NUCLEAR MINERALS

NUCLEAR MINERALS Heavy metals; such uranium, thorium, radium, plutonium and lithium, are sources of nuclear energy. Uranium is the most impot1 among these metals. The main ores of uranium
pitchblende, uranite, samarskite and thorianite. The US, the leading producer of uranium. South Africa, Austrc Canada, Niger and France are other important produc Colorado, Utah and New Mexico in the USA are important areas of uranium deposits. Australia's import uranium areas are Port Darwin, the Rum Jangle and Radium Hill. The Rand and the Massef Central h significant uranium deposits in South Africa and Fra respectively. Cornwell in England and Katanga in Republic of Congo also possess some uranium.

As compared to uranium, the geographical distribut of thorium is much more restricted. Main ores of thori are monazite, allanite and thorianite. The largest depo of monazite are in India. Florida coast and Idaho in USA and coastal areas of South Africa also have thori deposits.

Beryllium (obtained from beryl, which is found association with feldspar and mica in pegmatites), zir nium (found in zircon in beach sands) and ilimenite (foll in the concentrated form in the beach sands) are otl important nuclear minerals.

FUEL/POWER MINERALS: COAL

FUEL/POWER MINERALS

1. COAL A principal mineral fuel, coal is a combustible, solid stratified rock of organic and mineral matter. The organic matter constitutes carbon (60 to 90 per cent), hydrogen (one to 12 per cent), oxygen (two to 20 per cent), nitrogen (one to three per cent) and also small amounts of phosphorus and sulphur. Coal occurs as a sedimentary rock in association with carbonaceous shale, sandstone and even fireclay in a regular succession and in repetitions. Gondwana coal is found as drifted deposits and tertiary coal occurs as in situ deposits.

Coal originates from the accumulation of vegetable matter in swampy areas on broad delta, coastal plains and basin lowlands. The vegetable matter is subjected to geo­logical processes that effect physical and chemical changes. The changes can be seen in the darkening of colour, increase in compactness, hardness and carbon content, and decrease in volatility and moisture. The growth in situ and drift theories explain the origin of coal. The complex process of coal formation involves physical and bacteriological agencies. Favourable climatic conditions for coal formation are mild temperature to sub-tropical climate with well­-distributed moderate to heavy rainfall.

Stages of Coal Formation Peat is the first stage of coal formation and varies considerably in extent and thickness. It has a high percentage of moisture and volatile matter. Carbon makes up only about one-third of its bulk.

Anthracite, the hardest variety, ranks highest amongst the coals. It has a carbon content of almost 95 per cent with practically no volatile matter. Only about 5 per cent of the world's coal is anthracite.

Economic Uses Coal, a primary source of heat and power (thermal power), is used in the production of water­gas; in metallurgical operations for the purpose of extrac­tion of metals like iron, zinc, etc.; in the production of coal gas, tar, coke, etc.; and to produce different types of varnish and germicides.

Distribution of Coal in the World Fenno-Scandinavia is one of the main deposits of peat in the world. Take (A) on P 196 of GS. The world's 50 per cent of anthracite comes from the Pennsylvanian fields of the USA. Russia, Ukraine, Kyrgyzstan and Kazakhstan account for another 25 per cent.

In overall coal production, China and the USA together contribute about 60% of the total coal production in the world. China has been the main coal producing country
in the world since 1986. Here, coal is mined mainly in the north in Inner Mongolia, Shansi, Anhui, Jiangsu, Henan and Hegei regions. In USA, coal mining showed a decline after the Second World War due to subsidised oil and gas prices, development of nuclear energy and environmental restric­tions, but it picked up after the oil crisis of the 1970s. Mining in USA is done mainly in the Appalachian region and in the interior stales.

In erstwhile USSR, major coal producing regions are Kuznetsk in Karganda, Kuzbas basin, Pechora basin, Donbass region and Tungus basin. In Europe, coal is mined in'Franco-Belgian coalfields, in Ruhr, Saar, Silesia, Pilsen, Saxony in Germany and in Poland, UK, Spain and the Central French Plateau.

