Emerging Mineral Resources in Northeast India: A Geological Survey Insight
Overview of Mineral Resources in Northeast India
Guwahati, June: Recent findings from a Geological Survey of India (GSI) report indicate that Assam and Arunachal Pradesh are becoming significant areas for various minerals, including graphite, vanadium, rare earth elements (REEs), base metals, gold, coal, and limestone. Meanwhile, Meghalaya and Nagaland are rich in limestone, coal, and some strategic metals.
Rare Earth Elements (REEs), which consist of 17 chemically similar elements such as lanthanum, neodymium, and yttrium, are essential for modern technologies, including electronics, magnets, and renewable energy solutions. These elements are categorized into light and heavy groups and play a crucial role in electric vehicles, wind turbines, and defense applications.
The report highlights that since 2015, significant resource estimations have been conducted in the region. Notably, Arunachal Pradesh has been found to contain 24.81 million tonnes of graphite and 17.17 million tonnes of vanadium. In Meghalaya, over 6,600 million tonnes of limestone have been identified, while Assam has more than 1,400 million tonnes of limestone and a strategic REE resource of 2.15 million tonnes in Arunachal Pradesh and 28.64 million tonnes in Assam.
In Arunachal Pradesh, the Lodoso area in Papum Pare district has revealed a resource of 2.15 million tonnes of REE-bearing ferruginous phyllite, with an average grade of 1.08% total REE, including Yttrium. Significant concentrations of Neodymium have also been noted in West Siang and East Kameng districts. The Jashora and Samchampi alkaline complexes in Assam have shown promising results through geochemical surveys, revealing REE concentrations between 1000 to 5000 ppm, along with elements like Nb and Y.
The granite gneisses in the Assam Meghalaya Gneissic Complex (AMGC) also show potential for REE and Rare Metal (RM) deposits.
In Meghalaya, the Sung Valley ultramafic-alkaline-carbonatite complex contains titaniferous bauxite cappings.
Assam's geological landscape is characterized by the sedimentary sequences of the Brahmaputra and Barak plains, along with the granitic and gneissic cores of the Mikir Hills and the Shillong Group rocks in central Assam. Traditionally recognized for its oil and natural gas reserves, Assam also possesses valuable deposits of iron ore, glass sand, limestone, and REEs.
Limestone is Assam's largest non-energy mineral resource, with over 1,490 million tonnes identified in the Dima Hasao district alone. These limestone deposits, found in the tertiary formations of the Jaintia Group, are suitable for cement production and other industrial uses.
Iron ore resources estimated at 18.29 million tonnes with an average grade of 37.45% Fe have been reported from the Chandardinga area in Dhubri district.
High-silica glass sand has been located in Nagaon and Karbi Anglong districts, while placer gold has been discovered in the Subansiri River basin in upper Assam. Although the gold grades are modest, these occurrences are significant indicators of potential upstream mineralization, according to the report.
Quaternary sediments are prevalent in the Brahmaputra and Barak River basins, forming the fertile plains of Assam and Tripura. While these areas are generally less promising for hard-rock minerals, recent studies suggest potential for placer gold and groundwater-hosted lithium.
From 2015 to 2024, the GSI has conducted over 200 mineral exploration projects and identified 38 potential blocks across multiple states, including Arunachal Pradesh, Assam, Meghalaya, and Nagaland, through Geological Reports (GRs) and Geological Memorandum (GMs).