1. Manny Mathuthu, Ntokozo Khumalo,
Malayita M Baloyi and Refilwe N Maretela
North-West University (Mafikeng) Center for Applied Radiation Science and Technology (CARST) Mmabatho, 2735, South Africa
Application of ICP-MS and Isotopic Techniques in Resolving Nuclear Forensics Signatures in South African Mining and Processing

2. Overview Aim of the Research Objectives Background Methodology
Present Results & Discussions
Conclusions

3. Aim of ICP-MS & Isotopic Ratio Technique
Apply the ICP-MS & Isotopic Ratio Technique to resolve nuclear forensic signatures in South African Uranium Thorium Mining and Processing.
Objectives are to:
Resolve the U-238, Th-232 nuclear forensics signatures for the mine using:
Isotopic Ratio Technique
ICP-MS Technique
Gamma spectrometry Technique
Develop a nuclear forensics Library for U & Th from the mine
Use Library to trace origin of interdicted nuclear material
Provide evidence for law enforcement and nuclear security

4. Background: Nuclear security
Prevention, detection and response to theft associated with illegal possession or transfer of radioactive or nuclear material and their facilities (Kristo and Tumey, 2013).
Fig 1: Prevention (LHS), Characterization (Middle) and Fingerprinting (RHS). (Davydov, Hutcheon et al. 2014)

5. Background Cont… Nuclear forensics
Examination of nuclear and or radioactive material for supporting nuclear security.
Nuclear forensic helps to characterizes nuclear material at each stage of the fuel cycle:
the uranium ore body underground,
the milling and processing of the ore,
enrichment of uranium in 235U,
nuclear reactor operation
the spent fuel (nuclear waste) stage
re-processing of spent fuel.
In this work we focus on the first two stages.

6. MATERIALS AND METHODS
Signatures Includes-
physical characterization, elemental, isotopic and chemical composition of the nuclear material
Techniques
Here we characterize mining and processing of U & Th using ICP-MS REE (Lanthanides), minor and trace elements.
Run samples in the ICP-MS under the Isotopic Ratio Method
We compare to the gamma spectrometry technique

7. Mine Tailing
Fig 2: The Fuel Cycle (Adapted from NRC)

8. Study Area
Mine Tailings
Mine Tailing
Fig 3: Study Area

9. Active Tailing
Fig 4: Sampling the Tailing slurry

10. Disused Tailing
Fig 5: Sampling at 50 year intervals ng at 50 year intervals

11. Fig 6: Instrument: NexION 300Q ICP-MS (Perkin Elmer)
ICP-MS Equipment Used
(A) ICP-MS for major and trace elements
Fig 6: Instrument: NexION 300Q ICP-MS (Perkin Elmer)

12. HPGe Detector Equipment Used
Fig 7: High Purity Germanium for Gamma spectrometry

13. ICP-MS Results for mining and Processing

14. Table 4:

15. Table:5 Fingerprinting the mines
Tailing Dam1
Tailing Dam 2
Comment
B, Th, U, Y, V, Ni and Ti
Strong suggestion that Phosphate was
used during
Processing
Phosphorite deposit, Apatite & fluorapatite minerals. Uranium is recovered from phosphoric acid
Ba,, Sr, Cr, Mo, Pb, Cu, Zn, Cd, Li, Fe and As
Ca, K, Mg, Mn and Fe
Absence of Se, Re, Lu
suggests that Uranium is NOT in a Coal-Hosted Ore
Studying these 22 elements more closely, the elements
which distinguished the U ore Source Dams from each particular mine were determined. See Fig 5.
Dam 2 has higher concentrations of Ca, K, Mg, Mn and Fe, which indicates leach processing of the U ore.
Lime pptn of impurities, Magnesia pptn of U

16. REE Patterns for Tailing Shaft water
REE Conc/ Chondrites Means
Fig. 8. Chondrite normalised REE patterns for Mine samples. REEs in order of A. (Chondrite data : Anders and Grevesse, 1989).

17. REE Patterns for Tailing 3.
REE Conc/ Chondrites Means
Fig. 9. Chondrite normalised REE patterns for Mine samples. REEs in order of A. (Chondrite data : Anders and Grevesse, 1989).

18. Table 6: Heavy metals concentration per Tailing:

19. Discussions on ICP-MS Results
The concentration of uranium is below 10 ppm for both tailing dam 1 and 2- absence of blackshale deposit but higher for Tailing dam 3-5.
Rb, Th, Cs, Pb, Ti and S represent a Quartz-pebble conglomerate deposit.
High concentration values of As and Ni and Mo are associated with uncorformity-type ore deposit.
V, Ti and Fe represent a type of leach solution when in situ process
Al, Mg, Ca, Fe, K, Mn are predominant in this mine. As a result, they are a distinctive characteristic of this mine.

20. During the processing of the ore, fingerprint is lost
During the processing of the ore, fingerprint is lost. However, Rare earth elements (REE) or Lanthanides, are used to determine the original deposit
Fig 8 & 9 show that La, Ce, (Pr) & Nd have high signatures for U (and low for Th)
A Chondrite normalized plot of the REE concentration versus the REE, arranged in order of atomic mass numbers, gives the characteristic Lanthanides patterns for the particular mine.
The (LREE), light rare earth elements (Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd; - cerium group), are dominant in this gold/uranium ore body.
Ca, Fe, W and Pb were impurities found in urinates and this is normally the characteristic of vein type hydrothermal deposit.
The increase of uranium in the T5W samples suggests:
Time scale for technology development over years
Poor processing methods
Poor value of uranium at that time

21. ICP-MS Isotopic Ratios
Fig10(a): Lead isotope ratio for water samples from the gold mine in SA.

22. (B) Low Th concentration
Fig 10(b): Lead isotope ratio for water samples from the gold mine in SA
207Pb/206Pb
208Pb/206Pb

23. Fig. 5 207Pb/206Pb versus 208Pb/206Pb for tailing samples.

24. Fig. 12 A plot 207Pb/204Pb versus 206Pb/204Pb for mine (fissure) water samples.

25. Conclusions
Rare earth elements (REE) are good signatures of the original deposit {La, Ce, (Pr) & Nd } and dominant group
In Fig 12 show Lead (Pb) isotope ratios for SA gold mine range from 12 %wt to 18.5%wt. This is distinctively different from UK, Germany, Poland, Italy, and Spain [Balcaen et al., 2010]. See also Fig 11.
First endmember point shows lack of Th232 in sample.
Ca, Fe, W and Pb were impurities found in urinates and this is normally the characteristic of vein type hydrothermal deposit.
Fingerprints suggests Phosphorite deposit in Apatite & fluorapatite minerals.
Uranium is recovered from phosphoric acid
Lime used for pptn of impurities &
Magnesia used for pptn of U

26. Acknowledgements
Authors would like to acknowledge the International Atomic Energy Authority for sponsoring this Project under CRP J2003.
We also acknowledge the assistance given by Dr Lebo Motsei and Chief Technician Ms Mpho Tsheole on the operation of the ICP-MS for Isotopic Ratio data analysis.

27. Thank you!!!