BELLE, W.Va. -- DuPont will soon begin dismantling a gravity-powered hillside pipeline that once provided water for the production of ammonia next to the company's plant in Belle.Plant manager Jim O'Connor said the pipeline was cutting-edge technology when it opened in 1930, slashing energy costs for ammonia production by about 70 percent. It was shut down in the 1950s.O'Connor told the Charleston Daily Mail the pipeline consisted of two systems with four pipes, each more than 1,000 feet long, that sent water down the 700-foot-high hillside.Distance and gravity combined to more than quadruple the water pressure from 100 pounds per square inch to about 450 pounds per square inch. Momentum then forced it back uphill.It was "quite the engineering accomplishment," O'Connor said, even by today's standards.But the system hasn't been used for several decades, so DuPont has decided to tear it down. DuPont now ships in ammonia to the plant from facilities on the Gulf Coast.A safety fence will be installed to prevent rocks or debris from going into U.S. 60, O'Connor said.DuPont crews also will remove an old rail line that hauled workers and material from the plant to the top of the hill.One lane of U.S. 60 will be closed for three weeks starting April 15 so the safety fence can be erected. The state Division of Highways will shut it down again for three weeks in September when the project is finished and the fence is removed.The pipeline does not hold any residual ammonia, and O'Connor said everything about it is "perfectly safe."Dismantling it should take until the end of August, and metal from the rail line and 30-inch pipes will then be recycled.O'Connor said he's been unable to determine how much it cost to build the pipeline, but tearing it down will cost about $1.2 million.