About Thai or Siamese Coins
Silver tiger-tongue money, sometimes called "Leech money" which the collectors called "Bar money." Leaf or line money which is called "Pig- mouth money." Flower money, braclet money and bullet coins and the above mentioned were the coins used prior to the flat coin manufactured in the kingdom of Thai King Rama V.
Royal Thai Mint

History
The Royal Thai Mint was established in 1860, under the Royal Decree of H.M. King Mongkut (Rama IV) , inside the Grand Palace, in the same building where the bullet coins had been made, and named "Rong Kasap Sitthikarn". Flat coins were minted since then. Considering the Mint was too small, in 1870 H.M. King Chulalongkorn (Rama V) ordered a new Mint to be built opposite to the old one, on the west side of the "Suwanbaribal Gate". It was later used as a royal storage.
And again in 1901, H.M. King Chulalongkorn (Rama V) ordered a new mint to be built near the Grand Palace to accommodate the expanding economy. With modern minting machines, the new mint was able to produce about 40 million coins per year. The opening ceremony was held on February 4, 1902.
By Royal Decree of H.M. King Prajadipok (Rama VII) the activity of the Royal Thai Mint was greatly reduced in 1930, partially due to the world depression at that time and partially due to the introduction of coins minted abroad.The Royal Thai Mint was reestablished in 1933, by Royal Decree, to be under the Crown Property Bureau, and was later transferred to be under the Treasury Department of the Ministry of Finance.
To increase production capacity and accommodate new modern machines, the construction of the fourth Mint began in 1968, in the area of around 4.4 acres, on Pradiphat Road, Bangkok. The building was completed and officially opened on August 25, 1972. This mint was able to produce about 750 million coin per year.
To replace the Old Mint on Pradiphat Road which located in the commercial centre of the city in a limited area, and was in an old, deteriorated, and crowded condition, the construction of the present Mint began in 1996, in the area of around 50.4 acres, on Phahonyothin Road in Phatum Thani province. The building and all facilities were completed in 2001. Its capacity is about 1,000 million coins per year.
Reference: http://www.treasury.go.th/indexeng/eng/coins_text.htm