 One source may indicate its use as early as the Tang Dynasty (~ 700--900 AD) while others seem to contradict this interpretation.Due to wars, invasions, famines, distrust of the government, overpopulation, a rising opium epidemic, and clashes between various "tongs" of miners, very little information exists about the industry between the 11th and 19th centuries, until a European miner named Felix Tegengren arrived to find the Chinese industry in shambles.Tegengren notes that ironsand was sluice mined in Henan and Fujian by local farmers and smelted over charcoal fires to make tools, but it involved a lot of work thus was very expensive.