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Effect of Humidity on Tensile Strength of Rocks in Selected Underground Coal Mines in Malawi

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タイトル: Effect of Humidity on Tensile Strength of Rocks in Selected Underground Coal Mines in Malawi
著者: Yasidu, U.M. 著作を一覧する
Fujii, Yoshiaki 著作を一覧する
Fukuda, Daisuke 著作を一覧する
Kodama, Jun-ichi 著作を一覧する
Maneya, G. 著作を一覧する
キーワード: Humidity
Tensile strength
Roof falls
Underground coal mines
発行日: 2017年 6月27日
出版者: American Rock Mechanics Association
誌名: Proceedings of US Rock Mechanics/Geomechanics Symposium 2017 (ARMA 2017)
開始ページ: ARMA 17-0217
抄録: One of the major challenges facing coal mines in Malawi is occurrence of hanging roof falls during the rainy season. Following this, the effect of humidity on the tensile strength of coal bearing rocks, arkose sandstone and fine-grained sandstone from Mchenga underground coal mine, was studied aiming to clarify the mechanism of roof fall in the underground mines and proposing countermeasures against the roof falls. Rock samples from the mine were treated in varying humidity levels. Some specimens were oven dried at 80C and a desiccant was used to attain low humidity. Moderate humidity was obtained using magnesium-nitrate-hexahydrate, high humidity was achieved by pure water and some specimens were vacuum saturated. Subsequently, Brazilian test was carried out to obtain indirect tensile strength along the sedimentary plane. For comparison, Neogene tuffaceous Kimachi sandstone from Japan was also tested, following the same conditions. It was confirmed that indirect tensile strength of the rocks decreased with increase in humidity. The sensitivity of indirect tensile strength to humidity for arkose and fine grained sandstones was 12% or 29% larger than that for Kimachi sandstone. The stronger sensitivity for Mchenga roof rocks would be because the rocks contain illite, whose strength is very sensitive to water, while Kimachi sandstone contains only less sensitive zeolite for clay minerals.
Rights: Copyright 2017 ARMA, American Rock Mechanics Association This paper was prepared for presentation at the 51st US Rock Mechanics / Geomechanics Symposium held in San Francisco, California, USA, 25-28 June 2017.
資料タイプ: proceedings (author version)
出現コレクション:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

提供者: 藤井 義明


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