著者

山路 法宏 岡本 信行 塩川 智 川野 誠矢 櫻井 宏信

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.6, pp.42-51, 2019-06-30 (Released:2019-06-28)

参考文献数

10

被引用文献数

3 9

---

Seafloor Polymetallic Sulphides (PMS) is deep sea mineral that is confirmed to exist within Japanese exclusive economic zones and expected to develop as a new supply source for Japan. However, deep sea minerals including PMS have not been commercially developed so far, although various countries are eagerly working it. Japan Oil, Gas and Metals National Corporation (JOGMEC) has been commissioned by Ministry of Economy, Trade and Industry (METI) to conduct practical study on PMS for commercialization. As part of the efforts, JOGMEC implemented “Excavating and Ore-lifting Pilot Test” from the middle of August to end of September 2017. In the test, JOGMEC succeeded in consecutive lifting of ore and sea water in a state of solid-liquid flow from a depth of approximately 1,600m for the first time in the world. Through the test, it became clear that there are still many technical challenges left to be resolved for development of PMS such as improvement in durability of equipment, system optimization, adjustability of ore grain size and slurry concentration and so on. JOGMEC will continue efforts aimed at commercialization of PMS from a long-term perspective.

著者

山崎 哲生

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan (ISSN:18816118)

巻号頁・発行日

vol.124, no.12, pp.829-835, 2008-12-25

参考文献数

31

被引用文献数

1

---

Japan has a manganese nodule mining claim in the Clarion Clipperton Fracture Zones, the Kuroko-type massive seafloor sulfide deposits (SMS) and cobalt-rich manganese crusts (CMC) in Japan's exclusive economic zone (EEZ) and the continental shelves. Japan needs to use these deep-sea mineral resources as future strategic metal and rare earth element supply sources. Furthermore, the development technologies have wide variations in applying for the other food and energy supply targets in EEZ and continental shelves and the same-type resources of Pacific island nations'.<BR>Some current topics in deep-sea mineral resources development and the development technologies are introduced. Possibility and necessity of deep-sea mineral resources development for Japan are discussed.

著者

福井 勝則 大久保 誠介 森山 守 青木 智幸 小塚 孝 松原 誠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ : journal of the Mining and Materials Processing Institute of Japan (ISSN:18816118)

巻号頁・発行日

vol.123, no.9, pp.467-474, 2007-10-25

参考文献数

14

被引用文献数

2

---

The main drive of Hida Tunnel for Tokai-Hokuriku Highway was excavated by a world-largest-class TBM with the diameter of 12.84 m. The TBM have bored over 3.0 km of the tunnel through Nouhi Rhyolite, Granite Porphyry and Hida Gneiss. The uniaxial compressive strength of these rocks was found to be extremely high. Such high strength accompanied by high content of silicon dioxide resulted in significantly high wear rate of the disc cutters mounted on the TBM.<BR>In this study, cutter wear was carefully measured together with the operation conditions such as thrust force, penetration rate, cutter-head rotation rate and the rock properties such as uniaxial compressive strength, rock strength estimated from TBM cutting force, abrasivity obtained from turning operation test, chemical composition determined by X-ray analytical microscope.<BR>It was found that the extent of cutter wear largely depends on position of the disc cutter; cutter wear per unit rolling distance near the fringe of cutter head was extremely larger than that near the center of cutter head. A combination of rock strength estimated by TBM cutting force and length of wear flat in turning-operation test was found to be an excellent index to predict cutter wear rate.

著者

坂田 章吉

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.12, pp.159-172, 2020-12-31 (Released:2020-12-25)

参考文献数

38

被引用文献数

1

---

Since multi-national oil development companies (herein after referred to as “companies”) employ significant CSR in the Federal Republic of Nigeria (herein after referred to as “Nigeria”), CSR in Nigeria is examined in this study. CSR has changed from only pursuing a “corporate objective”, which aims to achieve companies' stable operations, to emphasizing a “development objective” through which the “corporate objective” could still be achieved. However, it has been suggested that the “development objective” oriented CSR has not always been effective because companies had a tendency to emphasize the “corporate objective”, and the “development objective” was often incompatible with the “corporate objective”. Also, it has been suggested that government failure in its community development increased the people's expectation of companies to provide community development and that community development by CSR might ease the pressure on the government to undertake a developmental role. This study examines these points and the results are as follows. Since some CSR cases were found to have achieved both the “development objective” and the “corporate objective” simultaneously, it is possible that these objectives can be achieved in concert. Many of the people who expected community development by companies responded that companies had a responsibility to pay compensation for oil extraction from the Niger Delta/Nigeria, some responded that companies had social responsibility, and a few responded that companies may have been able to provide effective community development for their CSR. Furthermore, it has been inferred that companies were expected to pay compensation even though they payed taxes to the government, because the government provided only limited community development using these tax receipts. Thus, it appears that, expectation of compensation for oil extraction by companies and their social responsibility, as well as limited community development by the government, are the major factors that could increase the people's expectation of companies to provide community development and ease the pressure on the government.

