著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.2, pp.15-24, 2019-02-28 (Released:2019-02-28)

参考文献数

16

被引用文献数

1

---

The rheological properties of cement slurries (including fresh concrete and high concentration paste for filling etc.) are complicated, therefore they are approximated by the Bingham plastic model. In recent years, the application of Herschel-Bulkley model is recommended for drilling mud. The rheological coefficients of these models are obtained by using measurement results of the rotational viscometer or experimental results of the flow in a circular pipe, and the pressure loss in pipe flows is obtained from these rheological coefficients. Therefor it is essential to properly select the model in order to design the slurry transportation. In the field of well drilling, the flow in a concentric annulus with a relatively large pipe diameter ratio is approximated by the flow in a parallelplate, so it is also necessary to consider the flow in a parallel-plate. In this study, first, a method to determine the rheological coefficients by the least squares method from measurement results of the rotational viscometer using the function provided in a spreadsheet is shown and a method to quantitatively select the rheological model using Akaike's information criterion is also shown. Next, after the exact solutions of flows in a circular pipe and in a parallel-plate is summarized, an approximate expression of wall shear stress is derived and the error analysis is performed, and its effectiveness is confirmed by using past experimental data. In addition, a method of calculating the rheological coefficients by the least squares method from measurement results of flows in a circular pipe and in a parallel-plate using spreadsheet is shown and this method is practiced by using the experimental data of the flow in pipes.

著者

大久保 敬祐 高橋 弘樹 田口 正美

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.2, pp.8-14, 2019-02-28 (Released:2019-02-21)

参考文献数

27

被引用文献数

1

---

Pushed by human activities, the atmospheric CO2 concentration has reached levels which have made extreme weather events more likely, and which threaten permanent climate changes for the world. In order to combat this, CO2 emissions must be reduced significantly. Electricity production and industry are two sectors which contribute greatly to the production of CO2, thus a reduction in the amount of CO2 produced by thermal power plants and factories could make a significant contribution to combatting climate change. The electrochemical reduction of CO2 in those sources is considered very likely to be a solution to the problem. In this study, the activity of a Pt oxide electrode in the electrochemical reduction of CO2 was investigated in a sulfuric acid solution. Pt oxide electrodes have shown superior activity for the methanol oxidation reaction, which is the reverse reaction of CO2 electrochemical reduction. Cyclic voltammetry of the Pt oxide electrode in a CO2-saturated H2SO4 solution showed a definite anodic peak at 0.6-0.8 V vs. SHE, which was not observed in an Ar-deaerated electrolyte. Thus, it was determined that the anodic peak could be related to the re-oxidation of the reduction product of CO2 during cathodic polarization. The activity of the Pt oxide electrode for CO2 reduction was much higher than that of the Pt electrode. It was concluded that the residual oxygen, which was hardly detected in the Pt electrode, improved the activity for CO2 electrochemical reduction on the Pt oxide electrode. Gas chromatography-mass spectrometry of the electrolytic solution after CO2 reduction revealed that the reduction product was mainly CH3OH. These results should be very useful for developing a new electrochemical reduction system for converting CO2 into CH3OH.

著者

藤原 達央 大川 浩一 加藤 貴宏 菅原 勝康

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.1, pp.1-7, 2019-01-31 (Released:2019-01-31)

参考文献数

33

被引用文献数

4

---

This study investigated an effective method to desorb CO2 from low-concentration (0.2 mol/L) monoethanolamine (MEA) solutions using calcium chloride (CaCl2) and ultrasound irradiation at 25 ºC. The pH value of the solution had a large influence on the desorption ratio of CO2 from MEA solution under ultrasound irradiation. CO2 was successfully desorbed up to pH8.2, and it was impossible to desorb CO2 at pH over 8.2. It was clarified that CO2 desorption by ultrasound irradiation is useful for the concentration of MEA solution of up to 2.0 mol/L, because the pH rises above 8.2 when the concentration of MEA solution is increased to above 2.0 mol/L. It also became evident that the addition of small amount of CaCl2 further increases the amount of CO2 desorbed during ultrasound irradiation.

