Hazelwood Dredger 9 Fell Success
The final dredger demolition works carried out today (Thursday 6 May 2021) at the Hazelwood Rehabilitation Project proved another success, with the demolition of Dredger 9 described as ‘textbook.’ The Dredger was demolished by controlled explosive collapse on schedule at 11am, safely bringing to ground the piece of large mining equipment to enable processing and recycling.
The event followed months of demolition planning by the demolition contractor Delta Group, the ENGIE Hazelwood team and international subject matter experts. The dredger fell as planned onto a sand and clay dampening pad, which was set up to reduce any potential vibration impact. All of the blast cutting charges were fully expended with no misfires and, with a cool and misty day, no issues are expected with hot spots. Monitoring of the site will continue for 24 hours as a safety precaution.
Dredger 9, built in 1964, is the last of the dredgers demolished at Hazelwood. Dredgers 11 and 10 were also demolished by controlled explosive collapse in 2020, with a further two dredgers, 24 and 25, mechanically dismantled. An ENGIE spokesperson acknowledged that the final dredger demolition signals the end of an era.
Many people have been associated with the former Hazelwood Power Station and Mine and the bucket wheel excavators, which were symbolic of the industry. To this end the demolition today was not a cause for celebration but rather another step towards creating a landform available for future uses. Inspectors from Earth Resources Regulation (ERR) and Fire Rescue Victoria (FRV) personnel were on site as observers.
The photos show the moment of detonation and the the result, Dredger 9 safely on the ground.
Hazelwood dredger fell success
The second of the dredger demolition works carried out on Thursday 29 October at the Hazelwood Rehabilitation Project proved another success.
Dredger 10 came down a little after 10am with all key objectives of the demolition realised. The main outcome, a safe and successful fell, was achieved with Dredger 10 on the ground.
The dredger fell as planned onto a sand and clay dampening pad, which was set up to reduce any potential vibration impact.
All of the blast cutting charges were fully expended with no misfires. A thermal imaging sweep conducted by Fire Rescue Victoria (FRV) drone after the controlled collapse showed no hot spots. The immediate geotechnical inspections also showed no issues.
Inspectors from Earth Resources Regulation (ERR) and FRV personnel were on site as observers.
Monitoring will continue to ensure the area remains in a safe condition.
The focus of ENGIE and the demolition contractor Delta Group now switches to Dredger 9, which is scheduled for demolition in the next few weeks.
All dredgers once demolished will be processed and the material recycled.
Watch the demolition video here or below.
Successful first demolition of Large Mining Equipment
The first of the dredger demolition works were carried out on the 15th of October at the Hazelwood Rehabilitation Project proved a success.
Dredger 11 came down a little after 10am with the key objectives of the demolition realised. The main outcome, a safe and successful fell, was achieved with Dredger 11 on the ground.
Watch the demolition video here or below.
All of the blast cutting charges were fully expended with no misfires. A thermal imaging sweep conducted by drone after the controlled collapse showed no issues with hot spots. The immediate geotechnical surveys also showed no issues and batter stability throughout the mine was not compromised.
Post-blast monitoring will continue for a further 24 hours to ensure the overall area has not been impacted for batter stability.
The focus now switches to Dredgers 9 and 10, which will be demolished by the same process TODAY (Dredger 10) and in the following weeks (Dredger 9).
A review process for Dredger 11 has taken place in preparations for todays event. All dredgers once demolished will be processed and the material recycled.
How many dredgers are being demolished?
There were eight Large Mining Equipment (LME) machines in the Hazelwood Mine area to be demolished, including five bucket wheel dredgers.
Five pieces of LME – Dredger 24, Dredger 25, Mobile Slew Conveyor S94, Mobile Slew Conveyor S96 and the TS2 Travelling Stacker – have been demolished by conventional mechanical means.
The remaining three dredgers, 11, 9, and 10 have been be blast felled using an engineered controlled collapse due to the height of their superstructures. These three Dredgers are situated in the north-western corner of the mine void and are not visible from outside the mining licence area.
How will they be demolished?
Due to the height of their superstructures, Dredgers 9, 10 and 11 required explosive demolition. They ranged between 21 to 40 metres high, from 70 to 85 metres long and the heaviest had a service weight of 1,790 tonnes.
Specialised cutting charge explosives were be placed on each machine to cut through steelwork at strategic positions and ensure they collapsed safely. A compliant safety exclusion zone will apply for each demolition task.
The controlled felling methodology was selected by ENGIE Hazelwood’s demolition contractor Delta for health and safety reasons, following a detailed options analysis and risk assessment process in consultation with regulatory agencies (WorkSafe, EPA and ERR). The size and design of the four dredgers is such that attempts to demolish by conventional means are potentially dangerous – the explosive cutting charges will enable the weighty, suspended components of the dredgers to be brought to ground in a single event for safe dismantling and removal.
The dredger components will be progressively cut up and removed over a number of months, and the material recycled.
Are there any air quality considerations?
The decommissioned dredgers, as prepared for demolition, contain no asbestos. Any components suspected of containing asbestos were tested, and all asbestos containing material has been removed in preparation for demolition.
The blasts took place in a defined area at the western end of the mine, one of the furthest points from the Morwell township. The works are not expected to have any material impacts on surrounding air quality, however continuous air quality monitoring will occur.
Will demolition be noisy or cause vibrations?
Because of the location of each of the dredgers, significant noise or vibration issues are not expected to arise. The explosions may be audible within surrounding areas, but not at a level that will cause any concern.
As each dredger has been decommissioned it has been relocated to prepared demolition pads. Another damping pad has been installed at each dredger following geotechnical assessments to further reduce any impacts to the batters. No adverse affects are expected, however continual geotechnical monitoring will occur throughout the demolition process.
When will it take place?
The works began in mid October 2020 and the final collapse was safely achieved in May 2021. Once demolished, all material has been processed and removed from site over a number of months.
The demolition and clean up process requires manual and mechanical separation. All demolition work is to be undertaken by Delta Group in accordance with the ENGIE Hazelwood’s approved policies and procedures within the mine licence requirements.
What about any road closures?
No road closures are expected but we are working with Victoria Police and Regional Roads Victoria to ensure all issues are considered.
We will provide advice on the demolition process through a dedicated website www.hazelwoodrehabilitation.com.au as well as via our email database, local media, and direct mail to site neighbours. To join the email database, email firstname.lastname@example.org
ENGIE Hazelwood will seek to hold information sessions, subject to and guided by Government directions relating to COVID-19.
Sizes of the Dredgers requiring blast demolition:
Dredger 9 – 35m high x 85m long x 24m wide. Service weight 1565 Tonnes
Dredger 10 – 40m high x 82m long x 23m wide. Service weight 1790 Tonnes
Dredger 11 – 30m high x 85m long x 31m wide. Service weight 1675 Tonnes
Dredger 25 – 21m high x 70m long x 23m wide. Service weight 1010 Tonnes