Emergency crews were called to the Scout Moor quarry in Edenfield, near Ramsbottom, after reports that a crane had crashed around noon.
Lindsey Easton, 49, of Sowerby Bridge, Halifax was pronounced dead at the scene.
Police said the mobile crane is thought to have left the road at the quarry, collided with an earth bank and toppled over before coming to a halt.
Baldwins Crane Hire confirmed the victim was one of the company’s drivers but chose not to comment at this stage.
Officers said the crane was being driven on the private road through the quarry site at the time of the accident.
It is understood that the 500t crane was used over the weekend to replace a faulty turbine and was being driven from the job.
Police said the accident was being treated as an ‘unexplained incident’.
Two HSE inspectors visited the scene and are investigating the incident with Lancashire police.
