The man who understood and controlled the means and materials to make iron in early times may well have been a chief. Such was the strength, skill, and understanding that it took to deliver iron from ore. Ore deposits can be found in a number of natural sources such as hematite, goethite, or laterite. Traditionally, a good early source of early material was found as bog ore, a naturally occurring deposit (typically goethite in nature) found in bogs and swamps . Once the ore is gathered, a proper furnace needs to be constructed. Early furnaces were simple affairs sometimes consisting of of simple built up layers of clay mixed with straw and frit.
In this video, brought to us by Thijs van de Manakker (www.thijsvandemanakker.com), we can see construction of a simple bloomery furnace and a rather straightforward method of roasting iron ore prior to smelting.