Hey,
just found this Rich Silver Vein in the Gendarren fields / Icegate Gorge which has a 100% spawn chance on overflow server ( and 1x on your hometowm server)
It seems to be that it does not share position with other veins, tested it about 10 times and always got the vein
Friend of mine tested it works for him either ( only on overflow servers of course)
Map : Gendarren Fields Area : Icegate Gorge