Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi
To develop affordable countermeasures against the roof falls, the accident records of Mchenga Mine were investigated as the first step. Based on the accident records, it was found that roof falls occurred most in April and May. Humidity measurements were taken both in the underground mine and at sur...
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| Format: | Article |
| Language: | English |
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Wiley
2019-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2019/5350686 |
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| author | Umali M. Yasidu Yoshiaki Fujii Jun-ichi Kodama Daisuke Fukuda George J. Maneya Johnson Dandadzi Anjula B. N. Dassanayake |
| author_facet | Umali M. Yasidu Yoshiaki Fujii Jun-ichi Kodama Daisuke Fukuda George J. Maneya Johnson Dandadzi Anjula B. N. Dassanayake |
| author_sort | Umali M. Yasidu |
| collection | DOAJ |
| description | To develop affordable countermeasures against the roof falls, the accident records of Mchenga Mine were investigated as the first step. Based on the accident records, it was found that roof falls occurred most in April and May. Humidity measurements were taken both in the underground mine and at surface, and humidity peak appeared in April. The accident occurrence and the underground humidity had a positive correlation in which no roof falls could be expected under a humidity of less than a certain value. Effect of humidity on the indirect tensile strength of the rock samples collected from the mine was investigated, and it showed that the indirect tensile strength decreased with humidity. The diffusion coefficient was measured for the rock samples collected from Mchenga Mine as well as from Kaziwiziwi Mine, and the migration of water vapor into rock mass in the roof was calculated for Mchenga case. It was clarified that the weakening of tensile strength was transmitted upward at several centimeters per day from the immediate roof. This could explain the slight difference of the accident peak in April and May from the humidity peak in April. Introducing fresh and dry outside air, if possible, will not only improve the working environment but also contribute to a decrease in roof falls. |
| format | Article |
| id | doaj-art-8c7a3510baee4c9fb05f3d36dd28320a |
| institution | OA Journals |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Civil Engineering |
| spelling | doaj-art-8c7a3510baee4c9fb05f3d36dd28320a2025-08-20T02:09:34ZengWileyAdvances in Civil Engineering1687-80861687-80942019-01-01201910.1155/2019/53506865350686Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in MalawiUmali M. Yasidu0Yoshiaki Fujii1Jun-ichi Kodama2Daisuke Fukuda3George J. Maneya4Johnson Dandadzi5Anjula B. N. Dassanayake6Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, JapanFaculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, JapanFaculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, JapanFaculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, JapanDepartment of Mines, Government of Malawi, P.O. Box 251, Lilongwe, MalawiMchenga Coal Mine, P. O. Box 404, Mzuzu, MalawiUniversity of Moratuwa, Moratuwa 10400, Sri LankaTo develop affordable countermeasures against the roof falls, the accident records of Mchenga Mine were investigated as the first step. Based on the accident records, it was found that roof falls occurred most in April and May. Humidity measurements were taken both in the underground mine and at surface, and humidity peak appeared in April. The accident occurrence and the underground humidity had a positive correlation in which no roof falls could be expected under a humidity of less than a certain value. Effect of humidity on the indirect tensile strength of the rock samples collected from the mine was investigated, and it showed that the indirect tensile strength decreased with humidity. The diffusion coefficient was measured for the rock samples collected from Mchenga Mine as well as from Kaziwiziwi Mine, and the migration of water vapor into rock mass in the roof was calculated for Mchenga case. It was clarified that the weakening of tensile strength was transmitted upward at several centimeters per day from the immediate roof. This could explain the slight difference of the accident peak in April and May from the humidity peak in April. Introducing fresh and dry outside air, if possible, will not only improve the working environment but also contribute to a decrease in roof falls.http://dx.doi.org/10.1155/2019/5350686 |
| spellingShingle | Umali M. Yasidu Yoshiaki Fujii Jun-ichi Kodama Daisuke Fukuda George J. Maneya Johnson Dandadzi Anjula B. N. Dassanayake Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi Advances in Civil Engineering |
| title | Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi |
| title_full | Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi |
| title_fullStr | Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi |
| title_full_unstemmed | Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi |
| title_short | Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi |
| title_sort | influences of water vapor on roof fall accidents in selected underground coal mines in malawi |
| url | http://dx.doi.org/10.1155/2019/5350686 |
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