Originally posted by Reitak:

because i read somewhere , when i havent kill bonemass and go to mountain, then there will not spawn silver. and after i will kill him and go back to that mountain, it will not spawn silver as i was there before bonemass

You heard wrong. The silver is spawned on map creation, like copper or iron. It doesn't depend on a boss kill. The wishbone only helps you find it, it doesn't spawn it.