1. |
Ian KROP, Yoshiaki TAKAHASHI, Takashi SASAOKA, Hideki SHIMADA, Akihiro HAMANAKA, Joan ONYANGO, Assessment of Selected Machine Learning Models for Intelligent Classification of Flyrock Hazard in an Open Pit Mine, IEEE Access, https://doi.org/10.1109/ACCESS.2024.3352733, 12, 8585-8608, 2024.01. |
2. |
Fa-qiang SU, Jun-nan YANG, Xiao-long HE, Meng-jia DAI, Akihiro HAMANAKA, Yi-he YU, Wen LI, Jiao-yuan LI, Influences of removable gas injection methods on the temperature field and gas composition of the underground coal gasification process, Fuel, https://doi.org/10.1016/j.fuel.2024.130953, 363, 1, 130953, 2024.05. |
3. |
Fa-qiang SU, Xiao-long HE, Meng-jia DAI, Jun-nan YANG, Akihiro HAMANAKA, Yi-he YU, Wen LI, Jiao-yuan LI, Estimation of the cavity volume in the gasification zone for underground coal gasification under different oxygen flow conditions, Energy, https://doi.org/10.1016/j.energy.2023.129309, 285, 129309, 2023.10. |
4. |
Akihiro HAMANAKA, Yuma ISHII, Ken-ichi ITAKURA, Takashi SASAOKA, Hideki SHIMADA, Nuhindro Priagung WIDODO, Budi SULISTIANTO, Jun-ichi KODAMA, Gota DEGUCHI, Monitoring the gasification area and its behavior in underground coal gasification by acoustic emission technique instead of temperature measurement, Scientific Reports, https://doi.org/10.1038/s41598-023-36937-0, 13, 2023.06, Underground Coal Gasification (UCG) requires monitoring of the gasification area because the gasification process is invisible and the reaction temperature exceeds 1,000℃. Many fracturing events that occurred due to coal heating can be captured with Acoustic Emission (AE) monitoring technique during UCG. However, the temperature conditions to generate fracturing events during UCG have not yet been clarified. Therefore, the coal heating experiment and small-scale UCG experiment are conducted by measuring the temperature and AE activities in this research to examine the applicability of the AE technique instead of temperature measurement as a monitoring method during UCG. As a result, many fracturing events are generated when the temperature of coal is changed drastically, especially during coal gasification. Besides, AE events increase in the sensor near the heat source and AE sources are expanded widely with the expansion of the high-temperature region. AE monitoring is an effective technique for the estimation of the gasification area during UCG instead of temperature monitoring.. |
5. |
Bosong YU, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Fumihiko MATSUMOTO, Tomo MORITA, A jacking force study based on interpretation of box jacking records: A case study of curved rectangular box jacking in soft soil in Saitama, Japan, Tunnelling and Underground Space Technology, https://doi.org/10.1016/j.tust.2023.105228, 139, 105228, 2023.05. |
6. |
Fa-qiang SU, Jun-bo WU, Zhang TAO, Qi-chao DENG, Yyi-he YU, Akihiro HAMANAKA, Meng-Jia DAI, Jun-Nan YANG, Xiao-long HE, Study on the monitoring method of cavity growth in underground coal gasification under laboratory conditions, Energy, https://doi.org/10.1016/j.energy.2022.126048, 2023.01. |
7. |
Fa-qiang SU, Tao ZHANG, Jun-bo WU, Qi-chao DENG, Akihiro HAMANAKA, Yi-he YU, Meng-jia DAI, Xiao-long HE, Jun-nan YANG, Energy recovery evaluation and temperature field research of underground coal gasification under different oxygen concentrations, Fuel, https://doi.org/10.1016/j.fuel.2022.125389, 329, 2022.12, In this paper, UCG simulation experiments were carried out on selected coal samples to study the effects of the gasification agent ratio on the product gas composition and calorific value under different oxygen concentrations. Moreover, an energy recovery evaluation method based on stoichiometric theory was established based on the carbon (C) balance in the generated gas content, and the energy recovery rate and coal consumption of the underground gasification process were evaluated. Based on the composition of the produced gas and the thermodynamic law of conservation, an evaluation model of the underground coal gasification temperature field was established. The gasification chamber temperature in each stage was evaluated by calculating the reaction heat and sensible heat. The experimental and research