Prompt Fission Neutron (PFN) Borehole Logging Technology, Comparison with Gamma Logging Techniques

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1 Prompt Fission Neutron (PFN) Borehole Logging Technology, Comparison with Gamma Logging Techniques Russell Penney and Dennis Stevens AusIMM International Uranium Conference Adelaide June ASX: UXA

2 Acknowledgements Uranium Exploration Australia Limited (UXA) thanks UraniumSA Limited for permission to present data from their Mullaquana uranium discovery in South Australia. Disclaimer This presentation does not comprise a disclosure document. It does not constitute provision of financial product advice. None of the directors of UXA, its related bodies corporate, officers, employees or advisors makes or gives any representation, warranty or guarantee in relation to this presentation (whether orally, in document form or in any form whatsoever) or in relation to any information ( Information ) contained in it to the recipient of this presentation or any of its related bodies corporate, officers, employees and advisors ( Recipient(s) ). Information sourced from third parties and reported in this presentation has not been verified or updated; it is important that Recipient(s) take care to verify and update before taking in to account in any process of evaluation. The presentation is provided expressly on the basis that the Recipient(s) will carry out its own independent inquiries into the Information and make its own independent decisions about the affairs, financial position or prospects of UXA. UXA reserves the right to update, amend or supplement the Information at any time in its absolute discretion (without incurring any obligation to do so).

daily use at many uranium mines in the USA UXA recently purchased the PFN business and intellectual property from its owner in the USA PFN

3 Unique borehole logging tool provides immediate and fool-proof uranium analysis within the borehole by using neutron activation to measure 235 U PFN used in discovering Australia's most recent uranium mine Beverley and the Four Mile mine development in South Australia and is in daily use at many uranium mines in the USA UXA recently purchased the PFN business and intellectual property from its owner in the USA PFN technology is owned 100% by UXA and is available from GAA, an independently managed borehole logging company, a 100% owned subsidiary of UXA

4 238 U decay chain gamma gamma

5 Spectral gamma energy windows typical of airborne surveys, hand-held spectrometers and downhole gamma tools

6 Total Gamma includes gamma radiation derived from the decay of Potassium, Thorium, Lead and Bismuth Spectral Gamma uses energy windows to differentiate the origin of each gamma particle.: e.g. most airborne radiometric surveys Spectral Gamma tools measure the daughter products of 238 U to determine Uranium grade Both Total Gamma and Spectral Gamma tools suffer from disequilibrium issues

7 Many uranium deposits too young for uranium and gamma emitting daughter elements to be in equilibrium (7 half lives of the longest living daughter element = 560,000 years) PFN Uranium may also have migrated away from its daughter elements by chemical action Gamma, in this example, misses a significant zone of uranium

8 α U 238 Th 234 β U x10 9 Yrs β Pa Pa 234 α β γ Th 1.14 mins 24.5 days = alpha decay radiation = beta decay radiation = gamma radiation Gamma can be used to calculate uranium concentration as eu3o8 [ Indirect determination] α α α α α Th 230 Ra 226 Rn 222 Po x10 γ β 5 Yrs 8.3x mins Yrs 1590 Yrs days Valid only if daughters in equilibrium with parent! β Source: Natural Decay Series: Uranium, Radium, and Thorium; Human Health Fact Sheet, August 2005, Argonne National Laboratories, EVS γ 218 Pb 214 Po 214 β Bi 214 β Bi 210 Pb α Pb 210 Po 210 α Pb mins 19.7 mins 1.5x10-4 secs 22 Yrs 5 days 140 days Stable

9 PFN tool creates very fast neutrons (14MeV) and fires 10 8 neutrons per second Neutrons are slowed (Thermal) by collisions with the rock The generated neutrons collide with 235 U and splits the atom (Fission) Fast (Epithermal 2MeV) neutrons are produced PFN measures the ratio of epithermal(fast) and thermal(slow) neutrons

10 235 U is the only fissile material in the natural environment The Ratio of Epithermal to Thermal Neutrons is proportional to 235 U Uranium is in Isotopic Equilibrium 0.72% 235 U 99.27% 238 U Therefore % U 3 O 8 may be deduced from PFN results directly.

11 Calibration at AMDEL facility run by DWLDC in Adelaide Three pits of various grades of U 3 O 8 Barren zone also recorded Hole Correction Pit calibration for three different hole diameters Both Gamma and PFN components of the tool are calibrated in these pits Mine sites have their own calibration pits

12 Multiple runs are used to check repeatability and ascertain a ratio of epithermal/thermal for a particular known grade of U3O8 gamma PFN

13 2 y = x R² = O 3 U p % 1 PFN Linear (PFN) Grade in pit Ratio Epi/Thermal

14 Corrections for wet/dry hole situations Dry holes decrease correction factor. Difficult to provide quantitative results due to hole rugosity Aquifer fluid correction factor Higher salinity higher correction factor Porosity Higher porosity = higher aquifer fluid Drill hole size correction

15 y = ln(x) R² = r cto fa n ctio re o C PQ Hole Size Log. (Hole Size) HQ Hole size (mm)

16 0.15% In this example, Uranium and its daughter products are in Equilibrium U Grade from gamma logging is denoted as % eu3o8 PFN = Blue Line Gamma = Red Line U Grade from PFN logging is denoted as % pu3o8

17 An absence of Uranium occurs at a gamma peak at 35.8m This log demonstrates the necessity of PFN in defining uranium, and in quantifying the amount of uranium. Note the Negative or Positive Disequilibrium in the right hand column PFN = Blue Line Gamma = Red Line

18 PFN = Blue Line Gamma = Red Line 1.10% 0.65%

19 Uranium from a Tertiary Basin deposit Low grade Uranium in a hard rock environment 0.15% 0.03% PFN = Blue Line Gamma = Red Line 0.01%

20 Uranium from a calcrete hosted deposit Fluctuating groundwater causes disequilibrium Low grade Uranium in a hard rock environment - equilibrium 0.03% PFN = Blue Line Gamma = Red Line

21 Gamma log alone does not reveal a true picture of U distribution

22 PFN (red) shows the strong disequilibrium with little uranium in the wings of the deposit

23 The PFN tool can be used to guide exploration by following disequilibrium vectors to find the displaced uranium PFN = Blue Line Gamma = Red Line

24 PFN Currently being used at a number of uranium mines in the US Sandstone-hosted U deposits with roll-fronts

25 Gain certain knowledge of the presence and amount of Uranium downhole as opposed to measuring 214 Bi and 214 Pb with gamma Provides instant results to aid drill program adjustments instead of waiting for geochemical analysis Analyses a larger mass of host rock than core or cuttings Reduces analytical costs (reduce labour cost from collecting, handling and transporting radioactive substances and in geochemical assay costs and storage) Reduces drilling costs (no need to core)

26 PFN TECHNOLOGY (WORLDWIDE) IS AVAILABLE FROM GAA GAA also provides a wide range of geophysical borehole logging technologies, including Gamma Logging

27 Contact details: Dr Russell Penney ASX: UXA Uranium Exploration Australia Limited Registered Office in Adelaide, South Australia 43a Fullarton Road Kent Town, SA 5067

ASX ANNOUNCEMENT. High grade uranium mineralisation confirmed at the Minindi prospect

ASX ANNOUNCEMENT. High grade uranium mineralisation confirmed at the Minindi prospect 7 th November 2007 ASX Code: UTO ASX ANNOUNCEMENT High grade uranium mineralisation confirmed at the Minindi prospect HIGHLIGHTS New significant drilling results returned from Minindi Creek: o MCRC 198: