DETERMINATION OF THE RATIONAL LENGTH OF THE BLOCK ALONG THE STRIKE FOR EXPANSION TO PROVIDE SAFETY AND EFFICIENCY IN THE WORKING OF THE MEDIUM THICK IN-CLINED COAL SEAMS WITH THE ROOM AND PILLAR SYSTEM IN THE QUANG NINH COAL BASIN

摘要

An analysis of appropriateness of room-and-pillar method for extracting medium-thick inclined coal seams in Quang Ninh Coal Basin taking into account existing mining and geological conditions was carried out. Corresponding foreign experience of applying room-and-pillar method was considered in relation to the mines of Vietnam. Process flow sheet of first mining and extraction of medium-thick inclined coal seams by room-and-pillar method in complicated mining and geological conditions was developed, and optimal block length along the strike to provide the production safety and efficiency was determined.