The rock mass properties such as deformability and strength are highly dependent on the existence of cracks. The crack propagation directly influences the decrease of effective Young's modulus and rock mass failure, and the analysis of crack propagation is indispensable for the evaluation of mass properties.
In this study, crack propagation analysis was conducted by applying SC-DDM (stress compensation-displacement discontinuity method) to the two-dimensional multi-crack model. Since it is difficult to consider mechanical interaction between all cracks which has arbitrary arrangements, the homogenization method was introduced in the analysis. The model, crack homogenization model, consists of infinite numbers of unit cells and each unit cell has the same crack distribution. Consequently, all cracks behave the same and the mechanical properties of the entire model can be estimated from the analysis of representative unit cell. Here, the alternative model of a single crack set is assumed. The procedure of crack propagation analysis was introduced and the optimization method of crack propagation angle was discussed. In this study, the accuracy of the analyses was verified through the evaluation crack propagation angle and crack profiles, then the characteristics of the crack propagation analysis was discussed. It was proved that the results have enough accuracy and that this method is suitable for the crack propagation analysis. It was also found that this model has a peak strength during crack propagation process, and the relation between loading angle and crack propagation stress was discussed.

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Recently, the rock splitting method is often used to construct the tunnel because the blasting method is restricted in the construction site near city area suburbs. However, the working efficiency of the rock splitting method is extremely low. Therefore, the automation of rock splitting method has been receiving considerable attention to increase the working efficiency. This study is concerned with the automation of rock splitting method for tunnel construction. In order to automate the rock splitting task, the following tasks are necessary:
(1) Automatic recognition of holes drilled on the cutting face.
(2) Automatic control to make the tip of the bigger move to the recognized holes.
(3) Automatic insert of the bigger into the drilled hole.
In this study, the image processing procedure was proposed by using CCD camera and laser pointer in order to recognize the location of the holes drilled on the uneven cutting surface. Furthermore, the algorithm to insert the bigger automatically into the drilled holes by using the strain gauges attached on the bigger. It was confirmed through the model experiment that this algorithm worked well. If the hole is drilled vertically to the cutting face, it took 1 minute to complete the insert of the bigger. However, if the hole is not drilled vertically to the cutting face, it took 12 minutes to complete the insert of the bigger, and this time is much larger than that in the case that the hole is drilled vertically. Therefore, it was confirmed that the holes should be drilled vertically to the cutting face to increase the working efficiency by rock splitting method.

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On tunnel excavation, a prediction of geological conditions ahead of face is of the utmost importance to keep rapid driving and safety works. Fukui et al. in 2004 investigated the drilling performance at Suzuka tunnel with special care to the effect of hole length up to 50 m, and proposed V^* (normalized penetration rate) to estimate rock mass properties ahead of face. In this study, the method proposed by Fukui et al. was fully discussed and slightly modified. Thereafter, the method was applied to estimate rock mass properties at Suzuka tunnel and systematic in-situ measurements of V^* were carried out through the tunnel. It was found that the reciprocal of V^* is a good indicator for rock mass properties and suits the in-situ usage. The reciprocal of V^* has strong correlation with rock mass strength estimated by TBM cutting force and very useful to estimate and predict the rock mass properties ahead of face. For example, a fracture zone can be predicted by an abrupt change of the magnitude.

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Artificial low density aggregate (LDA) is mainly used in lightweight concrete. The use of highly efficient LDA is a convenient way to realize a high efficient lightweight concrete, because aggregate occupies 70 % of the volume in concrete. However since emphasis have mainly been placed in the production cost of LDA in the past, high quality LDA has yet been produced.
The purpose of this investigation is to improve the properties of LDA so that it has higher strength and lower water absorption, which in turn will expand its application. The LDA properties such as glass content, grain size of raw material, additional quantity of expanding agent, and heating pattern and the relationship between each property are studied. The results are;
(1) As Nambu et al. (1993) reported that when the glass content of starting material is increased, LDA strength is increased while water absorption is decreased.
(2) Finer the grain size of starting material, higher the strength and lower the water absorption of LDA.
(3) Grain size of SiC (Yakushima-Denko Corp.,CF-4000), as expanding agent, of less than 1μm is effective for the expansion of LDA.
(4) LDA made from perlite with around 90% glass content has double the compressive strength while only having one tenth of the former LDA.
(5) Decrease of expanding agent addition stabilizes the quality of LDA, because temperature influence becomes small.

