I'm trying to recover some data for a friend. It has been going for at least a couple weeks, but it seems to still be making progress. I had to set up a loop to retry ddrescue every 30 seconds when the drive disappears. Earlier today it was around 44%.
ddrescue finally finished yesterday, and it was able to get 99.91% of the drive. The partition table was corrupted, but I was able to use testdisk on the ddrescue image to rebuild it and then repair the NTFS file table to copy everything off.