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Geological 3D Modelling and Resource Estimation of Budenovskoye Uranium
Deposit (Kazakhstan)
Dr. Maxim Seredkin
Senior Resource Geologist
CSA Global Pty Ltd.
25/06/2014 www.csaglobal.com
Dr. Alexander Boytsov
Senior Vice-President
Thys Heyns
Senior Vice-President
Uranium One Inc.
Presented by:
Introduction
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Roll-front sandstone uranium deposits can be extracted using in situ recovery methods with low operational costs
Introduction - South Kazakhstan
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The production share from the Kazakhstan roll-front sandstone-hosted uranium deposits mined using the ISR method comprises 36% of the world total
CSA Global was retained by Uranium One to Resource Estimates for Budenovskoye deposit
CSA Global has completed modelling and significantly improved the method of modelling roll-front deposits.
Introduction - uranium deposits
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Budenovskoye is a World class deposits
Source of Initial data:
www.cameco.com, www.uranium1.com,
www.world-nuclear.org, www.armz.ru,
www.paladinenergy.com.au, www.bhpbilliton.com
Structure of roll-front deposits
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The mineralised bodies consist of several morphological elements: noses, wings and residual parts. Mineralised bodies are surrounded by radium halos.
Typical cross section of roll-front
Structure of roll-front deposits
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Example mineralised body in cross section at the Budenovskoye
Lower wing
Upper wing
Residual bodies
Nose
Structure of roll-front deposits
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Roll-front sandstone-hosted uranium mineralisation is spatially and genetically associated with a regional redox front
The distribution of nose parts marks the redox front
The wing and residual parts of rolls are distributed in the rear part of roll-fronts.
Budenovskoye deposit
plan view
Determination of U grades
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sampling
Ra(eU)
U
Rn degassing factor
assaying
K, Th
Ra(eU)
U
Ra halos definition
control method
REF
eU modify
gamma logging
prompt fission neutron logging
Determination of lithology
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electrical logging:
granulometric analysis
hydrogeological drilling
sampling
RL - resistivity logging ,
SP - spontaneous polarisation logging
RL (&SP) vs. grain size
definition of permeability
permeability vs. grain size
RL (&SP) vs. permeability
Why use indirect methods?
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Because screens (filters) need to be set immediately after drilling of operational wells.
Express wireline methods:
• gamma or prompt fission neutron logging
uranium mineralisation
• electrical logging
permeability of the host sediments.
Definition of mineralised intervals
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typ
ical
cro
ss s
ect
ion
Definition of mineralised intervals
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Anomalous intersections (eU > 0.01%)
Initial gamma logging
oxidized sediments
initial reduced sediments
Verification of mineralised intervals
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o s
amp
les
for
assa
yin
g
No
sam
ple
s fo
r as
sayi
ng
No
PFN
logg
ing
No
PFN
logg
ing
Definition of uranium grades
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typical cross section
Definition of uranium grades
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initial reduced sediments
oxidized sediments
residual
intervals
wing
intervals
wing
intervals
Definition of impermeable rocks
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Nu
mb
er o
f sa
mp
les
Dependence of electrical resistivity with grain size
Dependence of permeability
with grain size
Dependence of electrical resistivity
with permeability
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Definition of impermeable rocks
RL
SP
Impermeable sediments
Permeable sediments
RL - resistivity logging ,
SP - spontaneous polarisation logging
Interpretation of roll-front
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cross section
Interpretation of roll-front
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cross section
Wireframe modelling
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Nose parts modelling
(lines - stratabound redox front) Wing parts modelling
Residual parts modelling Impermeable sediments modelling
2 km
Wireframe modelling
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2 km
Mineralisation in the
Mynkuduk horizon
Mineralisation in the
Inkuduk horizon
Why grade x thickness (GT)?
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Leaching uranium from blocks with different GT
Because for ISR deposits it is important to use a metal accumulation index (grade x thickness or “GT”) to define the cut-offs for resource estimation.
The mineralised interval with 0.04% U x 10 m is better for ISR than 0.10% U x 3 m.
