The Khao Soon deposit was discovered by Siam American Mining Enterprise Co., Ltd in October 1970 (Shawe, 1984). After discovery but before a concession was granted by the government, the area was ‘rushed’ and illegal mining commenced with an estimated 30,000 people working the field.
The Khao Soon deposit was a major underground tungsten mine which operated for about 10 years up to 1979/80. The US Bureau of Mines Mineral Yearbooks (1971-1980) provides annual recorded tungsten production for Thailand and several cursory references to Khao Soon during the 1970s, in some of these years Khao Soon was responsible for 50% or more of all tungsten production and 75% of wolframite production in Thailand. While recorded tungsten concentrate production in Thailand during the period 1971-1980 was around 44,000 tonnes, actual production would have been much greater. Therefore, it seems reasonable that estimated concentrate production from Khao Soon was somewhere between 10,000-20,000t for the period 1971-1980. Local sources also indicate that small scale mining continued into the early 1980s.