Re-uploading a torrent for a file, for which already exists a torrent will be seen as duplicate upload (with the exception of collections).
Our system auto promotes torrents which are announced to be seed and had no download for a long period (understand here some months).
We as well clean manually the torrent list from torrents being identified as definitely dead, i.e. neither the members having completed the download nor the original uploader reacting to a reseed request within a week. However, due to low number of staff working on torrents, that cleaning got low priority.