results showed that when the volume fraction of oxygen in a gasification agent was in the range 40–70 % and the calorific value of the produced gas increased from 10.48 MJ/m3 to 12.48 MJ/m3. The calorific value of the produced gas increased with an increasing oxygen concentration. Furthermore, the energy recovery rate increased from 69.63 % to 83.88 %, indicating that the gasification efficiency of the UCG experiment can be significantly improved with an increasing oxygen concentration. The error between the theoretical value of the coal consumption and the actual monitoring value was within 10 %, which effectively evaluates the coal consumption in the gasification process. The theoretical calculation temperature was consistent with the experimental monitoring temperature results, and the reaction heat was found to also be linearly correlated with the gasification temperature. Therefore, this method can effectively determine the gasification chamber temperature. These monitoring and evaluation methods are expected to guide the analysis of subsurface field experiments.. |
8. |
Hiroto HASHIKAWA, Pisith MAO, Takashi SASAOKA, Akihiro HAMANAKA, Hideki SHIMADA, Ulaankhuu BATSAIKHAN, Jiro OYA, Numerical Simulation on Pillar Design for Longwall Mining under Weak Immediate Roof and Floor Strata in Indonesia, Sustainability, https://doi.org/10.3390/su142416508, 14, 24, 16508, 2022.12. |
9. |
Dyson MOSES, Hideki SHIMADA, Joan A. ONYANGO, Takashi SASAOKA, Akihiro HAMANAKA, Slope design in brecciated carbonatite complexes under high-stress regimes, Bulletin of Engineering Geology and the Environment, https://doi.org/10.1007/s10064-022-02993-5, 81, Article number: 494, 2022.11. |
10. |
Cho Thae OO, Dyson MOSES, Takashi SASAOKA, Hideki SHIMADA, Akihiro HAMANAKA, Joan Atieno OYANGO, Ulaankhuu BATSAIKHAN, Seelae PHAISOPHA, Ian Krop TSUMA, Design and Stope Stability Analysis of Multiple Concurrent Excavated Veins in Underground Mine; Case Study of Hermyingyi Tin-Tungsten (W-Sn) Mine, Geotechnical and Geological Engineering, https://doi.org/10.1007/s10706-022-02322-3, 41, 2, 1049-1072, 2022.11. |
11. |
Akihiro HAMANAKA, Takashi SASAOKA, Hideki SHIMADA, Shinji MATSUMOTO, Amelioration of acidic soil using fly Ash for Mine Revegetation in Post-Mining Land, International Journal of Coal Science and Technology, https://doi.org/10.1007/s40789-022-00499-9, 9, 2022.05. |
12. |
Ulaankhuu BATSAIKHAN, Hiroto HASHIKAWA, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Numerical Study on the Applicability of the Pipe-Jacking Method for the Main Gate of an Underground Coal Mining in Weak Rock Mass, Applied Sciences, https://doi.org/10.3390/app12031719, 12, 3, 1719, 2022.02. |
13. |
Peng MA, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Dyson MOSES, Tumelo K.M.DINTWE, Fumihiko MATSUMOTO, Baosong MA, Sheng HUANG, A new method for predicting the friction resistance in rectangular pipe-jacking, Tunnelling and Underground Space Technology, https://doi.org/10.1016/j.tust.2021.104338, 2022.02. |
14. |
Pisith MAO, Hiroto HASHIKAWA, Takashi SASAOKA, Hideki SHIMADA, Zhijun WAN, Akihiro HAMANAKA, Jiro OYA, Numerical Investigation of Roof Stability in Longwall Face Developed in Shallow Depth under Weak Geological Conditions, Sustainability, https://doi.org/10.3390/su14031036, 14, 3, 1036, 2022.01. |
15. |
Akihiro HAMANAKA, Fa-qiang SU, Ken-ichi ITAKURA, Kazuhiro TAKAHASHI, Jun-ichi KODAMA, Gota DEGUCHI, Experimental study on evaluation of underground coal gasification with a horizontal hole using two different coals, Fuel, https://doi.org/10.1016/j.fuel.2021.121556, 305, 2021.12, Underground coal gasification (UCG) is a technique to extract coal energy with heat energy and combustible gases through chemical reactions in the underground gasifier. In this study, an application of a coaxial UCG system with a horizontal hole is discussed by means of the model UCG experiments with a large-scale simulated coal seam having dimensions of 550 × 600 × 2740 mm. The two types of coal having 30.18 MJ/kg of calorific value with 7.9% of ash (type 1) and 22.66 MJ/kg of calorific value with 28.3% of ash (type 2) were used for the experiments to evaluate the effect of coal quality on temperature distribution