Minerals are naturally occurring substances with definite chemical and physical properties.
Uses of minerals
Mineral is an element or inorganic compound that occurs naturally. The main uses of minerals are as follows:
Development of industrial plants and machinery Generation of energy e.g. coal, lignite, uranium Construction, housing, settlements
Defense equipments- weapons, settlement Transportation
Communication-telephone wires, cables, electronic devices Medical system- particularly in Ayurvedic System Formation of alloys for various purposes
Agriculture- as fertilizers, seed dressings and fungicides Jewellery- e.g. Gold, silver, platinum, diamond
Table 3.1 Distribution and uses of major reserves and metals
2 Environmental impacts of mineral extraction
Major mines which are known for causing severe problems are given below: Jaduguda Uranium Mine, Jharkhand- exposing local people to radioactive hazards.
Jharia coal mines, Jharkhand- underground fire leading to land subsidence and forced displacement of people.
Sukinda chromite mines, Orissa- Seeping of hexavalent chromium into river posing serious health hazard, Cr6+ being highly toxic and carcinogenic.
Kudremukh iron ore mine, Karnataka- causing river pollution and threat to biodiversity. East coast Bauxite mine, Orissa-Land encroachment and issue of rehabilitation unsettled. North-Eastern Coal Fields, Assam-Very high sulphur contamination of groundwater.
3 Impacts of mining: Mining is done to extract minerals from deep deposits in soil. Environmental damages caused by mining activities are as follows:
Devegetation and defacing of lands: Mining requires removal of vegetation along with underlying soil mantle and overlying rock masses. This results in destruction of landscape in the area. Subsidence of land: Subsidence of mining areas results in tilting of buildings, cracks in houses, buckling of roads, bending of rail tracks and leaking of gas from cracked pipe lines leading to serious disasters.
Groundwater contamination: Mining pollutes the groundwater. Sulphur, usually present as an impurity in many ores is known to get converted into sulphuric acid through microbial action, thereby making the water acidic.
Surface water pollution: The acid mine drainage often contaminates the nearby streams and lakes. The acidic water, radioactive substances like uranium, heavy metals also contaminate the water bodies and kill aquatic animals.
Air pollution: In order to separate and purify the metal from other impurities in the ore, smelting is done which emits enormous quantities of air pollutants. Oxides of sulphur, arsenic, cadmium and lead etc. shoot up in the atmosphere near the smelters and the public suffers from several health problems. Occupational Health Hazards: Miners working in different type of mines suffer from asbestosis, silicosis, black lung disease.
4 Remedial measures
Adopting eco-friendly mining technology
Utilization of low grade ores by using microbial – leaching technique. In this method, the ores are inoculated with the desired strains of bacteria like Thiobacillus ferroxidans, which remove the impurities and leave the pure mineral.
Re-vegetating mined areas with appropriate plants Gradual restoration of flora
Prevention of toxic drainage discharge.
5 Case studies
1. Mining and quarrying in Udaipur
Soap stones, building stone, and dolomite mines spread over 15,000 hectares in Udaipur have caused many adverse impacts on environment.
About 150 tons of explosives are used per month in blasting. The Maton mines have badly polluted the Ahar river.
The hills around the mines are suffering from acute soil erosion.
The waste water flows towards a big tank of “Bag Dara".
Due to scarcity of water people are compelled to use this effluent for irrigation purpose. The animals like tiger, lion, deer, and birds have disappeared from the mining area.
2. Mining in Sariska and Tiger Reserve in Aravallis
The Aravalli range is spread over about 692 Km in the North-west India covering Gujrat, Rajasthan, Haryana, and Delhi.
The hill is rich in mineral resources.
Mining operations within and around the Sariska Tiger reserve has left many areas permanently infertile and barren.
The precious wild life is under serious threat.