Distribution of Coal in India In India, coal belongs to two principal geological periods, i.e., the lower Gondwana coals of Permian age, and Tertiary coals of Eocene to Miocene age. The greatest period of coal formation in India is the Permian. The important coal bearing formations are collectively known as Damudas and belong to the lower Gondwana system. The series of coal formations are Peat­lignite-bituminous-Anthracite. The lower Gondwana coals account for more then 90 per cent of the annual production of coal which is generally of bituminous rank. In Tertiary coalfields, lignite predominates.

The Gondwana coals are largely confined to the river valleys like those of the Damodar, Mahanadi, Godavari, etc. Tertiary coals principally occur in Assam, in the Himalayan foothills of Kashmir and in Rajasthan (Palna in Bikaner) in Eocene strata. Besides these, lignite deposits are found to occur in the South Arcot district of Tamil Nadu, in Kutch of Gujarat and also in the state of Kerala. The Neyveli lignite field of Tamil Nadu (which is of the Miocene Age) is the largest lignite deposit in South India.

Major Coal Fields The statewise list of major coal fields is given below.
West Bengal Raniganj.

Jharkhand Jharia, Bokaro, Giridih, Karanpura, Ramgarh. Madhya Pradesh Singniuli, Pench Valley. Chhattisgarh Korba.

Orissa Talcher, Himgir.

Andhra Pradesh Kantapalli, Singareni.

Tamil Nadu Neyveli (lignite).

Assam Namchik~Namphuk, Makum, Najira, Janji.

Meghalaya Umralong, Darrangiri

Production India at present is the fifth largest producer
of coal in the world. Coal is also India's largest mineral resource. Given our large coal reserves and the high cost of importing alternative fuels, it is important to develop advanced utilisation techniques and minimise environmen­tal dCKr'adation.

NON-METALLIC MINERAL: MICA

NON-METALLIC MINERALS
1. Mica The term 'mica' covers a large group of rock­forming minerals. Natural mica forms hexagonal crystals of varying size. Owing to its excellent dielectric strength, low loss power factor and insulating properties, mica is one of the indispensable minerals used in electrical and electron­ics industry. The main mica minerals are:

(a) muscovite also known as white-mica or potash mica.
(b) biotite known as black mica or magnesium iron mica.
(c) phlogopite, i.e., amber mica or magnesium mica.
(d) zinnwaldite, also termed as lithium iron mica.
(e) roscoelite or vanadium mica.
(f) fuschsite, Le., chrome mica.

Economic Uses

(i) Mica is used as an insulating material in electrical industry.

(ii) Muscovite, phlogopite splittings are used in making of build-up mica or micanite and other insulation products, for heat insulation and also electrical insulation.

(iii) In powder form, it is used in lubricating oils and
decorative wall papers.

Distribution in the World India is the most important mica producing country in the world and it supplies- 80 per cent of the world requirements of block mica.
Distribution in India The principal members of the mica group found in India are muscovite, phlogopite and biotite-all being hydrosilicates. The micas which are usu­ally associated with acid igneous rocks are formed towards the end of the process of crystallisation. They are mostly formed as pegmatite deposits consisting of very coarse grained igneous rocks occurring as dykes or veins.

Mica minerals occur in igneous, sedimentary and metamorphic rocks formed under different geological conditions. While muscovite occurs in pegmatites of acidic natur~, phlogopite mica is restricted to basic pegmatite. Commercial biotite is found to occur mostly in biotiteschists.

Mica is produced mainly in the three states of Jharkhand, Rajasthan and Andhra Pradesh. Major producing regions include the following.

Jharkhand Here, mica is extracted from the Hazaribagh belt, with Koderma contributing a large part of the country's total production.

Rajasthan Here, mica is mined in the Beawar, Ajmer belt, Banswara-Dungarpur belt, Bhilwara, Tonk and Kaunthal in Udaipur.

Andhra Pradesh Here, mica is extracted from Nellore
in Gudur district.

Reserves and Production in India India is world's leading producer of sheet mica and accounts for about 60 per cent of global mica trade.

Matalic Mineral: BAUXITE

BAUXITE The only ore from which aluminium is extracted is called 'bauxite', which is not a IJJineral but an aggregate chiefly, of gibbsite, boehmite and a little of kaolinite. Bauxite is a secondary product in between monohydrate diaspore and trihydrate gibbsite, i.e., be­tween AlP3Hp and A12033H2O. Thus it is a generic term for rock rich in hydrous aluminium oxide (AlP32HP). The bauxite ore has a typical oolitic or pisolitic structure and it is found in an amorphous form. Presence of about 50 per cent Al203 is considered to be the lower limit for good commercial bauxite.

