The Big Hole, Open Mine, Kimberley Mine or Tim Kuilmine is an open-pit and underground mine in Kimberley, South Africa, and claimed to be the largest hole excavated by hand, although this claim is disputed.

The first diamonds here were found on Colesberg Kopje by members of the "Red Cap Party" from Colesberg on the farm Vooruitzigt belonging to the De Beers brothers, in 1871.

It was excavated to a depth of 240 metres (790 ft), but then partially infilled with debris reducing its depth to about 215 metres (705 ft). Since then it has accumulated about 40 metres (130 ft) of water, leaving 175 metres (574 ft) of the hole visible.

There is currently an effort in progress to register the Big Hole as a World Heritage Site. The site offers tours, wedding venues and other hostings for events.