Within the sixties, the first industrial metal detectors were produced, and they were widely useful for mineral prospecting together with other industrial needs.??? ????? ??? ?????? ?????? ??? ??? ???????? ????? ????? ??? ???? ????? ???????? ???? ??????? ?? ?? ???? ??? ??? ??????? ?????????? ??? ??? ?????????? ?????? ?????? ???? ????? ????? ??????