of the gasification area and product gas quality. The oxygen-enriched air was used. The injection rate of the gasification agents was elevated during the experiments to analyze the effect on the product gas. The results show that the gasification area is expanded along the wall of a coaxial hole, not upwards for the type 2 coal with high ash content. The average calorific value of product gas for types 1 and 2 is 8.05 MJ/m3 and 6.91 MJ/m3 respectively, while an increase of injection flow rate produces an improvement of the calorific value for both types of coal. Additionally, it is suggested that the reacted carbon and the product gas volume can be estimated with the volume of oxygen injected regardless of the coal quality if the gasification efficiency and the reaction temperature are similar. These results help to estimate several important parameters, e.g. reacted coal amount, recovered gas volume, and recovered energy from the coal when the actual field implementation is designed.. |
16. |
Tumelo K. M. DINTWE, Takashi SASAOKA, Hideki SHIMADA, Akihiro HAMANAKA, Dyson N. MOSES, Ma PENG, Meng FANFEI, Seifei LIU, Ronald SSEBADDUKA, Joan A. ONYANGO, Numerical Simulation of Crown Pillar Behaviour in Transition from Open Pit to Underground Mining, Geotechnical and Geological Engineering, https://doi.org/10.1007/s10706-021-02022-4, 2021.11. |
17. |
Kai WEN, Wei ZENG, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Numerical and theoretical study on the jacking force prediction of slurry pipe jacking traversing frozen ground, Tunnelling and Underground Space Technology, https://doi.org/10.1016/j.tust.2021.104076, 115, 2021.06. |
18. |
Peng MA, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Tumelo K. M. DINTWE, Donjiang PAN, Investigation on the Performance of Pipe Roof Method Adjacent to the Underground Construction, Geotechnical and Geological Engineering, 39, 6, 4677-4687, 2021.02. |
19. |
Takashi SASAOKA, Pisith MAO, Hideki SHIMADA, Akihiro HAMANAKA, Jiro OYA, Numerical Analysis of Longwall Gate-Entry Stability under Weak Geological Condition: A Case Study of an Indonesian Coal Mine, Energies, https://doi.org/10.3390/en13184710, 13, 18, 2020.09. |
20. |
Takashi SASAOKA, Akihiro HAMANAKA, Takahiro FUNATSU, Hideki SHIMADA, Keisuke TAKAHASHI, Study on Addition of Surfactants Agents to Improve the Behavior of High Water Content Sediment for Rare Earth Mining in Deep Sea, Inzynieria Mineralna, http://doi.org/10.29227/IM-2020-01-64, 1(45), 183-188, 2020.07. |
21. |
Kazuki MAEHARA, Akihiro HAMANAKA, Takashi SASAOKA, Hideki SHIMADA, Seiya SAKUMA, Study on Control of Wall Deflection in Earth Stepped-Twin Retaining Wall Using Anchor Method by means of Numerical Simulation, Advances in Civil Engineering, https://doi.org/10.1155/2020/2710954, 2020, Article ID 2710954, 8 pages, 2020.01. |
22. |
Shinji MATSUMOTO, Akihiro HAMANAKA, Kaito MURAKAMI, Hideki SHIMADA, Takashi SASAOKA, Securing Topsoil for Rehabilitation Using Fly Ash in Open-Cast Coal Mines: Effects of Fly Ash on Plant Growth, Inzynieria Mineralna, 1(43), 13-18, 2019.08. |
23. |
Akihiro HAMANAKA, Takashi SASAOKA, Hideki SHIMADA, Shinji MATSUMOTO, Experimental study on soil erosion under different soil composition using rainfall simulator, Plant, Soil and Environment, 10.17221/68/2019-PSE, 65, 4, 181-188, 2019.04, Soil erosion is one of the major environmental problems in open-cut mines in tropical regions. It causes negative impacts including the removal of nutrient-rich topsoil, destroys aquatic habitat, dam and pond siltation, clog river by deposition of sediment, and water pollution in the rehabilitation process. Soil texture is an important factor to affect soil erosion. In this study, artificial rainfall experiment in laboratory scale was conducted to clarify the mechanism of soil erosion under the different soil composition and to discuss the method for minimizing soil erosion. Obtained results showed that the soil seal generated due to the presence of fine particle under high rainfall intensity is the main contributor to accelerate the soil erosion. Additionally, the surface coverage by the cover crops is most effective measures to reduce soil erosion because the both of coarse and fine contents runoff can be minimized while the arranging slope angle is effective for reducing the runoff of coarse contents and the soil compaction is effective to reduce that of fine contents. Soil erosion can be minimized by selecting prevention method considering the type of soil because the prevention effect on soil erosion is different depending on the type of soil.. |
