Copper is a Mineral that is implemented by Thermal Expansion and Galacticraft, both can be used as the same item but have different ore blocks, Consequently, the Galacticraft copper ore has a significantly faster mining time than it's TE counterpart. Copper is used in many recipes and is a good idea to have an as much as you can early on in the game and throughout.
Ore Processing Methods. Edit
Stone Furnace/ Redstone Furnace Edit
When smelted in a furnace it gives 1 Thermal Expansion Copper ingot regardless of the mod it's ore comes from.
When Pulverized it gives 2 Pulverized copper dust with a 10% chance of getting 1 Pulverized Gold dust, each dust can be smelted in a furnace to give one ingot per dust, this method is more efficient than using a furnace alone as it doubles the amount of ingots gained per ore.
Induction Smelter Edit
When smelted in an induction smelter with sand, it gives 2 Copper ingots with 5% chance of getting 1 rich Slag per ore.
When smelted with Pyrotheum Dust, it gives 2 Copper ingots with 15% Chance of getting 1 rich slag per ore.
When Smelted with Rich slag, it gives 3 Copper ingots with 75% chance of getting Slag.
When Smelted with Cinnabar, it gives 3 Copper ingots with 100% chance of getting a Gold ingot.
Pyrotheum Dust Edit
You can place the ore block in a crafting bench or your inventory crafting grid with one pyrotheum dust per ore to get 1 Copper ingot instantly.