著者

高本 拓

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.128, no.8_9, pp.500-510, 2012-08-25 (Released:2013-09-18)

参考文献数

15

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Indonesia produced 306 Mt of salable coal in 2010 almost 100% by surface mining. Rapid increase in production by surface mining, however, has brought strong concerns of sustainable supply ability of coal with current quality level in future. Thus, development of underground mining has been recognized to be important by the government and the coal industry in Indonesia.Since 1980’s until 1995, only 3 underground mines had been operated, and currently, there are only two operating underground coal mines with small scale. However, several underground projects with fully mechanized mining system have recently started pre development work, such as exploration, feasibility study and so on. The author expects that development of underground mines with bigger production scale would become active within a few years.On the other hand, the underground mining condition in Indonesia is more difficult than it in other countries. This paper describes the history and outlook of underground coal mining in Indonesia from technical points of view, and then discusses the technical problems for future development of underground mining in Indonesia.

著者

佐々⽊ 久郎 張 河猛 サルマワティ 王 永軍 チエ サムニアン ンゲレ ロナルド 菅井 裕一 張 曉明

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.136, no.9, pp.99-109, 2020-09-30 (Released:2020-09-30)

参考文献数

31

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There is a critical situation that a huge amount of greenhouse gases is emitted into the atmosphere from natural coal fires in underground coal seams and spontaneous combustions in coal piles in the world. To reduce the emissions of combustion gases, such as CO2, CH4, etc., some technical challenges and researches are required related to CO2 flux measurements, developing an effective chemical water-solution extinguishes coal fires and inhibits spontaneous combustion, constructing a numerical simulation model to treat the aging effect in coal heating rate. In this article, firstly, the previous studies were reviewed to explain measurement results of CO2 emission from coal fire/spontaneous combustion fields and the aging model used to simulate coal heating rate. Secondary, a trial development of some chemical solutions has been introduced to inhibit microscopic and macroscopic coal oxidations by forming a gel. Especially, sodium meta silicate solution showed a relatively good performance shifting the critical self-ignition temperature (CSIT) of a low rank coal to be 4 to 5℃ higher than that of water by forming gel with CO2 gases in the air and combustion gases emitted from coals. The brooking effect in macro scale by forming gel is also expected to extinguish coal seam fires by reducing aperture width in fractures connecting to the atmosphere. A numerical simulation using ANSI FLUENT has showed an extinguishing fire process of an underground coal seam including a horizontal fracture that is connected inlet and outlet fractures being air paths for air and combustion gas, respectively. Finally, the the research challenges required for technical developments have been proposed to carry a project extinguishing the coal seam fires and spontaneous combustions of coal piles with reducing CO2 emissions.

著者

高柳 悟 阿部 信二

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.719-722, 2007-12-25 (Released:2010-12-17)

被引用文献数

1

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The Hosokura Metal and Mining Co., Ltd. produces electrolytic lead (99.99% purity) and bismuth, antimony trioxide, crude silver etc. from recycled lead-acid batteries and various types of lead-bearing industrial intermediates. Mining and smelting of lead, zinc and silver bearing ores from the original Hosokura Mine began over 1,200 years ago, but was terminated with the closure of the mine in 1987 and, since then, the production of recycled lead and the treatment of mine wastewater have been continued. The current company was reorganized in March, 2006. Although the capacity for monthly lead production based on a blast-furnace operation followed by electro-refining is around 2,000 t /month, a serious shortage of recycled batteries triggered technology development to accept lead dross and lead residue etc.also as low grade raw material in the summer of 2005. Another main operation of this company is the treatment of mine wastewater, 15 t /min on average, from the closed mine and the effluents from lead plants to meet the water quality standard against toxic elements including lead. Overcoming the lead-leakage problem at this plant in May, 2002, the thoroughly renewed and strengthened water-treating system with a big deep bed filtration facility at the final stage enables us to contribute to the environment improvement of this area and rebuild the tight, friendly correlation with the surroundings. Both the plants are operating under the company policies of environmental conservation, compliance and community involvement.

