MAJOR LEAD-ZINC DEPOSITS OF INDIA
Submitted By: M. Siva Sankar Pavani Misra Zeeshan Ahmad
IMPORTANT LEAD-ZINC DEPOSITS OF INDIA Introduction Lead occurs in native state, but it is quite rare. The metal is bluish grey in colour and shows on its fresh surface a bright metallic luster which quickly oxidizes on exposure to air. It is so soft that it can be scratched with finger nail and shows a black streak on paper. It is quite heavy, the specific gravity being 11.34. Ores
Chemical composition
Characters
Galena
PbS
Cerussite
PbCO3
Anglesite
PbSO4
Massive, granular, cubes and octahedral forms, perfect cubic cleavage, lead grey colour, metallic luster, Hardness = 2.5, Specific Gravity = 7.4 to 7.6 Prismatic, often cruciform twinned crystals, radiating, granular, massive and compact. Colour can be white or grey. Hardness = 3-3.5, Specific Gravity = 6.55 Prismatic, also massive. Colour can be white, blue, grey, green or yellow. Admantine luster. Hardness = 2.5 – 3, Specific Gravity = 6.3 – 6.4
Lead is a soft, heavy, toxic and highly malleable metal. It is bluish white when freshly cut, but tarnishes to dull grey when exposed. It is usually found in ore with zinc. Zinc is a silvery blue-grey brittle metal with a relatively low melting (~419ºC) and boiling point. Specific Gravity of Zinc is about 7.15. It can be rolled into sheets or drawn into wire between 100ºC and 150ºC, but reverts into a brittle condition at 300ºC and maybe readily powdered under hammer. It is soluble in dilute acids. The chief ores of Zinc with their chemical composition and main characters are mentioned below: Ores
Chemical Composition
Characters
Sphalerite
ZnS
Smithsonite
ZnCO3
Tetrahedra and rhombododecahedra forms are common, also occurs as massive, perfect cleavage, black or brown in colour with white or reddish brown streak, resinous to admantine luster, hardness = 3.5 - 4, specific gravity = 3.9 - 4.2 Commonly in massive, reniform, botryoidal, encrusting, granular or earthy forms, perfect 2
rhombohedral cleavage, white, grayish, greenish or brownish white colour with white streak, vitreous luster, hardness = 5.5, specific gravity = 4 - 4.5
The uses of lead and zinc and their compounds are manifold and they rank next to copper as essential non-ferrous metals in the modern industry. The chief uses of both metals and their compounds are tabulated below: Lead Metal
Uses Storage battery, sheeting and piping, ammunition, alloys like solder, babbit metal, pewter etc.
Compounds Oxides (Red lead) Carbonates (White lead) Nitrate Arsenate Acetate
Zinc Metal
Pigments, glass making, flux and rubber industry Pigment Calico-dying and printing Insecticide Medicine
Uses Galvanizing, dry battery, tubes of toothpaste etc, alloys like brass, German silver and white metal
Compounds Oxides and Sulphides Chloride Sulphate
Pigments Soldering, preventing decay in wood Dying, glue making etc
The largest single use of lead today is in the manufacture of lead acid storage batteries while the single largest use for the zinc is in galvanizing industry. Zinc is normally associated with lead and other metals including copper, gold and silver. There are four major types of zinc deposits: 1. Volcanic hosted massive sulphides (VMS) VHMS deposits are polymetallic and are an important economic source of copper and
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zinc often associated with significant concentrations of silver, gold, cadmium, bismuth or tin. 2. Carbonate hosted (Mississippi Valley & Irish types) Limestone and dolomite are the most common host rocks. The zinc lead content usually ranges from 5%-10% with zinc usually predominating over lead. Concentrations of copper, silver and barite of fluorite may also be present.
3. Sediment hosted (sedex deposits) The host rocks are mainly shale, siltstone, and sandstone. Sedex deposits represent some of the world’s largest accumulations of zinc, lead and silver. The mineral has a high silver content. The lead/zinc content ranges from 10-20%.
4. Intrusion related (high sulphidation, skarn, manto, vein) These deposits are typically found in carbonate rocks in conjunction with magmatichydrothermal systems and are characterized by mineral association of calcium and magnesium. Typically the ore body contains more lead than zinc and is associated with silver.
Lead-Zinc deposits in India are localized mainly in the Precambrian formations of the Peninsular Shield and to a smaller extent in the lesser Himalayas. The important economically viable deposits are located in two main regions of India namely, Western Region and Southern Region with some scattered deposits in other parts of Northern and Eastern Regions.
