The greenhouse gas impact of IPCC and ore-sorting technologies

Abstract

In-pit crushing and conveying (IPCC) and ore sorting are two developing technologies that, in addition to providing likely economic benefits, also have the potential to reduce the greenhouse gas footprint of mining and mineral processing operations. A life cycle assessment study was carried out to provide estimates of the likely greenhouse gas reductions from the implementation of IPCC and ore sorting technologies in a hypothetical copper mining and mineral processing operation. Based on the assumed configurations and operating characteristics of the two systems, the results indicated that IPCC had 4% less (i.e. 3kgCO2e/t ore or 0.16kgCO2e/t ore.km) greenhouse gas emissions than truck haulage for the base case configuration. Using electricity generated from natural gas rather than black coal increased the greenhouse gas advantage of IPCC over truck haulage from 4% to about 22% (i.e. 14kgCO2e/t ore or 0.74kgCO2e/t ore.km). However, transport distance and annual plant feedrate affect the magnitude of these greenhouse gas reductions.A potential reduction of about 13kgCO2e/t ore in greenhouse gas emissions was estimated from the use of ore sorting technology based on black coal generated electricity, while with natural gas-based electricity the reduction was only 8kgCO2e/t ore. The mass rejection rate of the ore sorting device was the main operational variable affecting the magnitude of this reduction, although it is also affected by the specific comminution and concentration energy requirements of the ore. While the results indicate that ore sorting offers nearly four times the potential reduction in greenhouse gas emissions than IPCC did at the same annual plant feedrate for the base case configuration with black coal-based electricity, the situation was reversed with natural gas-based electricity, with IPCC offering nearly double the potential reduction in greenhouse gas emissions than ore sorting. However, it should be appreciated that due to the limited amount of publicly available data on these technologies at the present time, the results of this study should be viewed as first estimates only.