著者

佐々木 秀顕 岡部 徹

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.136, no.7, pp.77-87, 2020-07-31 (Released:2020-07-31)

参考文献数

174

被引用文献数

3

---

Over the past years, the significance of recycling Cu and its accompanying metals has been increasing. However, the frequency of anode passivation increases during the electrorefining of copper when the copper anode contains a high concentration of impurities. When the amount of secondary materials (scraps) used is increased, the process of electrorefining is frequently troubled because e-waste contains elements that induce anode passivation. Therefore, the development of passivation-prevention technology for low-grade copper anode is essential. This article reviews previous research on the behavior of impurities in the Cu anode and their effects on passivation. The guiding principles for developing passivation-prevention technology are also outlined.

著者

有馬 孝彦 佐々木 亮介 Carlito Baltazar TABELIN 田本 修一 山本 隆広 Tangviroon PAWIT 五十嵐 敏文

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.136, no.6, pp.64-76, 2020-06-30 (Released:2020-06-30)

参考文献数

21

被引用文献数

1

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Rocks generated from tunnel construction projects for roads and railways throughout Japan have often leached out hazardous trace elements, such as arsenic (As) and selenium (Se). In nature, the oxyanionic species of As and Se have a variety of chemical species, so speciation is one of the crucial factors in their migration through natural geologic media. In this study, column experiments consisting of four types of crushed rock samples containing As and Se, and a river sediment (RS) as an adsorbent obtained near the tunnel construction site were conducted to evaluate the leaching and adsorption behavior of arsenite (As (III) ), arsenate (As (V) ), selenite (Se (IV) ), and selenate (Se (VI) ). The results showed that the dominant speciation of As and Se in the effluent from the rock layer was As (V) and Se (VI), and that the addition of a bottom RS adsorption layer or the mixing of RS with the rock layer decreased the leaching concentrations of As (III), As (V), Se (IV), and Se (VI). Cumulative leachability (CL) for each speciation through the column experiments was calculated to evaluate the amounts of As and Se retained in RS. The calculated CL showed that the bottom RS layer or mixing of RS with the rock reduced the CL of As (III), As (V), Se (IV), and Se (IV) ranging from 60 to 89%, 73 to 89%, 9 to 75%, and 36 to 60%, respectively; however, mixing of RS with the rock layer was ineffective in decreasing CL of Se (VI). The reduction of CL may be due to adsorption and/or coprecipitation by iron and/or aluminum oxides contained in RS. These results indicated that utilization of RS for the bottom adsorption layer was effective in reducing As and Se concentrations irrespective of their speciation, although that of mixed with rock layer was effective only in reducing As concentrations irrespective of their speciation.

著者

岡本 泰彦 川畑 雅樹 正代 知幸 辻本 康平

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.136, no.6, pp.52-63, 2020-06-30 (Released:2020-06-30)

参考文献数

7

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Ube Industries' Isa Cement Factory introduced a rock cutting machine“2500SM”capable of continuous excavation by rotating a drum equipped with a cemented carbide bit from the viewpoint of effective recovery limestoneresources. Because it can excavate with low vibration and low noise, it can reduce the distance from the surrounding private houses that have been secured in consideration of the effect of blasting, and in order not to loosen the excavated surface, the bench angle of the excavated surface is steeply inclined and berm is minimized. It was because it was judged that the minable amount could be expanded by minimizing the berm. In the early stages of the introduction, cutting bits were broken unexpectedly, and the frequency of replacement increased, resulting in a decrease in mining efficiency. In addition, the excavation slope using a rock cutting machine“2500SM” has a smoother surface and no large cracks. In addition, in the evaluation using methods of elastic wave exploration, ground penetrating radar and infrared camera, the slope of excavation is compared with that by blasting. It was confirmed that the soundness was high. The effects of cutting bit improvements was evaluated, the expected excavation area, the soundness and safety of the rock slope, and the expansion of the minable amount that were expected when the rock cutting machine “2500SM” was introduced. In this paper,we repot the evaluation results.

