The Environmental Protection Agency on Friday said it plans to require mining companies to show they have the financial wherewithal to clean up their pollution so taxpayers aren’t stuck footing the bill. The proposal follows a 2016 agreement reached under court order for the government to enforce a long-ignored provision in the 1980 federal Superfund law. The requirement would apply to hardrock mining, which includes mines for precious metals, copper, iron, lead and other ores. It would cover mines and processing facilities in 38 states, requiring their owners to set aside sufficient money to pay for future clean ups. The...