Analisis Kestabilan Lubang Bukaan Akibat Peledakan Deep Mill Level Zone (DMLZ) PT Freeport Indonesia

Abstract

PT Freeport Indonesia (PTFI) is mining copper and gold deposits in Papua, Indonesia. Deep Mill Level Zone (DMLZ) underground mines, especially for undercut level blasting activities, are one of the mining sites that companies must pay attention to. To calculate Peak Particle Velocity (PPV), this study used ground vibration data from field measurements. The USBM equations (Duvall & Fogelson, 1962), Langefors and Kihlstrom (1963), and Ambraseys-Hendron (1968) were used to perform data analysis using linear regression distance scales. Evaluation of the effect of blasting vibrations on opening holes was carried out by numerical simulation using RS2 from Rock Science. First, numerical results are validated with actual data. The results of numerical simulation with input parameter damping ratio 2% show that the calculated PPV value is not much different from the actual PPV value. The calculation results showed that the PPV value of 68.15 mm/s was produced by 70.0 kg explosives. This amount of charge is equal to a blasting load of 4.67 MPa. The calculation results also show that the stability of the lower opening tunnel is in safe condition with a safety factor greater than 1.00. 

Keyword: Load dynamics, Underground stability, Peak Paticle Velocity (PPV), Scaled Distance (SD)