The singular most conspicuous natural objects that are found in abundance in the Kinta Valley are limestone hills and caves. They are reputed to be between 250 and 350 million years old, with the oldest over 400 million years. There are about 45 outcrops in total and they come in varying shapes and sizes. The extensiveness of the limestone deposits beneath the ground is remarkable. A geological survey conducted in 1960 estimated the amount to be in excess of 700 sq. km. The depth is unknown.
Kinta Valley’s limestone is made largely of calcite or calcium carbonate or dolomite (combination of calcite and magnesium carbonate). It is mostly white, pale grey or tinged with yellow although there are variations due to the presence of iron. Marble is found in some hills.
Erosion at the base of the outcrops has resulted in the formation of caves. The caves are magnificent both in size, features and in some instances, biological life.
Tin was found in abundance amongst the hills, washed down from the granite upper layers. This resulted in Kinta Valley becoming the world’s largest exporter of tin in the 20th century. The last deep quarry closed in the 1999. Today due to market demand, limestone quarrying continues unabated, despite protestations.
The limestone hills and caves are located between Kanthan, in the north and Kuala Dipang, in the south. Most are visible and accessible from the old trunk road. Gunung Tempurong, however, is best viewed from the PLUS Expressway.
Six limestone hills including their dedicated caves will be featured here. Descriptions of the hills and caves are made based on observations beginning from Gunung Lang in the north to Gunung Gajah in the south. The accompanying map will be a good guide for those keen on having a piece of the action. However, a word of caution for the brave hearts – you have to be physically fit to venture out on your own or with your friends. Ropes, torchlight, maps, hand phones, food and water are some of the items you must have on you.