Environmental impacts due to mining manifest as water pollution, land degradation, loss of biodiversity, air pollution, increase in health related problems, occupational noise pollution, vibrations, land subsidence and landslides. Karnataka being one of the mineral rich states of the country, mining provides substantial non-tax revenue to the state's exchequer. Since our state is one of the most biodiversity rich states, it is all the more important to use this natural resources available with least impact on the environment.
Of the state's total area of 1,92,000 sq.km, more than 40,000 sq.km of green stone belts are known to contain vast mineral deposits of gold, silver, platinum, copper, diamond, iron, manganese, chromite, lime stone, dolomite, etc. At present about 20 varieties of major minerals and five varieties of minor minerals are being exploited in the State. 568 mining leases of major minerals covering an area of 21,247 hectares, 5650 quarry leases of minor minerals covering an area of 4,526 hectares have been sanctioned in the state till December 31, 2004.
In western ghats area, iron ore mining activity has resulted in degradation of land and forest area and impacted the water quality in the Bhadra River on account of siltation and contamination of water by the ore. However, at present, no new leases are sanctioned for mining/quarrying and mineral exploratory work in western ghats area. However, Kudremukh area in Chikamagalur district is likely to become a hotspot in the future, if environmentally effective conservation measures like stabilisation of slopes in the mine area and appropriate protective measures for silt storage dam etc., are not put in place.
The mine tailings heaped in huge dumps in the adjoining areas of closed gold mine site in Kolar district and lack of concerted efforts for reclamation and rehabilitation has resulted in environmental problems in terms of adverse health effects, loss of productive land due surface runoff from waste dumps.
Large numbers of big quarries are situated at Malkhaed, Wadi, Sedam and Shahabad, besides a number of smaller quarries spread across district. Intensive quarrying and presence of cement factories has lead to environmental problems like land degradation and air pollution respectively, in these locations.