Study of Ground Vibration Reduction Using Fault Tree Analysis Method on Blasting Activity in PT. Semen Baturaja Persero, Tbk.

Abstract

Limestone mining activities at PT. Semen Baturaja Persero, Tbk use blasting activity that produces ground vibrations. Based on the measurement result on vibration level, the maximum value for vibration is 4.66 mm/s. The results of the data show that the level of emission has exceeded the standard limits for second class buildings (3 mm/s) based on (SNI) 7571: 2010 while the blasting activity is only 175-300 m from the nearest settlement. Fault Tree Analysis is used to analyze undesired events in a system or work set. Reconstruction of Fault Tree Analysis with Boolean algebra yields 5 event combinations that have the highest chance of generating ground vibrations. The event with the highest failure rate is X11 (the number of bursting holes simultaneously) with failure rate of 0.813 and X12 (fast timing delay) with failure rate (0.750). The USBM formulation obtained 3 mm/s vibration results when the number of bursting holes was reduced from 5 holes to 2 holes/delays with a quantity of 43 kg/delay. Based on Shotplus simulation, the company is advised to replace the blasting delay system from electricity to electronics to produce minimal explosion of ground vibration so as not to damage the environment.

Keywords

• Blasting
• flyrock
• Vibration
• powder factor