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Origin and Distribution of Uranium and Thorium Deposits in
India India has no significant reserves of Uranium;
the need for uranium is met through imports. Uranium is imported from Russia,
Kazakhstan, France, Canada and Australia. Uranium resources in India are
estimated at various stages of exploration, and the estimates of uranium
reserves for planning and commercial exploitation are prepared jointly by the
Atomic Minerals Directorate (AMD) and the Uranium Corporation of India
Limited (UCIL). The
identified conventional uranium resources in India are hosted by the
following type of deposits: 1.
Carbonate Deposit 42.24 2.
Metamorphite type 31.55 3.
Sandstone type 10.33 4.
Unconformity type 9.95 5.
Metasomatite 3.74 6.
Granite Related 1.99 7.
Quartz Pebble
Conglomerate 0.19 The
majority of these resources occur in following 5 uranium provinces. 1.
Cuddapah
uranium province, located in the Southern and South Central Regions. It
contains the Proterozoic unconformity related uranium deposit at Lambapur-Peddagattu in Nalgonda
district, Andhra Pradesh. The Cuddapah basin also
hosts a unique stratabound uranium deposit
associated with siliceous dolostone at Tummalapalle in Cuddapah
district, Andhra Pradesh. 2.
Singhbhum
uranium province, located in the Eastern Region.All
the deposits, presently being exploited,such
as Jaduguda, Narwapahar, Turamdih, and Bagjata occur in
this province.The other deposits in this belt are Mohuldih, Nandup, Rajgaon, and Garadih.All these
occurrences are of vein type. 3.
Mahadek
uranium province, located in the Northeastern Region. The Cretaceous Mahadek Formation in Meghalaya contains the largest and
richest sandstone-hosted uranium deposit of the country at Domiasiat (KPM deposit) in West Khasi Hills district. Another deposit of similar
nature is at Wahkyn where exploration activities
are in progress. 4.
Albitite belt
of Rajasthan and Haryana, located in Western and Northern Regions. The Meso-proterozoic Delhi Group of metasediments
in parts of Rajasthan and Haryana holds potential for metasomatic
and unconformity type of uranium mineralisation. A
small deposit hosted by albitised metasediments of Delhi Supergroup
has been established at Rohil and its extension. 5.
Bhima
basin, located in Southern Region. Comprising arenaceous
and calcareous metasediments of Bhima
Group deposited over basement granite, affected by number of East-West
trending major fault zones. A small sized medium grade uranium deposit has
been established in one such fault zone at Gogi.
Apart
from these economically feasible occurrences, a number of geological
situations occur, which may host potential uranium mineralization. Efforts
are underway to augment the uranium resource base of the country by
undertaking exploration activity in the following geological domains. 1.
Proterozoic
Basins: Nearly 33% of world uranium resources are found in the
Proterozoic rocks. Particularly the unconformity contact zones between the
Lower Proterozoic rocks with those of Middle-Upper Proterozoic ages have been
the prime locales for the Uranium mineralisation.
In India, a number of Proterozoic basins such as (i) Cuddapah
basin, Andhra Pradesh (ii) Aravalli-Delhi
fold belt, Rajasthan (iii) Gwalior-Vindhyan
basin, Madhya Pradesh (iv) Bhima basin, Karnataka
(v) Chhattisgarh basin in Chhattisgarh & Orissa exist where
multidisciplinary investigations have been taken up in search of
unconformity related uranium
deposits. 2.
Phanerozoic
Basins: Similarly nearly 18% of world uranium resources are
associated with Phanerozoic sandstones. In India too, the Phanerozoic
sandstones, particularly the Cretaceous basin of Meghalaya has been one of
the main targets for uranium exploration. One deposit has already been
established and the entire basin has been considered as one of the thrust
areas for uranium investigation. Other Phanerozoic basins considered
potential are (i) Siwalik basin of the Himalayas, (ii) Gondwana
basins of Central India. 3.
Fe-oxide
breccia type deposits: Particularly after the discovery of the
Olympic Dam deposit in Australia which alone constitutes 31% of world uranium resources
(RAR+EAR under <US $40/Kg U category - as per WNA publication), attention
has been given worldwide to look for uranium mineralisation
elsewhere in similar geological environment. In Indian scenario, such
environments exist in parts of Madhya Pradesh, Jharkand
and Meghalaya where investigations have been initiated with this objective. 4.
Quartz
pebble conglomerate deposits: Known Quartz-pebble
conglomerate (QPC) type of U-deposits constitute 13% of total world uranium
resources. They occur as basal Lower proterozoic
beds unconformably lying
above Archaean basement rocks. In India such
environments are observed at a number of places like Walkunji
in South Kanara District and Arbail
in North Kanara district in the Western Ghat Belt, Karnataka, Dhanjori
and Iron basins of Singhbhum district, Jharkand and Sundergarh
district, Orissa. Based on the number of anomalies located in these areas
survey has been intensified for locating QPC type of deposits. 5.
