The Wild Hunter Compendium

With the possibility that the mines can damage/kill mobs that spawn behind you as you circulate a map, its well worth it, as it increases training, maybe not in higher levels, but it does.

While this may be true, Ricochet is strong enough to destroy pretty much everything in one or two shots. Easiest (and probably quickest) way to train is to establish a path around your map, then follow that path while holding your Rico key down.

You would probably be wasting your time by dropping mines. Also, you would waste the explosion proc if you just so happened to be on the plat that you dropped the Mine on and killed everything before it could proc.

Edit: You can take from SA if you want, but I don't see how you would be gaining anything.