Known for copper mining, 'the Copperbelt' runs through northern Zambia and southern Democratic Republic of Congo. It is made up of Zambia's Copperbelt Province and DR Congo's Katanga Province. Copperbelt Province in Zambia includes both the mineral-rich areas and farming blocks to the south. The main Copperbelt cities sprang up from adjacent copper mining activities - Chingola, Ndola and Kitwe.Historically copper was used as currency in central African trade. In the 1920s it began to be mined commercially. In 1964 the newly independent Zambia based its socio-economic policies on its income from copper. From 2004 onwards, increased demand for copper due to the growing Indian and Chinese economies led to increased prices. Copper prices have recovered somewhat from the 2008 recession, whilst copper production is currently between 700,000 and 800,000 metric tons per annum.