citrus crops. Southern coastal regions include mixed forestry and farming land uses. Mining In the 2006-07 financial year mining contributed 9% of Queensland's gross state product (GSP). Queensland has significant coal, coal seam gas and bauxite deposits and some oil shale and natural gas reserves. Coal production in the 2008-09 financial year totalled 159 million tonnes leading to exports to 38 countries. Queensland exports half the world's coking coal which is used to make steel. Minerals including copper, lead, silver, zinc, bauxite, gold, phosphate rock, magnesite and silica sand are mined in the state. Dimension stone, that is, stone that can be cut for domestic use, including granite, marble, sandstone and slate are produced in various locations across the state. Queensland has the largest onshore oil and gas potential in the country as the state is relatively under-explored. Oil was discovered in the south west of the state in the early 1980s, leading to the construction of an oil pipeline from the Cooper Basin and Eromanga Basins to Brisbane. A series of gas pipelines, which began operating in the late 1990s, connects users in Mount Isa and Brisbane to the south west. Gemstones such as sapphire, opal and chrysoprase are also mined in commercial quantities. In the 2008-09 financial year Queensland collected A$3 billion in mining royalties. Coal seam gas Despite being positioned under prime agricultural land the Bowen Basin and Surat Basin are becoming intensively developed by the mining industry as Queensland's coal seam gas industry booms. In the ten from 2000, about 1200 wells have been sunk in the western Darling Downs, with that figure set to rise to 20 000 over the following decade. In 2010, coal seam gas was generating 30% of the state's electricity. Several international energy companies are investing in multibillion-dollar projects to convert the coal seam gas to liquified natural gas and export it via the Port of Gladstone. Landowners have raised concerns with the mining development ranging from a lack of compensation, property access, construction of gravel roads on farming land, water runoff from drill sites and the potential problems from the millions of tonnes of salt that will be brought to the surface each year. Refineries One of the largest alumina refineries in the world, Queensland Alumina, was built at Gladstone in 1967. Bauxite for the refinery is transported from Weipa to Gladstone via sea. Also located here is Australia's largest