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Zambia ventilation shaft project finalised

Mining contracting and engineering services company Redpath Mining Africa has completed what it has dubbed the “milestone” Synclinorium Ventilation Shaft project for Zambia-based copper miner Mopani Copper Mines.

Redpath Mining Africa’s Zambian branch, Redpath Zambia, was initially awarded the project by Mopani Copper Mines in 2014 and completed it in June this year. The project – which took 49 months to complete and required 135 crew members at its peak – forms part of Mopani Copper Mines’ recapitalisation programme to extend the life span of its Kitwe-based Nkana copper and cobalt mine by 25 to 30 years.

“The project is certainly a milestone project for Redpath and one that it will refer back to for years to come for its remarkable safety statistics, challenging conditions and introduction of novel raiseboring equipment,” Redpath Synclinorium project contract manager Cape Marais tells Mining Weekly.

Redpath Zambia mine planner Errol Harcombe explains that the project entailed the provision of a new ventilation shaft for deepening work on the 2 370 Level (L) of the mine’s main Synclinorium shaft, which will enable the mine to further expand its mining production operations. The shaft includes a new access drive that serves as the 550-m-long connection between the vent shaft and the main shaft. The new ventilation shaft supplies fresh refrigerated air to working areas in the main shaft.

Harcombe states that the project required two separate legs of development. The first leg was from surface down to 2 370 L and the second leg was from 2 370 L to 3 960 L, with a further 514 m of development also required on 2370 L to reach the ventilation shaft position. Conventional raiseboring and blind sink methods were used throughout the project.

The four-year project was not without its challenges, with waste rock handling having been a major challenge for the Redpath team on site, he adds. Mining operations and the Redpath team had to use the same rail system for their rock-handling requirements, which Harcombe says created a “logistical nightmare”. Transporting equipment down the shaft system was also hampered by this shared transport system, with orebodies requiring preferential transport, he points out.

While these initial challenges slowed operations down, they were solved through proper communication with mine management, carefully planning transportation and using muck bays, Harcombe explains.

Redbore 100 Enters Africa

The Synclinorium Ventilation Shaft project also marked the entry of Redpath Mining’s Redbore 100 raise drill into Africa for the first time.

The Redbore 100 – that can raisebore up to 8 m in diameter and reach depths exceeding 1 000 m – was shipped from Australia in late 2014 and used to drill a 1 117-m-deep and 6.1-m-diameter shaft in two sections of 670 m and 447 m.

“Transporting the Redbore 100 from Australia to arrive on site on time was a mammoth task,” says Marais, elaborating that the 76 t raisebore machine took three months to complete its journey.

The drill had to be shipped from Australia to South Africa and was then transported to Zambia in 34 shipping containers. A further five shipping containers holding additional spare parts for the drill were shipped from Redpath’s North Bay offices, in Canada, to Zambia.

“The Redbore 100 is the most powerful, largest-capacity proven raise drilling system ever manufactured,” says Marais.

Strong on Safety

Marais and Harcombe agree that the most remarkable feature of the Synclinorium Ventilation Shaft project was its positive safety record throughout the project duration.

Harcombe enthuses that “Redpath worked 1 500 lost-time-injury-free shifts, with only three minor medical incidents occurring during the entire course of the project”.

Marais attributes the positive achievements to Redpath employees abiding strictly to the company’s fatal risk elimination protocols, together with adherence to the client’s Mopani Way Safety Programme – an initiative aimed at making its operations safe and sustainable through several modern safety interventions.

“Throughout the project, morale and spirit was high and we all believed and trusted in one other,” concludes Marais.

Source: Mining Weekly

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