The high grade alluvial deposits at Pitinga were discovered at
the end of the 1970s in the course of a five-year exploration
programme. These deposits are shallow with a maximum
working depth for dredging of six metres. Simultaneous
Thailand
The modern commercial production of tin in Thailand began in
about 1870, but it was not until the early part of the 20th
century that the country became a significant producer. Most of
the tin produced in Thailand has been produced in the southern
provinces in the Malay Peninsula. The major ore reserves are
cassiterite but substantial quantities of columbite and tantalite
also occur.
Thailand was the first country to employ the dredge for offshore
tin mining in 1907 and onshore and offshore dredging still
accounts for about 27 percent of total production, by the late
1980s. Gravel pump mining became much more important
during the 1950s and 1960s as new power-driven machinery
replaced the older inefficient recovery systems.
excavation and suction dredging is capable of mining very low
grades of tin, thus greatly increasing the economic ore
reserves. Low mining costs have allowed production to remain
profitable even when tin prices have been low as in the last
few years.