Granite has been exploited since the earliest colonial days and was once quarried for the construction of lighthouses. Both the Raffles and Horsburg lighthouses were built of Ubin granite. At a later time, the quarries were of significance in providing aggregate for roads and concrete during the intensive government building programme of the 1960s.
The Ubin Quarry - by NT
It was the strikes of Singapore's quarry workers that persuaded the Housing Development Board (HDB) to open their own quarries in Ubin so that they could be sure of regular supplies. Now, however, granite can be easily obtained from elsewhere in the region where the labour costs are lower, and so quarrying will soon cease at Ubin. (Editor's note: The last active quarry, Aik Hwa Quarry, has already ceased operation.)
The abandoned quarries remain unused and officially out of bounds. They provide a potential source of fresh water and additional opportunities for recreation, but dangers of unsupervised swimming have unfortunately barred public access.