I'm struggling with copper ore!

I'm having a tough time with copper ore this time round. I've seen a video where a guy talks about the generation being random now. So I'm in the the Cold Forest Biome and all I've found is one huge chunk of granite so far.

Has anyone had any luck anywhere else??

Update: I found it!! It was in the Tundra/Boreal area at block level 12. This version is definitely tougher for ore generation. It took me around 8 hours of searching by myself.