In block caving, a large section of rock is undercut, creating an artificial cavern that fills with its own rubble as it collapses. This broken ore falls into a pre-constructed series of funnels and access tunnels underneath the broken ore mass. These mineworks are sheltered from the collapsing ore inside bunker-like mass of rock, and miners extract it continuously from here. The collapse progresses upward through the ore body, eventually causing large areas of the surface to subside into sinkholes.
Block caving is used throughout the world. As future mines access deeper and lower-grade ores, this method is likely to be used more widely. Block caving is attractive because it permits very large volumes of ore to be extracted relatively cheaply, increasing production and making lower grade ores economical to mine. Although still more costly than surface mining due to the inherent difficulty of underground operations, block caving is the only underground mining technique that achieves production rates equivalent to surface mining. However, it is only suitable for ore bodies with large horizontal and vertical extents.