FLYROCK EVALUATION TO REDUCE SAFE DISTANCE FROM 500M TO 300M AT PT. VALE INDONESIA, SOROWAKO, SOUTH SULAWESI, INDONESIA

Flyrock fragmentation is a rock or rocks that throwing by blasting. Rock fragments thrown beyond the safe radius can cause damage to mechanical tools. This study aims to determine the safe distance from flyrock result from blasting at the company and the factors that affect the flyrock distance. This study uses survey methods and quantitative analysis with calculations also analysis of theoretical flyrock distance predictions from the blast. Data collection at PT. Vale Indonesia uses Leica GS 14 and cameras to observe blasting activities. PT. Vale Indonesia run the project of mining process at Sorowako , Nuha sub-district, South Sulawesi Province. Field observation conducted and found that PT. Vale Indonesia stated for safe distance all heavy equipment and human are in 500m due to the incident that occurred in last decade, to change the safe distance for heavy equipment back to 300m, a technical study is needed as well as determining the value of the safety factor for throwing flyrock in every blasting activity carried out. Determination of the estimated maximum flyrock throwing distance using two methods namely the empirical method and the dimensional analysis method, the study is done in order to obtain accurate and precise results in accordance with the conditions of the blasting location. The empirical method used is based on Lundborg theory (1981) and, Richard and Moore (2005), while the dimensional analysis method is based on the theory of Ebrahim Ghasemi (2012). By using the dimensional analysis method from Ebrahim Ghasemi (2012) the deviation from actual flyrock throw is 38.1%, and with Richard Moore's empirical method with a deviation value of 70.5%. From these results, it is known that the method produces an estimate of the flyrock-throwing distance that is closest to the actual flyrock-throwing distance is the dimensional analysis method with a difference of 6 m with a safety factor value of 1.5, based on the dimensional analysis method, a trial was carried out to see the appropriate safe radius, to determine the current safe radius at Quarry PT. Vale Indonesia is appropriate or can be reduced.