Okay, so what you do is Google 42.zip download that and extract it.... Wait no don't do that, that will make your computer ever so slightly blow up. What you do is your go into the configs folder found in your .minecraft folder. Next what you do is find all the mod that generate copper and all of the other redundant ores. Disable them all, only leaving one ore from the mod of your choice to generate. For example, Disable Forestry and Thermal Expansion copper or tin, only leaving Mekanism copper and tin to spawn.