Economic Uses Bauxite is used in the manufacture of alum, aluminous sulphates and other chemicals; the construction of airplanes, automobiles, electrical appliances, etc; and the manufacture of containers, utensils and ma­chineries.

Distribution in the World Major bauxite producing countries in the world are Australia, Guin~a, Jamaica, Brazil, Surinam Yugoslavia, and the state of Arkansas in USA China, Malaysia, Indonesia, Turkey and India also contrib­ute small amounts.

Distribution in India Bauxite is associated with laterite rocks occurring extensively as blankets or cappings either on the plateau or hill ranges of peninsular India or in certain low level laterites in the inland area or in coastal tracts of the country. It is a result of the residual weathering process which leads to leaching of the silica.

The bauxite deposits are mainly spread over the Eastern Ghats. A statewise survey of bauxite reserves is given below.

Madhya Pradesh Nearly 30% of the country's prodlIC­tion of bauxite comes from Madhya Pradesh. Bauxite deposits here are found in Amarkantak plateau in Shahdot district, Maikala hills and the plateau region of Sarguja­Bilaspur- Raigarh-Katni.

Bihar In Bihar, bauxite deposits occur in Ranchi and Palamau.

Gujarat Here, bauxite is found in Jamnagar, Kaira, Sabarkantha, Surat and Kachchh.

Kamataka In Karnataka, bauxite reserves are found in Belgaum.

Maharashtra Kolaba, Kolhapur and Ratnagiri in Mahar.ashtra have copper reserves.

Tamil Nadu Here, bauxite is found in Salem, Nilgiri, Coimbatore and Madurai.

Uttar Pradesh Bauxite is extracted in Uttar Pradesh in Banda.

Jammu and Kashmir Here, high grade bauxite deposits are found in Poonch and Udhampur.

Metalic Minerals: TIN, LEAD and ZINC

TIN The main ore of tin 'is cassiterite or tinstone with about 75 per cent of tin. It occurs in igneous and metamorphic rocks. Nearly 80 per cent of the world's supplies come from alluvial deposits.
Distribution in the World Malaysia is the world's leading producer and exporter of tin. Other producers are Chma, Indonesia, Thailand, Nigeria, Zaire, Bolivia and Australia.

Distribution in India In India, Bihar, Jharkhand and Rajasthan are main l?roducers of tin.

5. LEAD AND ZINC The two metals, lead and zinc, rarely occur in native state. They generally occur in combination with other elements. Galena is the chief ore of lead while sphalerite or zinc blende is the chief ore of zinc. These sulphide ore minerals of lead and zinc are formed due to contact metasomatism, replacement by hydrothermal solutions. Galena is found in veins in lime­stones, calcareous slates and sandstones and occasionally in metamorphic rocks or in association with volcanic rocks, while zinc blende or sphalerite is found in veins in asso­ciation with galena, chalcopyrites, iron pyrites and other sulphide ores. The chief rock types associated with the sulphide ores of lead and zinc are pyrite, slate, dolomite and quartz.
Economic Uses (i) Lead is used in the construction of accumulators, for lead piping and sheeting cable covers, as pigments in glass making and in medicine.
(ii) Zinc is used for coating, galvanising iron and steel products, in the manufacture of pigments and alloys with other metals (like brass, bronze, german silver) and in the manufacture of batteries and electric appliances. Besides, it is widely used in textile industry, timber preservation, etc.
Distribution in the World Major producers of lead are the USA, Russia, Australia, Canada, Peru and Bulgaria. Leading producers of zinc are Canada, Russia, Peru, Aus­tralia and the USA.

Distribution in India Given below is a statewise survey of lead and zinc resources in the country.

Rajasthan Here, lead and zinc are extracted from the Zawar mines in Udaipur district and from Anguncha­Rampura in Bhilwara district. In these mines, silver ore is also extracted.

Andhra Pradesh Cuddapah district has the reserves. Gujarat Here, lead and zinc are extracted from Banaskantha, Vadodara, Panchmahal and Surat.

Lead and zinc reserves also occur in Meghalaya and Sikkim.

