i was smelting some iron ore and i was told the rings work for 140 ores.. but i used a brand new 1 and got 1 invo of ores done and it was gone, i have also had some where i got a bunch of ores how does that work

You probably used one before and didn't finish it, as it's based on the character, not the ring itself.

 

So i can use a ring for 139 ores then switch it, it would still use up the new ring after the next ore.

 

 

 

Edit: More info