During her routine evening jog with her dog in the Jerusalem woods last week, Tamar Simone was startled to come across something not routine at all - the exposed remains of an ancient stone structure that seemed to be freshly dug up. Yet the usual signs along the lines of "Archaeological dig, don't touch" were missing.

Smelling a rat, the alert citizen notified the Israel Antiquities Authority, which was as puzzled as she. Not only had it been unaware of the existence of the site; the inspectors who rushed over agreed that somebody seemed to have been excavating methodically, and with care. But it hadn't been anybody on behalf of the IAA, nor had any archaeologist not affiliated with it applied for permission to dig there.

Keeping a close eye on the site paid off: lo and behold, shortly the inspectors noticed a Haredi boy of "bar mitzvah age" – around 13 – loitering by the site. Not just loitering: he was watching closely.

"Before we could even ask what he was doing there, the boy ran up and openly and proudly told us that he and his friends were archaeology buffs and had done this excavation," says Amit Re'em, the IAA archaeologist in charge of the Jerusalem district.

Blissfully unaware they had done anything wrong, in fact with enormous enthusiasm, the youngsters had meticulously excavated the wine press, which was located by the Jerusalem neighborhood of Neve Yaakov. They had done such a clean job that it was clear from the get-go that the dig hadn't been done by robbers, says Re'em.

The wine press itself is a large one carved into the soft chalky stone of the Jerusalem hills, measuring 5 meters by 5 meters. It consisted of a roughly square-shaped area where the grapes had been stomped, leading the wine through "pipes" carved into the rock, until a final pit where the young wine is collected.

Although the wine press clearly dates from the 6th or 7th century, says Re'em, it's impossible to say – at least at this stage – whether it dates from the late Byzantine era in Jerusalem, or the early Muslim one.

The find is just one of many attesting to burgeoning agricultural activity in the north Jerusalem area of the time, and elsewhere. A similar find was made in 2010 archaeologists announced finding an unusually shaped 1,400-year-old wine press that was exceptionally large and advanced for its time. Measuring 6.5 by 16.5 meters, this one was discovered in southern Israel, some 40 kilometers south of Jerusalem, to name one of many finds.

It bears saying that unauthorized digs are against the law in Israel, pure and simple. "On the one hand it's a crime," Re'em told Haaretz. "On the other hand I realized it was done in innocence, and I was touched to the core by the boy's story – which reminded me of my boyhood, at age 12 or 13. We suggested that the boy and their friends channel their energies to works for the community," he said.

The IAA does beg to point out however that unprofessional archaeological mucking about can lead to the loss of precious information and citizens uncovering some historic find should contact it.

As for teenagers with archaeological interests, they can indeed participate in digs – coordinated with the IAA, which suggests they get in touch through its website.