In 2009, in the comments to this post on The Oil Drum we stumbled upon a mine of information on the operation of the Rossing uranium mine in Namibia. The data table provided numbers for the amount of energy used on site together with the amount of uranium mined. This provided an opportunity to calculate the energy return of the mining operation. Simply put ERoEI = energy contained in the U / the energy used to mine and refine it. There are some complexities but back then I calculated an ERoEI of 1200:1 The data has been updated and fresh calculations are presented below.
First a few words about Rossing. The mine is operated by Rio Tinto, one of the world’s largest mining companies. Discovered in 1928, operations began in 1976. According to Wikipedia Rossing is the 5th largest U mine in the world. The uranium ore is mined, milled and refined at Rossing and the energy numbers here reflect energy used to go from rock to yellow cake (U3O8 inset image up top).
Figure 1 Rossing mine.
Figure 2 Location map from Rio Tinto. Rossing is by Arandis (red dot)
The performance table provides data over 5 years:
Figure 3 Performance table from Rio Tinto.
My calculations are based on 2016.
The first important number to pick out is the energy use on site: 2,528,000 GJ [1]
The second is the uranium oxide produced: 1,850,000 kg [2]
The atomic mass of U = 238 and O = 16. U3O8 = 842 amu. U/U3O8 = 714/842 = 0.848
The third important number is uranium metal produced = 1,850,000 * 0.848 = 1,568,880 kg [3]
We can now calculate the fourth important number which is energy used to mine 1 kg = 2,528,000 GJ / 1,568,880 kg = 1,611 MJ/kg [4]
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