Definition GT in block model
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Initial block model – grades of U, % - cross section Two-dimensional gridded models – grade of U, % - cross section
Two-dimensional gridded models – GT of U, % - cross section 3-D block model – GT of U, % - cross section
Definition GT in block model
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Stratabound oxidation
zone
2 km
GT distribution at the Budenovskoye deposit – plan view
Mineral Resources CIM compliant
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Depletion of uranium
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Screens (filters) in operational and observation wells
Borders of operational blocks
In ISR operations, the host rock remains undisturbed while the valuable component is dissolved by the leaching solution
For a mine it is considered sufficient to volumetrically delineate contours of production blocks and to deduct the depleted metal (recovery and in situ loss) from the Mineral Resources. Grades and GT will decrease proportionally because the volume of rock mass remains.
200 m
Mineralised bodies – nose parts
Mineralised bodies – wing parts
Mineralised bodies – residual parts
Operational blocks
Operational blocks and mineralised bodies
2 km
Block model vs. production blocks
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Comparison of mineralised intervals in operational wells with mineralised bodies based on exploration drill holes
100 m 5 m
Mineral Resources as of 30/06/13
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Category Volume Tonne Productivity (GT) Grade Mineral Resources
‘000 m3 ‘000 m3 m x % kg / m2 U, % U3O8, % Tonnes M lb
Measured 43,227 73,487 0.46 7.8 0.072 0.085 52,646 136.88
Indicated 38,692 65,777 0.46 7.8 0.088 0.104 58,484 152.06
Measured & Indicated
81,921 139,265 0.46 7.8 0.080 0.094 111,131 288.94
Inferred 58,177 98,901 0.37 6.2 0.095 0.111 93,623 243.42
Mineral Resources based on 0.04 m% (grade x thickness) cut-off per hole
Mineral Resources based on CIM definition
Depletion estimated using losses 10%
Measured Mineral Resources based on exploration drilling density of 50 m x 200 m (excluding residual mineralised bodies)
Indicated Mineral Resources based on exploration drilling density of 50-100 m x 400 m (excluding residual mineralised bodies) and 50 m x 200 m for residual mineralised bodies
Inferred Mineral Resources are based on exploration drilling density of 100-800 m x 400-1600 m
Mineral Resources include Mineral Reserves
Mineral Resources 2013 vs. 2012
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0
20,000
40,000
60,000
80,000
100,000
120,000
Measured Indicated Inferred
RPA, 2012
CSA, 2013
RPA’s resource estimation was based on conservative transformation of GKZ resources to CIM Mineral Resources: Operational blocks -> Measured, C1 -> Indicated, C2 -> Inferred. CSA’s resource estimation is based on geological modelling including latest exploration data
Ura
niu
m, t
on
ne
s
8,1
37
52
,64
6
18
,25
0
58
,48
4
38
,37
6
11
1,1
31
+ 4
4,5
09
(+4
47
%)
+ 4
0,2
34
(+2
20
%)
+
72
,75
5 (
+18
8%
)
Conclusion
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Using the improved methodology of geological modelling and resource estimation discussed in this presentation,
the average differences between resource estimates based only on exploration drill holes and estimates using all production wells are less than 5 %,
whereas the classical approach of resource estimation based on cut off grade commonly gave differences in the order of 20 —90%.
Summary
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Work by CSA and Uranium One has: • developed an advanced and unique modelling methodology
for in situ recovery deposits, • modelled one of the largest and most complex sandstone-
hosted uranium deposits in the world, • successfully reconciled our resource modelling against
production results, • Seen the adoption by the mine of our modelling in order to
optimise production, where, • It is expected there will be a significant positive economic
impact from using our improved resource estimation approach,
• Geological model can be used for operational modelling with good economical effect,
• Measured and Indicated Resources were increased by 84,743 tU (321%)
Authors
Dr Maxim Seredkin Senior Resource geologist, CSA Global Pty. Ltd.
Over 17 years’ geological experience in exploration, deposit modelling and resource estimation for a range of commodities, but particularly uranium.
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Dr Alexander Boytsov Senior Vice President, Exploration, Uranium One Inc.
37 years of broad and advanced practical national Russian and international experience in uranium deposits exploration, resource estimation, mining, and processing.
Thys Heyns Senior Vice President, Senior Vice President, New Business &Technical service, Uranium One Inc.
30 years of broad and advanced practical international experience in gold, uranium and other deposits, exploration, resource estimation, and mining.
Contact CSA Global
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CSA Global (Head Office) Level 2, 3 Ord Street West Perth, WA 6005
PO Box 141, West Perth WA 6872
T +61 (0) 8 9355 1677 F +61 (0) 8 9355 1977 E [email protected]