Mica, Limestone distribution in India (Non-Metallic) – UPSC

• Non-metallic minerals contain no metal in the form that is extracted. Mica, limestone, dolomite, asbestos, magnesite, kyanite, sillimanite, gypsum, potash, sulphur and salt are the main ones treated here.
  • Coal and petroleum are non-metallic too, but they are studied apart as mineral fuels.
• Few of them match the metallic ores in value, yet they supply large industries: cement, fertilizers, steel flux, refractories and electricals.
• Geology and climate set their pattern.
  • Limestone follows the old sedimentary basins, including the Cuddapah and Vindhyan rocks.
  • Soluble minerals such as limestone, gypsum and salts are scarce in areas of high rainfall, and gypsum and salt concentrate in the dry north-west and on the coast.
• Dolomite, mica and gypsum were declared minor minerals on 10 February 2015. Their latest national resource figures therefore date from 1 April 2015, and their output comes from partial State returns. Mica became a major mineral again on 20 February 2025. The other minerals here have 1 April 2020 inventories.

Mica and Limestone

Mica

• Mica is a naturally occurring non-metallic mineral based on a collection of silicates, known as abhrak in Ayurveda. It occurs in the veins of metamorphic rocks, chiefly pegmatites.
• It is common in igneous and metamorphic rock and occurs occasionally as small flakes in sedimentary rock.
• Main types in India: muscovite (white or potash mica), phlogopite (amber or magnesium mica) and biotite.
• Properties:
  • Chemically inert and stable, and it does not absorb water.
  • A unique combination of elasticity, toughness, flexibility and transparency. It splits along its layers into very thin sheets.
  • A very good insulator, with a wide range of uses in the electrical and electronics industry. It withstands high voltage with a low power loss factor.
• Other uses: toothpaste and cosmetics, for its glittery look. It also acts as a mild abrasive in toothpaste.

Mica Reserves in India

• Mica is widely distributed. The most important mica-bearing rocks are in Andhra Pradesh, Maharashtra, Jharkhand, Odisha, Rajasthan and Bihar, with others in Gujarat, Haryana, Karnataka, Keralam (Kerala), Tamil Nadu and West Bengal.
• Total resources: 6,35,302 tonnes (1 April 2015), of which reserves are 1,14,433 tonnes. An earlier inventory gave 5,32,237 tonnes.

Mica Distribution in India

• Andhra Pradesh: long the largest mica producing State.
  • Nellore district produces the best quality mica. Its belt is about 100 km by 25 km, and the mica is light green, often stained and spotted.
  • Gudur taluka has the deep Shah mine, worked at about 300 m.
  • Visakhapatnam, West Godavari and Krishna are other important districts.
  • State returns show 16,822 tonnes in 2019-20 and 16,717 tonnes in 2020-21.
• Rajasthan: the second largest producer in classical accounts.
  • The mica belt runs about 320 km from Jaipur to Bhilwara and around Udaipur, about 96 km wide on average. It broadens around Kumbhalgarh and Bhilwara.
  • Bhilwara is the most important district. Jaipur, Tonk, Sikar, Dungarpur and Ajmer also produce.
  • State returns rose to 42,600 tonnes in 2021-22, from 16,000 tonnes in 2019-20. These recent figures are not on the same basis as the older dressed-mica output.
• Jharkhand: the third largest producer in classical accounts.
  • Mica lies in a belt about 150 km long and 32 km wide, running east-west from the Gaya district of Bihar through Hazaribagh and Koderma and on across Giridih and Munger to Bhagalpur.
  • It is the country’s richest source of high-quality ruby mica.
  • Kodarma was long described as the largest reserve of mica in the world. Kodarma, Giridih and Domchanch are the chief collecting centres, where mica is processed.
  • Munger in Bihar also has sufficient deposits.
  • Main centres of production in this belt: Kodarma, Dhorhakola, Domchanch, Dhab, Gawan, Tisri, Chakai and Chakapathal.
  • Outside the belt, mica occurs in Dhanbad, Palamu, Ranchi and Singhbhum.
• Other occurrences:

• Production trend:
  • Output climbed from 772 tonnes in 1947-48 to a record 28,347 tonnes in 1960-61, and stood at only 1,807 tonnes in 2011-12, with Andhra Pradesh giving 93%.
  • Plastics and synthetic substitutes, along with reconstituted mica, cut world demand for natural sheet.

