50 m-deep mine shaft discovered beneath Manchester road after giant sinkhole develops

Repair works are under way on a major road in east Manchester after a developing sinkhole revealed a mine shaft extending approximately 50 m beneath the carriageway.

The problem first became apparent when the road surface on Alan Turing Way began to sink, prompting the closure of part of the northbound carriageway. What initially appeared to be a localised depression was eventually traced to a much larger underground void associated with historic mining beneath the road.

Investigations continued for several months before the scale and nature of the problem were confirmed. The discovery of the deep shaft significantly changed the repair strategy, since restoring the road surface alone would not address the unsupported ground beneath it.

Manchester City Council has since placed more than 100 tonnes of concrete into the void as part of the stabilisation works. A reinforced concrete cap is now being constructed over the mine shaft to create a stable structural barrier beneath the carriageway.

Once the shaft itself has been secured, crews will still need to deal with the remaining voids beneath the road. These areas will be filled before the pavement structure is rebuilt and a new road surface is placed.

The sequence highlights the complexity that abandoned mine workings can introduce beneath modern urban infrastructure. A relatively small surface depression can sometimes indicate a much deeper loss of support underground, particularly where the location, geometry or condition of old shafts is uncertain.

In this case, the road had to remain closed while engineers established the extent of the void and determined how best to make the ground safe. Until the shaft was properly identified, permanent repairs could not proceed because the behaviour of the underlying ground remained uncertain.

The use of a concrete fill and structural cap provides a way to restore support while isolating the deeper shaft from the road above. The remaining backfilling and pavement reconstruction will then allow the carriageway to be reinstated once the ground is considered stable.

The route is expected to reopen in December, bringing to an end a lengthy closure caused by a subsurface feature that remained hidden beneath one of Manchester's busy roads until movement at the surface exposed the problem.