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.136, no.5, pp.40-51, 2020-05-31 (Released:2020-05-29)

参考文献数

11

被引用文献数

1

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The mud flow between the borehole and the drill pipe in well drilling can be regarded as the flow of nonNewtonian fluids through a concentric annulus. In recent years, the Herschel-Bulkley rheological model is recommended as a general fluid model of drilling mud because it encompasses the power law model and the Bingham plastic model. Also, in the field of well drilling, the flow through a concentric annulus is conventionally approximated by the flow between two parallel plates. However, its applicability does not seem to be examined because it is not easy to perform analysis of non-Newtonian fluid flow through a concentric annulus. For studies on laminar flow of viscoplastic fluids (fluids with yield stress) through concentric annuli, there are researches on Bingham fluid by Fredrickson & Bird and on Herschel-Bulkley fluid by Hanks. Since the equation of motion in viscoplastic fluid flow through a concentric annulus cannot be analytically solved in all of them, in their researches numerical calculations are presented by charts. However, it is not simple as a method to estimate the frictional pressure loss, because multiple charts are related. In this research, based on the results of previous authors' research7, 8), we investigate a method that can easily calculate the average wall shear-stress in laminar flows of viscoplastic fluids through concentric annuli. That is, using the results of circular pipe and parallel-plate, an approximate expression of viscosity factor in viscoplastic fluid flow through concentric annuli is derived and the error of the average wall shear-stress represented by the approximate equation is evaluated. Furthermore, a simpler approximate formula which can be calculated directly without numerical calculation is derived and its error is also evaluated. In addition, error assessment is performed to confirm the applicability of approximation by the flow in the parallel-plate for the flow in a concentric annulus, which has been conventionally done in the field of well drilling.

著者

伊藤 豊 竹内 誠人 見上 柊人 川村 洋平

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.136, no.5, pp.33-39, 2020-05-31 (Released:2020-05-27)

参考文献数

34

被引用文献数

1

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Productivity, safety and its improvement is also an integral part of a good mining operation. In recent times, due to constraints on time and cost, it has become increasingly harder to conduct training and safety inductions at mine sites. For the purpose of overcoming these limitations, the use of virtual reality (VR) is proposed for mining education and training. VR has already been introduced in the education and training of miners overseas, and quantitative studies on the effects of using VR for miner's education and training have been made. However, Japan has only one such application of VR for mining education, namely, “Virtual Mining Practice System” which was produced by Akita University, and there are relatively few cases where VR has been introduced in the Japanese mining industry. Furthermore, there has been no quantitative study to date on the effects of education using VR for mining education. Therefore, the objective of this study is to investigate the effects of a class that utilizes a VR application developed for mining education (Mining VR), as well as evaluate its learning outcomes. In this study, a method called randomized controlled trial (RCT) is used for evaluating Mining VR's effectiveness. Study participants are divided two groups randomly where one class makes use of Mining VR and another class using other non-VR material. After the classes are completed, a test is conducted and the average results of each group are compared by T-test. The results of this experiment showed that there were no statistically significant differences in skill of “understanding” and “knowledge retention” comparing two groups. On the other hand, results suggested that Mining VR has improved students'“ motivation” for class when using Mining VR.

著者

安達 謙 仲井 雄哉 三野 翔平 宮本 真之 北田 敦 深見 一弘 邑瀬 邦明

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.136, no.2, pp.8-13, 2020-02-29 (Released:2020-02-28)

参考文献数

19

被引用文献数

3

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The mechanism of nodulation in copper electrorefining process was investigated by experimental method and simulation, in particular as for its growth in height. Due to the high current density at the tip, the nodule height increased as an exponential function of the time for electrolysis. Therefore, the growth behavior of nodules was strongly affected by the size of the nucleus and the existence of the threshold size to lead an electrical short circuit was suggested. Since some nodules obtained in the industrial process included mold releasing agent carried from anode-casting process, mold releasing agents are considered to be one of the main causes of the large nodule and need to be removed for the improvement in the current efficiency.

