Economic geology of Sri Lanka

Economic geology deals with minerals and rocks which have an economical value for trading. Minerals and rocks in this island can be classified under several categories of economic geology (Table 1).

Table 1. Various kinds of economic minerals and rocks in Sri Lanka

Graphite 

Graphite in Sri Lanka is considered as one of the high quality in the world. It has a purity of 99% carbon. In Sri Lanka, graphite occurs as massive veins in rocks. The history of graphite mining in Sri Lanka is more than 300 years. There are two main mines for graphite extraction in Sri Lanka, one called Kahatagaha-Kolongaha mine and the second is Bogala mine. Kahatagaha mine has mined more than 1500 ft from the surface. At present different grades are produced and separated manually into different particle sizes (Figure 12). Even though there is a good demand for Sri Lankan graphite, the industry is not capable of compete with the international market due to high cost of production.

Mineral sands

The beaches of Sri Lanka are rich with various sands such as ilmenite, rutile, monazite, zircon, garnet and silica. The largest deposit of mineral sands is found in Pulmoddai, a beach placer deposit along the coast. Main mineral sands found in this deposit are ilmenite, rutile and zircon. These have been exported from 1967 as raw sands. However, processing of these minerals will add more value to the materials and this can be done by expanding and modernizing the industry, which will result more job opportunities.

Large monozite and garnet deposits have been discovered at Beruwala and Hambantota beaches. These can also be used for processing and exporting. The silica sand deposit at Madampe and Naththandiya is being used for the glass industry. The silica sand deposits of Sri Lanka has been estimated over 100 Ha.

Eppawala apatite

Eppawala apatite deposit was discovered in 1971. This reserve has been estimated at 40 million tones of phosphate. However, this phosphate has a very low solubility and it has been a concern of many chemists and geologists, finding a method to increase its solubility. That can reduce a huge amount of money by reducing the import of phosphate fertilizer.

Quartzite

Silica rich (100%) high quality quartzite is found in many places of Sri Lanka, such as Galaha, Wellawaya, Ambalamana and Akarella. These are mined at Galaha and Wellawaya as vein quartz however there is no processing has been taken place, which will be a value addition to the industry. Also as an environmental concern, mining vein quartz produce lot of weather resistant waste material. However, these can be used for building and construction industries.

Salt

Salt in Sri Lanka is produced from the evaporated sea water in the salterns (Figure 13). There were several salterns along the coast of Sri Lanka but unfortunately only two are working at this moment, Puttlum and Hambantota (Maha lewaya). Several salterns have been abandoned due to many reasons (Elephant pass, Nilaveli, Karagan, Palatupana, Palavi). If these become workable and produce salt, definitely we will be able to export salt as well.

Geology of Sri Lanka

Gems of Sri Lanka

Mining and the environment