Optimization of Trench Dimensions to Reduce Blast-Induced Ground Vibration in Gol-Gohar Sirjan Mine Using Numerical Modeling

Ground vibration is one of the detrimental effects associated with blasting that can damage the surrounding environment and nearby structures. In the Gol-Gohar mine in Sirjan, due to the surface expansion, the distance between the structures and the blasting blocks has decreased, leading to vibrations reaching the processing plant complex. These vibrations, by triggering sensors installed on the mills, cause power outages in the circuit, thereby increasing production costs. One solution to mitigate the waves reaching the processing plant complex is to excavate trenches along the wave path. These trenches, by creating conditions like a free surface and reflecting the waves, reduce the transferred wave energy and can prevent unnecessary shutdowns of the concentration circuit due to increased vibration amplitudes. In this study, using the discrete element software UDEC, the results of a field blasting operation were first validated, and based on the validated model, the impact of trench excavation on the propagation of blast waves was analyzed. Ultimately, the optimal dimensions of the trench, which maximizes energy absorption, were determined. According to the numerical analysis results, the excavated trench on each side of the structure should be more than 2m longer and excavated at distances greater than 3m from the structure. Meanwhile, the thickness (width of the trench) had no significant effect on wave attenuation. This trench can reflect approximately 60% of the blast waves.