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IAEA publication reviews advances in geophysical methods for uranium exploration

by Graham Chandler on May 27, 2013 library

Publication of a new eBook, Advances in Airborne and Ground Geophysical Methods for Uranium Exploration, proves timely as many countries see a rise in uranium exploration.

The publication is part of the IAEA’s nuclear energy series (no. NF-T-1.5, 2013). A free PDF version can be downloaded from IAEA.org. Print copies of the book can also be ordered from the website .

With gaps between the start of exploration and production typically stretching from 15 to 40 years many countries have seen a rise in uranium exploration since 2005. The world’s capacity for generating nuclear energy is expected to grow to between 511 and 782 GW by 2035. That could push annual reactor-related uranium requirements to as high as 138,165 tU.

According to the Vienna-based International Atomic Energy Agency (IAEA) newly designed geophysical instruments and their application in uranium exploration are contributing to an increased probability of successful discoveries. Their eBook, downloadable from IAEA.org, highlights advances in airborne and ground geophysical techniques and methods for uranium exploration, describing modern geophysical methods and demonstrating their application with examples.

The publication is comprehensive and serves as a handy sourcebook for exploration rookies as well as veterans, students as well as professionals. The authors weigh the pros and cons of various advances in airborne and ground geophysics as they apply to uranium exploration. Along the way, they explain the basic theory of radioactivity, nuclear radiation, and interaction with matter.

An early section summarizes radioactive raw materials and the basics of peaceful nuclear energy, explaining how natural radionuclides of uranium and thorium are used in nuclear power plants to generate electricity through controlled fission which generates heat to make steam and drive turbines.

Uranium and thorium, as well as their decay products, are sources of gamma radiation and release the radioactive gas radon. Modern radiometric instruments, which detect and analyze emitted radiation, are the primary means of prospecting and evaluating radioactive raw materials and their geological mapping. The radiometrics are typically complemented by traditional geophysical methods.

Different types of radiometric detectors are explained, including ionization chambers for detecting alpha radiation, proportional counters for X-rays and gamma rays, scintillation counters, and gamma ray spectrometers. The authors point out the respective uses and limitations of these detectors.

The eBook explains how electrical and electromagnetic method scan enhance our understanding of an area’s subsurface geological setting and considers the usefulness of such methods in complementing radiometric mapping. Such methods may prove advantageous when incorporated into an exploration strategy. For example, since uranium mineralization differs little in resistivity from the host environment and since the spatial extent of an orebody is often small, it may be difficult to detect uranium by measuring resistivity or conductivity. However, electrical and electromagnetic methods can detect subsurface geological targets often associated with uranium mineralization. Examples are provided.

The report explains each technique and its respective application in uranium prospecting. In similar fashion, it sheds light on gravity methods and magnetic prospecting (both of which can be used in geological mapping in the early stages of uranium exploration), as well as seismic prospecting and well logging (borehole radiometric data are essential for calculation of uranium reserves). Remote sensing is covered as well.

Techniques for the amalgamation of diverse data sets have made a big difference as far as interpretation and presentation are concerned. The authors point out that technology has facilitated an unprecedented integration of digital geophysical data with independent vector and raster information. Three-dimensional display capabilities have become commonplace.

Finally, the report addresses the advances suggested by its title. For example, new generations of gamma ray spectrometers, some of which use advanced higher-density scintillation crystals to improve detection efficiency at higher energies, weigh under 2 kg and incorporate isotope libraries. The authors summarize the current status of electrical, electromagnetic, gravity, and magnetotelluric methods, many of which have been enhanced by GPS developments.

The eBook suggests that progress in radiometric methods is closely tied to uranium exploration. As well, certain achievements in other geophysical methods have contributed to success in uranium exploration.

A number of uranium exploration projects worldwide serve to illustrate the eBook’s technical contents, and each is presented using diagrams, charts and photos. Coverage includes the new radiometric map of Australia, unconformity-related uranium deposits in the Athabasca Basin of Saskatchewan, and the East Kimberley region of Australia.


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