This might be stupid, but in my first playthrough i found an iron pickaxe head on a village so i didnt have to think this through. How da**** do i go from a flint pickaxe head to be able to mine something?? i have been mining for at least 40 mins and nada, no lvlup ,not even able to mine coal.
When you mouse over the pickaxe, it should have "mining XP". This has two numbers: The number of blocks you've mined using this pickaxe, and the number of blocks required to be mined before the pickaxe advances to the next level.
The flint pickaxe can be leveled to copper mining. Once this happens, you need to mine copper and aluminum, make a TiC smelter, and smelt yourself a copper pickaxe head. Then, apply the copper head to your flint pickaxe (once it's been completely repaired). Then, keep mining until your copper pickaxe can mine iron. Rinse and repeat.
Something to be aware of: I'm currently working on removing Tinker's Construct from the early-game progression. Once I complete the new early-game progression, it will still be installed, but it will no longer be required to advance your mining.