I just unlocked the
Steel upgrade from the library, but nothing has changed (I think). The tooltip reads
Unlocks Coal and Steel production
but I don't get any coal. To produce steel, one should combine 100 iron and 100 coal in the workshop. My smelter's (I've got 3) reads
Even when I increase happiness to 91% (with hunters loot) there is no coal.
According to this question, I should have 30% of the materials, but I've got 3K wood, 1.8K minerals and 600 iron. That should do the trick if a new building should be unlocked, I suppose.
So, how do I get coal in my kittens-game?