Sandstone Uranium Deposits in Phu Wiang Basin, Thailand Mr.Choengchai KRAIKHONG Department of Mineral Resources, Bangkok, Thailand E-mail: email@example.com The International Atomic Energy Agency’s“Technical Meeting on the Origin of Sandstone Uranium Deposits: A Global Perspective” 29 May – 1June 2012 at IAEA Headquarter Vienna, Austria
Content Overview Geographic Information of Thailand Sandstone Uranium Deposits in Phu Wiang Basin Genesis of The Phu Wiang Uranium Mineralization Controls of Uranium Distribution The results of the Phu Wiang Uranium Prospecting
Overview Geographic Information of Thailand Area 513,115 sq.km Highest Peak El.2565 MSL. Provinces 76 Changwat
The Geology of Thailand : Regional Geology Regional geology of Thailandwas described as the following of The sedimentary rocks sequence from the Cambrian to Cenozoic. The metamorphic rocks was described the older rocks as Precambrian to Lower Paleozoic. The Igneous rocks was described as Carboniferous, Permo - Triassic, Triassic, Jurassic, Cretaceous, and Quaternary.
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand The uranium mineralization in the Phu Wiang basin near the western edge of Korat Plateau, Thailand was discovered in 1970 after the recognition by an unusual concentration of uranium in ground water. The outcrop of uranium minerals associated with malachite in
Location map of Phu Wiang Uranium Prospect Area 17o 16o45’ U-Prospect 16o30’101o45’ 102o 102o15’ 102o30’ 102o45’
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand The Department of Mineral Resources (DMR),Thailand started to study the mineralized beds in cooperation with the US Geological Survey (USGS) in 1974 And International Atomic Energy Agency (IAEA) in 1976
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand The first results revealed : • a favorable environment for uranium deposits related to the geological similarity between the Khorat Plateau and the Colorado Plateau. • granites as sources rocks of the ‘red bed’ sandstones and the uranium mineralization. • the occurrence of carnotite and pitchblende (uraninite) associated
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand Based on these promising results • the DMR stared a drilling programme in August 1976, supervised by an IAEA expert. Until mid 1980 • 26 hammer downholes and 85 diamond drill holes penetrated the potential ore beds in the Sao Khua Formation (Unit B), discovering 3 small ore lenses
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand In 1978, the DMR and the German team discussed the objectives of the joint research programme and determined 5 fields of activities : 1. Structural interpretations of satellite imagery and aerial photographs in order to prepare a detailed tectonic map of the Phu Wiang Basin.
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand 2. Sedimentological studies of the Sao Khua Formation in order to provide detail information on the host rock. 3. Economic geological investigations in order to identify the uranium minerals, the uranium distribution and the genesis of the ore.
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand 4. Geochemical studies of magmatic rocks around the Korat Plateau in order to search for the possible source rocks of the uranium mineralization. 5. Prospecting tests in order to provide information for hydrogeochemical uranium prospecting as well as for radiometric borehole logging.
Sandstone Uranium Depositsin Phu Wiang Basin, Thailand The Thai-German research project was implemented between 1979 – 1981. The field work was concentrated on • sampling and investigating drill cores • sampling of sandstone outcrops of the Sao Khua Formation • mapping and sampling of Paleozoic sediments in the Petchabun province • sampling of groundwater from drillholes
structural interpretations of satelliteimagery and aerial photographs in order toprepare a detailed tectonic map of thePhu Wiang Basin.
Jpk JKpw Kpp Ksk Qa Kkk TRnpGeologic map of the Phu Wiang Uranium Prospecting area
Sedimentological studies of the Sao Khua FormationIn order to provide detail information on the host rock.
Detailed geologic map of the uraniummineralization in Phu Wiang Prospect area
Outcrop of uranium in sandstone at Pra Tu Tee Ma, Ban Nong Kham,Amphoe Phu Wiang, Khon Kaen Province.
economic geological investigationsin order to identify the uranium minerals,the uranium distribution and the genesis of the ore.
geochemical studies of magmatic rocks around the Korat Plateauin order to search for the possible source rocks of the uranium mineralization.
prospecting tests in order to provide information for hydrogeochemicaluranium prospecting as well as for radiometric borehole logging.
