The world oldest iron-smelting site is located in Lejja Nsukka, Enugu State, Nigeria. Dated back 2000 BC.
Lejja, Nsukka, in the present-day Enugu state, Nigeria is the location of a pre-historic archaeological site which contains iron smelting furnaces and slag that dates back to more than 2000 BC. The village square at Otobo ugwu which is likely the first village square in Lejja that contains over 800 blocks of slag with an average weight, between 34 and 57 kg.
Arranged in crescent shapes with mounds in the middle across a wide sitting area at Otobo Ejuona, as the arena is known, are hundreds of bits of smelting debris, or slags, recently carbon-dated to about 2000 BCE by a team of archaeologists and other experts from the University of Nigeria, Nsukka and Oxford University in the United Kingdom.
Slags are the waste byproduct produced when iron is heated in order to remove it from its stone ore. Tens of hundreds of these granite-like objects, are arranged in patterns by people of whom the present occupants of Lejja have no memory. However, for them the site has acquired religious significance and become central to the people’s existence, housing the community shrine and meeting place of the masquerade cult, as well as serving as a general meeting place.
Other smelting sites have been discovered in nearby places like Opi (dated 750 BC) , Umundu and Obimo, but none matched the antiquity of the Lejja site.
The slags, from which iron ore had been extracted, were transported to this site sometime in antiquity, and arranged in the patterns they were found. The most prominent pattern is the crescent shape made with the slags on the higher ground of the village square, which is faced by a mound of slags heaped together.
Other arrangements then spread out with the gentle slope of the square. In the middle there’s a raised mound of earth, around which slags are arranged. Other semi-circular heaps are also displayed around the square. To the right of the square, there’s a conical-shaped small building, the traditional masquerade’s house. At the base are also placed several slags.