METALIC MINERALS: SILVER, COPPER Coper

SILVER

The ore minerals are stephanite, agentite, proustite and pyrargyrite. Silver is found in the galena ores that may have up to one per cent of this metallic mineral.
Distribution in the World Mexico is the chid producer of silver; other producers are Russia, Canada, Peru and Australia.

Distribution in India In India, the lead-zinc ores of Zawar in Rajasthan yield silver. Silver is derived as a by­product in the Kamataka gold fields. The lead ores in Andhra Pradesh (Guntur, Cuddapah, Kumool districts), Jharkhand (Santhal Parganas, Singhbhum), Bihar (Bhagalpur), Gujarat (Vadodara district), Karnataka (the district of Bellary), Uttaranchal (Almora district) and Jammu and Kashmir (Baramula district) are also expected to yield some silver.

3. COPPER ORE Copper is the most important non­ferrous metal and was the earliest metal used bv man. In nature copper occurs in the native form and- in three principal combinations, viz., sulphides (chalcopyrite, bornite, chalcocite, tetrahedrite, covellite and enargite), oxides (cu­prite, tenorite) and carbonates (malachite and azurite). To be economically exploitable, copper ores should contain at least 2.5 per ceni of copper.

Economic Uses The metal is of great industrial impor­tance due to its high electric conductivity, high ductility and malleability. Thus it is mostly used in electrical manufac­turing. Besides, the copper alloys are used in buildings, automobiles, airplanes, naval ships, household utensils as weU as in metallurgy and paints. However, in recent years, the increasing use of glass fibres has reduced the pressure on copper.

Distribution in the World The world's largest pro­ducers of copper ores are the U5A, Russia, Chile, Zambia, Canada and Zaire. Chile is the largest producer.

Distribution in India India is deficient in copper ores and thus depends to a large ~xtent on imports. In India, copper ores occur as sulphides. They occur both in ancient crystalline and younger rock formations including the Cuddapahs, Bijawars and Aravallis.

It is mostly believed that copper deposits are formed through hydrothermal solutions either as cavity filling or replacement deposits. But replacement has been a more dominant process than cavity filling. The ores found in India are sparsely disseminated or locally concentrated in the form of bunches in the enclosing rocks.

Important copper deposits in India are:
Rajasthan Khetri complex which includes the Khi­Dariba area in Alwar district and the Khetri-Singhana area in Jhujhunu district. (Khetri copper deposit is one of the important copper deposits in the country.)

Jharkhand Singhbhum district

Andhra Pradesh Bondalamottu, Nalankonda and
Dhukonda in the Agnigundala belt of Guntur district; Ganikalava, Gumankonda and Somalapilli in Kamool dis­trict; and Garimanipenta in Nellore district.

Other important copper deposits of the country are in Himachal Pradesh-Kangra-Kulu valley: Mysore­Chit tal drug, Hassan, Bellary districts; West Bengal­Darjeeling, Jalpaiguri districts; Sikkim-Rangpo and Oickchu deposits which are found to occur in association with metamoJPhic rocks.

METALLIC MINERAL: GOLD

GOLD

Economic Uses (i) Gold is a precious metal and till very
recently constituted the international standard of exchange. (ii) In alloy state with other metals, it is mostly used in ornamentation. (iii) The industrial uses of gold alloys are in dentistry, and in chemical plants, thermo-couples, watches, X-ray equipment, photography and some medicines.

Distribution in the World The greatest producer is South Africa, with major mines in the Witwatersrand, Odendaalrus and Lydenburg. Canada, Japan, the USA, Zimbabwe and Ghana also produce gold.

Distribution in India In India, the vein gold deposits are found in Kamataka, Andhra Pradesh, Assam, Bihar, Madhya Pradesh and Tamil Nadu while alluvial gold is mainly found in Bihar, Assam, Uttar Pradesh, Madhya Pradesh, Kerala, Punjab and Meghalaya.
The Kolar gold field in Karnataka has been the principal source of gold production in India since 1871 when mining first started. It has four productive mines­Nandydroog, Champion Reef, Mysore and Ooregaum. The Champion Reef mine is the deepest mine in the world. Th~ Oharwar schists on which the Kolar gold fields are situated run in a north-south direction for 80 km. 'However, the quartz veins bearing gold are confined to only a 6-7 km section near Marikuppan. The mineralising solutions re­sponsible for the development of the auriferous veins of South India were probably derived from the magma which gave rise to champion gneisses. The Kolar field mined by the Bharat Gold Mines Limited has always had the highest output in India, but it now faces closure.
In the Raichur district, the auriferous veins occur within the schistose rocks of Dharwarian age. There are six auriferous quartz reefs of which the Oakley reef is the main producer. It is worked by Hutti Gold Mines Company of Karnataka state. According to the Geological Survey of India, the reserves in both these fields are estimated at about 4.5 million tonnes with a total gold content of about
45,000 kg. In addition ore reserves of about 60,000 tonnes with 8.5 gm per tonne have been indicated in Budini area.

