A new study in Environmental Research Letters uses satellite observations of nitrogen dioxide to estimate nitrogen oxide emissions at 14 of the world’s largest open-pit copper mines. The study found that emissions increase with increasing copper production and moved material volumes.

Business and Human Rights Centre invited Freeport McMoRan, BHP, South32 and Grupo Mexico to respond to allegations of high nitrogen oxide emissions. Freeport McMoRan and South32 responded. BHP and Grupo Mexico did not respond.