Well I only got a few weeks in last year.. This year I have about 80 hrs in and I'm started to figure it out.. This tribe of Indians and the key are from the old courthouse and county jail about 1850's,,, Then a hunting party in the front couple of days ago.. In the park yesterday, which isn't giving up the old ones easily, I found a couple of silver rings.. But a sweet high tone popped through then to iron, and I only could move the coil about a inch or so but the high tone was repeatable... Dug about 5" and sitting on a root was this quarter,, On the the edge of the root was a nail head protruding, a 4" nail !! Liking learning this machine..