New fields have been found at Kempinkote (Hassan district), HOimali (Shimoga district), Siddarahalli (Chikmaglur district), Bellara (Chitradurg district) and Munglur (Gulbarga district).

In Andhra Pradesh, the Ramgiri field of Anantapur district is the main source of gold.

CHROMITE ORE

CHROMITE ORE Chromite is the on Iv ore mineral of chromium and is an important alloying eiement in the manufacture of steel. Chromite is an oxide of iron and chromium with a theoretical composition of 32 per cent and 68 per cent. Alumina, iron oxide, magnesium oxide, lime and silica may reduce content.

Uses of Chromium Chromite is used in
(a) metallurgical industries in the production of various
non-ferrous alloys of chromium and also in the form of ferrochrome for manufacturiQg chrome steel;

(b) refractory industries due to its high resistance against corrosion, high temperature changes and its chemi­cally neutral character;

(c) chemical industries for the manufacture of chro­mium compounds like chromates and bichromates, chromic acid, etc.

Distribution in the World The world's leading pro­ducer of chromite is South Africa. Zimbabwe, Russia and Kazakhstan are other major producers.
Distribution in India In India the chromite deposits occur as the following Precambrian formations of penin­sular India.

(a) Deposits associated with the Dharwar metamorphic rocks in Karnataka and Maharashtra.

(b) Deposits associated with the metamorphic rocks of iron ore in Bihar, Jharkhand and Orissa.

(c) Fracture lineament emplacements in gneissic terrain
in Tamil Nadu.
(d) Younger deposits of the Himalayan-Arakan belt.
(e) Deposits of Andhra and those at Bembat' and Tashgaon (Ladakh), near Moreah (Manipur), near Kokapur and Vartha in Sabarkanta district (Gujarat) and at
Chakargaon (Andamans).

Major deposits of chromite in India are as follows:

Karnataka NuggchaIli belt which includes Byrapur, Chikonhalli, Pensamudra, Bhaktarahalli in Hassan district; and Kadkola, Talur, Gorur, Dodkanya in Mysore district.

Maharashtra Kankauli and Vagda areas in Ratnagiri district

Orissa Sukinda ultrabasic belt of Cuttack, Dhenkanal and Keonjhar districts. (The state is considered to have the largest chromite deposit in the country.)

Jharkhand Hills of Rorburu, Kiriburu, Kittaburu and Chittangburu in Singhbhum distrJct

Tamil Nadu Sittampudi in Salem district

4. NICKEL The main are is pentlaudite', a complex mixture of nickel, iron and sulphur, Nickel is also often found in association with copper. It is used for plating purposes as it does not rust. It is also less magnetic than iron, so it can be used in metal parts located near com­passes. Canada produces the largest amount of the world's nickel. Russia and Australia have large resources.

MANGANESE ORE

MANGANESE ORE In terms of composition of the manganiferrous ores with regard to the proportion of manganese to iron, it is customary to use the term manganese are for those containing over 40 per cent of manganese. The most common minerals are braunite, pyrolusite, psilomelane and manganite. The are contains impurities like silica, lime, alumina, magnesia and phospho­rus.

Manganese is used as a ferro alloy; it removes gases. and acts as a cleanser in the manufacture of steel. Man­ganese is also used as a decoloriser in glass, and in the manufacture of bleaching powder and electric batteries.

