"The Slag Hills or Slag Mounds were a pair of hills made up of slag and rubble just outside the Black Gate of Mordor."@en . "These were several artificial mounds of slag, refuse and rubble piled up outside the Morannon, upon which the Army of Elessar made its last stand during the War of the Ring."@en . . "The Slag Hills or Slag Mounds were a pair of hills made up of slag and rubble just outside the Black Gate of Mordor."@en . . "These were several artificial mounds of slag, refuse and rubble piled up outside the Morannon, upon which the Army of Elessar made its last stand during the War of the Ring."@en . "Slag Hills"@en . . . .