Overhand and underhand are terms used to describe the advance direction in underground mining. For an overhand advance, mining is proceeding in an upward direction; for an underhand advance, mining proceeds downward. These terms are most commonly used to describe stoping methods.

In cut-and-fill stoping, an overhand advance involves mining a horizontal slice of an orebody, then filling the space with a back fill material (mine waste, spoils). The backfill will serve as a new working platform for the operations and the process is continued upwards.

Alternatively, an underhand advance involves mining a horizontal slice of an orebody, then proceeding downward to the next slice. In this case, as mining advances a large open stope may be formed.

Figure: Overhand advance in cut-and-fill stoping (left) and underhand advance in open stoping (right). The ore slices are numbered in order of their extraction.