Hard rock mining
Stope and pillar is a
hard rock mining technique used to mine vast ore bodies by creating huge mined out underground "rooms" or stopes supported by surrounding pillars of standing rock. Coarse
ore is mucked out using
gravity to help move it down rock raises or shafts to waiting
trains of ore cars used to move it to the surface These trains can travel through long drifts or
tunnels ending in portals to the mills on the surface. Ore is also moved in skip buckets hauled up shafts and emptied into bins beneath surface headframe towers for
transport to the mill.
In some cases these stopes become exposed to the surface and become open pits.
Because of its high cost hard rock mining is now used primaly for valuable minerals such as gold and diamonds. The deepest hard rock mine in North America is a nickel mine in Sudbury, Ontario.