Effects of Blast Vibration on Unplanned Dilution in an Underground Metal Mine

One of the factors affecting overbreak or slough of the roof and walls of underground stopes, causing unplanned dilution is blast vibration. The amount of damage caused by earth vibration can be measured in terms of peak particle velocity (PPV). In this study, in order to investigate the effects of blast vibration on the occurrence of unplanned dilution, 72 three-component records acquired upon 24 blasts were obtained at underground Venarch Manganese Mines. Once finished with data analysis, scale distance was used to propose an exponential equation for predicting PPV based on the cubic root of the charge weight per delay. Then, the effect of blast vibration on walls and roof of the stope was examined on 24 different explosions, dilution values were recorded at various scaled distances to the face, and the relationship between them was determined. Equivalent linear overbreak/slough (ELOS) was used to determine dilution, with cavity monitoring system (CMS) being used to calculate it. Then a practical diagram was presented to predict the boundary of the dilution area from the explosion. Finally, The relationship between the amount of ELOS against the PPV was presented and it was determined if the PPV was fewer than or equal to 6.73 mm / s, the dilution will not occur.