The excavator operator is understood to have escaped without injury but was shaken after his machine toppled backwards into a central reservation drainage trench on the Costain project just north of junction 21A.
Thomas Plant had the short radius excavator on hire, which was being used by Manchester drainage contractor SGC Civil Engineering for drainage works in the central reservation area.
Felicity Clayton, National Highways’ regional sponsor, said: “Thankfully, no injuries were sustained by the driver or others as a result of the incident and the motorway network was unaffected.
“The machine was safely recovered on Friday afternoon using a rolling roadblock on both carriageways to ensure customer safety.
“The area was made safe and all drainage and earthworks activities stood down while a review of the safe system of work was undertaken – most of this work resumed on Monday.
“We and lead constructor Costain are now conducting a thorough review to understand exactly what happened and what measures need to be taken to minimise the risk of future incidents.”