The Mithril bar is the finished product after using an Mithril ore on a Furnace with 50 Smithing. While smelting, the reward for smelting each adamantite ore into bars is 7,500 Coins. To ensure that you receive the gold, keep an inventory slot open while training. Mithril bars can also be obtained from different medium tier monsters, along with Mithril dragon which drops five at a time upon death.