MechChem Africa January-February 2024

Dual-purpose vent and hoist shaft for Platreef Murray & Roberts Cementation was chosen to design and execute a retrofit for Ventilation Shaft 3 at Ivanhoe Mines in SA’s Limpopo province, which will now simultaneously allow for upcast air and hoisting. ⎪ Heating, cooling, ventilation and air conditioning ⎪ I n a project innovation that will allow early hoisting of ore at Ivanhoe Mines’ Platreef project, Murray & Roberts Cementation is repurposing Shaft 3 – a ventilation

shaft – to serve a dual function. “This is a unique project in many respects, as the shaft will be hoisting ore at thate same time as allowing upcast air to reach surface,” explains Graham Chamberlain, New Business Director at Murray & Roberts Cementation. “We were able to bring our well experienced experts into the planning process to develop a safe and effective solution.” The project has followed the sinking of the vent shaft by Murray & Roberts Cementation, which had required very accurate drilling, us ing raiseboringraise boring equipment guided by directional drilling technology. The 5.1 m diameter shaft meets horizontal development at a depth of 950 m below surface. “During this process, Ivanhoe looked at bringing forward some of their its ore gen eration activities, and this required adding hoisting capacity,” he explains. “The timeline for their main shaft meant that it would not be able to contribute to this capacity, so a team was established to consider how to retrofit the vent shaft into an early hoisting shaft.” As an integral part of that multidisciplinary team, Murray & Roberts Cementation con ducted a feasibility study on the options, al lowing for the selection of the most suitable methodology. The company also carried out the necessary designs, including winders and headgear as well as hoisting and tip

Murray & Roberts Cementation is repurposing Shaft 3 at Ivanhoe Mines’ Platreef project to serve a dual function, updraft ventilation and hoisting.

ping arrangements. In September 2023, the project was awarded to Murray & Roberts Cementation to implement, and is scheduled to take about two years. “This project stands out in terms of innova tion, adaptability, teamwork, and design,” he Chamberlain says. “With our many decades in the sector, we were able to draw on hundreds of years of experience in mining – and leverage this in our design team.” Among the range of technical challenges is the need to work within the vent shaft while it is performing its function of channelling an upcast current of air to surface. Any blockage of the air current in the shaft would affect the

development operation of the mine, so this is critical to avoid. “There needs to be periods during which we can reduce the ventilation, but we will have to ensure that air flow is always adequate,” he says. Another vent shaft is planned to add ventilation capacity for the future. Chamberlain points out that it will be necessary to deal with slight deviations in the shaft because, while accurately drilled, vent shafts are not designed to the same toler ances as hoist shafts. An important aspect of the design was the steelwork required to accommodate those deviations. “The work will be conducted by a relatively small team of our highly skilled people,” he says. “This will include the installation of a compact headgear using refurbished winders from our strategic stockholding.” The infrastructure will employ technology that will allow man less operation to enhance safety, using automated processes for loading and measuring functions, for instance. The project will require specialised sub contractors on much of the equipment employed, but the more day-to-day consum ables are procured locally to support local businesses. “In the absence of a supplier, we then develop their capability through our procurement system and enterprise develop ment commitment,” he says. “In this way, we foster small businesses and help to nurture them until they are self-sustaining.” www.cementation.murrob.com

Murray & Roberts Cementation was chosen to design and execute a way to bring early ore-hoisting to Ivanhoe Mines’ Platreef project by retrofitting the existing ventilation shaft.

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