Comparative analysis of ANFO and emulsion application on overbreak and underbreak at blasting development activity in underground Deep Mill Level Zone (DMLZ) PT Freeport Indonesia

Abstract

Underground Deep Mill Level Zone (DMLZ) mine PT Freeport Indonesia (PTFI) is still in development stage and currently has no production activities yet. In underground DMLZ mine, a trial of emulsion explosive has conducted since March 15th, 2017 where previously used was Ammonium Nitrate Fuel Oil (ANFO) explosive for tunnel blasting. This study purposes to analyse the results and impact of ANFO and emulsion explosive in order to know the advantages and disadvantages of each explosives. In this study, an overbreak and underbreak comparison evaluation was performed by ANFO explosives and emulsion in underground DMLZ mine tunnel blasting. Furthermore, processing data based on explosives specification data, explosives quantity, heading location and time that detonated, solid design and actual tunnel DMLZ of PT. Freeport Indonesia, also cross section data. After all the data were processed and analysed, it was concluded that the emulsion explosive was more effective for use in tunnel blasting. To optimize the effective blasting results it is necessary to redesign new drilling patterns and blasting geometry by used of radial crack method, so that they can be applied to DMLZ tunnels in the future.