24. |
Fa-qiang SU, Akihiro HAMANAKA, Ken-ichi ITAKURA, Gota DEGUCHI, Wenyan ZHANG, Hua NAN, Evaluation of a Compact Coaxial Underground Coal Gasification System Inside an Artificial Coal Seam, Energies, doi:10.3390/en11040898, 11, 4, 2018.04. |
25. |
Shinji MATSUMOTO, Shunta OGATA, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Ginting Jalu KUSUMA, Effects of pH-Induced Changes in Soil Physical Characteristics on the Development of Soil Water Erosion, Geosciences, doi:10.3390/geosciences8040134, 8, 4, 2018.04. |
26. |
Fa-qiang SU, Akihiro HAMANAKA, Ken-ichi ITAKURA, Wenyan ZHANG, Gota DEGUCHI, Kohki SATOH, Kazuhiro TAKAHASHI, Jun-ichi KODAMA, Monitoring and evaluation of simulated underground coal gasification in an ex-situ experimental artificial coal seam system, Applied Energy, 223, 82-92, 2018.04, In this study, to better simulate underground coal gasification (UCG), an artificial coal seam was constructed to use as a simulated underground gasifier, which comprised coal blocks excavated from the coal seam. This study reports the process and results of three independently designed experiments using coaxial-hole and linking-hole UCG models: (a) a coaxial model using a coaxial pipeline as a gasification channel, (b) a coaxial model using the coaxial pipeline combined with a bottom cross-hole, and (c) a linking-hole model using a horizontal V-shaped cross-hole. In the present work, the fracturing activities and cavity growth inside the reactor were monitored with acoustic emission (AE) technologies. During the process, the temperature profiles, gas production rate, and gas content were measured successively. The results show that AE activities monitored during UCG process are significantly affected by operational variables such as feed gas rate, feed gas content, and linking-hole types. Moreover, the amount of coal consumed during UCG process were estimated using both of the stoichiometric approach and balance computation of carbon (C) based on the product gas contents. A maximum error of less than 10% was observed in these methods, in which the gas leakage was also considered. This demonstrates that the estimated results using the proposed stoichiometric approach could be useful for evaluating energy recovery during UCG.. |
27. |
Zhiyi ZHANG, Hideki SHIMADA, Takashi SASAOKA, Akihiro HAMANAKA, Stability Control of Retained Goaf-Side Gateroad under Different Roof Conditions in Deep Underground Y Type Longwall Mining, Sustainability, doi:10.3390/su9101671, 9, 10, 2017.09. |
28. |
Akihiro HAMANAKA, Fa-qiang SU, Ken-ichi ITAKURA, Kazuhiro TAKAHASHI, Jun-ichi KODAMA, Gota DEGUCHI, Effect of injection flow rate on product gas quality in underground coal gasification (UCG) based on laboratory scale experiment Development of co-axial UCG system, Energies, 10.3390/en10020238, 10, 2, 2017.01, 同軸型UCGシステムの確立のため、室内石炭地下ガス化モデル実験を行い、注入ガスの流量が生成ガス質に与える影響に関して検討した。その結果、注入ガス量を制御することで、生成ガス質が制御し得ることが明らかとなった。. |
29. |
Fa-qiang SU, Akihiro HAMANAKA, Ken-ichi ITAKURA, Gota DEGUCHI, Kohki SATOH, Jun-ichi KODAMA, Evaluation of coal combustion zone and gas energy recovery for underground coal gasification (UCG) process, Energy & Fuels, 10.1021/acs.energyfuels.6b01922, 31, 1, 154-169, 2017.01. |
30. |
Akihiro HAMANAKA, Naoya INOUE, Hideki SHIMADA, Takashi SASAOKA, Kikuo MATSUI, Ikuo MIYAJIMA, Design of self-sustainable land surface against soil erosion at rehabilitation areas in open-cut mines in tropical regions, International Journal of Mining, Reclamation and Environment, 29, 4, 305-315, 2015.04. |
31. |
Akihiro HAMANAKA, Naoya INOUE, Shinji MATSUMOTO, Hideki SHIMADA, Takashi SASAOKA, Kikuo MATSUI, Ikuo MIYAJIMA, Rehabilitation of Open Cut Coal Mine with Paper Mulberry (Broussonetia Papyrifera) in Indonesia, INZYNIERIA MINERALNA Journal of the Polish Mineral Enginering Society, 15, 2(34), 159-163, 2014.12. |