The world's tallest steel headgear at Gold Fields South Deep Twinshaft Vent Shaft won the Mining and Industrial Category. With 5000 torqued bolts - all fitted, innumerable welds all passing the most stringent non-destructive testing and minimal distortion in spite of all the welding, the overall fabrication quality of this project contributed significantly to this award.

The completed structure stands 87m tall and has a mass of approximately 1900 tons. It is the tallest steel headgear in the world and is expected to extend the life of the mine by up to 60 years.

The judges said that this structure was 'especially impressive for two main reasons: steel was the only viable construction medium that could satisfy the complex, constraint-dominated client requirement and, secondly, exceptional technical and project management expertise was required to successfully execute the work in accordance with these requirements'.

They added that this particular project is a great story for structural steel as the material played a pivotal role in helping the mine to make its decision.

As the project team explains: 'Extending the height of the existing concrete headgear was not possible since its foundations were not designed to accommodate the additional mass. Since the existing headgear was still operational, destroying it and rebuilding the headgear was also not an option. The only viable option was to construct a new headgear from steel and erect it over the top of the existing headgear'.

The main framework consists of hollow section structural boxes welded up from plates typically 45mm thick. The plates are welded together with complete joint penetration welds. Each 10-metre section needs two kilometres of pre-heated, submerged arc welding runs.

The judges said that this project is a flagship for the use of steel for several reasons including that it's the highest in the world. "A most challenging requirement was fully satisfied by the excellent use of steel and the related design, fabrication and erection activities. Also, importantly, the site safety record was fantastic. Overall the outcome is a credit to all involved," they concluded.