Mica Exports

• India held a near monopoly of sheet mica for over a hundred years, and older accounts credit it with about 60% of world output and the place of largest exporter.
• Some grades of Indian mica stay essential to electrical manufacture worldwide.
• Exports still run high, as powder and scrap more than as sheet: 1,18,778 tonnes in 2023-24, of which powder was 76,315 tonnes and splittings 24,098 tonnes. Quantities were 28.4 thousand tonnes in 1960-61 and 126.4 thousand tonnes in 2013-14.
• Major exports are carried through Kolkata and Visakhapatnam ports.
• Older list of importers: Japan (19%), the USA (17%), the UK (7%), Norway (7%), then Russia, Poland, Germany and others.

• Coal and petroleum in this legend are the mineral fuels, not part of the group described here.

Limestone

• Limestone is a rock made of calcium carbonate, calcium magnesium carbonate, or both. Silica, alumina, iron oxides, phosphorus and sulphur occur in it in small amounts.
• Deposits are sedimentary and appear in rocks of every age from the Pre-Cambrian to Recent, with the Gondwana as the one exception.
• The two most important constituents are calcite and dolomite.
• Uses, on the older break-up of consumption:
  • Cement 75%, iron and steel 16%, chemicals 4%.
  • The rest feeds fertilizers, paper, sugar, glass, rubber and ferromanganese.
  • The latest output is even more one-sided: about 97.5% of limestone mined in 2023-24 was of cement grade.

Limestone Distribution in India

• Limestone holds the top position among non-fuel solid minerals by volume of annual extraction. Urban growth, housing and infrastructure keep raising demand.
• Total resources (1 April 2020): 2,27,589 million tonnes, of which 8% are reserves (19,028 million tonnes). An earlier inventory gave about 1,84,935 million tonnes. Portland cement grade is about 68%.

• This map also marks diamond, atomic minerals and salt, which do not belong to this section.

Limestone Production

• Production: 30.2 million tonnes (1980-81), 256.6 million tonnes (2011-12), 392 million tonnes (2021-22), 406 million tonnes (2022-23) and 452 million tonnes (2023-24). In 2023-24 India also imported 33.8 million tonnes.

• Others, 2014-15: Meghalaya, Odisha, Uttar Pradesh, Jharkhand, Assam, Keralam, Bihar, and Jammu & Kashmir gave the remaining 5%. In 2023-24 Maharashtra and Himachal Pradesh lead this group.
• Further districts:
  • Maharashtra: Yavatmal, Chandrapur, Nanded and Ahmednagar.
  • Odisha: Sundargarh, Sambalpur and Kalahandi.
  • Jharkhand: Palamu, Hazaribagh, Ranchi and Singhbhum.
  • Himachal Pradesh: Bilaspur, Kangra and Chamba.
  • Meghalaya: Garo, Khasi and Jaintia hills.
  • Uttar Pradesh: Mirzapur and Sonbhadra. Uttarakhand: Dehradun and Mussoorie. Jammu and Kashmir: Anantnag and Jammu.
• Cement-grade concentration: Kurnool, Kadapa and adjoining Andhra Pradesh, along with Kalaburagi, Vijayapura and Shivamogga in Karnataka, hold much of the cement-grade stone. Most Tamil Nadu deposits outside Salem are also of cement grade.

Other Non-Metallic Minerals

Dolomite

• Dolomite is an anhydrous carbonate mineral of calcium magnesium carbonate, ideally CaMg(CO₃)₂.
• The term also means a sedimentary carbonate rock composed mostly of that mineral. Another name for the rock is dolostone.
• Dolomite rock that also has calcite, or a mix of calcite and magnesite, is called dolomitic limestone.
  • A classical rule: limestone with more than 10% magnesium is called dolomite, and at 45% it is true dolomite.
• Uses: mainly blast furnace flux, a source of magnesium salts, refractories, and the making of fertilizer and glass.
  • Iron and steel take about 90%, with fertilizer next (4%), and ferro-alloys and glass (2% each).
• Dolomite is widely distributed in all parts of the country.

