A major operation is under way to finish a section of the new M7 motorway after part of the road collapsed into a bog.
Road authorities last night confirmed that the final section of the Limerick to Nenagh bypass would be completed by the end of the year.
The €425m road — which was due to open last year — will link the Limerick southern ring road with the Nenagh bypass.
The construction of the 38km road from Annacotty to Nenagh, Tipperary, was contracted to Bothar Hibernian almost four years ago and was due for completion in May 2009.
Contractors have run into serious difficulties at Annaholty bog, home to an iron age causeway and and where the almost-completed road collapsed earlier this year.
A large timber causeway was excavated in Annaholty Bog during archaeological works in advance of the N7 Nenagh to Limerick High Quality Dual Carriageway. Annaholty Bog covers a large area traddling the Limerick-Tipperary border between Castleconnell village and the Silvermines Mountains and would have been a major obstacle to north-south travel.
The causeway was originally 65-70 metres long, connecting two dry islands in the bog and at 7 metres wide would have been capable of taking heavy two-way traffic. The method of construction was the same as that of the renowned trackway at Corlea, Co. Longford:
It is understood that thousands of steel-reinforced concrete piles were driven into the bog to support the sinking road.
But following the collapse of the road surface, a concrete and steel bridge is to be constructed over the entire area in the hope of establishing a stable base for the road.
The National Roads Authority (NRA) says the final section of the road will open by the end of the year.
"We are being reassured by the contractor that the project will be completed by the end of the year, but this is a design-built contract so any of the costs incurred due to difficulties with the Anaholty bog is borne by the contractor," an NRA spokesman said.
Limerick County Council said it was satisfied that the contractor was dealing with the difficulties as best it could. A spokesman for the council stated that the contract company must itself address any difficulties that arise during the construction of the motorway.
"Under the terms of the contract between Limerick council and Bothar Hibernian, any issues arising from the construction of the motorway are to be addressed by the contractor in question."