著者

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.136, no.1, pp.1-7, 2020-01-31 (Released:2020-01-31)

参考文献数

26

被引用文献数

2

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Time dependence, probability distribution, and size effect have been investigated by many researchers and are still important issues in rock engineering. These seem to be different characteristics of rock but were found to be closely related to each other through laboratory tests with rock specimens in recent studies. In this paper, the theoretical aspects on the time dependence, probability distribution, and size effect of rock strength were explained, and some of the theoretical results were compared with the previous experimental results. The theoretical formulae based on the rate process theory that represent the failure progression of rock were introduced, and their relation to the theories of visco-elasticity and visco-plasticity was described. The exact solutions of the loading-rate dependence of strength and the creep lifetime were derived from the formulae and were compared with the experimental results of andesite. In addition, the exact solutions of the probability distribution of strength and creep lifetime and their relation to the statistics of extremes were described; the exact solutions of the size effect of strength and creep lifetime and their relation to the comminution theory were also described. The authors clarified what issues have been or have not been verified in previous studies and presented the subjects of future investigation.

著者

三宅 正男 石井 俊匡 山上 慶 平藤 哲司

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.12, pp.109-115, 2019-12-31 (Released:2019-12-26)

参考文献数

20

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Leaching of copper anode slime using hydrochloric acid (HCl) and hydrogen peroxide (H2O2) is performed to recover Au. It is imperative to reduce the amount of the costly oxidizing agent, H2O2, used in this leaching. In conventional conditions, the Se contained in the slime is oxidized and dissolved by the leachant as well as Au. If Au alone can be selectively leached, it should reduce the use of H2O2. The calculation of equilibrium potentials showed that when the concentration of HCl is high, it is possible for Au to be selectively leached, while the dissolution of Se is suppressed. The selective leaching of Au was demonstrated by experiments using 8 mol L-1 and 12 mol L-1 HCl solutions with various amounts of added H2O2. In the selective leaching, the increase in the leaching rate of Au with increasing amounts of H2O2 diminished after the leaching rate reached 80%. This may be because Au remained inside the Se particles, and the contact between Au and the leachant was physically inhibited by the Se layer encompassing the Au atoms. However, a leaching rate of Au of greater than 95% was achieved, even when the leaching rate of Se was less than 30%. From these results, it was confirmed that the use of H2O2 can be reduced by the selective leaching of Au compared to the cases in which all Se in the slime is dissolved.

著者

中田 英喜 横島 美香 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.135, no.11, pp.101-108, 2019-11-30 (Released:2019-11-28)

参考文献数

24

被引用文献数

3

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The objective of this study was to deepen the understanding of the immobilization process of selenium (VI)contaminated soil when using immobilization agents consist of MgO and iron (II) compounds. The objective was achieved by introducing diffusion cells that allows us to physically separate soil and immobilization agent, and measuring the valence of selenium as well as the concentrations in liquid, soil, and immobilization agent phases. Experimental data showed that the addition of immobilization agents induced desorption of selenium (VI) from the contaminated soil, and the desorbed selenium (VI) was reduced into selenium (IV) by iron (II) compounds. The formed selenium (IV) was then effectively immobilized by re-sorbing on soil particles and immobilization agents. Also found was that more amount of selenium (IV) was sorbed on the immobilization agents as hydration reaction of immobilization agents proceeded. These insights obtained in this study are fundamental but important information to fully elucidate the selenium (VI) immobilization mechanisms that are required to improve the reliability of immobilization technology.

著者

高橋 良尭 山口 耕太郎 笹岡 孝司 濱中 晃弘 島田 英樹 一ノ瀬 政友 久保田 士郎 佐分利 禎

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.10, pp.94-100, 2019-10-31 (Released:2019-10-31)

参考文献数

19

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Rock blasting is one of the most common techniques for rock breakage in the open-pit mining excavation. On the other hand, the application of the technique has been restricted by law since it may cause a serious impact on surrounding environment, such as flyrock, ground vibration and noise. According to the statistics, more than 70% of accidents relating to the usage of explosives is flyrock. This accident may cause serious damage to buildings, human beings, and objects in the surrounding area. However, a detailed guideline for prevention of flyrock has not been developed yet. From these points of views, a series of field experiments was conducted and initial velocity and flying direction of fragmented rock were discussed by considering blasting standard and rock mass conditions such as strength, fractures/cracks and joints. The result shows that powder factor and burden have strong influence on the initial velocity of fragmented rock. Not only blasting designs but also rock mass conditions, cracks/joints strongly effect on the initial velocity. In addition, it was also made clear that the existence of fractures/cracks/joints in the blasting face have an obvious impact on the direction of fragmented rock.