Classification The manganese ores, on the basis of their manganese content, may be classified into the follow­ing grades:

(a) Chemical grade
(b) Metallurgical grade
First grade More than 48% of manganese
Second grade 45-48% of manganese
Third grade 45% of manganese
(c) Manganese are 35-45% of manganese
(d) Ferrugenous manganese are 10-35% of manganese (e) Manganiferous iron are grade 10% of. manganese

For trade purposes, Indian manganese ores are clas­sified as follows:
(a) Battery grade 80-86% of Mn02
(b) Peroxide grade 78% MnO + 4% Fe
(c) High grade 46-48% of Mn
(d) Low grade 38-40% of Mn
(e) Ferrugenous grade 30-35% of Mn

Distribution in the World Former USSR, South Africa, Gabon, Australia, Brazil, France and India are major pro­ducing centres.

Distribution in India India is the third largest producer of manganese ore in the world. The country's most important ore deposits occur in the form of sedimentary stratified metamorphic deposits in the Dharwar system. The manganese deposits are generally either syngenetic (sedi­mentary) as in Madhya Pradesh and Maharashtra, epige­
82-87% of manganesenetic (residual enrichment and oxidation) as in Jharkhand, Orissa, Goa and Kamataka, or lateritic and supergene enrichments associated with the first two groups. On the basis of mode of occurrence and association with different kinds of country rocks, the Indian manganese ore deposits have been classified as

(a) gonditic ores which are associated with metamorphosed manganiferous sediments;

(bJKoduritic ores which are produced due to reactions between the country rocks and an invading magma or granitic compo­sition;

(c) lateritoid ores which are produced due to meta­somatic replacement and residual concentration. Georgia has huge deposits of manganese ore.
India is the third largest producer of manganese ore in the. world. The country's most important are deposits occu( in the form of sedimentary stratified metamorphic deposits in the Dharwar system.

In India, extensive and rich manganese deposits occur in Madhya Pradesh, Orissa, Jharkhand, Andhra Pradesh, Maharashtra and Karnataka. Indian manganese deposits display some distinct geological formations, which arc;

(a) deposits associated with the khondalite rocks (gar­net, sillimanite, gneisses) found in the Srikakulam district of Andhra Pradesh and in the Kalahandi and Koraput districts in Orissa;

(b) deposits associated with the iron ore bearing rocks (schists) found in Karnataka state in the Sandur hills, as the Bisgold-Yellapur deposits in North Kanara, and in the Chitradurg and Shimoga belt, and the Supa-Dandcli areil of North Kanara;

(c) deposits associated with limestone ilnd dolomite which occur in the Sausar-Manganese-Marble .province of Madhya Pradesh, Jharkhand and Gangpur (Orissa), Ratnagiri in Maharashtra, and Panch Mahal and Vadodara districts of Gujarat. The deposits of the group are generally ~mall and often have high phosphorus as in the case of ores from Srikakulam districts. Manganiferous shales and banded manganiferous rocks with friable layers of quartz are found associated with iron are group of rocks in Karnataka and Goa-Ratnagiri. In Jharkhand and Orissa the ore is low in phsophorous and h!gh in iron.

SURVEY OF IMPORTANT MINERALS

SURVEY OF IMPORTANT MINERALS

The important minerals of the world and their major producers alongwith India's position are surveyed here. METALLIC MINERALS: FERROUS GROUPS
1. IRON ORE One of the most widely distributed elements of the earth's crust, iron rarely occurs in free state. Like several other metals, iron ore deposits are associated mainly with igneous intrusions. Good quality iron ore is found in Russia, Ukraine, China, the USA, etc. Russia has the largest proven reserves of iron ore in the world. In 1999, China emerged as the biggest producer of iron ore in the world, followed by Brazil, Australia, India and Russia. Magnetite, haematite, limonite and siderite are the common types of iron ore.

A. Magnetite Magnetite with nearly 70 per cent iron content is the finest iron ore. Magnetite ore deposits are in igneous or metamorphic rocks. The banded type is considered to be the most important due to extensive occurrence, easy amenability to benefication by crushing and magnetic separation and agglomeration. Its colour ranges from dark brown to black.

Occurrence in the World It occurs in Sweden, Russia and Liberia.
Occurrence in India In India, magnetite deposits occur in Dharwar and Cuddapah systems of rock in the peninsula, in Karnataka, Andhra Pradesh, Tamil Nadu and Karnataka.