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A novel detoxification process for incinerator fly ash was proposed, and the removal mechanism of heavy metals from the fly ash was investigated. The process comprises of roasting the fly-ash extrudates with a rotary kiln, and removes heavy metals by chloridizing volatilization, giving harmless resultant extrudates which contain immobilized heavy metals at trace concentration. The developed roasting technique was unique, as it utilized chlorine originally contained in the fly ash and did not need additional chlorine source. Our detailed investigation proved that appropriate control of bed layer in the kiln could keep reductive atmosphere that should enhance volatilization of metals at either chloride or metals form.
The extrudates derived from the process, compared to conventional chelate-solidified ash or to melting solid matter, showed less metals elution at leachate test, as well as contained descended metals content which satisfied the soil environmental standards revised recently.

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In Japan, the mining industry has faced stagnation for a long time. The metal mining business is already in a contracting condition and has only a few operating mines. The Japan smelting business has a large share of production, about 10% of the copper and zinc in the world. However, the smelting business has started to consolidate the smelting sector of mining industry companies as an alliance because of competitiveness. In the world, globalism has been expanding by multinational corporations' worldwide activity. Now the Japan mining industry's smelting business is in a survival stage and mining business is disappearing even though Japan has superior technology and systems in the mining sector to develop underground small-medium scale deposits.
There are many issues for reversing the mining sector such as (1) consolidation of sectors among mining companies, (2) establishment of think tank,(3) training human resources, (4) development of small-medium scale deposits and (5) sulfide ore leaching. In the world, many small-medium scale mines have closed with environmental pollution because of a lack of competitiveness. Many small-medium scale deposits remain undeveloped. Japan has a possible way to reverse the mining business balanced with the environment by overcoming the above issues for undeveloped small-medium scale deposits for underground mining in the world.

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Historically, Japanese mining policy has been characterized by the protection of domestic mining activities against sudden changes such as free trade in 1963, economic depression after the oil shock, and exchange rate fluctuation. However, the number of domestic mines has dwindled since 1985 due to the appreciation of the yen, depressed metal prices and ore depletion, and now, there are only two operating mines in Japan, Hishikari and Toyoha. In contrast, Japan has developed a large-scale custom smelting sector, and most of the concentrates are imported from overseas. In the 1990s, Japanese companies actively materialized equity participation in development of large mines mainly in Chile in order to secure a stable supply of copper concentrates.
The world mining industry has been rapidly changing in terms of demand/supply, M & A, environmental issues and technical progress. The timely and accurate analysis of world mining information will be indispensable to the forecasting of possible future changes, strategy and sound mining policy.

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There are many factors which would be obstacles against stable supply of mineral resources, and unstable supply causes serious disruptions in both the economy and industry. Since supply conditions for each metal are different, it is impossible to simply discuss the reason why shortages occur. For base metals that have a long history of use like copper, iron, lead and zinc, it is relatively easy to clarify their market mechanisms, whereas for most rare metals it is difficult to discuss the relation between supply and demand. In the I.T. (Information Technology) industry, munitions industry and space development, new materials are continuously developed from many rare metals, and market mechanisms are always changed by these new materials. As a result, some rare metals used as high function materials are immediately needed for import. For instance, powdered tantalum has been in short supply as the demand for I.T. products, such as mobile phones and laptop personal computers, increase rapidly. This shortage causes a steep rise in price and the market shifts to speculation. Shortages are the most serious problem in Japan, worse than high prices, because we consume 20-25% of the world's products. Thus, lack of resources affects not only the economy but also technology.
In this paper, conditions of supply and demand of mineral resources were considered in base metals and rare metals.

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