Dolomite Distribution in India

• Total resources (1 April 2015): 8,415 million tonnes, of which reserves are 677.8 million tonnes. An earlier inventory gave 7,730 million tonnes.
  • Madhya Pradesh 27%, Andhra Pradesh 15%, Chhattisgarh 11%, Odisha 10%, Karnataka and Rajasthan 7% each, Gujarat 6%, Maharashtra 5%.

• Variation by year: in 2011-12 Chhattisgarh gave about 30% and Odisha about 22%. Recent State returns are partial: Andhra Pradesh about 21.3 lakh tonnes (2020-21) and Odisha about 15.5 lakh tonnes (2021-22).
• Odisha (Orissa): Birmitrapur alone was credited with 256 million tonnes of recoverable dolomite. In the Gangapur area, beds near Sukra run for about 100 km.

• On this map, “Meghalya” is Meghalaya.

Asbestos

• Asbestos is a group of six naturally occurring fibrous silicate minerals.
• It is commercially important for its fibrous character, infusibility, low heat conductivity and high resistance to electricity, sound and corrosion by acids.
• Two quite different minerals fall under the name:
  • A variety of amphibole, resembling tremolite.
  • A fibrous variety of serpentine (chrysotile), the more important, and about 80% of commercial asbestos.
• Its great value lies in its fibrous structure, filaments of high tensile strength and great resistance to fire.
• Uses:
  • Fireproof cloth, rope, paper, millboard and sheeting.
  • Aprons, gloves and brake linings in automobiles.
  • Asbestos cement sheets, pipes and tiles for building.
  • Brittle asbestos makes filter pads for acids, and with magnesia it makes magnesia bricks for heat insulation.
• Health hazard: breathing its fibres raises the risk of mesothelioma, asbestosis and lung cancer.

Asbestos Distribution

• Total resources (1 April 2020): 22.90 million tonnes, all remaining resources.
  • Rajasthan 13.61 million tonnes (59%) and Karnataka 8.28 million tonnes (36%). Older shares were 13.6 million tonnes (61%) and 8.28 million tonnes (37%), with the remaining two percent elsewhere.
  • The remaining 5% lies in Jharkhand, Andhra Pradesh, Odisha and Uttarakhand.
• Occurrences:
  • Rajasthan: Udaipur, Dungarpur, Alwar, Ajmer and Pali.
  • Andhra Pradesh: fine quality in Pulivendla taluk of Kadapa (Cuddapah) district, especially in a zone of about 15 km between the Chitravati and Papaghni rivers.
  • Karnataka: Hassan, Mandya, Shimoga, Mysore and Chikmaglur.
  • Jharkhand: Singhbhum district.
  • Uttarakhand: Chamoli district.
• Production has ended.
  • Output was 42,699 tonnes in 1993-94 and fell to 280 tonnes in 2011-12.
  • India has no working asbestos mine, and none reported output in 2022-23 or 2023-24.
  • All demand is met by imports of 4,65,449 tonnes in 2023-24, from Russia, Kazakhstan, Brazil, China and others.

Magnesite

• Magnesite is a carbonate of magnesium, formed when dunite (peridotite) and similar magnesian rocks are altered.
• Uses: primarily refractory bricks.
  • It is also the ore of metallic magnesium, a bonding agent in abrasives, and an ingredient of special cement for artificial stone and tiles.
  • Steelmaking consumes it too.
• Total resources (1 April 2020): about 459 million tonnes, with 66 million tonnes of reserves. An earlier inventory gave about 335 million tonnes.
  • Major deposits: Uttarakhand (Uttaranchal) 52%, Tamil Nadu 34% and Rajasthan 12%.
  • Smaller resources: Andhra Pradesh, Himachal Pradesh, Jammu & Kashmir, Karnataka and Keralam.
  • Tamil Nadu’s ore carries little lime and much silica. Uttarakhand’s is the reverse.
• Tamil Nadu is the largest producer. It has one of the largest deposits in the world and the largest in India, at the Chalk Hills near Salem town.

