AngloGold Ashanti was an early adopter of High Pressure Grinding Roll (HPGR) technology at both Tropicana Mine and the Gramalote Project. The increased energy efficiency achieved by HPGRs through confined bed breakage has been extensively researched in small scale tests, but slow industry uptake has resulted in fewer large-scale studies. This has resulted in few opportunities to demonstrate that small scale test work is capable of translating into real energy reduction at industry scale.
The first full survey of the Tropicana circuit has recently been conducted to assess its performance. These results are presented on energy curves to assess the individual performance of each reduction stage down the circuit and create baseline processing efficiency measures. In addition, the availability of lab-scale testwork conducted during project development allows the comparison with operating data i.e. validation of scale-up modelling in energy efficiency.
The investigation of HPGR circuits during the development of the Gramalote project provides another opportunity to showcase the efficiency of HPGR circuits and the energy curve methodology.
Dr Ballantyne presented this work at SME 2016. A published paper will follow. The author has given his permission for his presentation to be reproduced here. SME_Energy curve Ballantyne 2016