Innovative approach based on roof cutting by energy-gathering blasting for protecting roadways in coal mines

Abstract As underground mining progresses to deeper levels, roadway control has become a significant issue in the development of modern mines with characteristics of a high yield and high efficiency. To protect deep roadways from dynamic disasters, an innovative approach based on cutting the roof by energy-gathering blasting for protecting the roadway (CREGBPR) was studied. First, the key technique of energy-gathering blasting was introduced. CREGBPR was developed by using the blasting technique and to directionally cut the roof above the roadway following a specific design. Theoretical analysis, numerical simulation, and field tests were combined to analyze the roadway control mechanism of CREGBPR. Compared with the original approach, the CREGBPR approach uses the broken and expanded rock mass to support the fractured structure of the main roof, reducing the impact on the retained roadway. Furthermore, the improvement in the structure eliminates the roof overhanging the roadway coal pillar. The pillars can serve as integrated supporting bodies that bear the abutment stress. Meanwhile, the stress environment is improved significantly by the roof cutting effect; the stress evolution includes new areas in which the stress distributes more uniformly. As a result, these independent effects induced by CREGBPR are integrated to protect the roadway effectively. A field test was conducted to verify the effectiveness of CREGBPR. The roadway convergence and roof weighting were significantly reduced. The research results prove that the CREGBPR approach is feasible for engineering applications and can protect roadways in deep mines.