Minerals and Energy Resources

Every card in this deck

QMineral

AA homogeneous, naturally occurring substance with a definable internal structure. Rocks are combinations of minerals, and the physical and chemical conditions of formation give each mineral its colour, hardness, crystal form, lustre and density.

QOre

AAn accumulation of a mineral mixed with other elements, in which the mineral is concentrated enough to make extraction commercially viable. The formation it occurs in decides how easily, and how cheaply, it can be mined.

QHow do minerals occur in igneous and metamorphic rocks?

AMolten or gaseous minerals are forced up through cracks, crevices, faults or joints and solidify as they cool. Small occurrences are called veins and large ones lodes. Tin, copper, zinc and lead are obtained from them.

QHow do minerals occur in sedimentary rocks?

AIn beds or layers formed by deposition, accumulation and concentration in horizontal strata. Coal and some iron ore were concentrated under great heat and pressure over long periods, while gypsum, potash salt and sodium salt formed by evaporation, especially in arid regions.

QHow are bauxite deposits and placer deposits formed?

ABauxite forms when surface rocks decompose and their soluble parts are removed, leaving a residual mass of weathered material containing the ore. Placer deposits are alluvial deposits in valley sands and at the base of hills, holding minerals water does not corrode, such as gold, silver, tin and platinum.

QWhich minerals are obtained from the oceans, and why are most ocean minerals not used?

AOcean water holds vast quantities of minerals, but most are too widely diffused to be economically useful. Common salt, magnesium and bromine are largely obtained from ocean water, and ocean beds are rich in manganese nodules.

QRat-hole mining

ACoal mining by family members through long, narrow tunnels, practised at Jowai and Cherrapunjee in Meghalaya, where minerals are owned by individuals or communities. The National Green Tribunal has declared it illegal and ordered it stopped.

QHow are India's minerals unevenly distributed, and why?

APeninsular rocks hold most of the coal, metallic minerals and mica. Sedimentary rocks in Gujarat and Assam hold most of the petroleum, and Rajasthan has many non-ferrous minerals, while the northern alluvial plains have almost none. The differences come from geological structure, processes and time.

QMagnetite vs hematite iron ore

AMagnetite is the finest iron ore, up to 70 per cent iron, with magnetic qualities valuable in the electrical industry. Hematite has slightly less iron (50-60 per cent) but is the most important industrial iron ore by quantity used.

QName India's four major iron ore belts and a key mine or feature of each.

AOdisha-Jharkhand (Badampahar; Gua and Noamundi); Durg-Bastar-Chandrapur (Bailadila's super-high-grade hematite, exported via Visakhapatnam); Ballari-Chitradurga-Chikkamagaluru-Tumakuru (Kudremukh, a 100 per cent export unit); and Maharashtra-Goa (lower-grade ore exported via Marmagao).

QWhat is manganese used for, and which state was the largest producer in 2018-19?

AMainly steel and ferro-manganese alloy: about 10 kg is needed per tonne of steel. It is also used in bleaching powder, insecticides and paints. Madhya Pradesh was the largest producer (33 per cent), followed by Maharashtra (27 per cent).

QWhy is copper important, and where is it mined in India?

ACopper is malleable, ductile and a good conductor, so it is used mainly in electrical cables, electronics and chemical industries. India is critically deficient in it; the leading producers are Balaghat (Madhya Pradesh), Khetri (Rajasthan) and Singhbhum (Jharkhand).

QWhy is aluminium important, and where is bauxite found in India?

AAluminium combines the strength of metals like iron with extreme lightness, good conductivity and great malleability. Bauxite deposits lie in the Amarkantak plateau, Maikal hills and the Bilaspur-Katni plateau. Odisha was the largest producer in 2018-19, with Panchpatmali in Koraput the key deposit.

QWhy is mica indispensable to the electrical industry, and where is it found?

AIt splits into very thin sheets and has excellent dielectric strength, low power loss, good insulation and resistance to high voltage. The Koderma-Gaya-Hazaribagh belt of Jharkhand leads production, with Ajmer (Rajasthan) and Nellore (Andhra Pradesh) also important.

QWhy do we need to conserve mineral resources, and how?

AWorkable deposits are only about one per cent of the earth's crust and form far more slowly than we use them, so they are finite and non-renewable, and extraction grows costlier as quality falls. Conservation means planned use, technology for low-grade ores, recycling, scrap metal and substitutes.

QConventional vs non-conventional sources of energy

AConventional sources are firewood, cattle dung cake, coal, petroleum, natural gas and electricity (hydel and thermal). Non-conventional sources are solar, wind, tidal, geothermal, biogas and atomic energy.

QPeat, lignite, bituminous coal and anthracite

ACoal ranked by compression and depth of burial. Peat has low carbon, high moisture and low heating capacity. Lignite is soft brown coal, found mainly at Neyveli. Bituminous is the most used commercial coal; its high grade is metallurgical coal. Anthracite is the highest-quality hard coal.

QWhere are India's Gondwana and tertiary coals found?

AGondwana coal, over 200 million years old and metallurgical, lies mainly in the Damodar valley (Jharia, Raniganj, Bokaro), and also in the Godavari, Mahanadi, Son and Wardha valleys. Tertiary coal, about 55 million years old, occurs in Meghalaya, Assam, Arunachal Pradesh and Nagaland.

QWhy are heavy industries and thermal power stations located on or near coalfields?

ACoal is bulky and loses weight on use because it is reduced to ash. Transporting it over long distances is therefore uneconomical, so industries that use large quantities are set up close to where it is mined.

QIn what kinds of rock structures is petroleum found in India?

AIn anticlines and fault traps in tertiary rocks. In an anticline, oil is trapped at the crest of an upfold in porous limestone or sandstone, held by non-porous layers above and below. Gas, being lighter, lies above the oil. Main areas are Mumbai High, Gujarat (Ankleshwar) and Assam (Digboi, Naharkatiya).

QWhat is natural gas used for, and where are India's main reserves?

AIt is used for power generation, industrial heating, as raw material for chemical, petrochemical and fertiliser industries, and increasingly as CNG for transport and PNG for cooking. Major reserves are at Mumbai High and the Cambay basin, with new finds in the Krishna-Godavari basin.

QHow does hydroelectricity differ from thermal electricity?

AHydroelectricity uses fast-flowing water, a renewable resource, to drive turbines, as at Bhakra Nangal, Damodar Valley and Kopili. Thermal electricity burns non-renewable coal, petroleum or natural gas to drive turbines. Per capita electricity use is treated as an index of development.

QWhy do solar and wind energy have a bright future in India?

AAs a tropical country, India has enormous solar potential: photovoltaic cells turn sunlight directly into electricity and cut rural reliance on firewood and dung cakes. It also has great wind potential, with the largest wind farm cluster running from Nagercoil to Madurai in Tamil Nadu.

QWhy are biogas (gobar gas) plants especially useful in rural areas?

ADecomposing shrubs, farm, animal and human waste yields gas with higher thermal efficiency than kerosene, dung cake or charcoal. Farmers get both energy and better manure, and it saves trees and manure that would otherwise be burnt as fuel wood and dung cakes.

QWhy is energy conservation essential, and how can citizens help?

AEnergy is a basic need of every sector, and consumption keeps rising, yet India is one of the least energy-efficient countries. Conservation and renewables are the twin planks of sustainable energy. Citizens can use public transport, switch off unused power and use power-saving devices: energy saved is energy produced.