Specialist shaft sinking and mining contractor Murray & Roberts Cementation has successfully completed a reeve block system project at Ivanplats’ Platreef project, in Limpopo.

Ivanplats needed an innovative solution to remove the reaming head in the shaft and avoid costly standing time at the end of a raiseboring exercise for Shaft 2.

“An acceleration of the build plan at Shaft 2 had seen construction under way on the shaft’s headgear last year before the completion of raiseboring,” explains Murray & Roberts Cementation senior project manager Fred Durand.

He points out that, when a reaming head reaches the surface at the end of a raiseboring process, the company normally uses a mobile crane from surface to help it dismantle the machine and load it onto trucks for removal from site.

“With the acceleration of the mine’s plan for Shaft 2 readiness, however, the construction of the headgear had been brought forward – so it was no longer feasible to position a crane in that area to remove the raisebore machine.

“The kibble winder was not installed yet, so we had to engineer our way out of this situation to reduce raisebore standing time costs,” Durand states.  

The solution started with a visit from one of Murray & Roberts Cementation’s rigging specialists from the company’s Bentley Park training and technical facility near Carletonville. His concept was to make use of a reeve block – or pulley block – system and winch which could be secured with limited steelwork at the bank elevation.

“We prepared a proposal which described how reeve blocks could be secured to the sinking sheave wheel floor steelwork by means of slings and beam clamps. We would then use an 8 t electrical winch, secured to the bank, to operate the reeve block system,” Durand says.

After the Murray & Roberts Cementation team was satisfied that the methodology would work, they conducted a rigorous risk assessment and prepared the necessary mitigation measures.

The plan was then ready for the client’s consideration – leading to a green light to proceed.

Personnel and equipment were soon mobilised and the necessary medicals and inductions completed in preparation for the reamer coming to surface at the end of its 950 m journey from underground.

“Our solution worked perfectly, allowing us to strip the raisebore machine and hoist it to the bank area – to be placed onto the support bridge and moved out of the shaft headgear. A mobile crane then lifted the machine onto the laydown area, ready for removal,” Durand notes.

He concludes that Murray & Roberts Cementation’s uncompromising approach to safe working practices ensured that this engineering solution was applied safely and efficiently within the tight timeframe.

The company’s core safety values recently earned it the landmark achievement of eight-million fatality-free shifts.