Ugh, Metallurgy. I tried, REALLY tried to like the mod. Eventually it ended up being the same issue for me as GregTech: It adds progression purely for the sake of having progression, and makes a mess of things to do it. Tinker's Construct is much more the sort of mod that I had hoped Metallurgy would be. After fighting endlessly with metallurgy ore spawning in an attempt to get even Vanilla quantities of Iron, King Lemming added his ore spawn code to Thermal Expansion and I happily junked Metallurgy.