Search

The mining sector is currently confronted with an energy market and evolving regulatory landscape that exerts pressure on the industry to consistently enhance its strategies and decision-making in support of sustainable practices. Traditionally, the ore is transported using heavy-duty trucks powered by diesel engines which have been identified as a primary contributor to environmental degradation. An emerging and technologically advanced solution of considerable interest is the implementation of battery-electric trucks, which still generates some uncertainty about its actual impact on the environment. The primary hypothesis under investigation is that battery-electric vehicles have significantly lower environmental impacts than conventional combustion vehicles. Thorough research is needed to bridge this knowledge gap and robustly understand the environmental effects of these technologies in the mining context. This study uses Life Cycle Assessment to evaluate the potential environmental impacts of battery-electric trucks compared to diesel trucks in a theoretical underground mine. The study analyses the environmental impacts around three main stages: the raw material supply for the manufacture of the vehicles, the energy supply (electricity or diesel fuel), and other indirect impacts associated with the operation of both types of trucks. The characterization methodology used is the ReCiPe2016 Midpoint (Hierarchical) using open-access software OpenLCA v1.10.3 for the impact assessment. The functional unit selected is one ton of material transported over 1 km. Our results for the baseline Chilean scenario indicate that diesel trucks have a considerably greater environmental impact in two of the five categories studied: global warming potential and stratospheric ozone depletion. The energy supply is the 'hotspot' for the electric truck life cycle, while the diesel truck life cycle has the operation and the energy supply as the main environmental impact sources due to the upstream and direct emissions associated with diesel supply and combustion, respectively. However, when considering particulate matter formation and water consumption, electric trucks exhibit higher impacts due to the technologies employed for generating the electricity used to charge their batteries. Furthermore, the environmental profile of the electric truck improves considerably when renewable sources of electricity substantially substitute coal in the electricity mix, as projected in the Chilean policy context. The main novelty of this study is that it is the first initiative comparing a battery-electric truck with a diesel truck considering an approach to the underground operation reality for the mining sector. • Diesel truck has a greater global warming impact than electric truck. • The main impacts of electric trucks are due to raw materials and energy supply. • The energy supply stage causes the greatest impact on the life cycle of both trucks. • Renewable electricity projections boost Chilean mining's sustainability. [ABSTRACT FROM AUTHOR]

Life Cycle Assessment (LCA) is a widely-used methodology for estimating the potential environmental impacts of technological systems in nature. Relative maturity of this method has been achieved thanks to recent standardization efforts, although there are still several challenges, particularly in the minerals industry where LCA still needs to be strengthened and extended in use. An exhaustive review of recent LCA studies on mining and mineral processing operations was conducted to identify how these have dealt with various methodological challenges. A total of twenty-nine studies were found, most of which focusing on developed regions and in three commodities: coal (28%), aggregates (21%), and copper ores (14%). The source of data for background processes has been the Ecoinvent database in 45% of the studies analyzed, whereas the SimaPro software has been the preferred LCA tool in 66% of such studies. Although important advances have been made, significant issues remain. For instance, inconsistencies were found in the definition of the functional unit and system boundaries (temporal and technological). Further, the adoption of allocation criteria and the use of normalization and weighting in impact assessment have not been considered in most cases. While climate change was the main environmental hotspot (more than 90% of the studies addressed this impact category), the impacts associated with water use and waste management have been overlooked in most studies. Furthermore, mining and processing operations have been described as generic, averaged values or as simple functional relationships between system inputs and outputs using parameters without physical significance ("black box models") in several production chains, making it difficult to identify opportunities for environmental sustainability enhancement within the sector. The work then discusses the opportunity of improvement in LCA in the minerals industry through the incorporation of process simulation from a bottom-up perspective. Evidence from other industries and recent advances in the computational development of such tools for the mineral sector are reviewed, which suggests that there is an opportunity for reducing the epistemic uncertainty in future LCA studies of mining and processing operations through the combination of both approaches. Image 1 • Critical evaluation of recent peer-reviewed LCA studies in the minerals industry. • Methodological challenges of LCA within this sector are discussed. • Potential improvements in LCA from a bottom-up approach are examined. • Process simulation coupled with LCA can become a reality for the mining sector. [ABSTRACT FROM AUTHOR]