By Ari Rabinovitch

TZEELIM VALLEY, Israel (Reuters) – The disposable paper face masks offer little protection from the clouds of dust that fill the cliffside cave where Israeli archaeologists are wrapping up the largest excavation in the Judean desert of the past half-century.

Clipped into safety harnesses, volunteers stand at the cave opening, 250 meters (820 feet) above a dry river bed that leads to the lowest spot on earth, the Dead Sea.

They sift through an endless supply of dirt-filled buckets, and the dust they throw in the air reaches the far corners of the cave where a dozen workers crawling on hands and knees can’t help but cough.

The three-week excavation was the first part of a national campaign to recover as many artefacts as possible, particularly scrolls, left behind by Jewish rebels who hid in the desert some 2,000 years ago, before they are snatched up by antiquity robbers.

“These looters that operate in the area are experts at finding scrolls. We go after them, look for what they are looking for and try to catch them,” said Guy Fitoussi, head of the Israel Antiquities Authority robbery prevention unit in southern Israel. “This is the game. Like cat and mouse.”

The Dead Sea Scrolls, a collection of ancient texts written on papyrus and parchment, have already been rescued by scholars. They are among the earliest texts written in the Hebrew language and are on display in the Israel Museum in Jerusalem as a national treasure.

Now Israel wants to uncover whatever may remain in the desert hideouts before it is destroyed or ends up on the black market.

For a Wider Image photo essay on the excavation click: http://reut.rs/25zc4ZK

PISTOL-PACKING ARCHAEOLOGIST

According to Israeli law, all relics found on land or at sea belong to the state. Fitoussi, a pistol-packing archaeologist with authority to arrest looters, and his team catch about 100 of them each year. Most are fined; some are sent to jail.

In 2014, they arrested six people who were plundering this particular cavern, known as the Cave of Skulls, where seven skulls had been found from Jews of the Bar Kokhba rebellion against Rome in the 2nd century.

That raid, Fitoussi said, helped spur the multi-year government-backed excavation program and focused their initial efforts at this site, about a two-hour drive southeast from Jerusalem.

To access the cave, diggers don climbing gear and descend 20 minutes from their campsite along a steep path that hugs the rocky cliff. Inside, the grotto expands 160 square meters (1,720 square feet), including a number of cramped tunnels that extend deep into the mountain.

The limestone walls of the dry desert cave are perfect for preservation, said Uri Davidovich, an archaeologist from Tel Aviv University who was one of the dig’s directors.

One 19-year-old volunteer, working flat on her belly in a dark crawl space, dirt mixed with sweat covering her face and digging with her fingers, unearthed a thin, 25 centimeter (10 inch)-long rope that most likely was used by the Bar Kokhba rebels. A rope this length was a rare discovery, Davidovich said.

They haven’t found any scrolls yet, he said, but the artefacts found in this cave, and countless others nearby, will provide historians rare insight into how people lived 2,000 to 8,000 years ago.

(Editing by Jeffrey Heller/Jeremy Gaunt)