Solutions to prevent face spall and roof falling in fully mechanized longwall at underground mines, Vietnam

Abstract

Purpose. On the basis of analysis and assessment of geological conditions, technological parameters and support methods of a longwall, the author has pointed out the causes and rules of the phenomenon of face spall and roof falling in fully mechanized longwall. From there, the author proposes some solutions to prevent this phenomenon to ensure the safety of the longwall. Methods. The statistical, survey and analysis methods of actual field data are used to achieve research results. Findings. The results of applying solutions to prevent the phenomenon of face spall and roof falling are relatively good. There are some effective solutions such as the technique of force-pumping chemicals directly into the coal seam to increase the connection among the coal masses, the solution of force-pumping water into the seam combined with enhanced support at the place of face spall and roof falling on a small scale. Originality. There are many reasons and factors that cause the phenomenon of face spall and roof falling in the longwalls. In the present paper, the author focuses on 5 main causes and factors ruling face spall and roof falling in longwalls. On that basis, the author proposes 5 solutions that can be applied to prevent the face spall and roof falling in geological conditions of longwalls in Quang Ninh coalfield, Vietnam. Practical implications. The research results presented in the article will help mines be proactive in production. These technical solutions, after being applied in actual production, allowed to achieve quite good results, and effectively handled the phenomenon of face spall and roof falling in the longwall according to each specific geological condition. Thus, it is possible to develop technical and technological solutions for troubleshooting in fully mechanized longwall at some current underground mines of Quang Ninh coalfield, Vietnam.