Major deposits of magnetite reserves in these states are as follows:
Kamataka Kudremukh, Hariyur, Kunigal, Siddarhali, Shankarguddu, Ubrani, etc., in the Archi, Gangamula and Gangrikal hill ranges.

Andra Pradesh Chityal, Daturabad, Kalleda, Rabanpalli, Singreni, Gopalpur, Utla, etc.

Tamil Nadu Chettari, Belukkurrichi, Namagiri, Panchalais, Sittinglinge, Kanjamalai, Tirthamalai, and Mahadev hills in the Salem district. Kelur, Malnad and Devala and Nilgiri district.

Kerala mostly in the Kozhikode district and in Cherupa,
Eliyettimala, Nauminda, Naduvallur and Allampara.

B. Haemetite Haemetite iron ore contains about 65 per cent iron. It is hard, bumpy, compact and reddish in colour.
Occurrence in the World It occurs in sedimentary rocks in crystalline or powdery forms. The Lake Superior areas in USA, Qebec in Canada, Brazil, Russia, Liberia, China and Spain have the ore.

Occurrence in IndiaHaemetite ores contribute to more than three-fourths of India's total production of iron ores. They are found in the Cuddapah and Dharwar systems. 9f the peninsular Deccan. They mostly occur as laminated hematite, micaceous haematite, hematite breecia and haematite quartz schist.

Important haemetite reserves in India are as follows:

Jharkhand and Orissa Gurumahisani-Badampahar belt and Barajamada group which include Barbil, Gua, Bonai, Joda, Kiriburu, Suleipat, Gorumahisani, Noamundi, Barajamda, etc. Barajamada group, which covers part of Singhbhum district in Jharkhand and, contains the largest ore reserves in the country.

Madhya Pradesh and Chattisgarh Bailadilla Raughat and Aridongri group in Bastar district; Dalli-Rajhara group in the Durg:district; and the deposits in Jabalpur district.

Maharashtra Lohara, Pipalgaon, Asola and Surajgarh (in Chandraprabha district)

Kamataka Chikmaglur, Sandur, Bellary, Hospet, Shimoga and Chitradurga districts

Goa Bicholim-Sirigao deposits, Gudnem-Dignem-Surle deposits, Velgnem-Pale deposits and Arwalem deposits.

Andhra Pradesh Anantpur, Khamman, Krishna, Kurnool, Cuddapah and Nellore districts where the main producing centres are Jaggayapeta, Ramallakota, Veldurti, Nayudupetta and Bayyaram.

C. Limonite (Bog Iron) Limonite Ore is a brown ore occurring in sedimentary formations. Its iron content is less than 50 per cent and it has many impurities.

Occurrence in the World Limonite are occurs in
Alabama, USA.
Occurrence in India Uttaranchal, Uttar Pradesh and
Himachal Pradesh possess major reserves of limonite.

Uttaranchal Garhwal

Uttar Pradesh Mirzapur district

Himachal Pradesh Kangra Valley

D. Siderite Siderite is a carbonate of iron and is found
near coal fields. It is also a residual ore and has an iron content of 20 to 30 per cent. Sideritic deposits are of the Jurassic age and are found in England (Lincolnshire), France and Luxembourg. In India, sideritic ores, like limonitic ores, are found in Uttaranchal, Uttar Pradesh and Himachal Pradesh.

Reserves and Production of Iron Ores in India India occupies a very high position in the world in terms of reserves of iron are. The total in situ reserves of iron are in the country are about 1,23,17,275 thousand tonnes of haematite and 53,95,214 thousand tonnes of magnetite. Besides these, small quantities of ilmenite and limonite ores are also found. The resources of very high grade are are limited and are restricted in Bailadila sector of Chhattisgarh and to a lesser extent in Bellary-Hospet area of Kamataka and Barajamda sector in Jharkhand and Orissa. Indian are has low sulphur content which never goes above 0.6 per cent.

Classification of Minerals

CLASSIFICATION

Minerals may be classified according to their use in industry as follows.
(a) Metallic minerals: ferrous group. They include minerals like iron, chromite, manganese and nickel.
(b) Metallic minerals: non-ferrous group. These feature copper, lead, zinc, tungsten, aluminium, vanadium among others.
(c) Non-metallic minerals. They are mica, steatite, asbestos and others.
(d) Refractory minerals. They are used as heat resis­tants in furnaces and moulds. They include chromite, magnesite, kyanite, fireclays, sillimanite and graphite.
(e) Fertiliser minerals such as gypsum, rock phosphate and pyrite.
(f) Mineral fuels such. as coal, petroleum, natural gas and nuclear minerals.

