This record-breaking feat brings the value of successful turnkey jobs completed by Vanguard – in sub-Saharan Africa – to over R41 million, for the year to date.
The project involved the erection of a 49m long, 133t cold box for the new oxygen plant at the Mufulira smelter. The cold box column is a single complete unit, and therefore needed to be hoisted up as a single structure.
To achieve the required height, the system’s gantry towers were built up to 62m – the same height as a typical Johannesburg skyscraper. Vanguard designed and manufactured a hook specifically for this lift. The cold box was lifted, rotated 90 degrees, and then lowered into its final position.
Vanguard said: “Although strand-jacking is a known method of hoisting in other countries – particularly in Europe – it is new to Africa, and Vanguard’s system is the first of its kind in South Africa.”
Bryan Hodgkinson, managing director of Vanguard, added: “Our system is made up of four immensely powerful strand jack units – imported from Hydrospex in Holland – boasting a carrying capacity of 75t each. However, it has a huge potential capacity, as it can be expanded to include a total of 25 jacks.”
Hodgkinson said that the main benefit of using strand jacks was cost-effectiveness. “The only other viable option was to employ cumbersome, high capacity cranes, which would have cost more than three times as much, in this case,” he explained.
The gantries are claimed to be more portable than cranes “as they can be dismantled and transported to remote areas with ease – most of the equipment being carried in standard containers”.
The strand jack units are also said to be relatively compact and easy to move.
The lifting operation was controlled and synchronised through a laptop at ground level, via PLC. Vanguard boasted: “The accuracy of control achieved is remarkably within a deviation of just 1mm. In addition, the software employed has been specially developed and successfully proven in heavy lifting operations throughout the world.”
Other turnkey jobs by Vanguard over the last few months included projects in Beirut, Mali (North Africa), Namibia, Zambia, Botswana, Mozambique, Swaziland, and South Africa.
