Johannesburg World Cities Research Network. In 2011, the population of the city of Johannesburg was 4,434,827, making it the most populous city in South Africa. In the same year, the population of Johannesburg's urban agglomeration was put at 7,860,781. The land area of the municipal city () is large in comparison with those of other major cities, resulting in a moderate population density of . The city was established in 1886 following the discovery of gold on what had been a farm. The city is commonly interpreted as the modern day El Dorado due to the extremely large gold deposit found
Mineral industry of Africa zinc), and Zambia (copper and cobalt). The mineral industry's exports make up an important part of the African gross income. Ongoing mining projects of more than US$1 billion are taking place in South Africa (PGM 69%; gold:31%), Guinea (bauxite and aluminium), Madagascar (nickel), Mozambique (coal), Congo (Kinshasa) and Zambia (cobalt and copper), Nigeria and Sudan (crude petroleum), Senegal (iron), and many others. The Department of Mineral Resources of South Africa reported that investment in newly committed precious metals projects in South Africa—those for which funds had already been committed or were being expended—was $8.26 billion in 2005. An additional $9.56