Metallurgy 2: Core is the core mod in Metallurgy 2, required for all other Metallurgy 2 mods to load.

Because Metallurgy 2 changes the ore spawning system, and expands the potential spawning to all 128 block levels in the world, it changes the default numbers for vanilla ore spawning, specifically Iron Ore, Gold Ore, Redstone Ore, Lapis Lazuli Ore, Diamond Ore and Emerald Ore Ores. However, this can be disabled by editing the config file for Metallurgy 2: Core, and changing "true" to "false" next to the relevant ore, to have it revert to Vanilla spawning patterns. Default Veins per Chunk and Ore per Vein counts are listed on the aforementioned Ore pages.