Uranium Exploration Status in Bangladesh: Conceptual Study IAEA: Technical Meeting on Uranium from Unconventional Resources Vienna, Austria, 4 7 November 2014 Ratan Kumar Majumder Nuclear Minerals Unit Bangladesh Atomic Energy Commission E-mail: ratankm@yahoo.com,
Overview 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.
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 Alluvial Fan Deposits Residual Deposits Residual Deposits Alluvial Deposits Alluvial Deposits Deltaic Deposits Deltaic Deposits Tertiary 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.
Possible Uranium Formation Zones within Bangladesh 88 90 92 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) 26 24 22 N PLATFORM HIMALAYAN FOREDEEP SOURCE AREA DS DINAJPUR SLOPE RANGPUR SADDLE SP BOGRA SLOPE HINGE ZONE DS Dinajpur Slope SP Stable Platform FARIDPUR TROUGH BARISAL HIGH SHILLONG MASSIF DFB SYLHET TROUGH SOURCE AREA HATIA TROUGH DFB Dauki Fault Belt EMB Eastern Mobile Belt EMB BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles
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 88 90 92 26 HIMALAYAN FOREDEEP SOURCE AREA DS DINAJPUR SLOPE RANGPUR SADDLE SP DS Dinajpur Slope SP Stable Platform SHILLONG MASSIF DFB DFB Dauki Fault Belt EMB Eastern Mobile Belt SOURCE AREA N PLATFORM BOGRA SLOPE SYLHET TROUGH 24 HINGE ZONE 22 FARIDPUR TROUGH BARISAL HIGH HATIA TROUGH EMB BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles The Dauki Fault Belt situated close to the Mahadek uranium formation belt in the southern fringe of Shilling Massif
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 88 90 92 26 HIMALAYAN FOREDEEP SOURCE AREA DS DINAJPUR SLOPE RANGPUR SADDLE SP DS Dinajpur Slope SP Stable Platform SHILLONG MASSIF DFB DFB Dauki Fault Belt EMB Eastern Mobile Belt SOURCE AREA N PLATFORM BOGRA SLOPE SYLHET TROUGH 24 HINGE ZONE 22 FARIDPUR TROUGH BARISAL HIGH HATIA TROUGH EMB BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles Stable platform (SP) is characterized by the occurrence of Gondwana Basin which is similar to the India uranium bearing Satpura Gondwana Basin
Gondwana Basin in Stable Platform The Gondwana sediments overlying the basement rocks in the Stable Platform may contain uranium.
Siwalik Sediments 88 90 92 26 HIMALAYANFOREDEEP SOURCE AREA DS DINAJPUR SLOPE RANGPUR SADDLE SP DS Dinajpur Slope SP Stable Platform SHILLONG MASSIF DFB DFB Dauki Fault Belt EMB Eastern Mobile Belt SOURCE AREA N PLATFORM BOGRA SLOPE SYLHET TROUGH 24 HINGE ZONE 22 FARIDPUR TROUGH BARISAL HIGH HATIA TROUGH EMB BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles Dinajpur Besides, gravels Slope beds is characterized of alluvial fan by have Siwalik originated sediments from which Darjeeling is and capable Sikkim of belts, hosting that are Uranium two reportedly as found uranium in Jammu potential zones and of uranium. Hamirpur, Mio-Pleistocene Siwalik Formation in India
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. 26 24 22 N PLATFORM HIMALAYANFOREDEEP SOURCE AREA 88 90 92 DS DINAJPUR SLOPE RANGPUR SADDLE SP BOGRA SLOPE HINGE ZONE DS Dinajpur Slope SP Stable Platform FARIDPUR TROUGH BARISAL HIGH SHILLONG MASSIF DFB SYLHET TROUGH SOURCE AREA HATIA TROUGH DFB Dauki Fault Belt EMB Eastern Mobile Belt EMB BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles
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.
Previous Uranium Exploration Activities in Bangladesh 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. 26 24 22 N PLATFORM HIMALAYANFOREDEEP SOURCE AREA 88 90 92 DS DINAJPUR SLOPE RANGPUR SADDLE SP BOGRA SLOPE HINGE ZONE DS Dinajpur Slope SP Stable Platform FARIDPUR TROUGH BARISAL HIGH SHILLONG MASSIF DFB SYLHET TROUGH SOURCE AREA HATIA TROUGH DFB Dauki Fault Belt EMB Eastern Mobile Belt EMB Mineralogical Analysis of this samples has indicated the presence of radioactive mineral Thorite and Uranothorite. BAY OF BENGAL Tertiary Sedimentary rock exposures Gondwana Sediments and basement rocks of shallow depth MAYANMAR 0 40 miles
Previous Uranium Exploration Activities in Bangladesh 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 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
Concentration in ppm Significance Results 1200 1000 800 600 total leached 400 200 0 Fool Tala (Tipam Fm) M alnichara (Dupi Tila Fm) Telihati (Dupi Tila Fm) Lalakhal (Tipam Fm) Bhitirkhel (Dupi Tila Fm) AREAS Uranium content in some samples of greater Sylhet district, collected during 1976-1985.
Concentration in ppm & ppb (for ws) Significance Results 160 140 120 100 80 60 40 20 0 1994-95 1995-96 1996-97 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 RS- L. Dupi Tila sst. SS-Soil sample STS-Stream bed samples WS-Water samples Uranium content in different types of samples of Dauki Fault Zone collected during 1993-1998.
Summery 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.
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