Area-wise, Rajasthan is the largest state in India with varied geographical features. Major part i.e. 61% area is covered with desert or semi desert including 11 districts. The climate in this part is dry with scanty rainfall. Despite these negative aspects, nature has been very kind to this state in the sense that it has showered it with rich mineral wealth.
The state of Rajasthan is at par with other mineral rich states like Madhya Pradesh, Karnataka, AP, Chattisgarh, Jharkhand. Total 79 minerals are reported out of which 59 are produced commercially in this state. Except high grade iron ore/high grade coal all other minerals are found here. The state govt. receives 3000 crores annually as royalty, mining industry gives direct indirect employment to 2 lakh people.
Tungsten is a metal of strategic importance. It is used in making high speed cutting tools, special steel for defense purposes. Following article gives a brief outline of tungsten mineral occurrences in the state of Rajasthan:-
Image Courtesy: By Alchemist hp via Wikipedia
Tungsten Mining in Degana District, Nagaur
This deposit is located 7 kms NW of Degana town which is located along Jodhpur-Jaipur broad gauge line. Another line connects this town with Delhi via Churu Rewari route. Tungsten mineralization was discovered in 1913. Mining commenced in 1916 and continued up to 1989. Before independence British controlled mining operations. After 1947, Indian Bureau of Mines, Rajasthan state DMG took up this work.
In 1980s area was given to M/s.Hindustan Zinc ltd. a govt. of India undertaking. Now the mining lease area is with Vedanta Resources. It is not out of question to mention that for many decades Degana was the only mine in country producing tungsten mineral concentrates. In this deposit tungsten (Wolframite) occurs in 3 hillocks vij. Rewat, Tikkali & Phyllite. Mineral is associated with quartz veins located along shear zones in granite and also as stock works in above hills. Tungsten also occurs as alluvial deposit around foot hills. Indian Bureau of Mines – I.B.M. has carried out systematic exploration and computed following reserves.
Lode deposit – 53000 Metric tonnes with 0.54% WO3
Alluvial deposit – 3.3 Million tonnes with 0.04% WO3
Stock works – 2.5 Million tonnes with 0.25% WO3
Degana has been the largest mine in country for Tungsten. Its area is 201.44 hectare. Total reserves in the country are 50.22 M.T. out which Rajasthan has 6.25 MT reserves, i.e. 12% of country’s total reserves. Regular mining stopped at Degana in the year 1989. Since then only old dumps of excavated material are treated to produce concentrates. The treatment comprises crushing, grinding, primary and secondary gravity separation, floatation. Treatment is essential because Wolframite the main tungsten mineral is associated with other minerals like quartz, mica, feldspar, sulfide and topaz.
2.Balda District, Sirohi
This area is around 6 kms NE of Sirohi in SW Rajasthan. Here the mineralization is localised in quartz pegmatite veins related to Erinpura granite suite. Greisnisation is very prominent. Wolframite and Ferberite are the main minerals. flourite of +90% CaF2 occurs as gangue mineral and can also be utilized. Almost the entire area lies in forest.
3. Tungsten Mineral Occurences in Kararavav-Bhimana, District, Pali
This area is located along the western margins of Aravalli hills. Here scheelite bearing skarns were discovered by deptt. of Mines & Geology, Rajasthan during mineral survey work between 1984 to 1987. Skarns are developed at the contact of impure limestone and granite Apart from scheelite, other minerals are calcite diopside, epidote and quartz. Departmental drilling in this area has indicated that at depth scheelite mineralization is quite feeble. Incidentally this mineral is Calcium Tungstate and currently is not being used as an ore.
Recommendation:- It is clear from above that Degana deposit is the only deposit which can be further developed.
Written By: Rakesh Giri Goswami
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