Okay, I haven't found any other support questions (or any posts in IC2) about where Copper spawns. However, given my mines are at a minecraft height of 6 (minimum that bedrock allows for a flat floor), I've found very little copper. I was wondering if copper spawns only in a set level range, or if I'm just unlucky enough to find only tin in my tunnels. 
Question: Copper Generated?
-
copper seems to be found more on higher levels. between 65-40 you will find loads!
-
65 to 40...
Well, I'd better learn how to use a magnetizer, then
thanks. -
thats btw just a raw assumption, but i also saw, that far below (below 15) you almost dont find any copper.
-
I usually mine around layer 15, and usually have alright results. Try finding a cave system, then you will have so much copper you wont know what to do with it.
-
I took a look at the Copper generation algorithms in mod files, and can say that copper only generates between layers 10 and 70. The highest concentration is layer 40. Get to diggin'.