著者

加藤 達也 福島 諒 佐藤 康市 山縣 三郎 所 千晴

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.12, pp.151-158, 2020-12-31 (Released:2020-12-25)

参考文献数

51

---

The objective of this study is to clarify the zinc removal mechanism and construct a quantitative model for column experiments using a natural component of organic soils, namely leaf mold. We performed column experiments using actual acid mine drainage (AMD) at several conditions. After column experiments, the residues in the column were analyzed by x-ray absorption fine structure (XAFS) analysis. These experimental results highlighted that when leaf mold, limestone, and iron powder were filled in the column, the zinc removal mechanism was not only surface complexation for leaf mold but also the formation of zinc sulfide. Whereas, when only leaf mold was filled in the column, that was only surface complexation for leaf mold. Based on the above results, we constructed a quantitative model incorporating surface complexation by leaf mold, sulfate reduction reaction by sulfate-reducing bacteria, Fe2+ dissolved reaction from leaf mold, and one-dimensional transport against the height of the column. The experimental results of pH and the concentration of each element were successfully represented by the quantitative model.

著者

加野 友紀 石戸 経士 中尾 信典

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.12, pp.140-150, 2020-12-31 (Released:2020-12-18)

参考文献数

45

---

Heterogeneity in mudstone/shale layers has significant effects on seal layer integrity. The presence of intralayer sandstone channels in a seal layer may allow the buoyant CO2 to escape from the reservoir, even if the globally averaged permeability of the seal layer seems low enough. On the other hand, multi-layered structures are known to work often as baffles for the upward migration of CO2 in formations. In this paper, we investigate the storage capacity of multilayer formations with discontinuous seals. Numerical simulations are carried out to study the effects of seal layer discontinuity on the long-term behaviour of CO2 injected into deep saline aquifers. To represent a seal layer composed of low permeability rocks intersected by sandstone channels, ‘MINC' doubleporosity model is adopted. Also conducted is sensitivity analysis to investigate the effects of key parameters such as capillary pressure, relative permeability, temperature, and the thickness of the formations. The results show that CO2 injection into a sufficiently deep multi-layered reservoir enables CO2 to be stored and trapped in and around the reservoir without reaching to a shallow aquifer, even though seal layers have discontinuities. The upward movement of CO2 is greatly affected by capillary pressure of sandstone channels in seal layers. The relative permeability and the temperature-dependent CO2 properties have a significant effect on the final plume spread and the amount of CO2 dissolved or fixed by residual gas trapping.

著者

竹原 孝 及川 寧己 藤井 孝志 宮崎 晋行

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.11, pp.134-139, 2020-11-30 (Released:2020-11-28)

参考文献数

28

---

A project of CO2 injection in the Ishikari coal basin (Yubari-shi, Hokkaido, Japan) since 2002 has shown that injection of CO2 into coal seams affected their permeability. Adsorption of CO2 caused swelling of the coal matrix and lowered the permeability of coal seams, probably because of closure of cleats and pores in the coal seams. However, a temporary recovery of permeability was observed after subsequent injection of N2, suggesting that some amount of adsorbed CO2 was replaced by N2 and the closure of cleats and pores were mitigated. However, the changes of mechanical properties of coal in the process are not yet fully understood. In this study, we injected CO2 and N2 into coal specimens recovered from the Ishikari coal basin and observed the changes of coal strength under hydrostatic pressure and temperatures typical of a coal basin. We conducted triaxial compressive strength tests on the coal specimens to clarify the effects of CO2 and N2 on the mechanical properties. Our results are summarized below.1) We verified that swelling and shrinkage of the coal were associated with adsorption and desorption, respectively, of CO2.2) The triaxial compressive strength tests showed that injection of CO2 caused decreases of peak strength and Young's modulus.3) Both coal strength and Young's modulus recovered when previously injected CO2 was replaced by N2.