著者

森田 進 大塚 武夫 前田 治

出版者

The Mining and Materials Processing Institute of Japan

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.123, no.12, pp.707-710, 2007-12-25 (Released:2010-12-17)

参考文献数

3

被引用文献数

1 1

---

Japan New Metals (JNM) was established in 1963, as a joint venture between Mitsubishi Materials and Awamura Mining, and has consistently produced tungsten, tungsten carbide and molybdenum powder from raw materials. Based on the nonferrous manufacturing technologies, we have produced high purity tungsten powder, heteropolyacids and several non-oxide ceramics powders. These are used for electronics devises, hard components and chemicals. In order to avoid the risk related to the supply of tungsten raw materials greatly dependent on China, JNM started a recycling business since 2002. Tungsten is recovered from cemented carbide scraps by the chemical process in the Akita plant.

著者

尾原 祐三 吉永 徹 濱地 亮

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.12, pp.222-231, 2018-12-31 (Released:2018-12-27)

参考文献数

19

被引用文献数

4

---

This paper described the use of a drone in collecting data and analyzing images for monitoring of rock slope. The drone consists of four electric rotors and equips with 4K camera. Firstly, the fundamental experiments were performed by the developed monitoring system with the drone. A measurement accuracy was discussed for method of collecting and using image data. As the results, it is made clear for obtaining a high measurement accuracy that the distance between slope surface and drone is less than 20m for collecting data, and that the overlap of images is 80%, and that GPS data and coordinates of GCP (Ground Control Point) are used in analyzing images. After that, the system was applied to rock slope of an open pit mine and a quarry. The three dimensional model can be constructed with a high accuracy. Furthermore, the change of shape of rock slope can be estimated with the lapse of time. Basing on these results, it is concluded that the developed system is very effective for monitoring rock slope.

著者

成田 光好 大鹿 淳也 豊原 哲彦 岡本 信行 白山 義久

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.131, no.12, pp.634-638, 2015-12-01 (Released:2016-01-01)

参考文献数

9

被引用文献数

2

---

Japan Oil, Gas and Metals National Corporation (JOGMEC) conducted the Environmental Impact Study research from 2008 fiscal year under contract to the Ministry of Economy, Trade and Industry (METI) for the commercialization of Seafloor Massive Sulphide (SMS). It is necessary to consider the potential impacts of mining on the surrounding environment and to promote the project for long-term perspective. Particularly, because the specific chemosynthetic ecosystem and the unique biological communities exist around the hydrothermal area, the quantitatively evaluations of the environmental impacts and the conservation measures of biodiversity to avoid or reduce the effects on them as much as possible is required. The environmental assessment programs consist of baseline survey, environmental impact modeling, and the methodological concepts that will be applied to conserve biodiversity. In this paper, we will introduce the review of the project during 2008-2012 and the future prospects of EIA project for SMS mining.

著者

清水 賀之 畠山 信夫 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.10, pp.142-150, 2018-10-31 (Released:2018-10-26)

参考文献数

21

被引用文献数

5

---

A numerical analysis is conducted to examine an air-lift pumping system for mining rare-earth rich mud under 6000m deep seabed around the Minami-Tori-Shima. The numerical scheme in the analysis adopts the one-dimensional drift-flux model, which solves pressure and velocities as well as volumetric fractions of each phase in the air-slurry two-phase flow along a lifting pipe. The empirical formulas derived from experiments using rare-earth rich mud around the Minami-Tori-Shima estimate the pseudoplastic viscosity and the rheology constant as a function of volumetric concentration of mud in slurry. They are devised in the scheme to evaluate the pressure drop in air-slurry two-phase flow as the power-law fluid. Parametric studies were conducted to examine steady characteristics of the air-lift pumping system by changing the air flow rate, the water depth where the air was injected and back pressure. As a result, the basic characteristics of the air-lift pumping system were clarified. For example, with the air flow rate of 6kg/s, depth of water where air was injected of 3000m, back pressure of 0.2MPa (G), 6040m lifting pipe out of which 6000m is submerged, and 40m is above sea level, pipe diameter below the depth where the air was injected of 0.15m and above that depth 0.2m, it was found that the maximum mud flow rate was 1.01x103t/d, volumetric concentration of mud was 6.2%, slurry velocity was 3.8m/s, mixture velocity at the exit of the lifting pipe was 52m/s and power required was 2.0x103kW. In addition it was found that the performance of the system decreases when using the scheme as the power-law fluid compared with the one using the Mori-Ototake formula as Newtonian fluid. Furthermore, specifying back pressure is useful because of increased efficiency of the system, as well as for keeping the mixture velocity down at the exit of the lifting pipe.

