudstone. On the other hand, for siliceous mudstone strain-softening behavior was observed and pore pressure decreased rapidly after peak stress regardless of confining pressure value. Diatomaceous mudstone yielded under hydrostatic pressure of 10 MPa in isotropic consolidation test. This yielding was regarded as pore collapse based on the variation of hydraulic conductivity which was estimated from variation of volumetric strain in isotropic consolidation test, effective porosity and microscopic observation before and after the yielding.
Understanding initial stress condition in deep underground is important for such construction as rock cavern for geological disposal of HLW and underground power plant. Neogene sedimentary rock is widely distributed in Japan. There are only a few studies of initial stress measurement in Neogene sedimentary rock mass in Japan due to difficulty of measurement. Evaluation of initial stress condition around Horonobe Underground Research Laboratory Project was carried out in order to understand initial stress condition and applicability of AE, DSCA and hydraulic fracturing (HF) methods to Neogene sedimentary rock. Initial stress values obtained from AE method is smaller than overburden pressure due to time dependency of Kaizer effect. It would be difficult to use AE method as initial stress measurement method for Horonobe Siliceous rocks. Principal stress values by DSCA are similar to those by HF tests. Directions of maximum horizontal principal stresses are approximately in E-W and corresponded to HF results. In HF, rod type and wire-line type systems were compared. Workability of rod type was much better than wire-line type. However, re-opening pressure were not able to be precisely measured in case of rod type system due to the large compliance of the packers and rods. Horizontal maximum and minimum principal stresses increase linearly in HF results. Deviatoric stress is acting at shallow depth. Initial stress condition approaches hydrostatic condition with depth. Direction of maximum horizontal principal stress was in E-W direction which was similar to tectonic movement around Horonobe URL by triangular surveying.
This study considers a method for evaluation of porosity of biogrouted geomaterials. First, we visualized the internal structures of the specimens by using micro-focused X-ray CT scanner. We tested Souma sand, gum tips, plastic pellets, steel balls and glass beads as geomaterial to find suitable geomaterials for evaluation of porosity: geomaterials whose CT-number histogram was bimodal. The results clarified that one of the geomaterials, glass beads whose particle size was 0.50-0.71mm, was suitable for evaluation of porosity. Second, we calculated the porosity of the glass beads by using a method for evaluation of porosity based on a maximum likelihood thresholding method considering the effect of mixels. The result showed that the ratio of the porosity of grouted geomaterial to that of ungrouted geomaterial was 0.98 to 0.99. On the other hand, the value estimated by the measurement of changes in concentration of calcium ion was 0.98. Thus, both values closely agreed. Therefore, this study clarifies that the method enables us to evaluate small change in porosity with great accuracy.
The experimental trial of collecting SDA (small domestic appliance) in Akita prefecture was carried out based on the concept of RtoS (Reserve to Stock, "artificial ore deposit design") from December, 2006. The artificial ore deposit design is a trial which improves circulation of metal resources, aiming at recovery of metal resources. We installed boxes at more than one hundred points such as city offices, community centers and supermarkets to collect SDA from citizens. We also collected small and middle sized WEEE (Waste Electrical and Electronic Equipment) from municipal waste disposal facilities in Odate city. As the result of conducting the experiment for twenty five months, at least four hundred and fifty kinds of EEE (total weight was 44,410 kg) such as video cassette recorder, cellular phone, electronic substrate and adapter were collected. To pursue effective collecting method, we changed the place where boxes were installed and analyzed the relationship between the collection weight and the magnitude of population within the area around each box by using GIS (geographic information system) . The results showed that the amount collected from the public facilities increased with population, however, the amount collected from the supermarkets was almost constant with the population.