On April 26, 2019 students from the Corlia Roberts Diamond Education College visited Petra Diamond Mine for an exiting educational tour of their underground mine in Cullinan South Africa, a small town 30 km to the east of Pretoria.
“Cullinan” a small town along the diamond route that is heavily reliant on tourism and the mine that dominates the skyline. The town was named after diamond magnate Sir Thomas Cullinan
Ever since the first South African diamond was found by a schoolboy in 1867 along the Orange River bank near Kimberley, these gemstones have held a strange allure.
Taking a tour of the South African diamond mine was one way of exploring the mystique around them and illustrating to the students the mining process.
The students were taught that not only are diamonds the most fascinating and beautiful of gems, they are also the hardest substance on Earth, making them doubly valuable with a hardness of 10 on the Mohs scale.
The Mohs scale is used to measure the relative hardness of a mineral by its resistance to scratching. From softest to hardest, the ten minerals of the Mohs scale are talc (measuring 1 on the scale), gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and diamond (measuring 10 on the scale).
Petra Diamonds Cullinan Diamond Mine comprises a carrot-shaped volcanic pipe – the oldest in the world. In 1905, the Cullinan Diamond, a giant gem of 3 106 carats, was unearthed 9m below the surface. The massive diamond was presented to King Edward VII of Great Britain on his 66th birthday.
The Underground tour is the only tour of its kind worldwide, approximately 800 Meters deep beneath the Earth students were able to experience first hand the underground operations of the Cullinan Diamond Mine.
“A truly memorable experience to see the kimberlite, diamond bearing rock” said our student group
The tour took around four hours. Before departure, everyone got their full protective overall at the on-site changing rooms. There was a training session before the tour on how to use the self-rescue pack, a mandatory wearable along with a battery pack to power your cap-mounted light.
From the change room, the tour moved on to the mine lamp room, before heading down to mine cage and down the mine shaft.
The final stop was the diamond cutting and jewelry shop on situated on site.
Petra Diamonds operates four producing diamond mines in South Africa. These are all underground kimberlite pipe mines, Cullinan, Finsch, Koffiefontein and Kimberley Underground.
Petra Diamonds also had three smaller Fissure Mines, namely Helam, Sedibeng and Star, but Sedibeng and Star have recently closed and Helam is being run down for closure.
Petra Diamonds has a record of turning De Beers’ unprofitable South African mines into financial successes.
According to Nicky Oppenheimer, the son of Harry Oppenheimer and former Chairman of De Beers, the reason for this was “De Beers was operating the mines with too large a cost structure, something Petra doesn’t have.” The underground kimberlite mines were purchased from De Beers Consolidated Mines