A discovery in India offers the furiously advancing world a rare opportunity to pause in its breathless celebration of the stampeding progress surrounding 3D metal printing and reflect on the very beginnings of metal production.
An ancient metal manufacturing unit has been unearthed in the Pudukkottai District of the South Indian state of Tamil Nadu. Here, on the banks of the River Vellar and amid the hard and rugged laterite structures in the interior forest of Porpanaikottai, a team of historians and epigraphists (experts on the study of inscriptions and epigraphs) have found compelling evidence of the fascinating early days of metal smelting.
Fourteen round furnaces are erected like a row of loyal, ancient soldiers here, each about five metres from the next. Eleven of these massive structures are quite significant in diameter. As a unit, the collection offers a rare insight into the conventional method early man employed to boil metal ores in rough-hewn circular furnaces.
The researchers also discovered an oval-shaped cooling chamber in the area, which sprawls across about 40 acres.
Of their find, researchers speculate that ancient metal makers would heat metal ores to the melting point and then cool them in the chamber, with the single one doing the job for the entire furnace fleet.
A few cast-about heavy stones were also uncovered nearby, possibly waste materials from the factory.
This ancient relic of our industrious ancestors’ metal-production efforts is believed to be 2,500 years old. Its discovery sheds fresh validation on our understanding of how cast iron came to be. The Chinese developed a furnace in 513 BC that was—notably—hot enough to melt iron. This facilitated the world’s first cast iron. Before that, iron’s melting point (1,528 ºC) was simply too high for primitive furnaces.