7. Cylindrical Slag Block: Archaeological Discoveries in Lejja, South-eastern-Nigeria

By Chioma Vivian Ngonadi (@ChiomaNgonadi12)

The process of precolonial metalworking is recognised by the presence of material fingerprints such as slags, remains of blooms, or finished objects (Chirikure 2013). In Lejja-Igboland, southeastern Nigeria, iron smelting is an indigenous craft specialization that flourished on an industrial scale from around 2000 BC (Eze-Uzomaka 2013). Evidence, in the form of relic furnaces and extensive slag and tuyere remains, are widely visible in the landscape today. The vast number of slag blocks on the surface reveal that iron working in this region was a highly sophisticated, long-lived and well-developed tradition with techniques that involved relatively large-scale metal production (Ngonadi 2017). The main village square in Lejja contains over 800 slag blocks weighing between 34 and 57 kg (Eze-Uzomaka 2013).

The discovery of an in-situ cylindrical slag block in association with tuyere fragments at the depth 158 cm, on a recent archaeology survey and excavation in Lejja in 2016/2017, was particularly interesting. This slag block weighed 41 cm with a diameter of 35 cm and showed great similarities and affiliation with the cylindrical slag blocks seen at the Lejja village square and surrounding areas. With the discovery of these signatures, my PhD research will add to the broader bodies of important research that maintain that iron working in this region is early and long standing with multiple technologies apparent throughout time. Such iron working technology might have resulted in a dense concentration of population and complex social heterarchical organization with social, economic and political significance.

Image: In-situ Slag Block at Amaovoko-Lejja Excavation Unit II, author’s own photograph.


Eze-Uzomaka, P. (2013). Iron and its influence on the prehistoric site of Leija. In J. Humpris and

Ngonadi, C.V. 2017. The Emergence of Agriculture in Lejja Southeastern Nigeria: An Archaeobotanical Investigation. BlueSci Magazine, 40:8

Shadrack, C. 2013.  The Archaeology of African Metal Working.  In P. Mitchel and P. Lane (eds.), The Oxford Handbook of African Archaeology. Oxford University Press

Rehren (eds.), The world of Iron: 3-9. London: Archetype.



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