|
|
| Fig. 1: Koeberg Nuclear Power Plant. (Source: Wikimedia Commons) |
Though Africa is only home to two nuclear reactors, the continent has been responsible for aiding the nuclear programs of countries around the world for years through their supply of uranium. [1] South Africa, home to the continents only nuclear reactors (see Fig. 1) and so far the only country in the world to renounce its indigenously developed nuclear potential has supplied a large amount of uranium to the world through its large reserves of natural uranium. [2] South Africa's uranium program has propelled the country to an international status of prestige, but the status has come at a price to the uranium miners health.
The techniques of extraction for uranium mining are proportionate as follows: In-situ leach (44.9%), underground mining (26.2%), open pit (19.9%) and heap leaching (1.7%), with the remaining 7.3% arising as a result of byproduct from other mining operations. [3] Uranium ore is generally processed through grinding the ore materials to a uniform particle size, which is then treated through chemical leaching to extract the uranium. This results in a dry powder form of the natural uranium commonly referred to as "yellow cake." The waste products that follow this process include mill tailings, sandy waste that contains heavy metals, Radium, and other radioactive contaminants. As the Radium of these piles decay over time, it releases Radon, a highly radioactive gas. [3] The radioactivity of the tailings largely depends on the grade of the ore mined, which can vary from 1 Bq/g to 100 Bq/g. The main risks associated with these tailings are γ radiation from the Radium decay, Radon gas, radioactive dust material blown by the wind to neighboring areas, and increased concentrations of toxic heavy metals that contaminate surface and groundwater sources. Because of their high sulfide content, these tailings contribute to the acidification of groundwater, which in turn accelerates the release of radioactive and other dangerous elements. [3]
Uranium miners are exposed to radiation because of the high radioactivity of some of the atoms that they are exposed to during mining. Th-230, which has a half-life of 80,000 years, is the parent product of Ra-226, which means there is a continuous production of the isotope. Radium, has a half-life of 1600 years, and is the parent product of Rn-222 gas, which has a half-life of 3.8 days. [3] Additionally, high levels of silica dust exposure have proven to be a surrogate for the exposure to radon daughters. [4] The decay products of this Radon gas have irreversible adverse health effects on humans downwind, such as a significant increase in the occurrence of lung cancer and South African Uranium miners often face this fate. [3]
The nuclear industry has allowed South Africa many privileges on the world stage. Moreover, South Africa's uranium industry has made monumental social and economic impacts on the country. While South Africa's progression in the nuclear world has bred positive benefits its lasting effects on their environment and the uranium miners could prove to do more harm than good in the future if more isn't done to regulate the industry's hazardous impact.
© Ramona Greene. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] S. Pfeil, "Future of Nuclear Energy in South Africa," Physics 241, Stanford University, Winter 2018.
[2] P. Baxevanis, "The Nuclear Weapons Program of South Africa," Physics 241, Stanford University, Winter 2013.
[3] M. Stevens, "Environmental Impacts of Uranium Mining," Physics 241, Stanford University, Winter 2017.
[4] E. Hnizdo, J. Murray, S. Klempman, "Lung Cancer in Relation to Exposure to Silica Dust, Silicosis and Uranium Production in South African Gold Miners," Thorax 52, 271 (1997).