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Distribution and Reserves of Pb-Zn ores in India State
District
Area
Andhra Pradesh
Cuddapah
Gollapalle, Verikunta, Zangamarajupal Agnigundala Belt Nallakonda
Guntur Prakasam
Total Grade (%) Reserves (ores in million tonnes) 8.319 Pb- 0.64 to 8.99 Zn- 1.08 to 4.21
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0.55
Avg. Pb and Zn is 2 to 5.5
7.775
Avg Pb – Zn is 4.5
1.0
Zn – 3
0.118
Pb – 0.4, Zn – 2.83, Cu – 1.35 Pb – 6.69, Cu – 0.32 Pb - 0.51 to 5.49, Zn – 0.4 to 7.3
Tamil Nadu
Godda, Jamui, Hesatu-Belbathan Banka, Belt Deogarh, Hazaribagh Banaskantha Ambamata Chitrasani Vadodara Khandia Nagpur Kolari and Tambekhani Bhandara Mendki Khasi and Umpyrtha Jantia Hills Sundargarh Sargipalli Mayurbhanj Kesarpur Ajmer Ghughra Lohakan Sawar Tikhi Bhilwara Rampura-Agucha Pur Banera Sirohi Deri (RamgarhDelri Belt) Udaipur Zawar Rajpura-Dariba East Sikkim Bhotang and (Rangpo) Dikchu South Arcot Mamandur
Uttar Pradesh
Pittoragarh
Ascot
1.03
West Bengal
Darjeeling
Gorubathan
3.250
Total
All India
Bihar
Gujarat
Maharashtra
Meghalaya Orissa Rajasthan
Sikkim
2.63 332.71
0.95 0.679
359.017
Pb – 1.09, Zn – 2.59, Cu – 1.08 Pb – 1.15, Zn – 5.3, Cu – 0.6 Pb - 2.64, Zn3.95, Cu – 2.32 Pb – 4.01, Zn – 4.23 About 5 million tonnes of Pb and 18.5 million tonnes of Zn
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Western Deposits The Western Region comprises Rajasthan and Gujarat States. Copper-lead-zinc mineralization occurs as bi-and multi-metal deposits and 95% of National Ore Resource is confined to this region. There are two distinct metallogenic provinces; the north-eastern parts characterized by predominantly copper rich province, confined to the rocks of Delhi Supergroup, whereas in South Rajasthan and North Gujarat, the mineralization is chiefly lead-zinc ores with subordinate copper in the rocks of Pre-Aravalli, Aravalli and Delhi Supergroup (Table 1). AGE
GROUP
2 – 1.2Ga
Delhi Supergroup Sirohi Group
DEPOSITS
Ajmer lead-zinc belt Deri-Ambaji lead-zinccopper belt
2.5 – 2.0Ga
Aravalli Supergoup Udaipur Group
Zawar lead-zinc belt
Bhilwara Supergroup
Rajpura–Dariba-Bethumani
Rajpura Group
belt Pur-Banera lead-zinc-copper belt
3.2 – 2.5Ga
Hindoli group
Rampura-Agucha
Mangalwar Complex Sandmata Complex
Bhilwara Supergroup Rajpura-Dariba–Bethumani Belt Latitude: 24º58’N Longitude: 74º08’E 7
Size of Deposit: It is an underground mine. Tonnage of this deposit is 7.4MT. The Zinc grade is 6.26%, Lead grade is 1.56% and Silver grade is 82.6g/t.
Geological Distribution: The Rajpura-Dariba-Bethumani belt forms the western limb of BaneraBhinder synform extending from Bhinder in the South to Banera in the North covering a distance of about 130km. The Dariba-Bethumani belt, extending from Bethumani in the North and Dariba in the South is composed of a group of folded metasedimentary rocks belonging to the Bhilwara Supergroup. Numerous old workings, gossans and ferruginous breccias have been recorded in the southern part of the belt in the Rajpura-Dariba area.
