Experimental and Numerical Study on the Influence of Cut Design, Deviation Factor, and Rock Mass Quality on the Blast Pull Performance

In underground mines, development headings such as tunnels and access are essential structures of mining infrastructure. Blasting is the most preferred excavation method for ore and waste rock extraction. Many parameters can significantly influence blast pull performance (BPP); some are controllable (blast design, deviation factor), while others are uncontrollable, such as geological-geomechanical parameters. The current study investigates the influence of cut design, deviation factor (Df), and rock mass quality on BPP. For this purpose, a field investigation was conducted in an underground copper mine to ascertain the influence of geological-geomechanical parameters on BPP. Experimental and numerical analysis reveals a significant relationship between the deviation factor and the borehole length, and it is recommended that the distance between the empty hole and the first burden should be less than 0.15 m to optimize the blasting effect. Furthermore, different statistical analyses were established, and the BPP was directly correlated to the geological strength index (GSI) with two to four joint families. The powder factor is related to BPP for cut designs Bc₁/B’c₁ and Bc₃/B’c₃ for medium-quality rocks. In addition, a linear regression model was used to determine the relationship between the powder factor and the GSI.