Complex Smithing is a mod that makes mining a little more grindy and realistic. Copper, iron and gold ores now drop chunks that must be collected on a crafting table to form their powdered variant. When cooking it, you will get the hot ingot, cool it by throwing it into the water.
The mod also changes the order in which minerals must be obtained. Now you need a copper pickaxe to get iron. Iron pickaxe can't break diamonds, you need one made of gold (tempered)
In addition, you can also find new underground biomes
