Application of Shallow-Hole Blasting in Improving the Stability of Gob-Side Retaining Entry in Deep Mines: A Case Study

Abstract

The hanging of hard roof strata in the gob-side retaining entry in deep mines could lead to dynamic disasters. The pressure relief mechanism for the hard roof strata using shallow-hole blasting was investigated by a combined method of theoretical analysis, numerical simulation, and field test in the Sanhejian coal mine. The shallow-hole blasting model was established using LS-DYNA3D(Livemore software of explicit dynamics analysis code). The evolution and propagation law of effective stress induced by shallow-hole blasting was analyzed. The parameters related to shallow-hole blasting were determined via a combined method of numerical analysis and theoretical calculations. These were applied to the field tests. The effect of shallow-hole blasting on the strata control of deep gob-side retaining entry was studied by comparing two scenarios in the field: a deep gob-side retaining entry with and without shallow-hole blasting. It was found that the convergences of the entry decreased due to the shallow-hole blasting. This indicates that shallow-hole blasting is a good technique to maintain the stability of the gob-side retaining entry with a hard roof in deep mines.

Keywords

• gob-side entry retaining
• deep mine
• shallow-hole blasting
• hard roof