The builders of the Atlantic Coast Pipeline are pulling the plug on the project as companies continue to meet mounting environmental opposition to new fossil fuel conduits in the U.S. Duke Energy Corp. and Dominion Energy Inc. said Sunday that they were abandoning the proposed $8 billion pipeline—which aimed to carry natural gas 600 miles through West Virginia, Virginia and North Carolina and underneath the Appalachian Trail—citing continued regulatory delays and uncertainty, even after a favorable Supreme Court ruling last…