Optimization of ISR I j ti d E t ti S tInjection and Extraction Systems

Presented by: Shawn Leppert

Leppert Associates

NRC/NMA UraniumNRC/NMA Uranium Recovery Workshop

July 1-2, 2009 Denver, Colorado

A Uranium Mine Prospect

Opportunity – Uranium Ore has been Delineated within a Fluvial DepositsFound within water-bearing geologic units 100+ feet below ground surfaceData indicate the uranium is potentially present in mineable quantitiesData 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 & GeochemistryMaximize the Extraction of Uranium Ore Efficient Lixiviant Delivery/RecoveryMinimize Environmental Liability Placement of Monitoring Network

Understand the subsurface setting Geology, Hydrology, & Geochemistry

Minimize Required Restoration Tight Control of Lixiviant Distribution

Contributing FactorsSubstantial Site Surface and Subsurface DataFluid Hydraulics are Predictable

Minimize Required Restoration Tight Control of Lixiviant Distribution

Fluid Hydraulics are PredictableUncertain Shallow Geology (even with a large number of geologic logs)

Solution – Develop A Regimented Quantitative Decision Framework

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 FrameworkData 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 Mine Permitted W ll T t d A t d d P ti bl

Increases

Accurate Extraction/Injection Well Simulation

Finite-Element Surface Representation

Dynamic Front Generation

Explicit Water Table Emulation

Wells Tested, Accepted and Practicable

Accurate Extraction/Injection Well SimulationDynamic Front Generation

Direct Simulation of Separate LiquidsTelescopic Mesh Refinement

Faulting/Fracturing Coupling with Geochemical Model

FEFLOW Model Development

Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh

Total of 1,050,408 Elements

FEFLOW Model Development

Aerial ViewFinite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh

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

Porous Media Property Distribution

Total of 1,050,408 Elements

Geology Defined by LogsVery Fine Grained MediaFine Grained Media

Uranium SymposiumUranium SymposiumUranium SymposiumUranium Symposium

FEFLOW Model Development

Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh Lateral Inflow of

GroundwaterRiver Influence on Aquifer

Precipitation-Based Recharge

Porous Media Property Distribution

Total of 1,050,408 Elementso qu e

H d li B d i

Geology Defined by th LogsVery Fine Grained MediaFine Grained Media

Hydraulic Boundaries

Precipitation Recharge Local Creek

Lateral Flow

FEFLOW Model Development

Finite-Element Mesh

54 Layers, 55 SurfacesTelescopic Mesh

Generator PumpP i

Hypothetical

Porous Media Property Distribution

Total of 1,050,408 ElementsGenerator Pump

ControllerPumping

Well

H d li B d i

Geology Defined by th LogsVery Fine Grained MediaFine Grained Media

Flow Control/Meter Apparatus

Hydraulic Boundaries

Precipitation Recharge Local Creek

Lateral FlowWell 1Well 2 SimWell 3 SimWell 1 SimWell 3Well 2

Calibration

Hydraulic Stress Tests Parameter Estimation

Target – Hydraulic Heads

Parameter Estimation

Lixiviant Delivery/Recovery System Design

Ore Body ScenarioModerate

Permeability

MixedPermeability

UraniumOre

LLowPermeability

Lixiviant Delivery/Recovery System Design

Ore Body Scenario

Examine the Injection

Lixiviant Delivery/Recovery System Design

Ore Body Scenario

Examine the Injection

Mechanical Design

Lixiviant Delivery/Recovery System Design

Ore Body Scenario

Examine the Injection

Mechanical Design

Optimized DesignOptimized Design

Lixiviant Delivery/Recovery System Design

Ore Body Scenario

Examine the Injection

Mechanical Design

Optimized DesignOptimized 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 ControlledMechanical Design

Optimized Design

• Favorable if the Lixiviant is Controlled

(2) Average Residence Time of LixiviantOptimized Design

Sweeping Design

• Maximize Recovery … Minimize Residence Time

(3) Volume of Lixiviant Remaining after ½

Scenario Comparison

(3) Volume of Lixiviant Remaining after ½ Year of Clean-Water Injection/Extraction• Minimize Restoration Activities

Lixiviant Delivery/Recovery System Design

Ore Body Scenario

Examine the Injection

2 da

ys

,152

ft3

6 ft3

Mechanical Design

Optimized Design13

106

days

4,44

9,

3,11

2,03

6

ft3 ft3Optimized Design

Sweeping Design

79 d

ays

2,89

8762

f

3,11

2,03

6

Scenario Comparison88

,608

ft3

102,

762

ft3

Mechanical Optimize Sweeping

Quantitative Hydrogeologic Decision Framework

Geology

Data Evaluation Decision

Pilot Tests & Additional Characterization

HydrologyQuantitative ModelElectronic

Hydraulic Property Estimation

Hydrology

GW Quality Tables (dynamic)

Hydrostratigraphy Tables (static)

Hydrologic Tables (dynamic)

Event Tables (dynamic)

Database

1

0 . 5

L e g e n d

N

F r a c t i o n o fI n j e c t i o n M a t e r i a l

Lixiviant Delivery & Recovery System Design

Geochemistry Geochemical Table (Static)Well Construction Tables

(static)

(dynamic)L S 5 0 1 1 M

L S 5 0 1 2 M

L S 5 0 1 3 M

0 . 1

0 . 0 5

0 . 0 1

0 . 0 0 5

0 . 0 0 1

0 . 0 0 0 5

0 . 0 0 0 1

L o s t S o l d i e rA r e a o f I n t e r e s t

D r a w n b y : M A W0 2 / 2 3 / 0 7

P o t S u r f l p k

F i n a l L i n eS t e a d y S t a t e

W e l l

System Performance Monitoring

Reports/PermitsReclamationGeophysical

Conclusions

Demonstrated how the Quantitative Decision Framework can be used to Assist in the Design of a Hydraulic Lixiviant Delivery and Recovery Systemg y y y y

Optimize the design to maximize its efficiency

Comparison of three design alternatives using three quantitative design criteria

Design 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 other

Place an effective subsurface monitoring network

Develop a thorough understanding of the subsurface setting Challenges

End