Specialist rope access company Skyriders has completed two major projects involving the extension of a chimney stack at Syama gold mine, in Mali, and the building of a recreational bungee jumping facility at the Orlando Cooling Towers, in Soweto, south-west of Johannesburg.
Skyriders has an established team of level one to level three rope access technicians that are trained in various specialist applications, including non- destructive testing.
The company’s involvement at Syama gold mine saw its rope access technicians extending the existing 75-m chimney stack to 100 m. The extension was required as a sulphide concentrate process was being adapted, which would result in harsher emissions.
Skyriders technical director Brownlee Barry says that, by using rope access techniques, the company’s technicians determined that there had been no significant loss in the wall thickness of the chimney’s shell, giving the green light for the extension to go ahead.
Multidisciplinary consulting practice DPA Specialist Consulting Engineers and consulting engineering firm Walker Ahier & Holtzhausen were the design team for the extension.
The extension was made up of 12 cans, each 2 m high, 2 m in diameter and 940 kg in weight. The cans were fabricated with flanges, both top and bottom, and were bolted together to form the extension.
“The largest crane available on site had a capacity of 200 t and a reach of 85 m.
“This meant that beyond the installation of the first can, we were on our own.
“As a result, a purpose-made gin pole was designed by consulting engineering firm KP Energy and then fabricated in South Africa.
“The gin pole was used to hoist the cans by means of a 5-t winch, which was positioned on an adjacent building,” says Barry.
In addition to the extension of the chimney stack and owing to the value associated with rope access, the company’s technicians completed various other ser- vices, including welding, corrosion protection and installation of electrical instrumentation, lightning protection and fall- arrest systems.
The Orlando cooling towers, in the Ekhaya district of Soweto, are the location of Skyriders’ newest venture involving bungee jumping, abseiling and swinging.
The power station, which is adjacent to the towers, was closed in 1998 after being in operation for 56 years.
It was in 2000 that Skyriders MD Bob Woods became involved when he was called in to install the suspension equipment for the painting of the towers.
Barry says that, as there was no means of accessing the top of the towers, bolts had to be installed forming a ‘bolt ladder’ to enable the installation of the access system.
After spending significant time on site and realising the potential of the towers, Woods began the long process of turning the towers into an adventure centre aimed at promoting Soweto as a key tourist destination.
Woods says that the site is the fruition of many years of nego- tiation with the local municipality, engineers and bridge builders.
Detailed plans for the adventure centre were approved late in 2007 and a lease agreement was signed in November 2007 for the use of the towers as a vertical adventure facility.
Construction began in January 2008 with the lift up the side of the western tower being com- pleted in mid-March and the stairs and platform being installed by the end of July.
Meanwhile, the bridge spanning the two towers was installed last month. The bridge, which was still in sections, was hoisted into position 100 m above the ground by using purpose-made gantries and winches. It was assembled 100 m above the ground on the rim of the towers. The bridge will serve as access between the two towers and as a bungee jumping facility.