"/castsequence reset=6 find herbs, find minerals" - that should work, the reset is for it to automatically which back to find herbs as the first one, although if you done fishing too, you could add find fish onto it and then the reset would actually be more helpful
otherwise, just:
/cast find herbs
/cast find minerals
would probably do the trick
Wouldnt you have to keep hitting it though. I was hoping for someway in game to keep it cycling though ultimately I can make a quick ACTools macro to hit the keys that I put the spells on. I dont need anything else cause its on my DK thats L64 leveling both herbs and minerals.