TUNGSTEN OCCURRENCES IN RAJASTHANBy

Rakesh G.Goswami,Geological-Mining Consultant,

Jodhpur,Rajasthan.

Tungsten is a metal of strategic importance. It finds use in making of cutting tools, special steel for defence purposes. Following paragraphs give a brief outline of tungsten mineral occurences in the state of Rajasthan:-

1. Degana, Distt. Nagaur:-This deposit is located 5 kms. NW of Degana railway station. Tungsten mineralisation was discovered in 1913. Mining commenced in 1916 and and continued up to 1989. 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. The mine was worked in part by DMG, RSMDC and H.Z.L. I.B.M. has carried out systematic exploration and computed following reserves.

(i) Lode deposit - 53000 Metric tonnes with 0.54% WO3(ii) Alluvial deposit - 3.3 Million tonnes with 0.04% WO3(iii) 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 quartz, mica, felspar, sulphide and topaz.

2.Balda, Distt. Sirohi:- This area is around 6 kms NE of Sirohi. Here the mineralisation is localised in quartz pegmatite veins related to Erinpura granite suite. Greisnisation is very prominent. Worlframilte and Ferberite are the main minerals. flourite of +90% CaF2 occurs as gangue mineral and can also be utilised. Almost the entire area lies in forest.

3.Kararavav-Bhimana, Distt. Pali:-This area is located along the western margins of Aravalli hills. Here scheelite bearing skarns were located during departmental survey 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 mineralisation is quite feable. Incidently this mineral is Calcium Tungastate and currently is not being used as an ore.

Recommendation:- It is clear from above that Degana deposit is the only locality which can be further developed.