Methods used in the uranium exploration project Gamma-ray Spectrometer survey Diamond Drill Holes Carborne Scintillometer (CBS) Survey Gamma-ray Borehole Logging
Genesis of the Phu Wiang Uraniummieralization The Phu Wiang Uranium Prospect exemplifies a special subtype of uranium deposits in the sandstones, The copper- uranium mineralization is associated with the mudstone pebbles forming layers in the channel sandstones and is derived from older pedogenic uranium accumulations. The genetic importance of such deposits to origin of deposits of main types is postulated.
Genesis of the Phu Wiang Uraniummieralization The Phu Wiang uranium deposit consists of three laterally associated lenticular ore layers with the minimum dimension of 30 x 10 m.,65 x 15 m. and 200 x 100 m. and thickness ranging from 0.3 to 1.2 m. The average grade is about 0.04 % eU3O8 (cutoff : 0.01 % eU3O8). The typical subsurface trend, shape and form of the ore-bodies in the Phu Wiang are shown in the drilling cross-sections As illustrated,the deposit is tabular and lenticular, trending parallel to the bedding and thus similar to the epigenetic,
Cross-sections of the uranium mineralization in Phu Wiang Prospect area
Genesis of the Phu Wiang Uraniummieralization Due to a very fine grain size of mineralization several analytical techniques including electron microprobe, energy dispersive spectrometry, electron scanning microscopy, X-ray diffractometry and ore microscopy have been applied in order to identify the uranium minerals. The analytical data indicate that coffinite is the principal uranium mineral and that a considerable amount of the uranium is bound in organic complexes or is absorbed on clay.
Genesis of the Phu Wiang Uraniummieralization Some electron microprobe data point to a possible presence of uraninite or uraninite- like mineral occurring in a submicroscopic mixture with coffinite. The X-ray analysis, however, yielded evidence of coffinite only. Other uranium minerals detected include carnotite and torbernite. Both minerals are extremely rare and their occurrence is restricted to the outcrop of mineralized sandstone. Associated ore minerals include
Genesis of the Phu Wiang Uraniummieralization These minerals disseminate in the mudstone chips as well as intragranular filling and grain coating. The paragenesis of ore minerals indicates clearly the predominantly sulfide zone character and low oxidation stage of the ore.
Drill holes location of the uranium mineralization in Phu Wiang Prospect area
Controls of Uranium Distribution The gamma-logging of the drill cores clearly indicates that uranium is concentrated preferentially in the gray to greenish conglomeratic or pebbly sandstone at the base of the ore bearing unit. The conglomeratic sandstone consists of massive sandstone as typical for upper flow regime in fluviatile environment and contains variable amounts of scattered pebbles (seams, galls, chips) of calcareous mudstone.
Gamma-ray Spectrometer logging in drill hole DDH 63
Controls of Uranium Distribution The presence of coalified plant fragments points to a surfacial origin of associated mudstone pebbles. Genetically, the conglomeratic sandstone can be used as an indicator for a cyclic deposition in fluviatile environment forming the best of a depositional cycle. However, layers of conglomeratic sandstone occurring in the middle and upper part of the ore bearing unit are uranium free, regardless of the content of coalified plant material.
Controls of Uranium Distribution The relationship between conglomeratic sandstone and the uranium mineralization indicates that the ore was controlled by lithologic type and the initial depositional cycle in a fluviatile channel environment. the results of economic geological investigation of the Phu Wian Uranium Prospect indicate little hope for the discovery of economic uranium deposits, The main reasons for this pessimistic outlook are that the mineralization is low grade, the ore lensed are small, the coffinite is very finely disseminated and a
Dinosaur remains were first found and reported in 1978 in the course ofUranium prospecting at Phu Wiang from the Sao Khua Formation.
Some of uranium occurrences in Pegmatite graniteIn western part of Thailand
Conclusion The sandstone uranium deposit in Phu Wiang basin contains low grade uranium of about 30-60 cm. thick at an average of 0.0407 % U3O8 Calculate ore reserve is about 14.5 tons of low grade ore in which about 1.7 tons of U3O8 at 0.04 % could be extracted. The tendency to find a big uranium deposit is rather rare
Conclusion Discovery of dinosaur remains in uranium prospecting at Phu Wiang are by products and led to the establishment of several dinosaur and geological museum in Thailand. The other uranium occurrences are too small or only traces in fluorite viens in granite and in pegmatite which can not be classified as economic deposits.