The mineral industry of Mozambique plays a significant role in the world's production of aluminium, beryllium, and tantalum. In 2006, Mozambique's share of the world's tantalum mine output amounted to 6%; beryllium, 5%; and aluminium, 2%. Other domestically significant mineral processing operations included cement and natural gas. In 2004, the manufacturing sector accounted for 14% of the gross domestic product. The Mozal smelter accounted for about one-half of manufacturing output but had a much more modest effect on employment. In 2012 the mining and quarrying sector accounted for 1.5% of the economy and energy accounted for 5%. However these sectors were expected to expand by more than 10% per year due to increased output of coal and gas. Gas reserves were estimated to be the fourth largest in the world. Production The production of coal was estimated to have increased by 193% in 2006; granite, by 150%; garnet, 103%; diatomite, 33%; marble, 0.3%; cement, 55%; bauxite, 2.6%; dumortierite, 92%; and limestone, 0.5%. The production of aquamarine, beryl, niobium (columbium), tantalum, and tourmaline was estimated to have decreased by nearly 14% in 2006. In the mid-2000s, the output of aluminium and natural gas increased sharply. Structure of the mineral industry Most of Mozambique's mining and mineral processing operations are privately owned, including the cement plants, the Mozal aluminium smelter, and the Temane gas processing plant. Artisanal miners produce gold and aquamarine, tourmaline, and other gemstones. Carbomoc E.E., which was the country's only coal producer, is state-owned. Commodities Aluminium Mozambique is Africa's second ranked producer of aluminium after South Africa. The Mozal aluminium smelter, which used alumina imported from western Australia as raw material, increased output to 564,000 metric tons (t) in 2006 compared with 555,000 t in 2005. Mozal's rated capacity amounted to 506,000 metric tons per year (t/yr); BHP Billiton planned to increase capacity by 250,000 t/yr by 2009. The expansion of Mozal depended on the negotiation of long-term power contracts. In the first six months of 2006, aluminium exports were valued at $637.8 million compared with $504.2 million during the same period in 2005. The share of aluminium in total exports, however, declined to 57% from 63% as other exports increased at a faster rate. E.C. Meikles (Pty.) Ltd. of Zimbabwe operates a small bauxite mine in Manica Province. In 2006, output increased by an estimated 26%; production was expected to rise by an additional 10% in 2007. Gold