The Environmental Protection Agency has delayed hundreds of mountaintop coal-mining projects for a new review of their environmental impact. Mountaintop removal has been widely criticized for endangering waters and streams in the Appalachian Valley. The review effectively overrides last month’s federal appeals court ruling that backed the Army Corps of Engineers’ authority to oversee mountaintop removals. Environmentalists had previously won court judgments affirming that the Army Corps violated the Clean Water Act. In a related action, the EPA also announced it will block two projects that had won Army Corps approval. The EPA says the mountaintop removals would have endangered streams in West Virginia and Kentucky with thousands of feet of mining waste.