Tsukumi is the greatest limestone supply region in Japan, and five companies are quarrying 30 million tons per year in this area. TODAKA MINE of TODAKA MINING CO, which is one of them is located in the west of this area, and is now quarrying 12 million per year . The total amount of limestone produced so far is to 370 million tons since commencement . However, the remaining quantity of limestone that can be won had decreased . In order to keep the stable limestone supply, development of a new mine is planned in Usuki, next to Tsukumi .
It was decided that this new quarry, conceived in the 21^st century, should be designed and developed to a corporate philosophy which values the well-being of local residents and their surroundings. The quarry project is designed to have a production capacity of 12 million tons per year, to be welcomed by the local community, and to secure the supply of limestone for future generations.

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Some 400 tons of platinum group metals (PGM) are yearly produced and used mainly for auto-catalyst, jewelries and electric appliances. The annual growth rate is currently more than 4%. Main resources for PGM exist predominantly in South Africa, Russia and North America, showing that they co-exist with Ni-Cu sulphide in the range of 5-10 ppm in their ores.
Meanwhile, technological developments for fuel cells are being promoted, in which PEMFC (proton exchange membrane fuel cell) should be used for vehicles and stationary power. The PEMFC needs platinum as a catalyst due to the lower reaction temperature. The imbalance between supply and demand of Pt should become one of critical paths for the PEMFC promotion, if Japanese Government target is realized.
This paper describes the forecast of supply & demand of Platinum based on various researches and investigations, and self-constructed model. Supply of platinum will be short in 2030's on schedule of the Japanese Government's scenario. Political countermeasure should be applied together with resources developments in order to secure the Pt resource.

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Methane hydrate (MH) is one of the potential resources of natural gas in the near future, because it exists in marine sediments or in permafrost regions worldwide. To evaluate the productivity of methane gas from MH reservoirs, it is necessary to develop a gas production simulator for doing case studies.
We have carried out an experimental research on MH dissociation process by hot-water injection as one of the thermal recovery methods, for clarifying the physical phenomena of gas-water multiphase flow in porous media and the properties of formation and dissociation of MH. In this study, we developed a new numerical theory for MH dissociation process in porous media, based on the phenomena experimentally observed. In the developed theory, MH phase is treated as two components system derived from irreducible and free water. As MH is not mobile due to its solid characteristics, we consider gas-water two-phase flow with MH formation. We also consider the change in reservoir temperature due to hear transfer, and formation and dissociation of MH. Absolute permeability and relative permeability of sand packs were measured under the presence of MH and models for the permeabilities were formulated as functions of MH saturation, etc. These models can estimate dramatic decrease in absolute permeability at high MH saturations, whereas relative permeability curves are shifted to lower water saturation at high MH saturations.
Using the developed theory, we carried out numerical studies for a laboratory core experiment of MH dissociation by hot-water injection. Simulation results on temperature distribution and gas production behavior during MH dissociation sufficiently agreed with the experimental data. Furthermore, it was found that the simulation was able to reproduce experimental pressure behavior associated with permeability change due to MH formation and dissociation.

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Calcium hydroxide (Ca(OH)₂), a combination of calcium carbonate (CaCO₃) and Ca(OH)₂ (two step) and magnesium oxide (MgO) were used as a neutralizer in the treatment of synthetic Horobetsu Acid Mine Drainage (AMD) by High-Density Sludge (HDS) recycling method to obtain the appropriate guidelines of optimum AMD treatment. The result during the initial neutralization demonstrated that at pH 7, arsenic, either As(III) or As(V) in solution, could be removed by adsorption to the sludge with a concentration in the supernatant solution below the Japanese regulated environmental effluent standard. The sludge generated in HDS recycling method with Ca(OH)₂ neutralization was composed of Fe(III) hydroxide combined with a high amount of gypsum (CaSO₄·2H₂O), the same as in the two step neutralization in which undissolved CaCO₃ was included. The sludge generated in HDS recycling with MgO neutralization was composed of basic ferric sulphate combined with a low content of undissolved MgO. The sludge-settling rate generally decreased as the recycling process proceeded. The settling rate of the sludge from MgO neutralization was faster than that of the sludge from the Ca(OH)₂ and two step neutralization. The Fe density of the sludge by MgO neutralization was highest compared to the other neutralization.

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In the previous reports we proposed a novel selenium removal process called Recycled Green rust/Ferrite Process, composed of an addition of ferrous ion source, an alkaline conditioning of a concentrated slurry, an anaerobic chemical reaction stage, and a return of the settled slurry after solid-liquid separation. This paper describes the results of continuous feeding test carried out in a pilot-scale plant with a feeding capacity 0.6 m³/h. Approximately 860-hour-feeding test was performed using the selenium-contaminated groundwater whose averaged selenium concentration of 0.88 mg/L. Selenium concentration in the effluent from thickener maintained less than 0.01 mg/L (selenium removal rate of 99%) until a net operating time reached 800 hours. For that period, oxidation-reduction potential leveled off -740mV vs Ag/AgCl electrode, and Fe²⁺/T-Fe ratio ranged from 0.61 to 0.68, indicating a strong reducing condition suitable for selenium removal. However, selenium removal deteriorated after 800h, when the liquid temperature fell below 17 degrees Celsius. In addition, results of the selenium concentrations were in qualitative agreement with the predicted values based on the simple reactor model using a continuous stirred tank reactor in series. These experimental findings demonstrated that our proposed process served a promising technique for selenium-contaminated water.

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