Morwell Land Movement
1. Princes Freeway at Morwell open to motorists
On Wednesday 21 September, Deputy Premier and Minister for Police and Emergency Services Peter Ryan and Member for Morwell Russell Northe opened the Princes Freeway at Morwell, following the completion of an extensive remedial works program.
The phased opening will gradually allow traffic back onto the closed section of the freeway and is in time for the September school holidays.
The re-opening gives motorists extra time to familarise themselves with the new traffic conditions before the holidays begin.
"These repair efforts are a culmination of months of work by the Coalition Government, Victoria Police and the Latrobe City Council in ensuring the freeway is in a safe condition for all road users," Mr Ryan said.
"All agencies and technical experts have worked tirelessly to develop the best possible solution to enable the freeway to re-open, with constant monitoring and testing of land movement in addition to the drilling of 50 horizontal drains at the base of the Hazelwood mine area."
2. What Happened?
Following a heavy rainfall event on February 5, 2011 small but significant movement occurred in the northern wall of the Hazelwood Mine. As a result of the movement, cracks appeared on the surface of the Princes Freeway and the adjoining area. A section of the Princes Freeway running between the mine and the township of Morwell was temporarily closed.
The Department of Primary Industries (DPI) arranged for the Chair of the Technical Review Board and other geotechnical experts to review the incident and provide advice on remedial works required to ensure that the area was stabilised to ensure public safety and ultimately for the freeway to be re-opened.
The Technical Review Board was established in 2009 to provide advice to the Minister and Department on mine stability issues, with respect to reducing risks within the mining industry.
View the 19th August 2011 Public Information Session Presentation
3. Who Led The Response To The Event?
The Government formed an Emergency Management Team led by VicPol and including DPI, VicRoads, Latrobe City Council and International Power. DPI continues to work closely with all relevant agencies to ensure public safety and to keep the community and all relevant stakeholders informed of all recovery actions.
A stakeholder group was established to provide a co-ordinated response to the event led by the VicPol Incident Controller. This group has carried out a detailed analysis of the situation and put emergency measures in place.
An inter-departmental committee was also established to coordinate a whole-of-government approach to address the complex issues arising from the movement of the north wall of the Hazelwood mine.
4. What Is Dpi’s Role?
DPI is the regulator for mining and extractive industries in Victoria, and is overseeing mitigation works undertaken by International Power (who own and operate the Hazelwood Mine), LaTrobe City Council and VicRoads in an effort to reduce the risk of further land movement.
DPI led the geotechnical and hydrological aspects of investigations into the stability of the Princes Freeway at Morwell and the adjacent Hazelwood mine wall and drew on the advice of a range of technical experts on the best way to ensure the long-term stability of the area surrounding the road.
DPI continues to provide expert technical advice to other agencies and oversee remedial work carried out by International Power.
5. What Recovery Action Is Dpi Managing?
DPI is working closely with International Power Hazelwood (IPH), the local council and VicRoads. A number of recovery activities are well underway:
- A Quantitative Risk Assessment has been developed to inform decision making on what conditions are necessary for the road to be reopened.
- A review of remedial works and resultant risks was completed as the basis for re-opening the bypass.
- The Government has committed $2m to assist IPH begin work to remediate the main drain which passes through the area of instability.
- IPH and DPI have been working to reach agreement on the exact design and specifications of drain remediation.
- An extensive system of water level and ground movement observation points have been set up both inside and outside the mine to monitor ground conditions.
- A land movement survey of the residential area adjacent to the site has been completed.
- The drilling of 50 horizontal drain holes by IPH to release water from the area of instability has been completed.
- Real-time monitoring to immediately identify any further movement has been installed both at the freeway and within the mine.
- Two independent reviews have been completed - a review of public safety issues and a peer review of all technical advice received.
- A feasibility study has been completed by IPH into further earthworks and other remedial works to limit longer term movement at the site.
- A scenario workshop to establish and manage protocols for any emergency situation has taken place.
- An aerial survey of the affected area has been undertaken.
- IPH has commenced remedial works on the Northern Batters surface drainage system, which will better manage surface water within the batters .
6. What Happens Next?
Mr O’Brien said VicRoads has lined the 300 metre central median along the currently closed section of the freeway; and other strengthening works including injecting grout into underground holes has taken place.
The monitoring of ground movement around the freeway area will continue, even after the repoening of the road to traffic,
Around the clock monitoring of the freeway will detect any change which may result in the need for a temporary closure in the future
Work will continue to finalise the longer-term solution for the use and design of the Morwell Main drain, to prevent as much as possible more water entering the area of instability.
