Modern Mining April 2023

COPPER

Milestone reached on Palabora shaft-sinking The ventilation shaft being sunk by Murray & Roberts Cementation at Palabora Copper Mine has reached a depth of 800 m – a significant milestone as this represents two thirds of the final depth of 1 200 m. The mine is owned and operated by Palabora Mining Company (PMC).

T he shaft, which has a diameter of 8.5 m (includ ing the concrete lining), forms an integral part of PMC’s Lift II project, a new mining block which will eventually replace Lift I and extend the mine’s life by more than 15 years. Founded in 1956, PMC runs underground and surface opera tions and the extension of the life of the mine will increase shareholder value and sustain the jobs and livelihoods of the surrounding communities. The scope of the contract encompasses only shaft sinking as no station construction or lateral development is required. Blind sinking is being undertaken to a depth of 1 190 m before a 10 m drop raise completes the shaft. Originally an open-pit mine, Palabora – which is currently South Africa’s only primary copper producer of any significance – moved, with the com missioning of Lift 1, to being an underground block cave operation in the early 2000s. The new block, Lift II, is being constructed 430 m below Lift I, and is already in the very early stages of production although Lift 1 remains the main source of ore. Murray & Roberts Cementation’s contract to sink the ventilation shaft was awarded in February 2019 and, according to Fred Durand, senior project

manager, should be fully complete by the end of the first quarter of 2024. “Current progress on the con tract is good and we are regularly achieving 40 or more lined metres of advance every month,” he says. He adds that the excellent relationship between PMC and Murray & Roberts Cementation has been a highlight of the contract. “We work as partners and share a common vision for the project. They obvi ously engage strongly with us but they also respect our expertise when it comes to shaft sinking and we appreciate this.” The blind sinking method is being used to sink the shaft. “Studies undertaken prior to the project going out on tender looked at alternatives, such as raise-boring and slype-and-line, but ruled them out as ground conditions are not favourable for these methods,” explains Jas Malherbe, Murray & Roberts Cementation’s on-site project manager. “Blind sink ing was the only real option available.” Malherbe, who was with PMC prior to joining Murray & Roberts Cementation to manage the vent shaft contract, says the project has been challeng ing because of the ground conditions. “The nature of the rock mass is such that blasting tends to produce large rocks, which are difficult and time-consuming

20  MODERN MINING  April 2023