Uranium Exploration Status in Bangladesh:

Conceptual Study

Ratan Kumar Majumder

Nuclear Minerals Unit

Bangladesh Atomic Energy Commission

E-mail: ratankm@yahoo.com,

IAEA: Technical Meeting on Uranium from Unconventional Resources

Vienna, Austria, 4 – 7 November 2014

Bangladesh Atomic Energy Commission (BAEC) is very

much interested to get uranium from indigenous sources.

BAEC has been operating nuclear mineral exploration

program by its limited resource.

Bangladesh is geologically made mostly of sedimentary

rocks and it is only possible to mineralize sedimentary

types of uranium deposits under favourable reducing

environment.

Overview

Tectonic Framework of Bangladesh and Adjoining Areas

Stable Pre- Cambrian

Platform

Geosynclinal Basin

Paleo-continental slope

which separates the above

two units

Geological Set-up of Bangladesh

• Alluvial Fan Deposits

• Residual Deposits

• Alluvial Deposits

• Deltaic Deposits

• Tertiary Deposits

Alluvial Fan Deposits

Residual Deposits

Alluvial Deposits

Deltaic Deposits

Tertiary Deposits

Prerequisites for Uranium Mineralization in Sedimentary

Formations

The Source of Uranium

Granotoids & metamorphic equivalents.

Concentration- 2 to 50 ppm (Mann, et al. 1978).

Rocks with high concentration uranium might be considered to

be ultimate source.

Dissolution of Uranium

Uranium bearing source rocks are disintegrated and dissolved

by the action of weathering & erosion.

Mode of Migration

Uranium is migrated to the depositional site by groundwater

and/or surface water flow

Prerequisites for Uranium Mineralization in

Sedimentary Formations

Environment of Deposition Suitable environments for uranium deposition in the order of

decreasing favorability are fluvial – lacustrine – littoral – lagoonal – shallow marine (Nininger, 1977).

Reducing environment, where sediments contain 1-3% organic matter.

Morphology of Depositional Site Closed or partially closed basins. Linear and elongated crustal depressions. Sandstone beds, confined by shale beds. Tectonic and Structural Setup Cenozoic foreland margins of orogenic belts (Gabelman,

1970). Convergent plate boundaries (Nininger, 1977).

Identified Favorable Geological Factors

o The sedimentary successions of Bangladesh have

continental sandstones with lignite and organic matter

which make them favorable host rock for sedimentary

uranium.

o The shield areas around Bangladesh are considered good

source areas for uranium.

o Overall geological control and structures

o Probable mobility of uranium solution

Creteria Fevorable for Uranium Accumulation in

Bengal Basin

Gabelman (1970) suggested that the southern side of the Himalayan System is favorable for low temperature mineralization of uranium.

As Bangladesh falls within this zone and all of the prerequisites are present in the geological setup of Bengal Basin, so it may be considered suitable to become a uranium country.

Considering these favorable criteria, Bangladesh has been

divided into 4 zones based on tectonics and structural setup, rock exposures, and depth of probable host rocks suitable for exploration.

Considering the possible criteria

for uranium formation within

Bangladesh territory has been

divided into 4 zones as:

o Eastern Mobile Belt (EMB)

o Dauki Fault Belt (DFB)

o Stable Platform (SP)

o Dinajpur Slope (DS)

Possible Uranium Formation Zones within Bangladesh

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Major Sandstone-type of Uranium Deposit in India

Jammu-Harirpur -Mio-Pliestocene Siwalik Formation

Meghalaya, Shillong Plateau-Cretaceous Mahadek Formation

Bawra-Satpura, Madha Pradesh-Permian Formation

Dauki Fault Belt (DFB) Area Favorable for Uranium

Formation

The Dauki Fault Belt situated close to the Mahadek uranium

formation belt in the southern fringe of Shilling Massif

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Dauki Fault Belt

Map showing

radioactive anomalies

in Meghalaya (India)

and drainage pattern

across DFB

Schematic Subsurface

Characteristics Across DFB

Gondwana Basin in Stable Platform

Stable platform (SP) is characterized by the occurrence of

Gondwana Basin which is similar to the India uranium bearing

Satpura Gondwana Basin

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Gondwana Basin in Stable Platform

The Gondwana sediments overlying the basement rocks in the Stable Platform may contain uranium.

Siwalik Sediments

Dinajpur Slope is characterized by Siwalik sediments

which is capable of hosting Uranium as found in

Jammu and Hamirpur, Mio-Pleistocene Siwalik

Formation in India

Besides, gravels beds of alluvial fan have originated from

Darjeeling and Sikkim belts, that are two reportedly uranium

potential zones of uranium.

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Eastern Mobile Belt

In this zone-

Exposed Sandstones

High intensity of structural disturbances

Allowable organic matter content

Drainage patterns

are the most important features in favor of uranium formation point of view.

