Just have to rage

[Catapult]

Oh, man. Go to Camp Skull Valley, strike at +3, and you'll get more than enough copper ore. For the longest time, I only mined there, and it seemed like I was never getting anything but copper. I actually left to go find zinc.

Indeed, to get copper you need to go back to lower grade nodes. The lack of SP once you're higher ranked may be a put-off, but it's the only way to get that copper in bulk. >_>