Posted by: Saving Water SA (Cape Town, South Africa) - partnered with Water Rhapsody conservation systems – 11 April 2010
Progress towards the demolition of the two Athlone cooling towers is proceeding smoothly, as the City works towards a demolition date around Sunday 30 May 2010.
A professional team, which includes an environmental scientist, was appointed on 10 March by means of a competitive process to oversee the technical, environmental and heritage aspects of the project and to prepare for a safe demolition.
The decision to demolish the two iconic towers follows structural damage to one of the cooling towers during the early hours of Sunday, 14 February 2010, when the stabilising rings around one of the towers became detached and fell to the ground. These rings were fitted as an additional safety and stability measure almost twenty years ago. Consulting structural engineers were immediately appointed to assess the damage and advise the City on what steps should be taken. Their recommendation was that the towers be demolished as soon as possible.
The City accepted the recommendation and has immediately proceeded to plan the demolition process.
Consulting engineers appointed to oversee the project did another detailed assessment of the towers following the initial assessment of 14 February. This report has been finalised and the second independent assessment endorses the first, that the demolition should proceed as soon as possible.
The time-lines for the demolition process are tentatively given as follows: The tender for the demolition of the towers will be advertised early in April and will close approximately three weeks later, whereafter the contractor will be appointed by the City. The date for the demolition of the two iconic towers will be determined by the progress made to safeguard staff and functioning infrastructure during the dangerous preparation of the towers for demolition.
It is anticipated that as many as three thousand holes need to be drilled into each tower to allow for the placing of controlled charges in the towers, ensuring that they collapse in a controlled manner under their own weight. Both towers will be imploded and collapse simultaneously. Between now and the date of demolition the towers are being carefully monitored for further collapse or damage.
The site is being monitored to identify possible problems with high winds before the demolition takes place. Cape Town wind records for the past five years are being studied and a wind monitoring instrument, controlled by the South African Weather Service has recently been erected on site.
“The Consulting Team is fully aware of all the environmental and risk implications that could result from the demolition and there is ample legislation in place to cover this aspect. The environmental and heritage aspects of the demolition process are critical issues that are being addressed before the demolition can take place and could possibly present a challenge to the anticipated time lines,” says Alderman Clive Justus, Mayoral Committee Member for Utility Services.
Whilst the potential for harmful emissions that could be released into the atmosphere has been raised, during their lifetime the towers were only used for the evaporation and cooling of steam from the coal fired power station. No pollutants or harmful emissions will be experienced or emitted during the demolition. The only likely pollutants would be cement dust from the collapse or implosion, and some dried algae from the walls.
In the meantime, various role players and affected parties are being consulted for their input in the demolition process, which includes a baseline environmental and heritage assessment.
The consultants are simultaneously preparing a detailed plan for the event, involving all Traffic Services and the City’s Disaster Risk Management Centre, as surrounding roads, including the N2 and Jan Smuts Drive, are likely to be closed for a short period during the actual demolition. The Airports Company of South Africa is being consulted to decide upon a provisional period of closure of the N2 that will cause minimal disruption to traffic heading to and from the airport Alderman said Clive Justus.