A STRETCH of the A1 has fully reopened to motorists after a mine shaft sink hole opened in the northbound carriageway near Gateshead.

Highways England completed urgent repair work to fill the void which measured about 140 cubic metres.

Engineers reopened the A1 between Coal House (Junction 67) and Lobley Hill (Junction 68) at around 6am this morning.

An old shallow mine shaft underneath the carriageway has been blamed for the road's collapse.

The sink hole was discovered near the Lobley Hill interchange at 10.45pm on Saturday, night while the road - which carries 90,000 vehicles a day - was closed for overnight roadworks by Highways England and its contractors.

A slight dip appeared in the road surface and workers cut around it to investigate only to find the large void beneath. 

The hole, identified as an old mining shaft, was around three metres deep and five metres wide and covers all lanes of the carriageway - one of the main routes north and to the Metrocentre.

Heavy congestion affected diversion routes through the Team Valley trading estate, the A19 and the A66.

The hole was filled with a specialist concrete mixture before it was fully resurfaced.

Contractors working for Highways England also drilled holes into the ground on Tuesday to pump more material underneath the repair to prevent a repeat collapse.

Extra measures were put in place to minimise disruption, which included introducing a contraflow on the southbound carriageway, lifting toll barriers for the Tyne Tunnel, and suspending roadworks on other key routes likely to be affected by diverted traffic.

Rob Beckitt, duty operations manager at Highways England said: “Safety is our top priority; we have to ensure the carriageway is totally safe before drivers use it.

“We and our contractors have been working hard with partners since the hole was discovered last night, and will continue to do so to make the carriageway safe as quickly as possible.

"In the meantime I urge all drivers in the area to check conditions before they set out and to leave plenty of extra time for their journeys. I would also like to thank drivers in advance for their patience as we carry out this complex task.”

Extra Highways England traffic officer patrols and recovery vehicles were on standby to quickly remove any contraflow breakdowns.

A diversion remained in place for local traffic through the Team Valley trading estate between junctions 67 and 68.    

Some planned closures for roadworks on the A19 were also suspended during the contraflow period.

The hole was not located in the current roadworks for the A1 Coal House to Metro Centre J67-71 scheme to widen the road to a three-lane dual carriageway, so other emergency roadworks were not delayed by the collapse.

The Northern Echo:

Diversion route