Big Hole

Big Hole, a large, defunct, open-pit diamond mine located in present-day Kimberley, South Africa. Considered to be the largest hand-excavated hole in the world and one of the deepest, it has a circumference of about 1 mile (1.6 km) and a diameter of roughly 1,500 feet (460 meters). The Big Hole (which was initially known as the Kimberley Mine) played an important role in South Africa’s diamond boom of the late 1860s and ’70s; see South Africa: Diamonds, gold, and imperialist intervention (1870–1902).

Excavation of the Big Hole began in 1871 at the hill called Colesberg Kopje (located on the farm of Nicolaas and Diederick de Beers, who were brothers) after two large diamonds were discovered in South Africa’s Kimberley region during the late 1860s. News of the earlier discoveries attracted thousands of miners and prospectors to the region. Many descended on Colesberg Kopje, where in 1871 a team of prospectors, led by South African Fleetwood Rawstorne, had identified pipelike structures containing diamond-bearing kimberlite in the hill (see also kimberlite eruption). The discovery attracted thousands to the site, and the de Beers brothers sold the farm later that year. (The farm and the mine later fell into the hands of English entrepreneur Cecil Rhodes, who formed the South African diamond producing and distributing company De Beers in 1880.) The town of New Rush (which was later renamed Kimberley) sprang up to serve the mine, swelling to 50,000 people by 1872. The mine operated between 1871 and 1914, with some 30,000 miners working it at its peak.

As the mine grew, water seeped into the pit, and rock from the walls cascaded down the slopes, which created a need to shift the excavation from open-pit mining to underground mining, which relied on the construction of tunnels and sunken shafts. A combination of added expenses and labor problems forced the mine’s closure in 1914. By this time, the open-pit portion of the mine had reached a depth of 787 feet (240 meters), and the underground portion extended to 3,599 feet (1,097 meters) below the surface.

The Big Hole yielded about 14.5 million carats (that is, 6,000 pounds [2,722 kg] of diamonds) over its 43-year operational history. In the present day, the hole measures about 705 feet (215 meters) deep; however, the bottom is not visible because groundwater seeps fill the hole with roughly 135 feet (about 41 meters) of water.

Some five decades after the mine’s closure, De Beers consolidated the artifacts, memorabilia, and a collection of structures that served the mine into the Kimberley Mine Museum, an open-air site featuring relics and restored equipment and buildings from Kimberley’s mining era. The Kimberley Mine Museum formally opened in 1971.