During mining, a binder, such as cement, is added to a portion of the tailings (leftover rock and it is placed back underground into the mined areas as a paste, through a process called ‘paste back fill’. The paste back fill will fill the mined out area and solidify, allowing miners to mine a new cavity adjacent to it through the “cut and fill” mining method. Each stope (mined cavity) is filled until eventually the entire mineral deposit is replaced with cemented paste backfill tailings. Approximately half of the tailings from the mill facility can go back underground in this manner. The environmentally friendly paste back fill method fills all mined cavities eliminating the possibility of large underground water reservoirs and problems with ground subsidence. There will never be more than a few percent of the underground workings open minimizing temporary water displacement.