Finished 6 today. The mag gets ~900 nT reading and then wigs out to 0 nT when walked over iron rebar sticking up from ground. Good to know. I got that reading at the bright spot in central-east part of first hectare of Gegharot, but saw no iron rebar or any other magnetically-susceptible objects on the surface. Although, I don't remember if it wigged to 0 nT then. It certainly was around/higher than 900 nT though. Interesting!