Sorry to take so long to reply, been away.
Partitions are divided parts of a drive and volume can refer to either partitions or if a drive is not partitioned, the whole drive itself. I apologize if I confused you.
From your description it sounds like you might have mounted the archive folder on the Mac desktop by opening it from the external. Then you created a new folder called current on the Mac desktop. Dragging from the archive to current under that situation would cause a copy since the archive folder is technically on the external. If this isn't the case... oh, well. IF your external is formatted as DOS it might have something to do with the third copy though I really am just guessing.
IF this isn't the situation, try removing the finder.plist. It is a preference file that holds certain information about how things are handled while in the Finder... which is the basic application that is running while you are moving things about your Mac and looking for things in the windows, list view, icon view, etc. By removing the plist to another folder or to the Trash (don't empty it). You will probably have to log out and back in to make the Finder create a new preference file. If you have made specific choices as to what size the icons are or the text for files, folders, you may have to redo them as they will be set to whatever default setting comes with the OS. Then try to move some of those files and see if there is any difference. If no difference you could put the finder.plist back if you wish. The system may ask you if you wish to replace the older, etc. and you may have to use your password to do so, not sure.
Otherwise I don't know of any particular reason why you are getting those duplicates. Maybe you could describe your drive setup a bit more clearly and how you created those folders.