I have a question that i want to see if anyone can answer or had the same experience,i have an old 1700s farm and this one area never grows any grass not even weeds i planted one of my coin gardens there years ago,and i can not pick up any coins at 2"- 8" depth not even in all metal mode,its not just the at pro its every detector Ive ever owned,now this area is where they dumped all the coal ash i saw that when i buried the coins about 15 years ago,every machine would ground balance normally and there not noisy in the area,just thought i would ask its been bugging me for years,i thought it was something to do with the coal ash.now the rest of the property im constantly pulling up good targets,just not that area.