著者

夏井 俊悟 梨元 涼太 問谷 一偉 澤田 旺成 菊地 竜也 鈴木 亮輔

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.8, pp.71-82, 2019-08-31 (Released:2019-08-27)

参考文献数

72

被引用文献数

1

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The transient behavior of the multi-interfacial flow can be modeled using recent Smoothed Particle Hydrodynamics (SPH) model. This developed numerical method is fully-Lagrangian particle-based approach, which can track the movement of many fluid phase directly. The advantage of this simulation model is a direct calculation in both of dispersed phase and continuous phase seamlessly. Thereby this model estimates transient behavior of interfacial behavior by predicting the changes of each interface shape. For example, numerical simulations have been performed for different conditions corresponding to different values of surface tension, viscosity and density, and the predicted topological changes as well as the theoretical interfacial shape of droplets can be validated. Based on this model, we carried out relatively large-scale interfacial flow simulations, investigated case studies of metallurgical processing, and evaluated the non-steady state flow of formed from various dispersed phase.

著者

中村 大 川口 貴之 千葉 貴久 伊藤 陽司 渡邊 達也 山下 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.132, no.1, pp.14-21, 2016-01-01 (Released:2016-01-16)

参考文献数

5

被引用文献数

1

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In this study, we conducted a follow-up survey of brick cracking on a brick wall in the parking space of JR Kitami Station and installed temperature sensors on the surface of the brick wall in order to measure changes in the brick wall temperature during late winter. In addition, we attempted to reproduce the brick cracking observed on the brick wall by conducting an indoor freeze-thaw experiment. The field investigation confirmed that the brick cracking on the brick wall occurred on the south-facing wall in the period from the coldest season to late winter. It was also confirmed from the records of the measured surface temperatures of the brick wall that, even in winter, the bricks could thaw in daytime and re-freeze at night, depending on the weather, solar radiation, and depth of snow coverage. Furthermore, we were successful in reproducing the brick cracking observed on the brick wall in the parking space of JR Kitami Station in the indoor freeze-thaw experiment. Our experience outlined above has demonstrated that frost damage can occur on the brick wall at JR Kitami station by a mechanism caused by the phenomenon of closed-system freeze-thaw, which the authors propose.

著者

林 良和 郭 柄霖 平島 剛 伊藤 竜也 中村 壮志 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.135, no.7, pp.63-70, 2019-07-31 (Released:2019-07-31)

参考文献数

23

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Removal of borate in mine drainages by co-precipitation with hydroxyapatite (HAp) was developed from a laboratory scale to a pilot scale. Weakly acidic initial pH facilitated to enhance dissolution of Ca(OH)2 and decrease the dissolved carbonate concentration, leading to efficient immobilization of borate and arsenate. The NH4H2PO4 lowered best the equilibrium B concentration among different phosphate sources, avoiding the lattice strain of HAp. The added molar ratio of P/Ca significantly influenced the decreasing behavior of the B concentration, showing the optimal value of 0.3. In case of P/Ca larger than 0.30, the excess concentration of PO43- was probably adsorbed on Ca(OH)2 particles to prevent the dissolution, resulting in inhibiting the formation of HAp. In case of P/Ca smaller than 0.30, the production of HAp was limited, leading to less immobilized borate. All the optimized conditions as above were applied to the pilot scale with a 250 L reactor, where borate concentration was effectively reduced in also both batch and continuous tests.

