Board Thread:Let's talk about the Wiki!/@comment-25205196-20170209192204/@comment-28286242-20170416150025

The smelter starts out with one available slot. I opened the second slot which cost 6 diamonds. The third slot costs 9 diamonds. I assume the progression for the smelter is: 2nd = 6 dia, 3rd = 9 dia, 4th = 12 dia, 5th = 15 dia and so on.