Optimization of ISR 

I j ti d E t ti S t Injection and Extraction Systems

Presented by: 

Shawn Leppert 

Leppert Associates

NRC/NMA Uranium

Recovery Workshop

July 1-2, 2009 

Denver, Colorado
A Uranium Mine Prospect

Opportunity

– Uranium Ore has been Delineated within a Fluvial 

Found within water-bearing geologic units 100+ feet below ground surData indicate the uranium is potentially present in mineable quantities Data indicate the uranium is potentially present in mineable quantities

Challenge

- Can the Uranium Ore be Extracted Cost Effectively 

Using Hydraulic Methods; if so How?

Understand the subsurface setting Geology Hydrology & GeMaximize the Extraction of Uranium Ore Efficient Lixiviant Minimize Environmental Liability Placement of MonitoUnderstand the subsurface setting Geology, Hydrology, & GeMinimize Required Restoration Tight Control of Lixiviant D

Contributing Factors

Substantial Site Surface and Subsurface DataFluid Hydraulics are PredictableMinimize Required Restoration Tight Control of Lixiviant DFluid Hydraulics are PredictableUncertain Shallow Geology (even with a large number of geologic logs

Solution

– Develop A Regimented Quantitative Decision Framewo

Site Specific Information has been Modified to Protect Its Propriety Nature
Quantitative Analysis as a Part of the 

Regimented Decision Framework

A Hydraulic Simulator Integrates Hydrogeologic and Hydrogeochemical Data into a Dynamic Decision Framework Data into

a Dynamic Decision Framework

The Decision Framework can Evolve as an Understanding of the Subsurface Quantitative Analysis Tools Have Advanced Since the Last ISR W ll T t d A t d d P ti blIncreases 

9 Accurate Extraction/Injectio9 Finite-Element Surface Repr

9 Dynamic Front Generation9 Explicit Water Table Emulation

Wells 

Tes

te

d, Accep

te

d an

d

Practicable

Dynamic Front Generation Accurate Extraction/Injectio

9 Telescopic Mesh Refinement

9 Direct Simulation of Separat

9 Faulting/Fracturing

9 Coupling with Geochemical M
FEFLOW Model Development

3⁄4 Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic MeshTotal of 1,050,408 Elements
FEFLOW Model Development

Aerial View

3⁄4 Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh

Cross-Section B-B’ Cross-Section B-B’ Cross-Section C-C’ Cross-Section C-C’

3⁄4 Porous Media 

Property Distribution

Total of 1,050,408 ElementsGeology Defined by LogsVery Fine Grained MediaFine Grained Media
FEFLOW Model Development

3⁄4 Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh Lateral Inflow of River Influence Groundwater

on Aquif

er

Precipitation-Based 

Recharge

3⁄4 Porous Media 

Property Distribution

Total of 1,050,408 Elements

o qu e

3⁄4 H d li B d i

Geology Defined by th LogsVery Fine Grained MediaFine Grained Media

Hydraulic 

Boun

daries

Precipitation Recharge Local CreekLateral Flow
FEFLOW Model Development

3⁄4 Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh

Generator Pu

P i

Hypothetical

3⁄4 Porous Media 

Property Distribution

Total of 1,050,408 Elements Generator Pu

Co

Pumping 

Well

3⁄4 H d li B d i

Geology Defined by th LogsVery Fine Grained MediaFine Grained Media 

3⁄4

Hydraulic 

Boun

daries

Precipitation Recharge Local CreekLateral Flow

3⁄4 Calibration

Hydraulic Stress Tests Parameter EstimationTarget – Hydraulic HeadsParameter Estimation
Lixiviant Delivery/Recovery 

System Design

Ore Body Scenario 

Mixed

Permeability

Uranium

Ore
Lixiviant Delivery/Recovery 

System Design

Ore Body ScenarioExamine the Injection
Lixiviant Delivery/Recovery 

System Design

Ore Body ScenarioExamine the InjectionMechanical Design
Lixiviant Delivery/Recovery 

System Design

Ore Body ScenarioExamine the InjectionMechanical DesignOptimized Design Optimized Design
Lixiviant Delivery/Recovery 

System Design

Ore Body ScenarioExamine the InjectionMechanical DesignOptimized Design Optimized Design

Sweeping Design 
Lixiviant Delivery/Recovery 

System Design

Ore Body Scenario

(1) Volume of Ore Zone having

Comparison Criteria

Examine the Injection

(1) Volume of Ore Zone having

a Lixiviant Saturation >50%• Maximize Delivery• Favorable if the Lixiviant is Controlled Mechanical Design

Optimized Design

Favorable if the Lixiviant is Controlled

(2) Average Residence Time of Lix

Optimized Design

Sweeping Design 

• Maximize Recovery ... Minimize Resid

(3) Volume of Lixiviant Remaining 

Scenario Comparison

(3) Volume of Lixiviant Remaining 

Year of Clean-Water Injection/

• Minimize Restoration Activities
Lixiviant Delivery/Recovery 

System Design

Ore Body ScenarioExamine the Injection

2 days

,152 ft3

6 ft3 Mechanical Design

Optimized Design

13

106 days

4,449,

3,112,036

ft

3

ft3 Optimized Design

Sweeping Design 

79 days

2,898762 f

3,112,036 

Scenario Comparison

88,608 ft3

102,762 ft3

Mechanical Optimize Sweeping
Quantitative Hydrogeologic Decision 

Framework

Geology

Data Evaluation Dec

Hydrology

Quantitative Model Electronic 

GW Quality Tables 

(dynamic)

Hydrostratigraphy Tables 

(static)

Hydrologic Tables 

(dynamic)

Event Tables (dynamic)

Database

Geochemistry Geochemical Table (Static)

Well Construction Tables 

(static)

(dynamic)

Reports/Permits

Geophysical 
Conclusions

Demonstrated how the Quantitative Decision Framework can be Assist in the Desig y y 

n of a Hydraulic Lixiviant Delivery and Recove

Optimize the design to maximize its efficiencyComparison of three design alternatives using three quantitative desigDesign a system the will control the lixiviant so as to require only minor restoration efforts

One can Infer How the Decision Framework can Assist in the oth

Place an effective subsurface monitoring network Develop a thorough understanding of the subsurface setting 

Challenges
End