Chinese scientists have proposed developing “underground agriculture” in abandoned coal mine tunnels as part of a push to create a green, circular economy for the country’s massive mining industry. A team of researchers from Shanxi, a major coal-producing province in central China, described the idea late last month in the journal China Mining Magazine. An estimated 15,000 abandoned mines in China are expected to close by 2030. Insulated from surface weather and natural disasters, these...