Geological Map of Rajpura-Dariba 8
Type of Deposit: This ore deposit is stratabound and is enclosed in a sequence comprising metamorphic equivalents of ortho-quartzite, carbonates and carbonaceous facies which are flanked by a thick monotonous sequence of meta-argillites. Rajpura-Dariba ore body owes its importance to its multi-metal sulphide-sulphosalt associations within the ores. Economic Importance of Deposit: Zinc is dominant metal followed by lead and copper. The important trace metals are cadmium and silver. The sulphide ores at Dariba mine show mineralogical zoning. Copper, lead-zinc and iron rich zones appear successively from the footwall to hanging wall. Two important lodes namely, Main Lode and East Lode, which are separated by a distance of 150 m, occur at Rajpura-Dariba. The Main Lode is further divided into South lode and North lode. Ore Genesis: Rajpura Dariba is a SEDEX type deposit. Here the host rock is Dolomite and Graphite Schist. It is a stratabound, concordant, sheet-like/lensoid ore body. Rampura Agucha Lead-Zinc Deposit
Latitude: 25°49'56"N Longitude: 74°44'19"E
Size of Deposit: This is a Giant deposit. Its tonnage is 67.9MT. The Zinc grade is 13.36%, Lead grade is 1.87% and Silver grade is 48.4g/t. The metal content of ore treated from RampuraAgucha mine in Bhilwara district of Rajasthan was the highest at 15.19% (2.14% Pb and 13.05% Zn). The graphite-mica-sillimanite schist hosts the economic mineralizations in this deposit. The economic minerals in the order of decreasing abundance along with their ranges of modal percentages are: sphalerite (15-20%), pyrite (15-18%), pyrrhotite (12-14%), galena (1-2%) and sulphosalts (0.1-0.2%). Graphite is ubiquitous in the ore body (7-10%). The gangue minerals that amount up to 45% to 50% of the ore zone constitute quartz, feldspar (orthoclase, plagioclase), various micaceous minerals (sericite, chlorite, biotite), sillimanite with significant amount of garnets, amphibole, pyroxene, rutile, apatite etc. Geological Distribution: Rampura-Agucha is the largest opencast mine for zinc and lead, with a capacity of 6.15 million tonne per year lead zinc ore after a recent expansion. The ore body is 9
comparatively narrower and richer in grade in the northern part and wider in the southern. Thus open pit operation can go deeper only in the southern part. The general strike of the ore zone is parallel to the enclosing rocks, which is roughly NE-SW. The dip of the ore zone varies along the strike and depth. Near the surface, the dip of the hanging wall contact is steeper (75° to 80°SE) as compared to footwall contact (about 60° SE). In depth, dips of both the hanging and footwall contacts show a tendency to flatten. In general, the dip varies from 50° to 80°. The ore zone shows a variation in width, both along the strike and dip. The width of the ore zone gradually widens to about 95 to 100m.
Fig: stratigraphy map of major lead zinc deposits. 10
This lead-zinc deposit is located 15 km southeast of Gulabpura in the Bhilwara district, Rajasthan. The village Rampura, originally located adjoining the western flank of the deposit was rehabilitated in 1990, prior to the commencement of open pit operation and Agucha village is about 1.5 km southwest of the deposit. The proximity of these two village led to the naming of it as “Rampura-Agucha deposit”.
Map showing major Pb-Zn mines of Rajasthan, India
Ore Genesis: Mineralization is predominantly in graphite-mica-sillimanite gneiss/schist over a strike length of 1550m. The ore zone has a sharp contact with the hanging wall and footwall. The hanging wall side of the lode is the richest and also wide, followed by comparatively lean grade in the middle and a narrow, rich, footwall zone. Coarse-grained crystalline galena, associated with pyrite and pyrrohitite are seen in the hanging wall rocks. The mineralizations in hanging wall and footwall contacts is invariably fine to coarse-grained, and is made up of sphalerite and galena with numerous inclusions or rounded to sub-rounded discrete grains of feldspar, quartz, hornblende, sillimanite and dark green chlorite. 11
The deposits form a part of pre-Aravalli Banded Gneissic Complex consisting of gneisses, schist and intrusive of acidic and basic igneous rocks that occupy, predominantly, the southeastern plains of Ajmer and Bhilwara.
Geology of the Deposit: Since a greater part of the area is capped with soil cover and fresh rock exposures are very few, much of the information for detailed geology has been gathered from the drill cores. The rock units show NE-SW strike with steep dips in hanging wall (75°-80°) and moderate dips in footwall (60°-65°) towards south-east and plunges towards NNE. The sequence of rocks, from hanging wall to footwall, can be broadly grouped as under:
Garnet-biotite-sillimanite gneiss with intermittent bands of calc-granulites, amphibolites and aplites/ pegmatites
Garnet-mica-sillimanite gneiss/schist
Garnet-biotite-sillimanite gneiss with lenses of quartzo-felsphathic bands, amphibolites, pegmatites and aplites
Granite gneiss, and
Mylonitic rocks.
