The use of microalgal sourced biodiesel to help underground mines transition to battery electric vehicles

The widespread use of fossil fuel sourced diesel underground has various associated health and environmental hazards, and additional energy demand and costs associated with necessary ventilation. One way to reduce these impacts is by utilizing a biodiesel-blend, which generates lower levels of harmful emissions from underground equipment and can be produced regionally, reducing the impact of transportation. Furthermore, this would help allow use of existing machinery during transition towards more widespread electrification underground. Therefore, the concept of an integrated supply and use chain within the mining industry is examined based on biodiesel from acidophilic photosynthetic microalgae cultivated using CO2 in smelter off-gas. A life cycle assessment (LCA) was conducted to compare the environmental impacts of production, transportation, and end-use of fossil fuel sourced diesel to biodiesel-blended fuel across four underground metal ore mine sites (Canada, Poland, Zambia, and Australia). The outcomes from assessing four key environmental impact potentials (global warming, eutrophication, acidification and human toxicity) demonstrate the advantages of using biodiesel-blends. The integration of biodiesel resulted in changes from ¡22.5 to þ22.8% (global warming), from ¡18.9 to þ26.3% (acidification), from ¡6.1 to þ27.3% (eutrophication), and from ¡21.0 to ¡3.6% (human toxicity). The results showed reduction across all potentials for two mines and reduction in human toxicity potential for all sites.