Modern Mining September 2021

SHAFT SINKING, RAISEBORING AND UNDERGROUND DEVELOPMENT

With a team comprising some of the most experienced profession- als in shaft sinking, United Mining Services (UMS) is gearing up for the pre-sinking of two shafts for the Karowe Underground Mine Expansion Project (UGP) in Botswana. UMS gears up for shaft sinking at

F ollowing the completion of the feasibility study for the Karowe UGP, UMS was appointed by Lucara Botswana Pty Ltd and JDS Energy & Mining Inc. in October 2019 to engineer and design the shaft sinking of the production shaft (8.5 metres in diameter), and the ventilation shaft (6 metre diameter), both reaching a depth of approximately 750 metres below surface. Lucara Diamond Corp.’s 100% owned Karowe mine is one of the world’s leading producers of large, high quality, Type IIA dia- monds. Fully commissioned in 2012, Karowe (which means ‘precious stone’ in the local language) is an open pit mine with operations until 2026. The UGP will extend Karowe’s mine life to at least 2040. At the end of 2020, Karowe’s total Probable Mineral Reserve is estimated at 53,9 Mt containing 7,4-million carats including stockpiles. According to Lucara, the Karowe mine remains one of the best producing mines of high quality +10,8-carat diamonds, hav- ing yielded five of the 10 largest diamonds in recorded history and is the only mine to have recovered three diamonds greater than 1 000 carats. As recently as July 2021, Lucara announced the recovery a 62,7-carat fancy pink diamond from Karowe – the largest fancy pink gem to be recovered in Botswana, and one of the world’s largest rough pink dia- monds on record. Track record Dr Pieter Louw, group executive project ser- vices at UMS and UMS’s project manager, says the company’s wealth of knowledge and expertise in shaft sinking played a key role in securing the contract, and that the company is bringing in the heavyweights in the industry for the project. Louw himself has a long history in under- ground mining and shaft sinking, having worked for major players in the mining and engineering sectors. He was involved in the De Beers Venetia Underground Project fea- sibility study as well as a number of other feasibility projects for mines that are now in development or have already started production. Louw explains that the two shafts at Karowe will be blind sunk using conventional drill and blast techniques. The production and ventilation shafts will both have equip- ment installed to pre-sink to a shaft depth of 100 m if required to accommodate the main

Drill rig in the Karowe ventilation shaft.

22  MODERN MINING  September 2021