Mining is the biggest contributor to Namibia's economy in terms of revenue. It accounts for 25% of the country's income. Its contribution to the gross domestic product (10.4% in 2009, 8.5% in 2010, 9.5% in 2011, 12.3% in 2012, 13.2% in 2013, 11.6% in 2014) is also very important and makes it one of the largest economic sectors of the country. Namibia produces diamonds, uranium, copper, magnesium, zinc, silver, gold, lead, semi-precious stones and industrial minerals. The majority of revenue (7.2% of GDP in 2011) comes from diamond mining. In 2014, Namibia was the fourth-largest exporter of non-fuel minerals in Africa. Overview Namibia has a long tradition of mining. In 2018, mining contributed 14% of GDP and expanded 28%. Extensive exploration in Namibia for base metals, diamonds, gold, natural gas, and uranium has been attributed, in part, to the rise in world commodity prices. Under the Mining Act, the natural resources of Namibia belong to the State. However, the state in Namibia is limited to the role of a grantor-regulator than an owner-operator. One of the main challenges of the mining industry is the lack of water resources, as the availability of fuel and electric power. A mining policy in Namibia was developed in 2003 through research with the information made available by key stakeholders. Production World Bank pointed out that mining in Namibia grew an average of 4.6% over the 2000–2012 period. The growth of the mining sector is influenced by the global economy and demand, in contrast to the agricultural industry in Namibia, which is influenced by environmental conditions. In 2019, the mining industry contributed over 300 million dollars to government revenue. The whole industry contributed around 2.2 billion dollars to the national economy in the same period. However, a drop in diamond and uranium production caused a contraction of 11,1%. Lower mineral commodity prices led to the declining expenditure on exploration. In 2006, manganese, diamond, and fluorspar output increased by 158%, 24%, and 15%, respectively, compared with that of 2005, and copper, lead, wollastonite, and zinc posted significant production declines. The increase in manganese was attributable to the expansion of production at the reopened Purity Mine (formerly the Otjisondu Mine). The decline in copper output could be attributed in part to instability during the transition of ownership of Ongopolo Mining and Processing Ltd. Lead and zinc output declined in part because of a short strike by workers