Aravalli Supergroup Zawar Lead-Zinc Belt Latitude: 24º19’N Longitude: 73º41’E
Size of the Deposit: It’s a bulk Mississipi Valley Type, underground mine with an annual capacity of 1.2 million tonnes of lead & zinc ores. The tonnage of this complex is 7.3MT. Here the Lead grade is 2.04%, Zinc grade is 3.77% and in Sinesar Khurd Complex tonnage is 6.4MT, and the Lead grade is 2.76%, Zinc grade is 5.32% and Silver is 143.5g/t.
Geological Distribution: Zawar belt has been the oldest centre of lead-zinc production in the
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world. This Group has underground mining complex which consists of four underground mines namely Mochia, Balaria, Zawarmala and Baroi. These mines have a capacity of 4000 TPD. The present structural disposition of Zawar area is the manifestation of two distinct major periods of tectonic cycles, each of which was characterized by intense folding and faulting. In Zawar area, the north and south limb of cross fold is represented by Mochia, Balaria and Bowa, whereas Baroi and Zawarmala represent the NS trending and N plunging first generation fold system.
Map showing Zawar Mining Complex, Rajasthan
Geology of the Deposit: The Archaean basement comprising of gneiss, schist, amphibolite, quartzite and granite dating back to 3.2 to 2.5Ga showing unconformable relationship with the Aravalli cover rocks, is clearly marked in and around Udaipur. Stratigraphic succession, established by Roy et.al.,(1984) for the Aravalli Supergroup of the type area around Udaipur and Zawar show two major groups separated by an unconformity. The Upper Aravalli Group consists 13
of greywacke-slate-phyllite, quartzite, dolomite and silty arenite (host for sulphides of zinc and lead) while carbonaceous and pelitic phyllites, dolomite, quartzite, stromatolite, phosphorite, chlorite schist, amphibolite, quartz arenite and local conglomerate belong to Lower Aravalli Group. In general, Aravalli rocks in Udaipur-Zawar region show a low-grade metamorphism. The recrystallisation of the silicate minerals suggests the grade of metamorphism to be of greenschist facies.
Map showing major production and smelting capacities of Pb-Zn Deposits in India 14
Ore Genesis: The mineralization occurs as sheeted zones, veins, stringers and disseminations, forming lenticular bodies arranged in overlapping enechelon pattern. The individual ore shoots persist along strike between 50 and 500 m, dip between 50° and vertical and plunge between 30° and 60° west or north. The ore body varies in width between 1 and 40 meters. The mineralization is restricted solely within dolomitic horizon along with the structural control, but regional stratigraphic and lithological control is also evident. The main sulphide minerals are sphalerite, pyrite and galena. Chalcopyrite, pyrrhotite and arsenopyrite are the associated minerals. Appreciable amount of silver and cadmium occur within the ore minerals.
Other Deposits of Pb and Zn in India Sargipalli Latitude: 22º03’N Longitude: 83º55’E
Age: 1.6Ga
Size of the deposit: This deposit has a capacity of 500tpd lead ore but has not reported any production for the last few years. The tonnage of this deposit is 2.06MT. The Lead grade is 6.7%, Copper grade is 0.33% and Silver grade is 51g/t.
Geological Distribution: Sargipalli mine is in Sundergarh district of Orissa. This deposit is sediment hosted (shale-hosted). The host rocks are paleoproterozic calc-silicate rock, chert, dolomite, dolomitic schist, marble, mica-chlorite schist, quartzite and tourmalinite. The host rock thickness is 150m. The rocks overlying the ore are paleoproterozoic marble and siliceous dolomite, and thickness is greater than 200m. The rocks underlying the ore are metaconglomerate and quartzite and their thickness is more than 600m. Related igneous rocks include amphibolites and granite-pegmatite.
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Map showing sulphide mineralization in Sargipalli
Ore Genesis: A stratabound, lead-dominant sulfide deposit (SEDEX type) occurs at Sargipalli, Orissa, India, at the interface of metamorphosed quartzwacke to quartzose clay and calcareous rocks of Proterozoic age. Ore minerals found are argentiferous galena, chalcopyrite, sphalerite, pyrite, pyrrhotite, arsenopyrite, and a little tennantite and tetrahedrite. Here both the host rocks and the ores got metamorphosed to the low amphibolite facies. Restriction of ore mineralization to definite stratigraphic zones, interbanding of ores of contrasted composition with metasediments, virtual absence of cross-cutting veins, variation of ore mineralization with variation in sedimentary facies, isofacial metamorphism of both the ores and the host rocks, absence of intense shearing or faulting along the ore zone, absence of wall-rock alteration, etc. suggest that the ore materials were deposited through sedimentation in an aqueous medium during accumulation of the associated rock-forming sediments. Mobilization and remobilization of the ore materials during later geological processes were insignificant.
