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. 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 state with rich mineral wealth. State is at par with other mineral rich states like MP, 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 2lakh people.
Mineral search is a continuous activity in any country. Central as well as state govts. are engaged in mineral survey work, after change in mineral policies now private companies can also go for mining of oil, gold and tungsten. Geologically Pali disstt. has Pre Cambrian rock formations. Recently Geological survey of India, western zone has also discovered a new area having rare earth elements in Pali district in central Rajasthan.
To a laymen rare earth metals could be like any other metal. But to a student of science it means a lot, like the fact that these are a group of 17 elements in periodic table of elements, namely scandium, yttrium and lanthanides,15 elements in the periodic table with atomic numbers 57 to 71. Although these elements tend to occur together, the lanthanide elements are divided into two groups, viz. Light & heavy. General properties of rare metals are that they are silvery to gray in colour, ductile and malleable.
Rare earth elements are used in several high technology industrial products. Their presence in alloys, ceramic and glass compounds and in oxide compounds provide special material properties. In metallurgy, alloying and addition of rare earth elements to steel increase strength and thermal stability. The cracking of petroleum requires catalysts containing various rare earth elements to increase the amount of short hydrocarbon molecules in the product.
In the ceramic and glass industry rare earth element containing compounds are used for high temperature materials, for coatings, polishing, colouring, decolouring and as glass additives. The main other uses of rare earth elements are in permanent magnets, phosphors in color television tubes, x-ray tubes, fluorescent lamps, high quality magnets, medical lasers, electronic and computer screens, i pods and energy efficient fluorescent lamps.
Rare earths are characterized by high density, high melting point, high conductivity and high thermal conductance. These unique properties make them indispensable for a variety of emerging and critical technology applications relevant to India’s energy security i.e. clean energy technology, defence and civilian application etc. rare metals play a significant role in modern day high-technologyindustries .
To meet ever increasing demand for these RM and REE it is necessary to make concerted effort to augment the resource position of our country. Few years ago the survey for rare earth minerals was exclusive domain of Atomic Minerals Division-AMD of Govt. of India, but during last one decade Geological Survey of India has also entered in the field of REE exploration work.
Following lines provide information about a new rare earth mineral find in Rajasthan state by Geological Survey of India. This new mineral find is located near village Dhani, disstt Pali in central Rajasthan. This can also be approached by Marwar-Ahemadabad broad gauge line, nearest rail station is Rani. Mineralization is associated with hydro thermally altered granite. This prospect came to light after GSI survey work in the year 2012-13 and 2013-14. It is not out of question to mention that geologist of state DMG had also examined this area in 1991 and reported occurrence of rocks having unusual composition, at that time it was described as hybrid rock. Now same is found to contain rare earth elements. Picture of this hybrid rock is posted for benefit of readers.
Picture of rock containing possible occurrence rare earth elements in Dhani area, photo by Rakesh Giri Goswami
Map showing location of Dhani near Rani
According to GSI report REE mineralisation in Dhani Granite area, Pali district, Rajasthan area are being explored. Channel samples from hydrothermally altered Dhani granite indicate ∑REE of more than 0.1%. Five zones of REE mineralization have been identified which are as follows: Mineralized zones Width x assay Zone-I 1m X 0.24 %∑REE, Zone-II 1.5m X 0.10 %∑REE, Zone-III 2m X 0.32 %∑REE, Zone-IV 1.5m X 0.64 %∑REE, Zone-V 2m X 0.14 % ∑REE 5.
It is not out of question to mention that China dominates the mining and trading of rare earth minerals in world. It supplies 95% of all rare minerals consumed by world.
By Rakesh Giri Goswami