Search goes on for uranium reserves in Andhra Pradesh

Syed Akbar
Hyderabad: After successfully striking uranium reserves in the Nagarjunasagar belt, the city-based Atomic Minerals Directorate for Exploration and Research will now take up magnetic and gamma ray spectrometric surveys in parts of Kurnool and Kadapa basins for detection of uranium and thorium reserves.
The electromagnetic, magnetic and gamma ray spectrometric surveys will be carried out by helicopters covering about 11000 km area in Kurnool sub-basin and Kadapa basin. The aerial exploration work will be completed in one year.
AMD will initially take up testing of 900 line Km in a test block of 15 Km X 15 Km and on its successful completion, the remaining area will be released for survey at an estimated cost of Rs 5 crore. Multiparameter (gamma-ray, magnetic) geophysical surveys are useful in mineral exploration and bedrock mapping studies.
"There's a possibility of encountering a number of surprises in the metallogenic evaluation of the terrain when probed at greater depth than that is usually superficially perceived," says a senior official of the AMD.
Kadapa and Kurnool basins are endowed with rich mineral wealth. The
middle-upper Proterozoic Kadapa basin, has been well known for a variety of mineral resources, such as diamond, barite, asbestos, copper and lead, besides limestone and Kadapa slabs. Some of the world’s finest and famous
diamonds, such as Kohinoor and Regent are the product of this basin. About 25 per cent of the world’s barite resources are present within the basin.
Though Uranium exploration was initiated in the late 1950’s to
search the quartz-pebble-conglomerate type uranium mineralisation which had dominated the world uranium supply at that time, a proper scientific survey is yet to be taken up. The basal Gulcheru conglomerates at the base of Kadapa basin were found to be thoriferous. Subsequent exploration in the late 1980’s, brought out significant uranium mineralisation in dolostone.
A significant breakthrough was achieved in early 1990’s when uranium mineralisation was located along the unconformity between Srisailam Formation of Kadapa Super Group and the basement granites,
thereby establishing in India, for the first time, the presence of unconformity
related uranium mineralisation - a category considered most potential world over.
Earlier studies by AMD recognised three distinct types of uranium mineralisation, strata bound, fracture controlled (both basement granite and sediment hosted) and unconformity-related type. The present work, which will be allotted after May 15, when the tenders for the present work will be opened, will give more focus on the uranium reserves in Kadapa and Kurnool areas.