just keep using ur pick until it levels up.
ah, I knew tools leveled up, but I didn't know the mining level went up with the level... The more you know...When you first craft a tool it will only mine up to the level of the head(I.e.copper will only mine copper or lower). As you use it, it will gain xp and once it levels up it will mine the next level of ores.
Thankyou.
Edit: pickaxe levelled - It got silky... yay slow pickaxe