Base Metal and Iron Ore Mining - IFCof iron. The documents on Aluminum and on. Coal Mining and Production also deal with min- ing activities. . burden (waste-to-ore) ratio for surface mining of.iron in waste from iron tailings,Tailings - WikipediaTailings, also called mine dumps, culm dumps, slimes, tails, refuse, leach residue or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are distinct from overburden, which is the waste rock or other . These tailings contain large amounts of pyrite (FeS2) and Iron(II) sulfide.