Underground mining contractor Murray & Roberts Cementation and its client Palabora Mining Company (PMC) completed the last blast in the development of the miner’s new ventilation shaft at PMC’s Lift II copper project, in Limpopo, which took its depth to a final 1 200 m below surface, in January.

The 8.5-m-diameter upcast ventilation shaft – which holed through to an already developed return airway at depth – is vital to PMC’s Lift II project, which is intended to develop access to ore resources sufficient to extend the life of this copper mine beyond 2040.

The ventilation shaft will replace the two existing ventilation shafts from the Lift I project, which are likely to be affected as they are in the Lift I zone of influence.

Murray & Roberts Cementation senior project manager Fred Durand says a key achievement is the project’s fatality-free record, earned over more than a million hours worked.

“The achievement of a million fatality-free hours, reached in November 2023, is more than just a number,” he says, adding that it reflects the “deep-rooted safety culture that has permeated every aspect of the project”.

The innovative shaft sinking methods, used for the first time in South Africa, were also carefully focused on achieving zero harm, notes Durand.

For PMC’s Lift II project, Murray & Roberts Cementation employed its Canadian shaft sinking methodology, adapted to what became called “the PMC way”. This method included an innovative solution to poor ground conditions, where the sidewall of the shaft was closed up within 48 hours by means of the shaft being lined with concrete after every 3 m of advancement in the sinking process.

“Among the improvements that this facilitated was the removal of the hazardous work by rock drill operators at the shaft bottom, who would traditionally have to install temporary support,” explains Durand.

“We also decided not to conduct concurrent work in the shaft, so there was no risk of danger to anyone below when work was carried out from the stage.”

He emphasises the close collaboration between Murray & Roberts Cementation and PMC to ensure the success and safety of the shaft sinking project.

The project was significant insofar as to there being many lessons learned which can be taken forward into future projects, states Durand, thereby further improving the safety record of the shaft sinking practice.

“We are already looking ahead to two more important shaft sinking projects within the South African mining sector, where there is potential for certain of these learnings to be applied,” he points out.

Work Safe

A veteran of over 15 shaft sinking projects across Africa during his career, Durand admits finding aspects of “the PMC way” initially quite unusual when he joined the project in 2022.

“Ultimately, though, we all want to deliver safe projects, so there are many brilliant ideas that we have proven on this project.

“These strategies have been combined with the company’s leading mining and engineering expertise, and make us very excited about the future of shaft sinking and contract mining,” he says.

To facilitate streamlined scheduling on the project, the work was carried out through continuous operations with two 12-hour shifts taking place.

Durand notes that this is an improvement on the usual eight-hour shift system, which requires three shift changes, and takes up valuable project time; whereas the two-shift system requires only a morning and evening changeover of personnel.

In the final stages of the project, Murray & Roberts Cementation will strip out its services from the shaft, lift out the stage and dismantle the headgear.

Final demobilisation of the company’s infrastructure will be carried out during the first quarter of 2024, says Durand.