Holistic prospective life cycle analysis of a proposed copper and nickel mine in Minnesota

Decarbonization technologies promise to mitigate climate change and reduce greenhouse gas emissions. However, these technologies contain critical minerals, such as nickel, lithium, and cobalt. Minerals mining can have substantial environmental and social impacts. Prospective LCA can be used to project these impacts and compare them among proposed mines, especially in nations like the U.S. that aim to increase domestic minerals production. We therefore conducted a cradle-to-grave LCA on a proposed copper-nickel mine in the United States. Flotation processing was the largest contributor to energy, water, and greenhouse gas burdens. Wastewater treatment and closure also have sizeable energy and water demands. We also estimate that it takes decades or centuries to restore the carbon stock loss from land clearing from reclamation efforts. This analysis highlights the importance of often-neglected elements of a mine’s life cycle in LCA such as land clearing, wastewater treatment, reclamation, and closure.