Declining ore grades are pushing mining companies to find new ways to reduce the energy required to extract and process each tonne of material. As a result, crushing and grinding are becoming increasingly important areas for technological development, particularly as operators handle larger volumes of increasingly complex ore.
Weir is promoting processing flowsheets that combine high-pressure grinding rolls (HPGR), large-format screening, stirred milling and coarse-particle flotation. The company has cited potential energy reductions of up to approximately 40% from HPGR technology and around 38% from stirred milling in suitable applications. Metso is targeting the same challenge through HPGR, fine-grinding and vertical-roller-mill technologies. Its Loesche-based dry-grinding systems have been presented as capable of reducing energy requirements by up to approximately 40% for appropriate ore types.
Actual savings vary significantly depending on the deposit, ore characteristics and overall processing flowsheet. The potential impact is significant because grinding represents one of the largest electricity demands at many hard-rock mines.
Lower Grades Increase Processing Pressure
The challenge is particularly important for low-grade copper operations, where maintaining production can require substantially more material to be mined, transported and processed. Improving comminution efficiency can therefore affect more than electricity consumption. A more efficient processing circuit can influence both operating costs and infrastructure requirements.
Lower power demand may also reduce the amount of new generation, transmission capacity and backup infrastructure required for a mining project. In some cases, this can help lower capital requirements and potentially accelerate development.
Mining Equipment Procurement Is Changing
These considerations are also changing how mining companies evaluate processing equipment. Rather than focusing primarily on throughput, operators are increasingly examining energy consumption per tonne, equipment wear, maintenance requirements and downstream recovery when selecting mills and crushing technologies.
Equipment suppliers capable of improving several of these performance indicators at the same time can therefore gain an advantage in an increasingly competitive market. The underlying challenge is structural. Mining cannot depend on a continuous supply of increasingly high-grade deposits. Instead, producers will have to extract more metal from lower-grade and more difficult ores, making processing efficiency increasingly important. That puts comminution technology at the centre of efforts to manage deteriorating resource quality. What was once viewed largely as a sustainability opportunity is becoming a fundamental economic requirement for future mining projects.