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Mamandur (South Arcot District) Latitude: 12°0'53"N Longitude: 78°57'5"E Age: 2.6Ga
Size of the Deposit: The length of the deposit is 0.76km while the deposit thickness is 3.6m. Tonnage of this deposit is 0.92MT. Here the Zinc grade is 2.7%, Lead grade is 2%, Copper grade is 0.63% and Silver grade is 40g/t.
Map showing the ore zones of Mamandur deposit. (Stratiform and concordant nature of mineralization zone)
Geological Distribution: This deposit is in the south Arcot district of Tamil Nadu. It is also a sediment-hosted Pb-Zn deposit like the Sargipalli deposit. This deposit lies in the Peninsular Archean complex in the transition zone between charnockites on the west and migmatites on the 17
east. The Mamandur area is made up of migmatites and charnockites with bands of garnetiferous biotite sillimanite gneiss, magnetite quartzite and a suite of ultrabasic rocks comprising pyroxenite, gabbro, norite and anorthosite.
Ore Genesis: Host rocks of Neoarchean age include amphibolite, granulite, migmatite (arkose) and sillimanite gneiss. The host rock metamorphism varies from high grade granulite facies (800ºC and 8.5 kb) to as low as retrograde greenschist facies (275-255 ºC). The related igneous rocks include unmetamorphosed norite dike and sill. The multimetal lode comprises sphalerite, galena, chalcopyrite, pyrrhotite and pyrite with minor tetrahedrite, marcasite, cubanite, bornite etc. and is considered to be of the stratiform exhalative volcanogenic sedimentary type.
Bandalamottu (Agnigundala Belt)
Latitude: 16º13’15”N Longitude: 79º39’47”E
Age: Late Proterozoic
Size of the Deposit: The tonnage of this deposit is 8.319MT. Here the lead grade is 0.64 to 8.99% and zinc grade is 1.08 to 4.21%.
Geological Distribution: This is a sediment-hosted Cu-Pb deposit, in the Guntur district of the Cuddupah Basin. Here the host rocks include dolomite and phyllite. Stratigraphically the host rock belongs to the Cumbum formation of the Nallamalai Group, in the Cuddupah Supergroup. Tectonically this deposit is in the continental margin basin-foreland. The mineralized zone in the Bandalamottu hill is spread over a strike length of about 1200m with a down dip extension of about 500m. The main ore body is developed on the North-western flank of an anticlinal structure and consists of 5 overlapping lodes over a strike length of 400 to 600m. The thickness of the ore bodies ranges from 1 to 11m and the average thickness of
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individual lodes from 1.5 to 6.5m. The Eastern ore body is located on the eastern flank of the anticlinal structure which extends over a strike length of about 320m.
Geological map of Bandalamottu Area
Ore Genesis: This is an undifferentiated deposit (Carbonate-hosted deposit) formed as veins along bedding planes in (cherty) dolomite. Zones of lead-copper mineralization occur mainly in the upper part of the dolomite. Dolomite is fine-grained and massive and shows discrete carbonaceous matter in interstices between carbonate grains. Occasionally thin bands of chert are seen in carbonate host rocks. The mineralization is generally poor where the dolomites are associated with chert bands.
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REFERENCES International Journal of Earth Sciences and Engineering, ISSN 0974-5904, Vol. 04, No 02 - Spl issue, March 2011, pp. 12-20 Sarkar, S.C., 1974, Sulfide mineralization at Sargipali, Orissa, India: Economic Geology, v. 69, p. 206–217 Mookherjee, A., 1964, The geology of the Zawar lead-zinc mine, Rajasthan, India: Economic Geology, v. 59, p. 656–677 Pal, T., Deb, M., 2013, Chert association in the mineralized zone of the Proterozoic Dariba – Rajpura – Bethumni belt, Rajasthan: an oxygen isotope study and its implications, Current Science, v. 105, No.1 www.geologydata.info USGS mineral resources online spatial data (sediment hosted zinc-lead deposits) --------------; 2011, Indian Minerals Yearbook. Vol. 2, 50th edition, Lead & Zinc (Advance Release), Indian Bureau of Mines, Nagpur. --------------; 2000, Economic Geology, 2nd edition, Umeshwar Prasad, CBS Publication
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