著者

田中 敦子

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.136, no.11, pp.127-133, 2020-11-30 (Released:2020-11-28)

参考文献数

37

---

In this review, the status quo of social acceptance of CCS is discussed in relation with international efforts to establish understanding on CCS. The author analyzed suspended 43 CCS project cases out of total 133 cases, and identified major impacting factors: economic reasons, legislative reasons, political reasons and social protests were 50%, 25%, 10% and 12% respectively. All of these impacting factors are within the range of social acceptance considerations, and could be solved by stakeholder engagement efforts. The author reviewed ISO/TC265 CCS standards which encourages to establish preferable social acceptance on CCS project by way of stakeholder engagement process and risk communication process. The author summarized recommendations from CCS stakeholder engagement process. Then, the author surveyed reports on public perceptions on CCS and CCS outreach works. Finally, the author researched literally succeeded and failed cases in of social acceptance gaining among communities in vicinity of CCS site and discussed the issue.

著者

近藤 めぐみ 小澤 教良 藤巻 宏太 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.10, pp.117-126, 2020-10-31 (Released:2020-10-29)

参考文献数

13

---

The Une Mine excavates limestone by the bench cut method at Mt. Buko in the Chichibu area of Saitama Prefecture, Japan. Since the final rock slope, which is the largest scale in Japan, is beeing constructed at Mt. Buko, long-term monitoring and analysis have been carried out for the safety management of the rock slope. From the previous researches, a significant relationship between groundwater behavior and displacements of the rock slope was revealed, and suppressing the displacements of the rock slope, i. e., the reduction of the crack displacement rate, was accompanied by the lowering the groundwater level. Based on these results, countermeasures against the slope stability are being carried out in the mine. In this study, groundwater samples in the mine were collected and analyzed to characterize the groundwater chemistry, and to understand how the water quality was changed by rainfall and rock layers was examined. The results showed that the groundwater was classified into three depending on the layers, and that the groundwater in the alternated layer sensitively affected the rock slope.

著者

及川 寧己 竹原 孝 雷 興林 深沢 洋規 山口 勉

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.10, pp.110-116, 2020-10-31 (Released:2020-10-27)

参考文献数

17

---

Elucidating the sealing capacity of caprock is very important because CO2 sequestered in deep aquifers can remain there for several hundred years in the CO2 sequestration. Threshold capillary pressure is a key property affecting sealing capacity, and therefore, the ability to measure the threshold pressure of a target rock conveniently is highly sought after. In this study, data collected during the CO2 injection process in triaxial compression tests of mudstone supposed to be a caprock were used to measure threshold pressure via the dynamic method. These triaxial tests were conducted to study the mechanical properties of mudstone below depths of 1000 m. The threshold pressure for 23 out of 26 test samples was successfully measured. Measured values ranged from 0.54 to 1.57 MPa, which was within a reasonable range compared to the results reported by three other studies that used similar mudstone specimens. A small amount of shrinkage induced by a pore pressure decrease, which was caused by a threshold pressure, was observed in the experiment. The threshold pressure showed a positive correlation with the shrinkage, implying that this pressure might be estimated from the shrinkage. Thus, a volumetric elastic constant was calculated from the shrinkage assuming that the decrease in mean pore pressure was half of the threshold pressure. The mean volumetric elastic constant was 0.92 GPa, which was about 40% lower than that of the rocks from which the test samples were obtained. These results indicate that the shrinkage value cannot be directly used to estimate the threshold pressure, and that a correction of this shrinkage value is necessary.

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

---

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

---

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

中村 謙吾 佐藤 海里 川辺 能成 桑谷 立 駒井 武

出版者

一般社団法人 資源・素材学会

雑誌

日本鑛業會誌 (ISSN:18816118)

巻号頁・発行日

vol.132, no.1, pp.22-30, 2016

被引用文献数

2

---

It is important to understand the distribution mechanism of heavy metal elements in environmental systems, because the toxicities of various metals and metalloids significantly affect health risks. The heavy metals concentrations are controlled by a wide of variety environmental factors. This study aims to clarify main influence factors on the heavy metal distribution in sediment, soil, river in the Natori River, Sendai City. We firstly produced geochemical maps for heavy metal concentrations (As, Pb and Cr) of river sediment, neighboring soil (bulk component, soluble component in 1N HCl and in pure water) and river water. The heavy metals concentrations in river water increase from upper stream to down stream, whereas heavy metal concentrations in river sediments and soil vary little from upper stream to downstream. There are no anomalous distributions of heavy metals in the studied area, although many anthropogenic materials are found in sediment, soil and river water. The correspondence analysis was applied to investigate relationships of heavy-metal concentrations between sediment, soil and river water. The results indicate that the heavy metals (As, Pb Cr and Zn) in sediment, soil and river water are dominantly controlled by natural sedimentary processes, such as denudation and sedimentation. The proposed method could be further applied for other pollutants in various environment systems. From a viewpoint of risk assessment of heavy metals, it is suggested by the presence of closer relationship of heavy metals that contains the risk information of heavy metals.

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

---

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

---

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

---

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

---

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

---

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

---

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.