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Mining and the environment

All mining activities can create environmental degradation if the process is not well managed. These can cause environmental issues such as pollution of water, sedimentation, land degradation and health effects. Therefore, mining activities should manage effectively with lowest damaged to the environment.

Gem mining

Rupasinghe and Cooray (1993) have discussed about the environmental effects associated with gem mining in Sri Lanka. Since most of gem deposits in Sri Lanka found in valleys or as stream bed deposits mining methods can vary based on the type of deposit. However, gem mining is considered as the major factor for soil erosion and sedimentation at Ratnapura district. Other than that, tunnel mining causes land subsidence. Also, pollution of surface water by heavy metals associated with weathering of soil and increase in turbidity are common environmental issues related to gem mining in Sri Lanka. Accumulation of water in tanks or pits for washing gem gravels can help the mosquito breeding as well. All these could happen due to;

Stream bank mining
Removal of vegetation cover for mining
Washing 'illam' (gem bearing heavy mineral fraction) in water bodies
Release sediments into water
No way to back fill tunnels

Read a report on gem mining at Okkampitiya area

Sand mining

Sand mining is taken place in many downstream rivers such as Mahaweli, Kelani, Kalu etc. Sand from rivers, is necessary to maintain the sandy beaches. When sand is mined, the coastal beaches do not receive their replenishment and from coastal erosion the beach get eroded. Uncontrolled sand mining can cause, river bank collapsing, high turbidity in water and seawater intrusion. This can be evident in downstream part of the Kelani river.

Coral mining

Intensive coral mining is taken place in the southern coast due to various reasons; products are quality (lime) and saleable (coral, lime), income by the coral mining give a better lifestyle than the alternatives etc. Coral mining is a major cause for coastal erosion especially in the western and southern coasts. At the time of the tsunami, it was revealed that the coral beds reduce the effect of the wave and its destructive force.