Block caving is essentially the underground version of open-pit mining. It’s the only underground mining method that can reach similar production rates to surface mining operations, up to over 100,000 tonnes per day. The method involves undermining an ore body, then allowing it to collapse under its own weight. The ore body is drilled and blasted and the collapsed ore is removed through a haulage access, and as more material is removed the ore body caves in. This mining method is useful because it allows for huge volumes of material to be mined at relatively low costs, which makes lower grade deposits economical to turn into mines or new pits. Many large-scale open-pit operations have plans to progress into block caving operations over time, including Oyu Tolgoi and Grasberg. This mining method is typically used in situations where the ore body is both large and steeply dipping, and because of the depth below surface is not suitable for surface mining methods - New Pacific Metals Corp.