SXR Southern Cross Resources Inc Gamma Ray Intensity 238 U 214 Bi 214 Pb Gamma is the traditional tool used to measure eU 3 O 8 grade and evaluate resources… …but in some Roll-front deposits uranium is not in equilibrium with its daughters as they are too young. PFN: Disequilibrium Problem
SXR Southern Cross Resources Inc Hole 1 PFN: Schematic PFN Response Hole 2Hole 3Hole 4 No PFN response in low grade tails as daughters only PFN response directly measures 235 U concentrated in high grade nose
SXR Southern Cross Resources Inc Pulsed Neutron Source Down Hole Probe Drill Hole PFN: What is PFN Technology?
SXR Southern Cross Resources Inc PFN: Neutron Generator Tube High voltage accelerates deuterium ( 2 H) ions into a tritium ( 3 H) target 2 H + 3 H n + 4 He (En = 14.2MeV) Pulses at 1000 cycles per second & emits ~10 8 neutrons per second
SXR Southern Cross Resources Inc Pulsed Neutron Source Epithermal & Thermal Neutron Detectors Ratio gives % 235 U 14 MeV Neutron Flux Epithermal Neutron To Thermal Neutron (by Collision with rock) Thermal Neutrons Induce Slow Fission of Natural 235 U in rocks 2MeV Prompt Neutrons emitted from 235 U fission Down Hole Probe Drill Hole PFN: What is PFN Technology
SXR Southern Cross Resources Inc Ratio of Epithermal to Thermal Neutrons is Directly Proportional to 235 U Only 235 U is Fissionable in the Natural Environment Deposits considered in Isotopic Equilibrium 0.72% 235 U 99.27% 238 U 1.48 U 3 O 8 lbs/ft U 3 O 8 lbs/ft U 3 O 8 lbs/ft 3 Thermal Neutron Flux Epithermal Neutron Flux PFN Results
SXR Southern Cross Resources Inc Wireline Log Output Induction & Guard -Define lithology by measuring porosity using EM and Electrical methods. Similar to SP / Resistivity but better suited to highly saline conditions Natural Gamma -Total count natural gamma radiation measured by up to three scintillometers with varying NaI crystals sizes eU 3 O 8 (Black) -Calculated from calibrated natural gamma using a number of factors) pU 3 O 8 (Red ) -Direct measure of U 235 insitu using ration of epithermal to thermal neutrons – PFN
SXR Southern Cross Resources Inc PFN: Advantages Crucial for most Tertiary Uranium deposits as they are young and suffer extreme disequilibrium Uses a safe neutron generator rather than a radioactive source Produces an accurate direct measurement of insitu uranium over narrow intervals Results are instantaneous Measures a large sample volume (500mm sphere) Obviates the need to drill core Can be used during ISL mining to quantify recovery Exploration tool – disequilibrium vector towards mineralisation Colin Skidmore (October