The 1862 Gold Rush at Grimes Creek just north of what is now Boise Idaho and west of Idaho City, pulled enough gold out of the ground to completely pay for all the material to equip soldiers and armies for the Union.
In fact if you were captured they released you if you agreed not to fight which the far majority of these individuals went to the gold rush in Idaho and you can see it in the ghost town names half of them are Northern and the other half are southern names. Funny a lot of them were actually political name like Leesburg Vicksburg Fredericksburg as places of Confederate battles.
There is actually Union factions as well as Confederate ones and then on top of it there was the Chinese.
Gold has such an amazing and vibrant history.