The Stress Compensation-Displacement Discontinuity Method (SC-DDM) is improved to precisely analyze the internal stresses of homogenized compressible joints, and interdependent effects of them are discussed by analyzing the joint-tip fracture upon the maximum circumferential stress criterion. A relative joint compressibility ratio is proposed to represent the compressibility of the joint. The internal stresses are represented by a central joint stress coefficient and a joint stress function, and they are formulated as a function of elastic and in-elastic displacements in the joint, which are represented by a set of central displacement coefficients and joint displacement functions. The analysis is carried out by taking an overall slide on the joint surface into consideration. Additionally comparing the compressible solution to the in-compressible one, it is discussed that the joint compressibility plays an important role to determine the critical pressure of the joint-tip fracture, along with the joint spacing.

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Tangent modulus method was investigated as one of core-based methods for rock stress measurement and was compared to DRA method. It was clarified that the preloaded stress level was accurately estimated as the stress level at the bending point on the stress-tangent modulus curve by the tangent modulus method. Relationship between duration of load application and maximum delay time for stress memory was investigated by carrying out the both methods. The bending point gradually became vague as the delay time increased in the both methods. The accuracy of estimated stress level of the preloading was almost the same for the both methods. It was shown that the preloaded stress level was accurately estimated from the rock specimen which had been preloaded for approximately one week and had been left for approximately six weeks.

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Decomposition reactions of aqueous CN^- ions by TiO₂ photocatalyst, ozone and/or hydrogen peroxide were investigated. The principal findings obtained are as follows:
1) The presence of dissolved oxygen was necessary to decompose aqueous CN^- ions photocatalytically. CN^- was oxidized to CNO^- with TiO₂ catalyst, and then to CO₃^2- and NO₃^-. Oxidation reaction of CNO^- to CO₃^2- and NO₃^- was far slower compared to that of CN^- to CNO^-. Photocatalytic oxidation reaction of CNO^- at pHs 7 and 10 proceeded distinctly faster compared to that at pH 12.
2) Although ozone oxidation of CN^- took the same paths as photocatalytic reactions, but it was faster than that of photocatalytic routes. Combined use of photocatalyst and ozone for the decomposition of CN^- was more efficient.
3) Decomposition product of CN^- with hydrogen peroxide was found as CNO^- and N₂. Joint use of hydrogen peroxide and photocatalyst promoted reaction of CN^- to N₂.

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To clear chemical forms of boron in coals and its origin, specific gravity separation tests for 4 coal samples were performed, and the boron concentration in each sample was measured. The boron concentration in coal has a high positive correlation with the vitrinite content in coal. Other maceral, exinite containing a large amount of resinite, indicates extremely low boron concentration. It is found that the boron concentration in coal decreases with increase of resinite content. In minerals such as quartz, kaolinite, montmollironite, illite, dolomite, and calcite, illite contains the highest concentration of boron. However, the boron concentration of illite does not affect on that of coal, because illite content in coals is very little (bellow about 1%). Since the boron concentration in minerals is low, consequently, it is difficult to remove boron in coal by the deashing operation. The origin and the chemical form of boron are discussed. It is seemed that boron in coal is consisted by water-soluble compounds and water-insoluble compounds. As the water-soluble compound, it is estimated some compounds such as boric acid and borate originated from immersion of seawater or ground water and biogenic fixation by plants. The water-insoluble compounds will probably borosilicate originated from flowing into sedimentary layer with ground water or seawater.

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Acid mine drainage is a profound environmental problem in many mining environments that compromises the quality of surrounding surface and ground water resources. The process initiates when pyrite and other metal sulfides are exposed to near-surface atmospheric conditions and in presence of oxygen and water, oxidize to produce various hydrated metal sulfate salts. When reaching streams, lakes and rivers, the acid mine drainage can compromise natural equilibria and incorporate toxic metals into the aquatic food chain.
A large amount of flyash from the coal combustion is produced. About 80% of flyash in Japan is now utilized and the remains are dumped at disposal sites; however, the life of these sites is limited. Therefore, in this study, an effort was made to analyze the filling materials by applying flyash as a part of its recycle and utilization.
This paper describes some factors to generate acid mine drainage and discusses measures to control acid mine drainage in order to avoid environmental impacts from coal mines in Indonesia. Also, rehabilitation method using flyash is discussed and the fundamental study using the leaching test is carried out.