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Uranium Exploration Activities in

Different Potentials Zones of Bangladesh

Previous Uranium Exploration Activities in Bangladesh

1976-1985: Exploration of Uranium and Thorium in Bangladesh (EUTB) with the assistance from IAEA and UNDP.

Exploration Area: Chittagong , Chittagong Hill Tracts and Sylhet districts.

Regional reconnaissance survey in more than 2000 sq. km areas of greater Chittagong and Chittagong Hill Tracts and Sylhet districts .

Resulted more than 150 surface radiometric anomalies, aerial survey in Jaldi anticline and semi-detailed to detailed survey in 450 sq km areas of Sylhet, Jaintia and Harargaj structures.

Previous Uranium Exploration Activities in Bangladesh

Radon survey has also been carried out in 35 sq km areas of Sylhet anticline and Jaintia Structure.

About 27 shallow bore holes have been drilled in Sylhet region that have resulted more than 85 anomalies.

The highest radiometric counts occurred in Phooltala Reserve Forest within the Harargaj anticline of Moulavibazar district, which was about 6000 cps (60 times the BG counts).

Chemical analysis of this sample has indicated the presence of 1020 ppm total uranium.

Mineralogical Analysis of this samples has indicated the presence of radioactive mineral Thorite and Uranothorite.

Previous Uranium Exploration Activities in Bangladesh

HIMALAYAN FOREDEEP

INDIA

SHILLONG MASSIF

SOURCE AREA

INDIA

MA

YA

NM

AR

BAY OF BENGAL

INDIA

DINAJPUR SLOPE

RANGPUR SADDLE

BOGRA SLOPE

HIN

GE

ZONE

FARID

PUR TROUGH

SYLHET�

TROUGH

BARISAL H

IGH

HATIA�

TROUGH

IND

IAN

P

LA

TF

OR

M

SOURCE �

AREA

Tertiary Sedimentary rock exposures

Gondwana Sediments and basement rocks of shallow depth

88° 90° 92°

26°

24°

22°

0 40 miles

DS

SP

DFB

EMB

DS Dinajpur Slope

SP Stable Platform

DFB Dauki Fault Belt

EMB Eastern Mobile Belt

Exploration and Exploitation of Atomic Minerals in Joypurhat – Sylhet Area in the Dauki Fault zone (1995-1998):

Exploration Area: Netrokona, Sunamgonj, Moulavi Bazar and Sylhet districts

Previous Uranium Exploration Activities in Bangladesh

Previous Uranium Exploration Activities in Bangladesh

Exploration and Exploitation of Atomic

Minerals : Joypurhat – Sylhet Area in the

Dauki Fault (1995-1998):

One drill hole (EDH-52) that was drilled

by Geological Survey of Bangladesh

(GSB) at Madarpur in Mitapukur,

Rangpur was logged that resulted an

anomalous reading, which was 25 times

higher than the background, in the

crystalline basement rocks.

Radioactive counts 4 to 6 times

background in Jadukata valley. At one

place it reaches upto 10 times.

Radioactive counts upto 3.5 times

background near Rangpani river.

Maximum Subsurface counts 225 cps

(depth 2 m) at DH-2 drilled at Assampara

0

200

400

600

800

1000

1200

Con

cent

rati

on in

ppm

Fool Tala (Tipam

Fm)

M alnichara (Dupi

Tila Fm)

Telihati (Dupi Tila

Fm)

Lalakhal (Tipam

Fm)

Bhitirkhel (Dupi

Tila Fm)

AREAS

to tal

leached

Significance Results

Uranium content in some samples of greater Sylhet district,

collected during 1976-1985.

0

20

40

60

80

100

120

140

160

Con

cent

ratio

n in

ppm

& p

pb (f

or w

s)

RS 72.85 78.52 0

SS 23.95 147.72 27.89

STS 62.4 101.55 0

WS 11.54 50.27 7.197

1994-95 1995-96 1996-97

Uranium content in different types of

samples of Dauki Fault Zone collected

during 1993-1998.

Significance Results

RS- L. Dupi Tila sst.

SS-Soil sample

STS-Stream bed samples

WS-Water samples

Summery

Uranium occurrences discovered so

far in the north-eastern region of

Bangladesh show presence of

uranium in total (60-1036 ppm) and

leachable form ( 13-988 ppm).

Uranium occurrences discovered so far in the north-eastern

region of Bangladesh show presence of uranium in total of

60-1036 ppm.

Mineralogical studies using XRD techniques have

confirmed the presence of uranium/thorium rich atomic

minerals thorianite and uranothorite in the radioactive

sandstone from Fultala.

Thorianite and uranothorite contain uranium up to 42%

and 15%, respectively.

Chemical analysis of the bulk samples from Fultala contain

1100 – 1400 ppm uranium oxide.

Thank you all