著者

片岡 みなみ 尾原 祐三 Leona VAVRO Kamil SOUCEK Sang-Ho CHO Sang-Sun JEONG

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.5, pp.33-41, 2019-05-31 (Released:2019-05-25)

参考文献数

32

被引用文献数

5

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岩石のモードI破壊靭性を評価するための試験法がこれまでに数多く提案されてきているが,同じ岩石の破壊靭性を異なった試験法で評価し,得られた結果が比較されることはまれである。このため,破壊靭性に及ぼす試験法の違いが明らかにされているとは言い難い。また,岩石の破壊靭性は試験法の違いだけでなく,用いる供試体寸法によっても影響を受けると考えられる。これらの影響を明らかにするために,様々な破壊靭性試験が行われてきた。しかし,これまでの実験では,同じ岩石で作製された供試体数が十分でなかったり,あるいは供試体寸法の違いの範囲が狭かったために,それらの影響を明らかにするまでに至っていないと考えられる。 本論文では,来待砂岩を供試体として用い,3種類の破壊靭性試験法,すなわち,CB試験,SCB試験およびSNDB試験を実施し,破壊靭性に及ぼす試験法の影響を検討するとともに,半径12.5mm〜150mmの範囲の供試体を用いたSCB試験を実施し,供試体寸法の影響を検討した。この結果,CB試験とSCB試験による破壊靭性はほぼ同等の結果を得ることができたが,SNDB試験の破壊靭性はそれらの値より小さく評価されることを示した。また,供試体寸法が大きくなるとともに破壊靭性も増大することを明らかにした。

著者

佐藤 康晴 清野 文雄 小笠原 啓一 山本 佳孝 佐藤 徹 平林 紳一郎 清水 賀之

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.4, pp.124-131, 2013-04-01 (Released:2014-04-14)

参考文献数

20

被引用文献数

5 9

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The motion of a single MH-bubble in quiescent fluid was examined experimentally. If a methane-gas bubble is placed under the condition that hydrates nucleation can initiate, typically at high pressure and low temperature, a thin methane hydrate film is formed on the bubble surface and it alters the motion of the bubble in the fluid drastically. It behaves as if solid did.To clarify the fluid dynamics of MH-bubbles, we devised the special apparatus which enabled us to observe the three dimensional behaviours of the MH-bubbles under high pressure condition. The three dimensional motions of the MH-bubbles were captured by two high-speed cameras whose resolution was 1024*1024 pixel at 500Hz. To analyze the motions of the MH-bubbles, Direct Linear Transformation Method was adopted.Equivalent diameter of the MH-bubble was altered from 3.8 to 7.8 mm, which corresponded to the range from 555 to 1155 in Reynolds number, by replacing the nozzles with different diameters.The MH- bubbles in this range exhibited the zigzag motion, while methane bubbles the spiral motion. Main findings in this research are as follows:(1) The aspect ratio, the height to width ratio, decreased linearly with the increment of the equivalent diameter of a MH-bubble. This reflects the fact that the shape of the MH-bubble shifts from spherical to ellipsoidal. (2) Strouhal number which characterizes the zigzag motion of the MH-bubbles increased with Reynolds number. (3) The drag coefficients were measured up to the Reynolds number of about 1000. The drag coefficient of a MHbubble departs from the standard drag curve when the shape deformation become notable. After that, it rise in accordance with the progress of the deformation. These phenomena also have been observed in the behaviour of a bubble with a surfactant.

著者

児玉 淳一

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.135, no.4, pp.31-32, 2019-04-30 (Released:2019-04-27)

著者

武山 詳 坂口 清敏 渡邉 則昭 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.135, no.3, pp.25-30, 2019-03-31 (Released:2019-03-29)

参考文献数

26

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Gypsum aggregate specimens have been used in the present study, because brittle, semi-brittle and ductile stress-strain behaviors of the specimen can be controlled only with confining stress level at the room temperature. At confining stresses up to 40 MPa, tri-axial compression and fluid flow experiments have been conducted on the intact specimens and single fracture specimens. It has been indicated that stress-strain behavior is independent of existence of fracture. Moreover, permeability of the single fracture specimen is much higher than intact specimen at conditions of brittle, semi-brittle, intermediate state between semi-brittle and ductile and ductile condition. On the other hand, permeability of the single fracture specimen is not so different from that of the intact specimen at conditions of a transitional behavior between semi-brittle and ductile stress-strain behaviors. As for the geothermal reservoir in the semi-brittle and ductile region, it was suggested that the fracture is retained and permeability is maintained when fracturing occurs due to hydraulic crushing or the like.