Block caving is an underground mass mining method used for the bulk extraction of large, low-grade porphyry deposits. Courtesy of WSP

The mass mining technique of block caving—where miners undercut an ore body, causing it to collapse and letting gravity do much of the work of fragmenting the ore—is not a new method. It is the chosen approach for the very largest of underground copper and gold mines, such as PT Freeport Indonesia’s Grasberg copper-gold mine in Indonesia, Codelco’s El Teniente copper-molybdenum mine in Chile and Rio Tinto’s Oyu Tolgoi copper mine in Mongolia.