Furnace

furnace is placed in one of the garden plots to use, I recommend if you get one from another player to run it through research so that you can build them yourself. you will need coal from the caves in your backpack to run it. you put iron (possibly other ores, I only have iron) in and click smelt. 100 iron ore yield 20 metal in 1hr 45mins and consumes 10 coal to run for that amount of time