The resources from mines are kind of redundant when you get large amounts of them. How about making them useable for crafting by adding three new recipes that you have at the start of the game
2 Iron to make 1 fine iron for crafting chainmail , rings etc
2 horses to make 1 wolf pelt for crafting cloaks , leather armour etc
Between 2 and 10 crystals to make 1 Flawless Crystal for crafting weapons , shields etc