I think the Miner is a bit to "useful", and I think I found a way to balance it.
Maybe instead of getting you the whole ore. It would get you 2-6 nuggets (Always Random).
9 nuggets = 1 ore.
Now that being said. Nuggets should be added. They are already added with RP2, I figure IC2 can also use RP2 nuggets or IC2 can make there own for those who don't want to play with RP2.
There should be 4 nuggets, Iron, Tin, Copper and gold although gold nuggets are already added in the vanilla.
Anything that is not an ore will be mined normally. So Diamonds, coal, uranium and redstone should not be affected.
What do you think?