PART of the National Cycle Route at Brynmawr will close for three years while work to dual the Heads of the Valleys road between Gilwern and Brynmawr takes place.

The first 1,200 metre stretch of route 046, which starts at the Brynmawr roundabout, is closed up until its intersection with Bridleway 49/39 and 49/37 until January 2018.

The closure has been made to allow for a new ‘Gateway Bridge’ to be built over the new A465 road and a gas main diversion.

Cyclists and walkers can still enjoy the area using the old railway line that runs between Brynmawr and Blaenavon and starts at the same point. The diverted National Cycle Route 492 is slightly longer and will be clearly sign-posted.

Gwyn Smith, South Wales East area manager for Sustrans Cymru, said: “Unfortunately the nature of the works has meant it has proved impossible to keep the route open on its current alignment.”

“Although the diversion will be slightly longer, it will use part of a new section of route and be clearly signed and we will also be updating our online mapping to aid those planning their journey.”

“This is only a diversion and, when the works are completed, the route will be returned to its original alignment.”

Work to dual the 8.1km section of the scheme began in December and will take 180 weeks to complete. It is the fourth of six sections in a scheme to dual the road between Abergavenny and Hirwaun.

The scheme includes the construction of 16 major structures, over 11.4km of restraining walls as well as excavation of over 1.2million metres cubed of material.

The construction firm Costain Limited, which is carrying out the work, has said that the start of the project overlaps to some degree with the completion of section three between Brynmawr and Tredegar but that every effort will be made to minimise any disruption to those using the road.

The two projects meet some 200metres west of the Brynmawr roundabout with section three due for completion in June of this year.

Early work on the Gilwern to Brynmawr stretch will include site clearance and land surveys with a small level of traffic management and daytime lane closures.

The scheme includes a 50mph speed limit, improved junctions and viewpoints of the Gorge, extra laybys at Sale Yard and Clydach gorge and a safer cycling crossing at Brynmawr and a split-level carriageway.

It will link up with the Abergavenny to Gilwern stretch that was completed in 2008 and the Brynmawr to Tredegar stretch. When finished, it will provide a continuous dual carriageway between Abergavenny and Merthyr Tydfil.