著者

杉尾 学 豊田 典明 梶谷 啓介 大和谷 誠 中原 健一

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.130, no.10_11, pp.453-464, 2014-10-01 (Released:2015-10-02)

---

Sumitomo Osaka Cement Co., Ltd. (SOC) Kokura Mine and Mitsubishi Materials Corporation (MMC) Higashitani mine adjoiningly operate limestone mine at Hiraodai area in Kita-Kyusyu city, Fukuoka prefecture. MMC Higashitani mine need to replace underground facilities when bench down from current mining level in order to secure future minable deposit. SOC Kokura mine has undeveloped mining area between Higashitani mine, but cannot utilize their plenty minable deposit since there is no way to carry limestone to their cement plant because Kokura mine is located inland. In order to solve above issues, both mines started joint development project by focusing on the following five points. 1 Utilize the limestone deposit in SOC's undeveloped mining area and boundary area of both mines. 2 To plan production and shipping quantity for the purpose that all joint develop area can end mining at the same time. 3 Confirm content of installed facilities and investment cost between both companies and clarify way of cost allocation. 4 Ensure the safety operation and seek minimum cost. 5 Joint work to acquire necessary license/Approval and to solve social issue with local community. This joint project is not only aim to secure the limestone deposit, but also enable us to built long term supply system, obtain new customers and improve operating ratio by joint use of their facilities. And this approach would be the one of the ideal model of limestone mine.

著者

石川 明良 谷繁 岳志 田井 朝香 鈴木 祐麻 新苗 正和

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.9, pp.131-136, 2018-09-30 (Released:2018-09-27)

参考文献数

13

被引用文献数

4

---

Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Rh (III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RhCl6-n(H2O)n(3-n) - (n=1-6) . The problem of solvent extraction of Rh from chloride solutions has not yet been solved and there is no effective industrial extractant for Rh. PGMs are traditionally separated from one another and the other metals by a complex series of selective precipitation techniques. These are generally inefficient in terms of the degree of separation achieved. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods. Adding Sn (II) to a Rh (III) feed is a good procedure which can be used to make Rh react more easily to extraction, however, stripping of Rh from the loaded organic pahse is very difficult. In the present study, the extraction of Rh from hydrochloric acid solutions with tri-n-octylamine (TOA) and tri-octyl methyl ammonium chloride (TOMAC) were tested to clarify the effect of addition of Sn (II) on the extraction of Rh and stripping of Rh.

著者

覺本 真代 坂本 靖英 宮崎 晋行 青木 一男 瀧口 晃 安井 彩 森 二郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.9, pp.117-130, 2018-09-30 (Released:2018-09-12)

参考文献数

37

---

Depressurization process is regarded as the most effective process for gas recovery method from the viewpoints of gas productivity and economic efficiency among in-situ dissociation processes of Methane Hydrate (MH) existing in marine sediments. However, it is supposed that consolidation and deformation of the stratum occurs due to MH dissociation and increase of effective stress in the stratum during operation of depressurization. Consolidation and deformation wreak negative friction on the production well. As a result, the production well may suffer large compressive or tensile stress. In the worst case, it may cause shear failure, tension failure and crushing. Therefore, in order to improve the accuracy for evaluation of stress distribution occurring on production well during depressurization, it is necessary to construct the numerical model enable to reproduce unsteady change of the relationship between shear stress and strain occurring on the contact surface between well and layer and introduce into geo-mechanical simulator. In this study, targeting three contact surface locating above depressurization interval such as 1) casing-cement, 2) casing-layer and 3) cement-layer consisting of different material, we conducted push-out test in laboratory in order to evaluate the frictional behavior at these contact surface based on the relationship between displacement and axial load. From experimental observation, it was found that shear stress occurring on the contact surface linearly increased at the initial stage in the case of steel-cement specimen. On the other hand, for specimens consisting steel-clay and cement-clay, non-linear increase of shear stress was confirmed in the process leading to the shear strength. In addition, shear strength τmax for each contact surface increased depending on effective stress σ ', effective friction angle δ' and effective cohesion c' as failure criteria was estimated based on τmax and σ '. Then, constitutive equation of variable compliance type was applied for reproduction of the relationship between displacement and shear stress observed in a series of push-out test. Through numerical simulation by introduction of this constitutive equation, we confirmed the validity of modeling of the frictional behavior.

