Graduation Year

2016

Degree

M.S.E.V.

Degree Name

MS in Environmental Engr. (M.S.E.V.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

James Mihelcic, Ph.D.

Co-Major Professor

Qiong Zhang, Ph.D.

Committee Member

Jaime Corvin, Ph.D.

Keywords

Energy, Langer Heinrich Uranium, Mining, Resource Management, Sub-Saharan Africa, Water

Abstract

Uranium mining and nuclear power is a controversial topic as of late, especially in light of the recent Fukushima event. Although the actual use of nuclear fuel has minimal environmental impact, its issues come at the very beginning and end of the fuel’s life cycle in both the mining and fuel disposal process. This paper focuses on a life cycle analysis (LCA) of uranium mine in the desert nation of Namibia in Southern Africa. The goal of this LCA is to evaluate the environmental effects of uranium mining. The LCA focuses on water and energy embodiment such that they can then be compared to other mines. The functional unit of the analysis is 1kg of yellowcake (uranium oxide). The processes considered include mining and milling at Langer Heinrich Uranium (LHU). The impact categories evaluated include the categories in ReCiPe assessment method with a focus of water depletion, and cumulative energy demand.

It was found that the major environmental impacts are marine ecotoxicity, human toxicity, freshwater eutrophication, and freshwater ecotoxicity. These mainly came from electricity consumption in the mining and milling process, especially electricity generated from hard coal. Milling tailings was also a contributor, especially for marine ecotoxicity and human toxicity. The other electricity generation types, including nuclear, hydro, natural gas, and diesel contribute to marine exotoxicity and human toxicity as well. Hydro-electricity, tailings form milling, sodium carbonate, and nuclear electricity also cause freshwater eutrophication at the LHU mine.

The major contributor of the water depletion was hard coal generated electricity consumption as well. Tailings also led to a level of water depletion that was significant but much smaller than that of the coal-based electricity.

In terms of energy, weighting portrayed the main energy used to be nuclear power, in terms of MJ equivalents. Nuclear power was then followed by fossil fuels and finally hydropower. Most of the energy used was for the uranium mining process rather than the milling process.

As expected, the direct water, and energy values, 0.5459 m3 and 97.34 kWh per kg of yellowcake, were much lower than the LCA embodiment values of 282.67 m3 and 76,479 kWh per kg of yellowcake. When compared to other mines, the water use at LHU was found to be much lower while the energy use was found to be much higher.

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