So there would be (A few or a lot of floors down in the mines (Like the televator levels). There would be a well (Unbuilt and or built.) which would allow you to drop items in it and it would teleport into a chest (Chests) on the surface near the televator which would (maybe) be made of stone. and this would be free of cost (Only up. no teleporting stuff down.). It would work as a way for people to continue downwards in the mines and when you run out of space they can send stuff back up. It could work like that they can only send a certain amount of stuff then it would deactivate for like a day or two (In game of course). another idea is that there could be certain chests that once you open them you can only take a certain amount of items from it and then it will disappear (or lock) or it could be once its closed it will disappear and reappear after a day. the chests would have really good loot and treasure. Another idea (Similar to this) is that there could be two pillars both holding a valuable item. and only one can be chosen. so you would have to choose one and let the other go. It would reactivate (Put new items on the thing) in like a few days. anyways just a few ideas.