著者

船津 貴弘 平島 美和 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.8, pp.110-116, 2018-08-31 (Released:2018-08-28)

参考文献数

2

---

An Advanced Graduate Program in Global Strategy for Green Asia (GA) is a component project of the "Program for Leading Graduate Schools" which is supported by the Japan Society for the Promotion of Science (JSPS) and started in 2013. The concept of a “Green Asia” is a bold ideal. Some of the most challenging global environmental conditions now exist in Asia. Many developing countries face the difficult task of raising millions of citizens from poverty. Consequently, environmental concerns are often overlooked. The key to this complex issue is scientific innovation and a transfer of knowledge from technologically advanced to less advanced nations. This educational program aims to cultivate leaders in science and technology who are able to contribute to the realization of an Asia where ecology and economic growth can coexist. Only 20 exceptional students including 10 Japanese and 10 international are allowed to enroll in the GA program each year. This elite group are taught in a bespoke educational environment, also benefitting from the vast collective resources and shared facilities of KU. The students are offered a financial support in order attract the premium candidates and to maximize the available study time by avoiding the need for part time jobs. The students of the Green Asia Education Program follow a stage gate system. This system comprises of six stages, Research Laboratory Rotation, Practice School, Coursework, International Seminar, Internship and the Green Asia Seminar. All activities described above are carried out in English in order to educate international and multicultural sense. Through these program, the students acquire five abilities, which are research, global perspective, leadership, practice and system landscape. In addition, applied skills such as expansion, analysis and upstream thinking skill are also trained by various activities, especially, practice school and international internship. As first batch students had finished this program in March 2017, we introduce the GA program and how the program is managed and carried out in order to make this program better.

著者

高野 雅俊 浅野 聡

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.8, pp.105-109, 2018-08-31 (Released:2018-08-22)

参考文献数

12

---

Gallium is used as a raw material for a CIGS solar cell. In the manufacturing process of CIGS solar cells, only 30% of the target material is used, and the rest is not used and becomes a spent target scrap. In order to recover gallium from spent target scrap, we investigated the process composed of hydrometallurgical treatment only which does not require pyrometallurgical treatment. We describe the details of the developed process in this report.

著者

児玉 淳一 立川 多久登 中 良介 濱中 晃弘 板倉 賢一 出口 剛太 福田 大祐 藤井 義明

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.7, pp.91-98, 2018-07-31 (Released:2018-07-31)

参考文献数

24

---

Small-scale underground coal gasification (UCG) model tests with a linking hole were carried out using two types of specimens made of either block coal or crushed coal to clarify their characteristics of combustion and gasification. Many similar characteristics were found between both specimens in terms of temperature change and its spatial distribution as well as concentration and heating value of each gas product as long as the crushed coal specimen was sufficiently consolidated. The shape and dimension of the cavity formed in the both specimens were also similar. Texture of the both specimens was changed after the combustion and gasification. Initiation of radial cracks from the linking hole was found in the both specimens. Within the zone with the radial cracks initiation, grains in the crushed coal were bonded whereas cleats in the block coal were healed. The grain bonding and the cleavage healing can be explained by melting and expansion of coal due to temperature increase. The radial cracks are likely initiated after the grain bonding or the cleavage healing due to tensile thermal stress induced by temperature gradient in the coal specimens. It can be concluded that the characteristics of combustion and gasification of the crushed coal and the block coal are similar because both types of coals become similar in texture through combustion and gasification. These results indicate that characteristics of combustion and gasification of coal seam can be mostly estimated from a model test with artificial coal seam made of crushed coal.

