granite quarries About 25 per cent of Singapore’s land area has granite exposed at the surface. Known as Bukit Timah granite, these main outcrops are found in the Central Hills, in the Changi Hills and on Pulau Ubin. A hard but versatile stone, granite has been used for a wide variety of purposes, from road foundations and ballast on railway lines to ornamental buildings. In the first half of the 20th century, small quarries were located throughout those areas where the rock was exposed; extraction was carried out in a variety of places according to local needs.

Granite quarrying in Singapore reached its peak in the mid- 1970s, when there were 21 major quarries employing 1,230 workers. From the early 1960s, however, there were problems with quarry workers suffering from silicosis (a lung disease caused by breathing in silica dust). A survey of quarry workers in 1971 showed that 15 per cent of workers were suffering from this disease. The government imposed dust control regulations and also stopped renewing quarry licences. By 1995, there were only three operational quarries left. These have since closed down. The main ornamental stone companies in Singapore, such as Central Granite Industries, have thus taken to importing raw materials from neighbouring countries.

In the 1990s, quarries in Pulau Ubin supplied between 30– 40 per cent of the country’s needs. Some of Ubin’s disused quarries have since been flooded, are overgrown with vegetation, and have become scenic attractions.

See also geology.