Have a look at my solution to this problem at https://github.com/Cadiboo/WIPTechAlpha/blob/master/src/main/java/cadiboo/wiptech/util/ModEnums.java (ModMaterials)
all my metals are registered here with properties (hasOre, hasNugget, hasTools etc.) and registration is done automatically based on this. It’s even possible for other mods to add, remove & modify the materials