THERMAL IMAGERY-AN APPROACH TOWARDS EXPLORATION OF HEAVY MINERALS IN BEACH PLACERS

Globally, there has been an increasing demand for Uranium and Thorium. Unsustainable exploitation of radioactive and heavy minerals from the beach sands is extremely detrimental not only to the beach system resulting in heavy erosion and contamination but also to the ecological balance of the area. This generates a need to adopt unique, suitable, and rapid methodology to explore and recover the radioactive minerals in the most optimal way. This paper highlights an integrated approach of remote sensing and radioactive reconnaissance survey to explore uranium and thorium. The study aims to assess the natural radioactive contents around Podampata, the eastern coast of Odisha, India. In this context, samples were collected to measure the gamma radiation from ²³⁸U, ²³²Th, ⁴⁰K, and the absorbed dose rate using Micro R survey meter and Gamma surveyor 2. In order to map the radioactive minerals, thermal imagery of the study area was undertaken using the Landsat-8 data set and subsequently using ArcGIS. The absorption and reflection pattern of the sand samples containing radioactive minerals were delineated from the texture of the heavy minerals. The minerals which show significant variation in their reflectance, at different spectral bands can be effectively mapped by using multispectral data with the help of ENVI’s spectral angle mapper. The region, which exhibits the highest temperature obtained from thermal imagery, comprises of more radioactive minerals and are dark in texture. Successful implementation of the current methodology can be replicated for the entire Eastern coast of India, for the effective management not only for the exploration of REE bearing minerals but also to extract the same in better manner rather than being entirely dependent on routine methods like dredging.