Last updated 20 March 2023
Work to repair the significant landslip on Tyalgum Road is set to progress, with a $16 million contract awarded to local construction company SEE Civil Pty Ltd.
The contract was awarded following an extensive tendering process, supported by a Letter of Agreement from Transport for NSW, and will allow the contractor to progress design work from 30% to 100%.
A further $4 million will go towards additional costs on the project, such as land acquisition and site work, bringing the total cost of the Tyalgum Road landslip repair to $20 million.
SEE Civil is also the preferred contractor for the $2.3 million project to restore the two slips on Limpinwood Road – the main alternative access route to Tyalgum village. Transport for NSW is currently assessing the proposed works prior to Council awarding of the contract.
Design work for Tyalgum Road is expected to take until late May to complete, with work expected to start on site around the same time.
The contractor’s design work will include the provision of temporary access through the Tyalgum Road site, with the aim for this to be in place by the latter quarter of this year.
Limpinwood Road will remain open to one lane as per the current situation while reconstruction work takes place, which is also expected to start at the end of May.
Mayor of Tweed Shire Chris Cherry said it was great to finally see progress on restoration of the Tyalgum Road landslip.
“This is the biggest and most complex of the Tweed’s landslips caused by the devastating flood of February-March last year and today’s announcement represents a significant milestone in the Shire’s recovery,” Cr Cherry said.
The major landslip on Tyalgum Road is about 950 metres east of Van Den Broek Road. There is another slip about 1 km west of this major landslip.
The damage site is more than 100 metres in width, some 60 metres in length and appears to comprise of some 6-10 metres depth of material which has slipped.
One-way traffic arrangements at the secondary landslip site, about 1 km west of the main slip, will remain in place.
The process of rebuilding
The list below summarises the high level processes we need to follow to fix the landslips at Tyalgum Road. Given our current knowledge of the sites, it’s difficult to provide accurate dates for each part of the process. There may be opportunities to run some of those in parallel however, we won’t know until we start to confirm the preferred solution. The outline below will give you an idea of why the works will take at least 12 months.
- Geotechnical procurement (completed)
Fixing landslips is a complex engineering task. It is crucial that the foundation of the slip is properly stabilised to prevent a similar failure occurring in the future. Specialist geotechnical engineers are used by Council to investigate the best option suited to Tyalgum Road’s specific site conditions. Only then can the missing piece of road be constructed over this new foundation.
The geotechnical assessment is broken up into 2 stages:
- Stage 1 is a preliminary assessment to make recommendations about the short term safety of the site.
- Stage 2 involves boring holes to investigate the soil in and around the slip including scientific testing, this information is used to determine options to fix the slip.
- Design and construction tender (awarded)
We draft a design and construction document in preparation for the tender process. We then advertise the tender, evaluate all submissions then select the preferred tenderer based on the NSW legislation and our Procurement Policy which define specific processes and minimum timeframes. The tenderer then develops the design for approval by Council and Transport for NSW.
- Environmental assessment (ongoing)
All work Council undertakes, including the repairs required on Tyalgum Road, requires approval under the Environmental Planning and Assessment Act – in much the same way as residents need a Development Approval to carry out renovations on their homes. This is to ensure there is minimal environmental impact during the construction of the work and that the final construction won’t cause any additional impacts to residents or the environment.
- Consultation with the community (ongoing)
We will consult with residents and businesses who will be directly impacted by the works to ensure they are not adversely affected by our activities. If they are, we will put in place measures to minimise these impacts.
There are several properties through which we are likely to require access to carry out the work.
At high level, a typical construction process to fix significant damage such as those sustained along Tyalgum Road would involve site establishment, excavation of slip areas, foundation works, wall construction or stabilisation structural works as well as earthworks, drainage, road subbase, pavement, line marking and safety barrier works.