The remaining structure of Boiler House 4, Unit 7, at the former Hazelwood Power Station was successfully felled on the 15th of December 2020 using explosive demolition methods.
The structure and dust suppression measures behaved as modelled, ensuring the safety of all site personnel as well as the local community.
The controlled collapse took place at 2pm on Tuesday the 15th December 2020 as scheduled.
Immediate inspection by thermal imaging drones showed no hot spots, although the site will continue to be monitored for the next 24 hours.
Extensive fire suppression systems were put in place in the lead up to the works as a precaution against any fire issues and worked well.
Dust, noise and asbestos monitoring results will be available within the next 48 hours and will be publicly available on this website.
Demolition of the two remaining dredgers in the mine area will take place in 2021 as will the remaining three Boiler Houses (3, 2 and 1).
When will the Boiler Houses be demolished?
Following the successful controlled collapse of the eight Hazelwood Chimneys in May 2020, the way is clear for the demolition of the Boiler Houses that were part of the former Hazelwood Power Station. There are four Boiler Houses, each housing two units.
The remaining Boiler Houses, 3, 2 and 1, are planned for demolition in 2021. The Boiler Houses will be demolished one event at a time.
While the initial demolition of Boiler House 4 resulted in a partial completion, the results of on-site monitoring at the event provided confidence around the processes in place. Workers and members of the public remained safe and without injury and there was no threat or risk to the local community or the environment.
The results of monitoring for noise, dust and asbestos indicated that the demolition complied with all applicable regulatory standards. Noise data confirms no exceedances of the 140dB(L) OHS Noise standard at the Hazelwood Project boundary and local communities. Furthermore, all asbestos monitoring confirmed no positive detections of asbestos fibres anywhere on site.
- With reference to the EPA AirWatch Criteria, the monitoring results confirmed that the air quality was of a GOOD standard with reference to PM2.5 and PM10 at monitored boundary locations post the Stage 4 Boiler House demolition.
- Measured noise levels at the town boundary of Morwell and Churchill were 130dB(L) and 128 dB(L) respectively, both below the recommended OHS Noise standard of 140 dB(L).
- With respect to Asbestos monitoring program, all monitoring results were below the laboratory detection limit of 0.01 fibres/mL of air in general accordance with the OHS Regulations 2017. S.R. No. 22/2017 and Membrane Filter Method for Estimating Airborne Asbestos Fibres [NOHSC:3003(2005)].
The monitoring reports are available on the Boiler House Demolition – Monitoring report page.
How will the Boiler Houses be demolished?
Because of the size and design of the boilers, the safest methodology for demolition is by controlled explosive collapse. This methodology was decided after undertaking engineering and risk evaluations subject to regulatory oversight.
Each of the Boiler Houses is 65 metres high, includes some 20,000 tonne of material and has been constructed using a suspended boiler design. A controlled explosive collapse, similar to the successful chimney controlled collapse earlier this year, means the structures will be safely brought to ground and the material then removed.
Exclusion zones and traffic management
To ensure the safety of the workforce and broader community, a 700 metre exclusion zone will be set up around each stage when demolition takes place.
On the morning of each demolition event, Delta will establish some localised road closures. This includes closure of Brodribb Road between Nadenbousch’s Road and Cemetery Avenue.
Traffic on the Princes Freeway will be slowed to 60 kilometres per hour and traffic controls will be in place to stop vehicles from parking on the side of the carriageway. Traffic will also be slowed to 80 kilometres an hour on the Strzelecki Highway. This is in accordance with the approved traffic management plan.
Other local roads are likely to affected and people should expect some minor delays.
Notice will be provided to local residents and the community prior to each demolition event.
What about asbestos?
Works to identify and remove hazardous materials including asbestos so far as reasonably practicable have been conducted in preparation for the blast felling event.
As with any industrial building constructed when Hazelwood was built, asbestos material was used in various ways. However, following an extensive controlled removal program over the past 16 months, all accessible asbestos within the boiler structures has been removed in accordance with a Division 6 Audit and Asbestos Management Plan.
Through the safety management process developed by Delta and ENGIE Hazelwood, with the oversight of regulators including WorkSafe, it has been identified that there is a minimal amount of residual asbestos remaining, which is fully encased within the steel structure itself.
The explosive charge design has been developed to minimise and mitigate any disturbance of the encased asbestos. As a further mitigation, the Blast Management Plan also makes provision for water suppression through the fell sequence, as successfully demonstrated in the controlled chimney collapse.
As each Boiler House is demolished, any asbestos-contaminated materials will be removed from the fell zone and transported on internal roads to the EPA-licensed onsite asbestos cell for safe disposal.
Air monitors will be set up at the site boundary locations and surrounding the fell zone, similar to the set up for the controlled chimney fell event, consistent with the requirements of Government approvals.
What about noise?
As Unit 8 of Boiler House 4 has been demolished, the amount of explosives required to demolish Unit 7 is expected to be less than used in the first activity in November. However, regardless of this and while controls have been implemented to reduce any external noise emissions as far as possible,local residents are likely to hear a loud noise at the time of the demolition, for a few seconds. This is unavoidable, given the size of the structure, and the nature and placement of the explosive charges necessary to safely effect a controlled collapse.
Weather patterns are expected to play a part and modelling is continuing to identify favourable meteorological conditions that will minimise noise impacts to the extent possible.
Extensive noise, vibration, asbestos and dust monitoring will be implemented throughout the site and in close proximity to neighbouring townships.
What about dust?
The safety of workers and the surrounding communities is the primary concern so the demolition will be carried out when weather conditions are favourable so as to reduce the noise emissions and dispersion of dust as far as possible.
Further, Delta will install dust mitigation measures around the blast site using a combination of pre-wetting down, and boosted pressure pipe with sprays reaching about 30 metres high around the base of each Boiler House.
As the demolition event will only be carried out in favourable weather conditions, it is likely that the date for the demolition of the boilers will only be able to be announced close to demolition.
Consequently, this date could change at any time due to weather with further updates to be provided to regulators and the community.
Do regulatory and other external organisations have a part to play?
Oversight of the planning and safe performance of the works is provided by WorkSafe Victoria and the Environment Protection Authority Victoria (EPA), and also the Independent Building Certifier.
Planning meetings with emergency services stakeholders including Victoria Police, Ambulance, FRV and Regional Roads Victoria have taken place and will continue until the demolition is complete.
Direct stakeholder information is provided to regulatory bodies such as WorkSafe and the EPA.
Where can I find out more?
Information about the demolition works and advice on the dates for demolition is provided via our email database, local media, the ENGIE Hazelwood website and direct mail to site neighbours. To join the email database, email email@example.com