EXPLOITING MINERAL RESOURCES

EXPLOITING MINERAL RESOURCES

The minerals have to be exploited profitably, if their economic worth is to be realised. The profitability of mining operations depends on the value of the mineral and mining the costs. The mining costs would depend on the size of the deposit; grade of the ore; method of mining; transport and labour cost; and availability. Minerals occUr in varied formations, so different methods are needed to extract them from the surrounding rocks.

Open-cast mining is the easiest and the cheapest way of mining minerals occurring near the surface. The over­burden (the earth or other rock bands lying above the mineral-bearing strata) is removed and the ore is extracted layer by layer till the mineral content becomes too small or the pit becomes too deep for economic mining. Quarrying rock sucn as limestone, gravels, igneous rocks, and clay for bricks, involves open-cast methods.

When the ores lie deep below the surface, under­ground mining methods have to be used. Simple adits or inclined tunnels may be sufficient; however, often enough, vertical shafts have to be sunk to reach mineral seams. In case of minerals such as salt, potash, or sulphur, pipes are to be drilled down to the deposits and superheated steam or water injected to dissolve the minerals. The liquid is then pumped to the surface, where the water is evaporated to leave behind the mineral.
Minerals occurring in alluvial deposits are usually recovered by placer mining methods. The alluvium is mixed with plenty of water and then the mixture is rotated till the lighter particles (sand, mud, dust, stones) are washed off. The heavier ores with greater specific gravity are left behind and can be separated. In small deposits or stream beds, the method employed is panning. The disadvantages of panning are: creation of waste material, pollution and silting up of rivers. When alluvial deposits occur on the side of a valley or as a thick terrace deposit, hydraulic mining is employed.

Mining can have harmful effects: it can cause lands to become derelict, leading to wastage of agricultural and industrial land, besides endangering health and physical well-being. Abandoned mines often subside and lead to house collapse. The landscape is left ugly and desolate.

Minerals

Minerals are naturally occurring substances having a definite chemical composition. They are grouped into classes, generally as rocks, non-metallic, mineral fuels and metals.

OCCURRENCE

Metallic minerals, such as copper, tin, lead and zinc may occur in almost pure form in veins-a fissure in rock strata containing a thin deposit of crystalline rock formed by extremely hot solutions rising from magma-and lodes (very thick veins). An ore is a deposit from which a mineral is obtained. In some ores, several metals are associated together---e.g., silver and mercury are associated with lead and zinc. Some minerals occur in beds or layers which have formed due to deposition, accumulation and concentration in horizontal strata of the earth's 'crust. Examples are coal and some grades of iron ore. They are concentrated as a result of long periods under great heat and pressure.

Minerals like gypsum, potash salts and common salt are formed by the evaporation of lakes in desert areas. Bauxite is formed by the deep-weathering of a variety of rocks under tropical conditions with a climate of seasonal rainfall. Minerals like gold, tin and platinum are highly resistant to weathering, and may get removed in small particles from veins by erosion and carried off by running water in streams and rivers to be deposited in the plains or valleys below. These are known as alluvial deposits. Tin, gold, platinum, chromite, tungsten, diamonds and zircon are recovered from alluvial deposits by placer mining methods.

Minerals are distributed very unevenly over the earth's surface. In some places, e.g., in the Urals of Russia, in theCanadian Shield, the Katanga in Zaire, and in South Africa, a variety of minerals occur in great abundance:- M: the Amazon basin, the Netherlands, Denmark and some of the Central American states are poor in minerals.

Some min­erals are found in restricted areas of the world: tin, vanadium, nickel, cobalt, gold and asbestos are examples of such minerals. More than 50 per cent of the world's tin comes from eastern Asia (Malaysia, Thailand, China, Indo­nesia); the USA is the largest producer of some minerals such as molybdenum, sulphur and phosphates; Canada dominates in nickel production. Many of the more valuable minerals, including gold, are found chiefly in Africa, with South Africa accounting for nearly 70 per cent of the total. Africa also holds valuable deposits of cobalt, diamond and platinum.