著者

濵中 晃弘 蘇 発強 板倉 賢一 髙橋 一弘 佐藤 孝紀 児玉 淳一 出口 剛太

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.7, pp.81-90, 2018-07-31 (Released:2018-07-31)

参考文献数

24

---

Underground coal gasification (UCG), a technique used to recover coal energy by the in-situ conversion of coal into gaseous products, enables recovery of coal energy from the potential coal resources abandoned under the ground for either technical or economic reasons. However, it might be difficult to adopt conventional UCG systems in Japan because of geological conditions that are complicated by the existence of faults and folds. Additionally, it is difficult to control the combustion/gasification area during UCG process because the process is invisible. Therefore, a co-axial UCG system that is compact, safe, and flexible to adopt is suggested with monitoring system by means of acoustic emission as an alternative UCG system. This UCG system has superiority in terms of applicability compared to the conventional one, but the recovered energy from the coal is relatively low because the gasification area in a co-axial system is limited around a well. In order to develop co-axial UCG system with high efficiency, the model UCG experiment with a large-scale simulated coal seam were conducted. It has been shown that 1) the gasification period can be extended by adopting proper oxygen inflow, 2) it is possible to control the combustion/gasification area and the product gas quality by controlling the position of oxygen inflow, 3) acoustic emission monitoring is an effective technique to evaluate the combustion/gasification area.

著者

矢岡 隆 西嶋 章

出版者

The Mining and Materials Processing Institute of Japan

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.123, no.12, pp.657-660, 2007-12-25 (Released:2010-12-17)

参考文献数

2

被引用文献数

1

---

Hikoshima Smelting Co., Ltd. is located at the western end of Honsyu. The plant switched from a horizontal retort process to an electrolytic zinc process in 1970. Hikoshima Co., Ltd. had made various improvements to reduce the operating costs about roasting, leaching, purification, electrolysis, casting, labor-saving and so on. In addition, the annual capacity extended from 55,000 tons to 74,000 tons during several expansion stages.Main products are zinc alloys for hot galvanizing and zinc anodes for plating.This paper describes these recent improvements and operations.

著者

山口 梅太郎

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.6, pp.67-73, 2018-06-30 (Released:2018-06-30)

参考文献数

14

---

The Chichibu region located in Saitama Prefecture is a limestone mining area. Mt. Buko limestone deposit is located in the Chichibu region and is being collaboratively mined by Chichibu Taiheiyo Cement, Ryoko Lime Industry, and Buko Mining companies by bench-cut from the top of Mt. Buko. Since the start of mining from the top, Mt. Buko has produced about 260 million tonnes of limestone until the end of March 2017 and a large rock slope (over 400 m high, about 2 km wide, and with overall inclination of 45°) has formed. Currently, managing the stability of the rock slope is considered the most important and critical issue at Mt. Buko. The Task Group for Research on Rock Slope in Chichibu Area (Chichibu Zanken) was established before the start of the cooperative mining at Mt. Buko. The Chichibu Zanken is composed of engineers (especially younger engineers) from the three companies and its first meeting was held in November 1973. In the 45 years since then, the Chichibu Zanken has continued to meet and has held a total of 450 meetings. In the beginning, activities of the Chichibu Zanken were more fundamental, focusing on collecting information on slope stability and studying to design a stable rock slope. Since around 1994, monitoring and analysis of slope behaviors have actively intensified. After the typhoon in September 2007, a significant but short-term slope displacement was detected. From analysis of current and previous data, it was found that the rock slope was affected by heavy rainfall. Therefore, slope drainage, pavement to suppress water permeation, steel pipe piling, retailing rock piling on the rock slope, and their effects on slope stability are important discussion subjects for the Chichibu Zanken. Mining of Mt. Buko is ongoing and making the slope to extend further. The Chichibu Zanken is set to play a key role based on accumulated knowledge and cooperation to solve future unforeseen problems.

著者

永井 燈文 柴田 悦郎 中村 崇

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.129, no.12, pp.694-700, 2014-12-01 (Released:2014-12-01)

参考文献数

19

被引用文献数

2 2

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Platinum group metals(PGMs), such as rhodium(Rh) and ruthenium(Ru), are rare and unevenly distributed in the earth's crust. They are used in automobile catalytic converters and electronic equipment. The consumption of such rare resources is unsustainable; therefore, recycling technologies are needed. In this paper, the chemical properties and separation/recovery of Rh and Ru, and PGM smelting/refining technologies are reviewed. In PGM refining processes, Rh and Ru are converted into chloride complexes. To effectively separate each metal, operating conditions of the reaction have to be optimized. The valences of PGM chloro-complexes change with redox potential, and the distributions between chloro- and aquo- complexes vary with chloride ion concentration. The Ru and Os oxides are separated by distillation.

