Ancient Ironworks discovered in Angkor Wat – Cambodia
In 2010 ancient ironworks were discovered in the Preah Vihear province in Cambodia, from archaeologist Thuy Chanthourn of the Royal University of Fine Arts, who was looking for an old settlement dating back 1,500 years ago.
Since then he has been able to dig three meters in depth unearthing pieces of pipes, smelted iron and clay objects. Using the thermoluminescence dating method the sites looks to have been about 1,200 years old. However Thuy believes that digging another three meter would show sites much older than that and he hopes to do that in the near future.
Those iron sites indicate that iron has been used a lot in that period of time for construction not only of weapons and armour but also for tools used for building the temples (like iron bars and joints).
You can read more here.