Neath Port Talbot Council has said that the lane closures on Cwmavon Road in Port Talbot following a landslide on 30 December could remain in place for several months.
In a statement, the council praised engineering staff for reopening the road just nine days after the ground movement but added that permanent repairs could take some time.
The council said that its engineers have held initial meetings with a specialist design contractor to discuss mitigation measures and the design of a permanent solution to allow the road to fully re-open to two-way traffic.
A statement from the council said: “The landslip happened after a period of very heavy rain and staff worked quickly to remove almost 300t of debris allowing the road to re-open with one lane closed by January 8 this year.
“Now, further testing and analysis of the rock along the very steep bank where the landslip happened is required before a final design solution can be implemented, materials procured and manufactured and a civil engineering construction contract let to carry out the physical construction work.
“This will take several months and the temporary lane closure and traffic lights will need to remain in operation for safety reasons.
“The council will be funding all the necessary works in order to fully re-open the highway affected by the landslip above Cwmavon Road which happened on unregistered land not owned by the council.”