Thailand ranked second in tungsten and third in tin production in 2002, and ranked fifth in feldspar and eighth in gypsum in 2001. The country also had considerable resources of diatomite, dolomite, limestone, potash, rock salt, and a wide variety of other industrial minerals. In 2000, Thailand produced 50 mineral products and had 730 operating mines, of which 34% were limestone quarries; 652 of the sites were industrial mineral mines, 55 were metal mines, and 23 were coal mines. The mining industry employed 19,619, 24% of whom worked in limestone quarrying. Other important minerals were barite, natural gas, gemstones, lead, crude petroleum, silica, and zinc. Most mineral production was for domestic consumption, except for gypsum, and tin and its byproducts (ilmenite, monazite, struverite, tantalum, and zircon), 70% of which were exported. Thailand was a net importer of minerals, mainly because of its large import bills for coal, crude petroleum, iron and steel, primary aluminum, refined copper, gold, refined lead, and silver. Thailand's resources of most metallic minerals and fuel minerals were small. The mining and quarrying sector, which accounted for 2% of GDP in 2000, grew by 7.5% in 2000 and 9.1% in 1999, mainly as a result of a substantial increase in the production of crude petroleum and natural gas. Cement production was a leading industry in 2002.
Tin ore production in 2000 totaled 1,930 tons (metal content), most of it exported; tin was mined mainly on the southern peninsula—52% was produced from offshore dredging. Tin production has been steadily declining in the face of falling world prices and output curbs. Tungsten output (metal content) was 30 tons. Other metal minerals exploited on a small scale included antimony, cadmium, iron ore, lead, manganese, tantalum, zinc, and zirconium. Exports of 155 tons of tantalum metal powder earned $42 million in 2000. Iron ore production dropped to 50 tons (metal content), from 61,000 tons in 1999, because iron ore mining operations stopped in the provinces of Nakhon Si Thammarat, Phetchabun, and Prachuap Khiri Khan. No gold or silver was produced in 1997–2000, nor monazite rare earths in 1998–2000. Development of Akara Mining's open-pit operation began in 2000 on the Chatree gold project (eastern edge of Chao Phraya Basin), and the 1.5 million ton per year operation was expected to produce 4,449 kg per year during its first three years, beginning in 2001. Total measured, indicated, and inferred resources for Akara Mining's area of exploration were 14.5 million tons (2.6 grams per ton of gold and 12 grams per ton of silver), of which proven and probable reserves were 8.2 million tons (3.1 grams per ton of gold and 14 grams per ton of silver).
Among industrial minerals, feldspar output was 542,991 tons, down from 684,983 in 1996; gypsum production was 5.83 million tons, down from 8.56 million tons in 1997—72% of gypsum came from Nakhon Si Thammarat and Surat Thani, and 4.2 million tons were exported, earning $46 million. Hydraulic cement production was 25.5 million tons, down from 37.1 million tons in 1997. Thailand also produced barite, ball clay, kaolin clay, diatomite, metallurgical-grade fluorspar, gemstones (rubies, sapphires, topaz, and zircon), phosphate rock, salt, silica sand (glass), stone (calcite, dolomite, limestone, marble, marl, quartz, and shale), and talc and pyrophyllite. In addition, resources of bentonite and copper have been identified; bentonite has been mined. Exploration in the past five years has focused on copper, gold, and potash. Thailand could soon become an important producer of potash in Asia and the Pacific region—the Somboon deposit was estimated to contain more than 300 million tons of sylvinite ore, with prospects for a 2 million ton per year potash mine, and the Udon deposit was estimated to contain more resources than the Somboon deposit. One copper deposit, at the Puthep project, near Loei, had ore reserves of 42 million tons of heap-leachable ore at a grade of 0.52% copper.
The government's underlying policy has been to conserve the country's mineral resources and to shift the emphasis to exploration, development, and exploitation of minerals consumed domestically, such as ball clay, feldspar, gypsum, kaolin, silica sand, limestone, lignite, phosphate, potash, rock salt, and zinc, and away from minerals that were predominantly exported, such as antimony, barite, fluorite, tantalum-columbium, tin, and tungsten. Thailand's mining industry consisted of a small mining and mineral-processing sector of ferrous and nonferrous metals and a large mining and mineral-processing sector of industrial minerals. All mining and mineral-processing businesses except coal, natural gas, and crude petroleum were owned and operated by private companies.