Minera Valle Central (MVC) produces copper concentrates from tailings from the world's largest underground copper mine, Codelco's El Teniente mine, a copper producer for the past 100 years with remaining ore reserves lasting many more decades. MVC is treating all the fresh tailings from El Teniente's present production and has the right to treat the higher grade tailings from a 200 million tonne abandoned tailings impoundment known as Colihues.