MILAN (AP) — The operation to transport an injured spelunker out of a cave in northern Italy cleared a difficult passage Tuesday to leave the uncharted part of the Bueno Fonteno cave and enter the main tunnel, rescue officials said.

The operation, now in its fourth day, was expected to continue at least another day and a half. Rescuers rested every 90 minutes to check on the condition of Ottavia Piana, 32, who suffered multiple fractures when she fell 5 meters (13 feet) while exploring an uncharted part of the cave on Saturday.

It was her second time in 17 months to be rescued from the cave near Lago d’Iseo northeast of Bergamo, rescue officials confirmed.

Video showed her wrapped in blankets and strapped to a stretcher being passed through narrow passageways by a team of helmeted rescuers. Doctors said she had fractures to her face, ribs and knee.

More than 120 technicians have been assisting in the round-the-clock operation since members of her team alerted authorities Saturday evening that she was trapped.