4 August 1914
On 4 August 1914, work was stopped at the Kimberley mine after 43 years of operation. The mine became uneconomical to operate as it reached a depth of 1 083 m without yielding production. This event ended a pioneering episode in South African engineering history. The history of the Kimberly mine began with the discovery of diamond in 1867. The discovery of diamonds in South Africa attracted many Europeans who were lured by the prospect of making their fortune at the diamond mines. Famous politicians and businessmen like Barney Barnato and Cecil John Rhodes made their fortune at the Kimberly mines. Africans from the rural areas adjacent to Kimberley were also attracted to the mines. The most significant of these were the Barolong and the Batlhaping, Tswana groups that, historically, have been inhabitants of the area. The date of 14 August 1914 is given by one of the sources for the same event.
References

Archaelogy South Africa, 1996, ‘The Digging Stick’ from Archaeology South Africa, Vol 13, No. 1 [online] Available at www.archaeologysa.co.za [Accessed: 04 July 2011]|Susan (n.d), ‘The Big Hole Kimberly’ from Hub Pages [online] Available at www.hubpages.com [Accessed: 04 July 2011]|Wallis, F. (2000). Nuusdagboek: feite en fratse oor 1000 jaar, Kaapstad: Human & Rousseau.