The province of West Kalimantan has one of the highest concentrations of Chinese people in Indonesia. The estimated half a million Chinese-Indonesians form more than 10 per cent of the population, descendants from marriages between Chinese and Dayak counted in.
From 1720 the Chinese came to the archipelago in big numbers to work in the tin mines on the island of Bangka. Inspired by this, the Malay ruler of Sambas asked Chinese people to take a job in the goldmines. Migration started on a small scale in 1750, but got larger around 1790. The invitation was everything accept a deed of humanity.
Chinese were prohibited from trading and doing agriculture, so they were forced to buy everything against high prices from the sultan. As soon as they were strong enough, the Chinese got rid of all demands, and they formed unities (kongsi), based on the clans they had in China. Between 1790 and 1820, in the good times of gold mining, the kongsi flourished. In 1810 the Chinese community already counted 40,000 people.
Most Chinese settled around the neighboring goldfields of Mandor and Montrado, between Pontianak and Sambas. The kongsi formed two federations; the one controlled the fields of Mandor, the other the fields of Montrado. Both had a specific task-division: farmers grew rice and other food for the miners, while other groups took care of the construction of canals. These were used for bringing water to the sluices in which the clay was washed. The fields in Western Kalimantan were rich and the gold was very pure (18 to 21 carat), but the success of the gold mining was mainly due to hard labor and a good useful exploitation of water.
When the revenues dropped, violence and arguments broke out in the Chinese community. Big fights between the federations separated and divided the Chinese, and faced with a strong Dutch army, Mandor soon capitulated. The Montrado-Chinese were able to defend themselves because of their unity. They kept on trading through Singkawang. The big revolt in Java (1825-1830), forced the Dutch to retreat from Borneo. Borneo and the Chinese were left alone until the empire of raja Brooke in Sarawak drew attention.
Renewed Dutch force lead to a governmental reorganization of Western Borneo and a big military expedition, which broke Chinese stronghold in Montrado. The arguing kongsi were dissolved, but by that time the big gold mining activities were already finished. Most Chinese could not afford a return to China, so they settled in Western Borneo.