 The Chinese countryside was rich in deposits of both an iron ore containing a high content of phosphorus, and coal, a fuel that burns at a high temperature.Around 1200 BC the Chinese developed a method of smelting the rocky ore into pig iron, which was then remelted and poured into molds (cast) to form cast iron.Although the metal was very brittle, this method was able to produce iron in much greater volumes than bloomery smelting, and with vastly higher yields of metal per ore. By the 1st century BC the Chinese iron-industry was by far the largest and most advanced in the world.