著者

幾尾 憲伍 蒋 飛 辻 健

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.5, pp.60-66, 2018-05-31 (Released:2018-05-31)

参考文献数

18

被引用文献数

1

---

Hydraulic properties of fracture are directly related to shale-gas production, oil/gas reservoir and geothermal reservoir distribution. The permeable fracture could work as fluid pathway, but the fracture sealed by minerals (i.e. less permeable fracture) could work as seal in reservoir. Thus, hydraulic properties of the fracture are important in reservoir fluid managements. Because fracture typically has heterogeneous geometry, it is difficult to model the fracture using analytical approaches (e.g., rock physics model). Permeability of fracture is often measured by laboratory experiments, however few studies have focused on calculating permeability by using fluid flow simulation on digital fracture models. Here we used Lattice Boltzmann Method (LBM) to calculate the fluid behavior in 3D digitalized fracture models. The permeability derived from LBM simulation agrees with the laboratory-derived results. We used two natural fracture models: before and after shear deformation. We observed large-scale fluid flow network in the sheared model. We further observed permeability anisotropy for the sheared model, although the anisotropy was not clear in the non-sheared model. The permeability normal to shear direction is larger than that parallel to the shear direction. We then discussed the Representative Elementary Volume (REV) of the hydraulic properties of these fracture models. We extracted several subdomains (i.e., small fracture models) from the whole model and estimated permeability of the subdomains. When the size of subdomain is small, the values of estimated permeability widely vary by the location of subdomain. Convergence of the permeability data is found when the model size is close to the whole model. The REV of the sheared model is larger than that of the non-sheared model. Because the hydraulic properties of fracture models smaller than REV are largely influenced by local heterogeneity, the estimation of REV using the proposed method is important to calculate meaningful hydraulic properties.

著者

片岡 みなみ 羽柴 公博 福井 勝則

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.3, pp.41-45, 2018-03-31 (Released:2018-03-30)

参考文献数

27

被引用文献数

2

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It is known that the rock strength increases with an increase in loading rate. Many studies on the loadingrate dependence of rock strength have been performed under two environments, namely water-saturated and airdried conditions, and the loading-rate dependence has not been investigated well under the conditions of various water saturations observed in situ rock masses. In addition, the quantitative relation between the loading-rate dependence and water saturation has not been examined. In this study, the uniaxial compression test of Sanjome andesite under various water saturations was carried out and the dependence of the strength on the loading rate and water saturation was investigated. The test was performed with alternating two loading rates and the strength corresponding to each loading rate was determined from a single specimen. The test results show that the strength increase with a ten-fold increase in loading rate is almost the same under various water saturations and that the strength increases with a decrease in water saturation. Based on the test results, the theory to explain the dependence of the strength on the loading rate and water saturation was suggested. The variation in the strength was discussed to validate the theory.

著者

澤山 兼吾 土屋 範芳

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.3, pp.46-52, 2018-03-31 (Released:2018-03-30)

参考文献数

21

被引用文献数

2

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Environmental impact assessment was conducted at the Ohitachi Mine (Cu-Zn-Pb) located in Odate, Akita Prefecture, Japan. Zn concentration in river water exceeded the environmental standard (30 µg/L) even in the downstream of the Mine. Here, treatment facility for acid mine drainage had already constructed, however, the capacity of the facility was not enough to protect the environmental standard of Zn in the downstream. We calculated Zn load (mg/s) and concentration of Zn (µg/L) in individual watershed along the mainstream and branches. Several watersheds which emitted high concentration of Zn were recognized in the mining area. Particularly, discharge of Zn along the mainstream and watershed which includes open adit shows strong effects to concentration and load of Zn in river water. Based on concentration of Zn in river water and flow rate, we calculated mass balance of Zn load between sampling points. In order to protect environmental standard of Zn (30 µg/L) around village in downstream, we have to reduce 4.22 mg/s of Zn load. In that case, we have to reduce discharge of Zn along the mainstream and from open adit in the mining area. Based on the load and concentration of Zn in individual watershed around the mining area, quantitative evaluation is possible to estimate environmental risks of heavy metals in the river water caused by abundant mine.