The main point of this mod is to add metal ores that will be needed by other mods eventually, so that these ores will already be in your world when you add a mod that needs them! No need to hunt for new chunks. Every ore is highly configurable and can be disabled individually. There are also some config options to disable entire categories of ores (they should be at the top of the file.)
There are also three "machines" currently. The Alloy Smelter, which is how you craft alloys, the Metal Furnace, which let's you get a little extra out of your ores, and the drying rack, which can be used to create leather and jerky. The Alloy Smelter and Metal Furnace run on furnace fuel, and other mods can add Alloy Smelter and Drying Rack recipes if they want to.