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Recently, underground coal mining has played an important role in supplying energy resources in most developing countries in Asia. As a result, the subsidence induced by underground coal mining has become a large environmental problem. In this paper, an evaluation support system is developed within a Geographic Information System (GIS) platform, including subsidence prediction and environmental impact assessment. The stochastic method is adopted to predict three-dimensional (3D) subsidence which consists of vertical displacement, tilt, curvature, horizontal displacement and horizontal strain. In addition, the model of the environmental impact assessment based on fuzzy logic is performed to identify building related subsidence damage classification. Furthermore, the developed system was applied to the coal mining planning in China in which the environmental impact such as buildings, railways, and rivers was predicted rigorously. The result of the prediction using the developed system demonstrates that the calculation time is approximately 100 times faster than that of the previously developed method. The developed system can be expected as effective and efficient tools to solve subsidence related environmental problems due to underground coal mining in developing countries.

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Hydrothermal treatments of mixtures of Beluga coal and Cryptomeria Japonica were conducted by using a slurry of 10wt% density, fed at 10 kg/h rate in the reactor of a bench-scale continuous equipment, the temperature and pressure of which were set at 300°C and 12 MPa, respectively. The reaction time was 30 minutes. It was found that, during the hydrothermal treatment, the yield of solid phase decreased and the total organic carbon (TOC) of liquid phase increased as the biomass-mixing ratio increased. That means that the biomass was more decomposable than the coal. Besides, volatile matter in the material sample showed a higher decomposability, as compared with fixed carbon, and part of the decomposed volatile matter was considered to produce new aromatic compounds and carboxylic acids through repolymerization to fixed carbon. As a consequence, the gross calorific value of the solid phase of the hydrothermally treated mixture became higher with increasing biomass-mixing ratio on a dry basis. Considering ash content, the solid phase showed negligible change in gross calorific value, independent of the mixing ratio; it was ca. 7300 kcal/kg on a dry ash-free basis. In addition, it is worth mentioning that a five-hour run using a bench-scale continuous equipment was conducted successfully.

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Communication in underground is essential for mine safety and the importance is increasing rapidly. JCOAL and CSIRO in Australia are cooperating a research project about underground communication and risk management information system. The aim of the research is to make a revolutionary new mine safety monitoring system that involves a total risk management information system called Nexsys in the center.
The new monitoring system intends to include a real time risk profile that indicates safety conditions in underground and decision support system that offer appropriate counter measures to mine operators in case of an accident. To realize these functions a knowledge base about various accidents is very important. Historical various accidents data on gas explosions and spontaneous combustions in Japan have been reviewed and a new accident knowledge base has been developed which includes newly-made three dimensional views of mine structure where the accidents occurred.
Ventilation is a key factor for underground mine safety. An abnormal condition in a ventilation network such as a mine fire or roadway collapse is reflected on ventilation airflow rates rapidly. A computer program to locate the abnormal condition in the network using the airflow data from underground through the mine monitoring system was also developed and tested to add a useful tool to the new monitoring system. The details about the method for locating of abnormal condition in the network are described in the paper.

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The Nagasaki Coal Mine Technology Training Center was established following the closure of Matsushima Coal Mine Co. Ltd. in November 2001. A part of mining concession area formerly owned by Matsushima Coal Mine was then purchased to be used as training facilities. The training program is focused on transfer of coal mine technology, and conducted by NEDO (New Energy and Industrial Technology Development Organization). The objectives of the training program is to promote the transfer of technology on underground coal mining to engineers from coal producing countries such as China, Indonesia, and Vietnam. For these countries, the technology will serve as valuable tool to face changes that will likely occur in near future. These changes include a shift in mining method from open cut to underground mining, or deterioration in mining conditions as mining locations become deeper and deeper. Through the technological cooperation and transfer of Japan's coal mining technology, efforts were made to achieve the stable coal supply-demand in Asian region and stable supply of foreign coal to Japan.

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Kushiro Coal Mine Co., Ltd. was established in December 2001 by the support of local financial circles, local governments including Kushiro-city and Hokkaido government, just after of the closure of Taiheiyo Coal Mine which had the history of approximately 80 years. The shallow part of mining area and mining machineries were transferred from Taiheiyo Coal Mine, Kushiro Coal Mine has operated in the sea level of -300m coal fields under the seabed.
The main business of Kushiro Coal Mine Co., Ltd. is coal mining business, international co-operation business (mainly the training project on coal mining technology) and environmental new business development.
This report mainly shows the results of technical and human exchanges between Kushiro Coal Mine and Asian coal producing countries supported by METI, NEDO and JCOAL.

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