The spatial footprint of the non-ferrous mining industry of Lubumbashi

In the south-eastern part of the Katanga Province (Democratic Republic of the Congo), high concentrations of copper and cobalt are found in the soils of the well-known “Copper Belt”. Industrial mining and smelting plants were installed under Belgian colonialism in the area and numerous other international companies have settled there since the end of the 1990s.
Due to dominant south-eastern winds, the metallurgic industry in Lubumbashi has been the source of spatially concentrated atmospheric deposits of non ferrous metal particles and associated substances in a cone-shaped zone, situated north-west of the original metal processing site. Though an empiric effect on vegetation had been noticed for decades, it had not been highlighted yet until recently that this was due to the metallurgic activity. The metal processing plant has dramatically reduced its activity after the independence, in 1960, but the results of the colonial period and current activity are still visible today.
The existence of this pollution cone has then been evidenced using two different techniques. Firstly, landscape metric comparisons of the vegetation and bare soil patterns in two study areas, one inside the pollution cone and one outside, have been applied on basis of a classified Quickbird satellite image (2005). Secondly, the city perception theory developed by Kevin Lynch has been used and adapted to the pollution issue and the context of developing countries, using trained experts and interviewed citizens.
The first method highlighted a higher fragmentation and lower vegetation presence inside the pollution cone, reflecting the negative impact of the atmospheric deposits. Those differences were higher for sites closer to the emission source. Lynch’s approach outlined the negative impact of diverse industrial plants on the perception by the local population. Six pollution districts and several contaminated paths, limits, nodes and polluting landmarks were identified. Those included the recently installed plants to the north and east of the city. Citizens even recognize them as part of the collective image of the city.
This has important outcomes, as the demographic pressure in Lubumbashi extended the city limits so that the metal processing plant is now fully included in the urban matrix. Therefore, a part of the local population lives within the pollution cone and faces contamination. Moreover, the rivers flowing near the plant, Kafubu and Lubumbashi, as well as the roads and railways linking different industrial sites are contaminated and represent contamination paths potentially spreading toxic substances all over the area. Sanitary evidences of this contamination have already been found in the area and particularly the pollution cone. Moreover, the recently installed plants, outside of the city, could face the same problems due to urban sprawl in the forthcoming years. This should be taken into account for the urban planning in Lubumbashi. Evidencing the ecological footprint of the non-ferrous mining industry is considered crucial to confront local decision makers with the negative impact of metallurgic industry within an urban context.