• Trend: output rose from 1.19 lakh tonnes (1951) to a peak of 5.28 lakh tonnes (1990-91), and dropped to 2.17 lakh tonnes (2011-12).
• Other deposits:
  • Uttarakhand: Almora, with a belt about 3.2 km long, and Chamoli, Bageshwar and Pithoragarh.
  • Karnataka: Hassan, Mysuru and Kodagu.
  • Rajasthan: Ajmer, Udaipur and Pali. Himachal Pradesh: Chamba. Jammu and Kashmir: Udhampur.

Kyanite

• Kyanite is a mineral of metamorphic rocks rich in aluminium.
• It goes mainly into refractories, metallurgy, ceramics, electricals, glass and cement, because it withstands high temperatures. Heating forms mullite, the basis of high-alumina furnace linings.
• It is also used in making spark plugs in automobiles.
• India has long been credited with the world’s largest kyanite deposits. It has all three commercial grades, and quality rises with alumina content:
  • First grade 62–64%, second grade 58–62% and third grade 54–58%.
  • Almost all resources are now low grade or kyanite rock: high and medium grade together are only about 1.4%.
• Total resources (1 April 2020): 105.68 million tonnes, of which only 0.84 million tonnes are reserves.

• Producers:
  • Jharkhand, Maharashtra and Karnataka long gave practically the whole of Indian output, and in 2011-12 Jharkhand gave about 98%.
  • Output is now tiny and has shifted: 3,324 tonnes in 2023-24, about 94% from Maharashtra and the rest from Jharkhand.
• Major deposits:
  • Saraikela in Jharkhand, where a bed of about 130 km runs from Lapsa Buru to Kharsawan. Once the world’s largest and best, it is nearly exhausted.
  • Bhandara and Nagpur districts in Maharashtra.
  • Chikkamagaluru (Chickmaglur), Chitradurga, Mandya, Mysuru, Dakshina Kannada (Dakshin Kannad) and Shivamogga in Karnataka.
  • Smaller: Odisha (Dhenkanal, Sundargarh, Mayurbhanj), Rajasthan (Udaipur, Bhilwara, Dungarpur), Tamil Nadu (Kanniyakumari, Tiruchirappalli), Andhra Pradesh (Nellore) and Telangana (Khammam).

Sillimanite

• Sillimanite closely resembles kyanite in both occurrence and use. Its main use is in refractory bricks.
• The main concentrations are in Tamil Nadu, Odisha (Orissa), Keralam, Andhra Pradesh and West Bengal.
• Total resources (1 April 2020): 72.27 million tonnes, of which 8.26 million tonnes are reserves. Granular high grade is about 74%.

• Major deposits:
  • Ganjam district in Odisha.
  • Kozhikode, Palakkad, Ernakulam and Kottayam districts in Keralam, where beach sands hold about 5–6% sillimanite.
  • Bhandara district in Maharashtra.
  • Udaipur district in Rajasthan.
  • Hassan, Mysuru and Dakshina Kannada districts in Karnataka.
  • Smaller: Meghalaya (Khasi hills), Assam (Karbi Anglong), Madhya Pradesh (Sidhi), West Bengal (Darjeeling, Bankura, Purulia).
• Production: older accounts gave Odisha about 56% and Keralam about a third. Reported mine output in 2023-24 was only 771 tonnes, all from Maharashtra, as an associate of kyanite.

