JOHANNESBURG (miningweekly.com) – Marking an important milestone in the construction of the $323-million Synclinorium shaft, at the Nkana mine, in Kitwe, Zambia, project owner Mopani Copper Mines has completed the installation of a 26.5 t permanent multirope winder, replacing a temporary 12 t sinking winder.

The shaft-sinking project was aimed at extending the life of the mine by a further 30 years – beyond the expected depletion dates of the existing Mindola North, South Ore Body (SOB) and Central shaft reserves of 2015, 2017 and 2018 respectively.

The new shaft would provide Mopani with access to some 115-million tons of ore at a grade of 1.9% copper and 0.09% cobalt.

Mopani Copper Mines CEO Danny Callow said the installation marked an important step towards completion of shaft construction.

“This was a mammoth task that has been executed diligently, professionally, on schedule and within budget. We are currently cold commissioning the winder and are quite happy with what we have seen so far, though full functioning of the winder is dependent on the completion of the main shaft,” he commented.

Callow added that the company was carrying out civil and other construction works at the loading station, located 1 234 m below ground, while mining development from the SOB to the Synclinorium shaft was in progress.

“With regard to our horizontal development underground, so far, we have developed the incline to the new crusher, the conveyor drive to the Synclinorium shaft and the decline to the shaft bottom.

“In terms of shaft sinking, we have less than 10 m before reaching the bottom of the shaft. We will then start equipping the shaft from the bottom-up before the end of 2014 and this will take another year to complete,” he outlined.

Preparations for the installation of a 64-m-high permanent headgear for the Synclinorium shaft were, meanwhile, well advanced and the company said it would soon receive the headgear structure from the manufacturers.

Preparatory works for the ventilation shaft’s raiseboring were ongoing, with the RedBore100 machine – one of the largest raisebore machines in the world and the largest ever to be operated in Zambia – being assembled for start of piloting and the raiseboring of the first leg.

The ventilation shaft had, meanwhile, been pre-sunk to a depth of 50 m below surface.

“The 6.1 m ventilation shaft will lie adjacent to the main shaft, be raisebored to a depth of 1 167 m and will serve as a lifeline for the main shaft. It will supply fresh refrigerated air to working areas underground,” Callow said.