General Information

Prior to October 15, 1975, North Eastern Region was a part of the Eastern Region with headquarter at Kolkata from where the surveys were being carried out. 

To facilitate survey and exploration, the regional centre was set up in 1976 at Shillong initially in a rented accommodation. Subsequently during April, 1987, the office was shifted to its own campus at Nongmynsong along with residential quarters for the officers and staff.

Broad Geological Features

Broadly following geological domains occupy major part of the region

i. Archaean basement rocks mostly exposed in Meghalaya and Assam.

 ii. Proterozoic supracrustals comprising Shillong group of metasediments in Meghalaya and extra peninsular rocks of Arunachal Himalayas comprising Bomdilla gneiss, Dirang schist, Sela groups of rocks, etc.

 iii. Mesozoic rocks represented by Mahadek sandstones and Carbonatites of Cretaceous period and  Sylhet traps of Jurassic period.

 iv. Tertiary sediments exposed in the states of Arunachal Pradesh, Assam, Meghalaya, Manipur, Tripura, Nagaland and Mizoram. Oil wells are located in some of these areas.

 v. Younger granites of 479 to 881 m.y.  emplaced into Proterozoic and Archaean rocks.

Summary of Investigations:Important finds

Radiometric surveys were intensified in the region after the establishment of headquarter at Shillong since 1976. Based on geological favourability criteria, surveys were initially targeted to Mahadek sediments of Cretaceous period. This resulted in identifying following deposits. 

Domiasiat (KPM deposit): Located in West Khasi Hills district, Meghalaya. It is a sandstone type deposit in which mineralisation occurs in Lower Mahadek arkosic sandstone with abundant carbonaceous matter and pyrite nearer to the granitic basement contact,  within a vertical depth of 50 meters.  Resource estimation was jointly evaluated by AMD & UCIL during 1993 and the deposit is ready for exploitation.

Wahkyn : It is located 10 km WSW of Domiasiat in a similar geological set up.  The mineralisation occurs over a large area on both banks of Wahblei river. Exploratory drilling is presently in progress only in the northern block. A number of other encouraging blocks around Wahkyn like Wahkut, Waiting, Lostoin are also available for exploration.

Other smaller deposits in the environ are as follows.

Uranium shows were also located at Tyrsad in  Proterozoic Shillong group of rocks, East Khasi Hills district, Meghalaya and Daling group of Proterozoic Era in Arunachal Pradesh, etc.

The following are the other encouraging uranium shows located in North-Eastern Region.

1. Anek, West Garo Hills district, Meghalaya: Uranium mineralisation occurs

along fractures in sheared granite. Secondary uranium minerals like autunite, meta-autunite, uranophane, and beta-uranophane are visible in the outcrop.

2. Kau Nala, West Siang district, Arunachal Pradesh: Uranium mineralisation is associated with magnetite bearing quartzite of Middle Proterozoic period. Uraninite and Brannerite are the uranium minerals identified

3. Jamiri, Kameng district, Arunachal Pradesh: Significant uranium occurrences are recorded near Jamiri village in phyllitic quartzite. Uranium minerals like uranophane, beta-uranophane, uraninite, and brannerite occur as disseminations and stringers.

Besides uranium, the Region also hosts Niobium occurrence at  Sung valley, Meghalaya and Samchampi alkaline complex, Assam associated with carbonatites. Samchampi carbonatite complex holds significant quantities of Nb, Ta, Y, P₂O₅, Fe, and LREE. 

Present Thrust Areas of Investigations

Since Lower Mahadek sandstones have been identified as a very potential horizon to host uranium mineralisation, they have been targeted for detailed radiometric survey and exploration wherever they are exposed particularly in the state of Meghalaya.

Surveys are also being carried out for possible unconformity related uranium mineralisation in the Proterozoic Shillong basin. Initially, such areas falling in Meghalaya and Assam have been taken up for investigations.

Investigations for Iron oxide breccia type are also being taken up in West Garo Hills district, Meghalaya.

Other Facilities

The region is equipped with facilities such as

Physics Laboratory

Chemistry Laboratory

Petrology Laboratory

Remote Sensing Laboratory