General
Information
| Area |
: |
2,55,000
sq km |
| States |
: |
Arunachal
Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland,
and Tripura. |
| Headquarter |
: |
Shillong |
| Address |
: |
Regional
Centre for Exploration and Research, AMD Complex, Nongmynsong,
PO : Assam Rifles, Shillong – 793 011. |
| Contact
Person |
: |
Dr.
R. Mohanty, Regional Director
Ph. : 0364-2537656
Fax : 0364-2534855
Email
: rdner.amd@gov.in |
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.
|
Location
|
District
|
Host Rock
|
|
Tyrnai
|
W.Khasi
Hills
|
Lower
Mahadek sandstones
|
|
Gomaghat
|
W.Khasi
Hills
|
Lower
Mahadek sandstone & conglomerate
|
|
Nonglong
|
W.Khasi
Hills
|
Lower
Mahadek sandstones
|
|
Sateek
|
W.Khasi
Hills
|
Lower
Mahadek sandstones
|
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
