Thank you so much for the replies and answers.
Genuinely, i used the machine in several locations, for Caves, voids and catacombs it works very well almost 80-90% of the result was correct just if i chose the right type of the soil either if it is sandy, stony, granite, salty or any other, and it gives me accurate depth.(+/- 1 m).
But when i tried to locate the metal it can't differentiate between minerals and real metals and it's depth.