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18 February 2015

Archaeology a vital key for mineral exploration in West Africa

By: Stephen Isaac, former archaeologist who leads the archaeology technical area for Earth Systems

Archaeology and mining have multiple connections if one is to scratch below the surface. This relationship is essential knowledge for mining projects in West Africa today.

A miner, for example, can gain important insights into the uses of a landscape and the minerals it contains through examining the history of settlement and activity in any given area. The archaeology of mining can in fact be a vital tool for tracing the evolution of technology, economies and power bases. As a consequence, it can help identify the best areas for further mineral exploration. Evidence of ancient mining and metallurgy for this purpose can be gleaned from either physical remains, such as ancient mines or artefacts, or from cultural remains, including historical texts or place names.

In many societies, place names are derived from the minerals found in those areas. For example, the Roman city of Argentoratum (modern Strasbourg) was likely named after silver mines in the area. Clearly the identification of place names for the purpose of mining exploration is likely to be more fruitful in locations where societies developed sophisticated literacy and cartography at an early stage in history.

Some of the most significant archaeological discoveries in West Africa have included evidence of the early mining of metal ores. The principal metal ores to be mined first were copper, iron and gold. Metal production has a history of stimulating economic activity, the rise of chiefdoms and even states in West Africa.

Copper

Copper ores can be smelted at lower temperatures than iron and metallic copper is easier to shape in the forge because it is softer, hence it is logical that evidence of copper working is found at an earlier date than iron-working sites. Although copper has been mined and worked for longer than gold and iron, there has been little evidence discovered to date that links it to the rise of kingdoms in the same way as gold and iron.

Discoveries in the Agadez region of Niger show signs of copper metallurgy as early as 2000 BC, making it the earliest recorded site of its kind in West Africa.

Copper metallurgy has also been recorded at Akjoujt in Western Mauritania. The Akjoujt site is later than Agadez, dating to around 850 BC. At around the same time, copper was being smelted in the Senegal River Valley, 400 km to the south.

In sub-Saharan West Africa there was only one other known source of copper that was commercially viable - Nioro-Siracoro in Mali. However, copper was also imported to West Africa from Morocco, the Byzantine Empire and Central Europe.

Although there is much written evidence of the copper trade between West Africa cities, there is no information on how people from the savannah and forest zones used or traded in copper.

Gold

Little is known of the early history of West African gold mining. While some Iron Age sites contain both iron and copper artefacts, the earliest archaeological finds of gold in West Africa come from Djenné-Jeno in the seventh century AD. In West Africa, three primary gold sources were exploited; Bambuk on the Senegal River, Buré on the Niger River and the Akan fields of northern Ghana.

Gold was a cornerstone of the Ghana Empire, which originated around 800 AD and controlled an area covering parts of modern day Mauritania, Mali and Senegal. Gold was also essential to the Mali Empire (1230 AD to 1600 AD) and subsequent Songhay Empire. Gold remained the principal product in trans-Saharan trade for many centuries.

Iron

The precise dates of the earliest iron-working in West Africa are uncertain. However, there is evidence of iron-working from at least as early as 1500 BC. Termit, a mountainous region of south-eastern Niger, has yielded evidence of iron smelting from this period. There is also evidence of iron-working by the Nok culture of central Nigeria at this time.

The Iron Age of Africa was based around the agricultural revolution, driven by the use of iron tools. In Nigeria, iron was fundamental to the rise of several important kingdoms - Dahomey, Benin and the Yoruba kingdoms, but primarily the Ife and Oyo kingdoms. The most important Iron Age Sites in West Africa are in Mauritania, Mali, Senegal and Nigeria. Large scale production of iron also took place in Guinea, Burkina Faso, western Togo and the Hausa-speaking regions of Niger and northern Nigeria.

Between the 12th and early 16th century in Benin, iron production was so extensive that it is deemed to be partly responsible for the gap in the rainforest between Ghana and Nigeria, as a result of using charcoal for smelting. Thousands of large slag mounds pepper the landscape, the largest representing production levels comparable to the Roman Empire. Currently, the slag mounds are being destroyed in large numbers for use as gravel on roads.

Archaeology and cultural heritage in contemporary mining projects

In order to comply with national legislation, most mining projects will need to produce a cultural heritage assessment as part of their Environmental and Social Impact Assessment (ESIA). Projects complying with World Bank standards will also need to demonstrate protection and mitigation of cultural heritage that complies with IFC Performance Standard 8 (Cultural Heritage).

As well as tangible archaeological sites, cultural heritage assessments of such projects will also need to consider sacred sites and the impacts of the project on intangible cultural heritage, such as cultural knowledge and community traditions.

Current and planned mining projects in West Africa have significant potential to yield further valuable information on the history of mining and metallurgy in the region. Metalworking is an essential element of the technological, cultural and economic development of the region.

For example, in recent years the Simandou iron ore project has led to the discovery of many ancient iron forges. Some of the artisanal mine sites were still being used for iron working activity until the 1960s. Sites such as these can also have contemporary religious or spiritual significance.

Any mining project should aim to protect cultural heritage resources, whether the sites or landscapes are known or whether they have archaeological potential. This should involve protection for all phases of the mining project as well as monitoring after mine closure in some cases.

The projects can also improve accessibility to or understanding of this heritage through active engagement and participation with local communities. Such engagement could have important socio-economic benefits - such as employment opportunities - and also help to engender pride in local sites and traditions.

Clearly it is also important to consider the archaeology of mining to determine new sites for mineral exploration. Even in countries with scarce historical records, essential clues can often be derived from place names and cultural sources, such as information from local people.

Earth Systems continues to work on ESIAs of mining projects in West Africa, including several with important archaeology and sites of cultural heritage significance that require protection. Earth Systems has offices in Senegal and Guinea-Conakry and has recent and ongoing experience with mining projects in Guinea, Senegal, Mali and Liberia.

The company has over 30 years of experience of working on mining projects throughout the world and has experts in all environmental aspects of mining.

For a list of article references or a detailed report including photographs, please contact Stephen on: stephen.isaac@earthsystemseurope.com

 

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