Helping to reduce mining industry carbon emissions: A step-by-step guide to sizing and selection of energy efficient high pressure grinding rolls circuits
Stephen Morrell
SMC Testing Pty Ltd, Australia
Keywords: Comminution, Energy efficiency, Carbon emissions, High pressure grinding rolls
ABSTRACT
Comminution is a major contributor to the Mining Industry’s carbon footprint. As most of the world’s leading mining companies have formally committed themselves to having net zero scope 3 carbon emissions by at least 2050, the pressure to significantly improve comminution circuit energy efficiency over the next 25–30 years will be intense. High Pressure Grinding Rolls (HPGR) circuits have the potential to reduce the Mining Industry’s CO2 emissions by up to 34.5 megatonnes/year, or 43.5% when compared to the established Autogenous (AG)/Semi-Autogenous (SAG)/Ball mill circuit alternatives. However, uptake of HPGR technology has been relatively slow. This may be due in part to the fact that costly and time-consuming pilot testing is still the norm for assessing, selecting and sizing HPGR circuits. This is in contrast to AG/SAG/Ball mill circuits where relatively cheap, fast and effective power-based methodologies are used.
To combat this limitation and help accelerate the adoption of this technology a power-based methodology has been developed which can be easily used to assess, size and select HPGR closed circuits in hard rock mining applications. Equations are derived which, on the basis of published data from manufacturers and full-scale operating plants, are demonstrated to accurately reproduce HPGR throughput capacity, installed power and specific energy for a wide range of HPGRs. A number of worked examples are included which demonstrate how the methodology can be applied in practice.