We have many resource conversion chains in the game (there are about 50 different resources). This chain is probably the hardest: iron ore smelted into iron bars, then a blacksmith makes them into pickaxes, which then get used to mine up more iron ore.
It’s tricky because it’s a feedback loop, it takes a lot of workers, and pickaxes are needed for all types of mining: gold, silver, and iron ore. Fortunately many towns make them, so it’s often possible to just buy them already made, at a premium.
