The accident happened at Longhoughton Quarry, Longhoughton Road, Lesbury in Alnwick.
Northumbria police said the driver of an excavator went into a hole which filled with water.
The man was brought out and paramedics treated him at the scene.
He was taken to Wansbeck General Hospital by RAF Boulmer where he was pronounced dead later that afternoon.
Police and Health and Safety Executive are making enquiries into the incident.
The 58 year old Northumberland man who died has not yet been named by the authorities.