Old mine dumps and tailings: real material, but permission is not optional

Historic mine dumps and tailings piles can genuinely contain overlooked material, mining operations of the past often discarded ore that was not economical to process at the time but may still be interesting to a collector today. That said, essentially all of these sites sit on private property or an active mining claim even when they look abandoned and are on otherwise public land, and collecting there without the landowner or claim holder's explicit permission is trespassing at best. Many clubs have arranged formal access to specific dump sites for organized field trips, which is a genuinely safe and legal way to experience this kind of collecting without the legal risk of showing up on your own.