Imanuel Hutahaean

2012-Present – Chief Flotation Metallurgist • Optimizing Flotation plant performance through investigation and analysis of metallurgical performance trends • Conduct flotation test in laboratory to analyze effect of grind size, primary and secondary collector, frother dosage, depressant and dispersant, for High Pyrite Ore (problematic ore) • Ensuring copper and gold recovery and final concentrate targets are achieved • Conduct reagent line distribution point review and the effect to flotation performance • Coordinating reagent test work to improve metallurgical performance • Monitor flotation circuit performance: check density and pH, pulling stabilization, reagent usage • Flotation equipment (rougher and column) inspection: making sure rougher and column run well. Interact with maintenance, electrical, and instrumentation department in following up inspection findings • Measure reagent consumption, monitoring and minimizing consumables usage and associated costs • Make weekly recovery prediction based on ore type prediction that will be delivered from mine

2008-2009 and 2010-2012 – Grinding Metallurgist • Grinding process control optimization by improving existing control performance together with Industrial Automation team • Ensure Safety, Health, and Environmental in every work • Optimizing Grinding plant performance through field investigation and metallurgical performance analysis • Supporting Operational with technical advise • Conduct field and laboratory test for several types of grinding ball media from different vendor to optimize ball mill comminution performance and budget evaluation • Conduct field and laboratory test to analyze effect of several level of bowl cavity (choke feed level) of pebble crusher in SAG Mill circuit related to crusher product quality, wear rate of crusher liner, and specific energy • SAG Mill, Ball Mill, Knelson and Cyclone inspections • Monitoring and Optimizing grinding ball media consumption • Make weekly throughput and grinding performance prediction based on ore type prediction that delivered from mine

2009-2010 – Crushing Metallurgist • Crushing process control optimization by improving existing control performance together with Industrial Automation team • Ensure Safety, Health, and Environmental in every work • Commissioning HPGR after first change out rolls • Conduct Laboratory evaluation for bypass, single pass, and double pass for HPGR circuit to analyze size distribution (P80 and P50), microstructure crack, specific energy, and specific throughput of HPGR • Optimizing Crushing plant performance through field investigation and metallurgical performance analysis • Secondary -Tertiary Cone crusher, HPGR Roll, and vibrating screen panel inspections