Gypsum

• Gypsum is hydrated calcium sulphate, white and opaque or transparent. Its beds lie among limestones, sandstones and shales.
• Uses:
  • Mainly ammonium sulphate fertilizer and the cement industry, where it makes up 4–5% of cement.
  • Plaster of Paris, moulds in the ceramic industry, tiles and plastics.
  • In agriculture, spread on the surface to hold soil moisture and help nitrogen uptake.
• Total resources (1 April 2015): 1,330 million tonnes, of which 37 million tonnes are reserves. An earlier inventory gave 1,286 million tonnes.
  • Rajasthan 81%, Jammu & Kashmir 14% and Tamil Nadu 2%. The remaining 3% is in Gujarat, Himachal Pradesh, Karnataka, Uttarakhand, Andhra Pradesh and Madhya Pradesh.
  • About 80% is fertilizer or pottery grade, and 13% cement or paint grade.
• Rajasthan dominates output.
  • Its share was once given as 81%, then over 90% (2011-12), and about 99% by 2014-15.
  • Latest State returns: 35.47 lakh tonnes in 2021-22, after 67.88 lakh tonnes in 2020-21.
  • Main deposits: Tertiary clays and shales at Jodhpur, Nagaur and Bikaner. Jaisalmer, Barmer, Churu, Pali and Ganganagar also have gypsum-bearing rocks.
• Elsewhere, in classical order of production:
  • Tamil Nadu: Tiruchirappalli district.
  • Jammu and Kashmir: Baramula, Doda and Uri.
  • Gujarat: Bhavnagar, Junagadh, Jamnagar and Kachchh.
  • Uttar Pradesh, with the former hill districts now in Uttarakhand: Tehri Garhwal, Dehradun and Mussoorie.
  • Smaller: Andhra Pradesh (Nellore, Guntur, Prakasam), Himachal Pradesh (Spiti, Sirmaur, Chamba), Karnataka (Kalaburagi) and Madhya Pradesh (Shahdol).
• By-product gypsum now exceeds mineral gypsum in quantity.
  • Marine gypsum comes from salt pans, mainly in Gujarat and Tamil Nadu.
  • Phospho-gypsum, fluoro-gypsum and boro-gypsum come from chemical plants.

Potash

• Potash is the common name of the fertilizer form of potassium (K), which is abundant in nature. Potassium is one of the three primary crop nutrients, and over 90% of potash goes into fertilizer. It is on India’s list of critical minerals.
• Total resources (1 April 2020): 23,091 million tonnes, all in the remaining-resources category.
  • Rajasthan about 89%, Madhya Pradesh 5%, Uttar Pradesh 4%, Bihar and Jharkhand about 1% each. Older shares were Rajasthan 94%, Madhya Pradesh 5% and Uttar Pradesh 1%.
  • Polyhalite makes up about 70%, with glauconite and sylvite much smaller.
• Production: the Indian occurrences have not been commercially worked, and no potash production is reported.
  • The entire fertilizer requirement is met by imports: about 3.43 million tonnes of potash fertilizer in 2023-24.
• Occurrences:
  • Evaporites: the Nagaur-Ganganagar basin in Rajasthan, Tso Kar in Ladakh, the Little Rann of Kachchh, and Rohtak and Sirsa in Haryana.
  • Glauconite sandstones and shales:
    • Madhya Pradesh: Satna and Sidhi.
    • Uttar Pradesh: Sonbhadra, Banda and Mirzapur.
    • Rajasthan: Jaisalmer, Chittorgarh, Kota, Karauli and Barmer.

Sulphur

• India has no mineable elemental sulphur reserves. Native sulphur resources are only about 0.21 million tonnes, all inferred, in the Puga Valley of Ladakh.
• Pyrites were used as a substitute for sulphur in sulphuric acid manufacture.
  • Pyrite resources stand at 1,674 million tonnes (1 April 2020), about 94% of them in Bihar.
  • The Saladipura unit in Rajasthan and the Amjhore unit in Bihar were closed in 2002–03, and there has been no pyrite production activity since 2003.
• Domestic elemental sulphur is a by-product, recovered from petroleum refineries and from fuel oil used as fertilizer feedstock.
  • Output was 9,76,615 tonnes in 2023-24, led by Odisha (26%), Keralam (22%), Haryana (17%) and Gujarat (14%).

Salt

• Salt is obtained from seawater, brine springs (salt water springs), wells, salt pans in lakes and rocks. Sea salt is about 82% of Indian output.
• India is the world’s third-largest producer of salt, after China and the USA, with about 280 lakh tonnes in 2022-23. It became self-sufficient in 1953.
• Gujarat is the leading State, at about 87%, a far larger share than the “nearly half” of older accounts.
  • Rajasthan gives about 6%, from Sambhar and other lakes, and Tamil Nadu about 4.7%.
  • Others: Andhra Pradesh, Maharashtra, West Bengal, Karnataka, Odisha and Goa.
• Rock salt is worked at Mandi in Himachal Pradesh, and older accounts also place it in Gujarat.
  • It is under 1% of Indian salt. The Mandi mine gave 1,002 tonnes in 2022-23 and nothing in 2023-24.
  • It holds only about 68% sodium chloride, so it goes to cattle feed rather than to table use.