Vein and Metasomatic type deposits: In recent past, Metasomatic/ vein type mineralisation
associated with albitite type of rocks emplaced in tectonised domains have been located in many parts of the
world, particularly in Russia and Kazakhastan. They
owe their origin to both magmatic and metasomatic
processes. Such geological set up also exists in India particularly in parts
of Rajasthan (Aravallis) and Andhra Pradesh.
Extensive efforts are being made for locating such deposits. 6.
Placer
Deposits: An important source of
uranium is the mineral monazite in which uranium occurs as a trace
constituent. Placer deposits of monazite occur in abundance as beach sands
occur on east and west coasts and in some places in Bihar. But the largest
concentration of monazite sand is on the Kerala coast. Other minerals like
apatite, zircon and sphene which occur in these placers, also contain traces of uranium. Over 15,200 tonnes of uranium is estimated to be contained in
monazite placers. The Atomic Minerals Directorate for
Exploration and Research (AMD) has established the presence of 1,71,672 tonnes of Uranium ore (U308)
as on 30.06.2011. One tonne of uranium ore yields
0.848 tonnes of uranium metal. State-wise details
of uranium resources are given in the following table:
The UCIL is presently operating five
underground mines (viz. Jaduguda, Bhatin, Narwapahar, Turamdih and Bagjata), one open
cast mine (Banduhurang) and two Processing Plants (Jaduguda and Turamdih) in East Singhbhum District and one underground mine at Mohuldih is under construction at Saraikela
Kharswan District (all in Jharkhand State). An
underground mine and ore processing plant at Tummalapalle
(Tummalapalle Uranium Project) in Andhra Pradesh
with a capacity to process 3000 tonnes per day (tpd) ore is in advanced stage of construction. An
underground mine and process plant at Gogi in Yadgir District of Karnataka is under pre-project stage. Some
common minor primary constituents of igneous rocks carry uranium and thorium
in isomorphous substitution for Ca,
some REE and other elements. Thorium Deposits in India Monazite is the chief source of thorium in the
world. Though it is a constituent
of some granites and pegmatites, these rocks are
not economically workable.
Monazite is concentrated by weathering into economically workable
deposits in beach sands in the coastal tracts of Australia, Brazil, Ceylon,
Malaysia and India. Other common accessory minerals of igneous rocks which carry
thorium (and uranium) in trace amounts as isomorphous
substitution are monazite, apatite, zircon and sphene.
Most of these minerals are resistant to weahering,
but they differ greatly in their resistance to attrition during transportation
with clastics.
Monazite, apatite and xinotime are most
easily reduced by attrition, but under favorable conditions these minerals
become enriched in sands and gravels which have been transported short
distances. They are found
frequently in heavy mineral resistate fraction of
terrestrially deposited clastics. Hence stream and beach
monazite-bearing placers are found in many parts of the world. Zircon, which also carries a large
portion of U and Th contents of felsic rocks, is a
common constituent of the resistate fraction of all
kinds of clastic sediments. These resistant minerals (monazite,
apatite, xinotime and zircon) may be removed from
erosional terranes of igneous rocks and become
concentrated in placer deposits in environments where rock destruction by
decomposition is predominant over that by disintegration, viz. the tropical
climatic zones. The thorium content of minerals contained in these placers is
considerably greater than the uranium content; therefore the deposits are
classified primarily as thorium-bearing placers. In India monazite is found in the coastal
tracts of Cuttak and Ganjam
districts of Orissa where the thickness of the placer is about 30 cm with a
monazite content of 2.5 percent. Minor occurrences have been noticed between Chilka Lake and Chicacole River
also. Thick ilmenite and monazite placers are found
around Vishakhapatnam and Bhimunipatnam in Andhra
Pradesh. The beach sands of the
coastal tracts of Kerala and Tamil Nadu are also very rich in monazite. They also contain ilmenite
and rutile. Monazite bearing
sands are best developed along the beaches of the southwest coast of India
between Quilon and Kanyakumari
(Lipuram, Pudur, Kovalam, Varkala and Neendakarai) and between Chowghat
and Ponnani.
On the east coast of India, monazite concentrations are not as good as
on the western and southwestern coasts, nevertheless small deposits are found
along the Vishakhapatnam and Tanjore coasts. Monazite bearing black sand deposits occur in the coastal
tracts of Waltair, Bimlipatnam
and Narasipatnam. According to the Atomic Minerals Directorate
for Exploration and Research (AMD), a constituent Unit of the Department of
Atomic Energy (DAE), India has 10.70 million tonnes
of Monazite which contains 9,63,000 tonnes of
Thorium Oxide (ThO2). According to a 2011 estimate by the US Geological
Survey, the global reserves stand at 1,913,000 tonnes.
India's thorium is mostly located in a contiguous belt of eastern coastal
states as placer sands. The following table shows the distribution of
thorium reserves in the country according to a 2016 reserve estimates :
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This website is hosted by
S. Farooq
Department of Geology
Aligarh Muslim University, Aligarh - 202 002 (India)
Phone: 9719421011
email: farooq.amu@gmail.com