Now you see it; now you don't. At exactly 10am on Sunday, 24 July a siren was heard, the small crowd in Gerard Sekoto Street collectively held their breath, and a minute later a single, very loud bang was heard.

In a second the North Boiler House become a cloud of dirty white smoke.

The smoke rose idly into the air and was blown eastwards towards the CBD. Another Johannesburg building had bitten the dust.

After an abortive implosion attempt last weekend, in which half the building fell a metre but remained upright, this weekend Wreckers Demolishers made sure of the job. Now construction of the new home of Anglogold Ashanti can begin in earnest.

The first clods of soil were turned by a large front-end loader on 1 July on what is to become known as Turbine Square, in Newtown.

AngloGold Ashanti
The historic site, home to the city's coal-fired power station dating back to 1927, is to get a new identity that will blend with the old buildings. Anglogold Ashanti, at present in offices in the diamond-shaped 11 Diagonal Street, will move into its new offices in March 2007.

The site originally consisted of three buildings - the Turbine Hall, the South Boiler House and the now imploded North Boiler House.

However, says associate architect Warren Stanley of TPC Architects, construction was delayed until the building was imploded and the rubble removed. Three levels of underground parking have to be excavated on the northern side of the site, with four storeys of offices above them.

Because the building was older than 60 years, the required heritage permission had to be obtained before the demolition could go ahead.

At the northern end of the site, there will be a long building, consisting of a concrete frame, face brick and modular glass panels, very much in keeping with the old concrete structure of the main Turbine Hall. The hall is a large, glass-fronted, voluminous concrete building, used in recent years as a concert venue.

Stanley stresses that Anglogold Ashanti is concerned to maintain the heritage of the site, and deeply respectful of the history of the old buildings.

He says TPC Architects tried various combinations in an effort to retain the North Boiler House, but it would have been impossible to build 450 underground parking bays on the site without demolishing it.

"We would have loved to have kept the boiler house; it's a lovely building."

The new building will not be taller than Turbine Hall and will have a pitched roof, like the other buildings on the site. The hall will remain as it is for the moment; it is rumoured that it could be converted into the new venue for the Johannesburg Art Gallery.

Tiber Bonvec Construction
However, the buildings on the site belong to Tiber Bonvec Construction and director Francesco Riviera says the hall probably will not be able to accommodate the large space the gallery requires.
"Forty percent of the hall is still used by the city, as it contains turbines."

Riviera says that at the end of the 1980s the site and its buildings were put out to tender, with a view to creating a shopping centre. The scheme fell on its face and Tiber bought the site.

The new building will join with the South Boiler House with a mezzanine platform deck, to be used for functions. On the eastern edge of the site a garden will be created, to be used as a public gathering space.

TPC Architects is responsible for the new JSE Securities Exchange building in Sandton, the Grace Hotel and Johannesburg International Airport domestic terminal.

Stanley says excavations of the site started at the beginning of the month and a concrete slab was found some metres below the surface. Work has stopped while an archaeologist is called in to ascertain that nothing of value will be destroyed.

The Turbine Hall complex was closed in 1961, according to the TPC heritage report, but the South Boiler House was re-opened in 1967, housing two gas turbines powered by jet engines.

An earlier power station was built in President Street in 1906. This became the Electric Workshop and is now the Sci-Bono Discovery Centre. A second station was built in 1910 and converted to a substation in 1938. This was later demolished and that site now contains the SAB Museum.