(1) Mica

Mica represents a group of minerals like muscovite (potash mica), biotitic (iron magnesium mica), phlogopite (magnesium mica) and lepidolite. Of these, the first two are of great economic value. Muscovite mica occurs in coarse-grained pegmalite dykes of igneous rocks and is colorless and trans­parent. The biotite mica is usually black in thick crystals and is found both in igneous and Metamora rocks.

Phlogopite mica also occurs in igneous rocks and its colour is yellow to brown. Workable mica deposits are found as veins or ventricular intru­sions of pegmatite’s in mica schist’s and mica gneisses. It occurs in the form of ‘books’.

Mica is mainly used as an insulating material in electrical goods and as a substitute for glass. It is impervious to heat and hence used in the peep-holes of furnaces, tanks and fighting planes. It serves as an insulating medium in high power motors in air-craft. It is also used in the radio industry and in radar.

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Large and clear sheets of muscovite are used in stoves, windows, lamps and marine compass. Small pieces of mica are ground to be employed in paints, lubricants, wall-paper, rubber and fire-resisting waif boards. Mica is also used in medicines. Mica split-) ting are used for manufacture of mica tape and cloth.

Mica is now artificially prepared by fusing quartz, magnetite, and bauxite and fluo-silicates under high pressure at a temperature of I4000C.

The tentative recoverable reserves of mica in three main producing states (Andhra Pradesh, Bihar-1 Jharkhand and Rajasthan) of the country are at 1,09,014 tones amongst which about 86 per cent lies in Andhra Pradesh.

Production

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India produces about 85 per cent of the world mica production. Prior to 1960 there was hugged of mica in the international market. Consequently highest production (28,347 tones) was re- r corded in 1961. Since then there has been gradual; decline in the production of mica so as to reach the lowest production in 2000-01 (1,154 tones). However, there was some sign of recovery in the coming year; the production being 2,026 tons in 2001-02 (cf. 1,807 tones in 19911 00).

The decline in production is mainly due to low demand of the mineral in the international market. The artificial mica has also played major role in this I respect.

Regional Distribution

Four states (Andhra Pradesh, Bihar-Jharkhani and Rajasthan) together contribute entire mica pro­duction of the country. Andhra Pradesh alone pro­duces over 73 per cent of the country’s output of mica.

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LJihar-Jharkhand-Bihar (including Jharkhand) occupies second place in respect of reserves (13,554 tonnes) and third is production (11.83%) of mica in the country. The states are also the largest producers of high quality block mica in the world.

The mica belt runs in east-west direction for 145 km from Gay a district in the west to Bhagalpur district in the east through Hazaribag and Munger districts with average width from 19 to 22 km and pegmatite content from 2 to 36 per cent.

There are about 600 mines in this belt with important centres like Kodarma reserve forest, Chatkari, Dhorhakola, Domchanch, Dhengura, Dhab, Gawan, Masnodih, Parsabad, Tisri, Bendi, and Garia in Hazaribag dis­trict; Mahesri, Nawadih and Chakai in Munger dis­trict; and Dabur, Singur and Rajauli in Gaya district. Hazaribag district alone produces over 75% of the country’s production of mica, followed by Munger (20%) and Gaya (5%).

Some mica is also obtained from Dhanbad, Palamau, Ranchi, Singhbhum, Nawada and Giridih districts. Bihar mica is usually of ruby colour while green, white, silvery are also found.

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Andhra Pradesh-Andhra Pradesh ranks first in reserves of mica (about 93,778 tones) and its production (72.56%) in the country. The main mica belt of Nellore district extends over 110 km in length (between Gudur and Sangam) and 16 to 25 km in width.

Important mines are at Kalyanarama, Kalichedu, Sitarama, Pallimita, Bashire and Pattabhirama. Nellore mica is light green in colour; it is generally stained and spotted. Ruby mica is also found in Krishna district in the west of Tiruvur and 6 other localities; in Vishakhapatnam, East and West Godavari, Anantapur and Khammam districts. Phlogopite mica with a light to deep amber colour occurs in Vishakhapatnam district near Kudia, and Majigudem.

Rajasthan-Rajasthan (reserves 1,682 tones) is the second important producer of mica in the country. In 2002-03 the state produced 190 tons of mica (15.6 per cent of India). Here mica belt stretches for a distance of 322 km from Jaipur in the north-east to Udaipur in the south-west (width 96 km).

Mica occurs in coarse granitic pegmatites, differentiated into quartz cores and feldspathic mica-bearing mar­gins. Main deposits of mica are found in Bhil wara (at Danta, Nat-ki-Neri, Toonka, Sidirias, Pratabpura, Ghoras, Baneri, Kangni,Chapri,Lambia,Eklinghura, Phulia, Shahpura, Gundhi, Potlan, Imantia and Beliya etc); Ajmer (at Ajmer, Bhinai, Kalinjir, Beawar, Balad, Ratanpura, Gilwara, Jalia, Lasani, Dadi, Champaneri, Kalatamkara etc); and Udaipur (Sardargarh,Bhagatpura,Gangapur, Kuanthal, Amet etc) districts. In Bhil wara and Udaipur districts ruby mica is generally found; elsewhere it is spotted. Some micadeposits are also found at Barla, Mankhand, Baroni and Palri areas of Jaipur and Tonk districts.

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Karnataka-In Karnataka mica bearing pegmatite does extend from 144 to 160 km from Am vala (Mysore district) to Belur (Hassan district). Impor­tant centers are Tagdur, Vadesamudra, Undavadi and Mundoor. The mica is of poor quality.

Tamil Nadu-Muscovite deposits occur in Tirunelveli (near Kovilpatti), Coimbatore (Vairemanlam, Munampalli, Sevattampalaiyam), Tiruchchirappalli (Kurumbapatti,Pallipati,Kadavurand Mundilmalai), Madurai (Agmalapatti and Vattalagundu), Dharmapuri and Kanniyakumari districts.

Madhya Pradesh – Chhattisgarh-In Madhya Pradesh mica is found in Sarguja (both ruby and green mica), Balaghat, Bastar, Bilaspur, Narsingpur, and Chhindwara districts.

Kerala-In Kerala scattered deposits of mica occur in Alleppe^ (at Maulhupa and Kulanda) and Quilon (around Ranni) districts. The important pro­ducers are Punalur and Nayyur.

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Others-Small quantity of mica is also found in Ratnagiri district (Maharashtra), in Ganjam (Duargaon and Chaktentuli, Cuttack, Koraput and Mayurbhanj districts (Orissa), in Spiti and Lahul district (Himachal Pradesh), in Goalpara district (Assam), in Purulia and Bankura districts (West Bengal).

Consumption and Trade

India produces about 85 per cent of world’s annual mica production. Of the total production about 10 per cent is utilised in the country mainly in electrical and electronic industries.

More than 90 per cent of the country’s production of mica is exported to earn valuable foreign exchange. Our main buyers include Japan (19%), U.S.A. (17%), and Great Britain (7%). Norway (7%), Russia, Poland, Germany, Czech Republic, Slovakia, Hungary and Netherlands. The export is in the form of block mica, splitting, condenser films, mica powder, mica waste and scrap. Kolkata and Vishakhapatnam are the main ports handling the export. In 2000-011ndiaexported63,200 tones of mica valued at Rs. 637 million (cf. 42,000 tones valued at Rs. 350 million in 1990-91).

There has been gradual decline in the production and export of mica in recent years due to severe compe­tition from Brazil, growing use of plastic and syn­thetic mica, rising cost of production, heavy export duty and growing internal demand. There is a need for quality control and research on new uses of mica to promote its export.