The Trump administration is escalating an effort to revive the flagging U.S. coal industry with a planned move next week to replace restrictive Obama-era climate policies with new rules designed to help coal-burning plants run harder and stay open longer.

The proposed new rules, which the Environmental Protection Agency plans is expected to release within days, would be the latest in a series of reversals of policies the Obama administration adopted to slow climate change. It would replace the agency’s so-called Clean Power...