One of our customers from China detected an amazing coin treasure using his OKM 3D ground scanner eXp 5000. He located hundreds of so-called cash coins buried in 3 meters depth.
Those coins seem to be 200 to 300 years old and date back to the Qing Dynasty which reigned the Chinese Empire from 1644 until 1911. Cash coins used to be a payment instrument of the lower class. That is why those coins were never made of silver and gold, mainly of copper or bronze.