KEGS- EXPLORATION 07 SYMPOSIUM GEOPHYSICAL CONTRIBUTIONS TO NEW DISCOVERIES 1 Synthetic Model...

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KEGS-EXPLORATION 07

SYMPOSIUMGEOPHYSICAL

CONTRIBUTIONS TO NEW

DISCOVERIES

Synthetic Model Testing and Titan-24 DC Resistivity Results at Wheeler River

An Athabasca-type Unconformity Uranium Target in Northwestern Saskatchewan, Canada

By: Jean M. Legault*, Quantec Geoscience Ltd., Toronto, ONDon Carriere, Carriere Process Management Ltd., Mississauga, ON

Larry Petrie, Denison Mines Corporation, Saskatoon, SK

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KEGS-EXPLORATION 07



DISCOVERIES

Wheeler River Case History

• Survey design based on initial synthetic model testing (best approach)

• Comparison of several array configurations(modeling and field application)

• Presence of major powerline impacts geophysics(choice of methods)

• Compare 2-D and 3-D Inversion results(improve understanding)

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DISCOVERIES

Titan 24 DCIP & MT

Overview

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DISCOVERIES

Common DCIP Electrode Arrays

Titan PldpdpCombinesPldp-left + Pldp-right

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DISCOVERIES

Standard Titan spreadN=0.5 to 23.5, a= 100m(552 data points)

Line Length 2.4 kmCurrent Injectionsinside Rx Array

N=0.5

N=23.5

Extended Titan spread(adding current extensionsbeyond end of receiver array)N=0.5-33.5, a=100m(approx. 1032 points)

Line Length approx. 4.4 kmCurrent Injections inside

& outside Rx Array

N=0.5

N=23.5

N=10.5

N=33.5

Titan-24 Pole-Dipole-Dipole Pseudosections

TITAN DCIP ARRAY CONFIGURATIONS

Note: Combinespldp & dppl data

Note: Combinespldp & dppl data

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DISCOVERIES

Case History: M-zone at Wheeler River

Commissioned byDenison Mines Corporation

in JV with Cameco Corporationand Japan-Canada Uranium Ltd.

April-May, 2007

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DISCOVERIES

• Define DC (+/- IP) signatures associated with:a) Uranium-bearing graphitic conductor at M-Zoneb) Granitic gneiss to the south-east of M-Zonec) Alteration chimney in sandstones above M-Zone

• Wheeler River mineralization occurs in 400m thick Athabasca Sandstone along the Unconformity, below alteration zone that is associated with underlying basement Graphitic metapelites known as the M-Zone conductive trend.

• Test Titan multi-parameter capability, with emphasis onGalvanic DC Resistivity (possibly also IP) using Pole-Dipole Array, in direct comparison with Dipole-Dipole and more widely used Pole-Pole Array.

Titan Survey Objectives

• Field Surveys were preceded by 2-D synthetic modeling study that tested for optimal array parameters (dipole size) and configurations (Pldp vs Plpl vs Dpdp array).

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DISCOVERIES

Introduction

Wheeler River Project

Key Lake

Moore Lake

WheelerRiverLocation:

HISTORIC NOTES

Since 1980’s, major powerline through property (along BL) – impacts EM follow-up.

Originally discovered in 1980’s (UTEM follow-up of Airborne) but remained unexplored until recently.

35km NE of Key Lake & 10km W of Moore Lake.

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KEGS-EXPLORATION 07



DISCOVERIES

BASEMENT AND UNCONFORMITY HOSTED URANIUM DEPOSIT STYLES

ALTERATION ASSOCIATED WITH UNCONFORMITY-HOSTED URANIUM DEPOSITS

M-ZoneDepositStyle:

Possible Targets:

1) Alteration Zone2) Unconformity3) Basement Graphite

Mineralization occurs: a) at unconformity,b) above graphite, c) with basement elevation change.

Silicification Clay-Alteration

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DISCOVERIES

WHEELER M-ZONE – AIRBORNE TOTAL FIELD MAGNETICS

0 200m

Road

M-Z

ONE

M-Z

ONE

Power

line

Drillh

oles

Grani

tic G

neiss

in B

asem

ent

Pelit

ic M

etas

edim

ents

in B

asem

ent

L100S

L100S

ZM

-06

ZM

-10

ZM

-11

VR

-20

5

- Ground SurfaceOverburden (<10m) ->

Manitou Falls C ->Sandstone(80-90m thick)

Manitou Falls B ->Sandstone(100-120m thick)

Manitou Falls A ->Sandstone(70-100m thick)

Manitou Falls D ->(10-20m thick)

- Unconformity

380-400m

WHEELER M-ZONE – GEOLOGIC SECTION ACROSS L100S

Basement Rocks ->Arkose-Anatexite (blues) Pegmatite-Granite (pink)Pelite-Graphites (grey-black)

UraniumMineralizedZone

0 50m

View Looking NE

GEOLOGIC NOTES

L 100S

BL

0E

M-ZONE DRILLING

0 200m

Plan View

M-zone consists of DDH Intersections along Graphitic Conductor and Elevation Change in Basement Topography.

Basement Dips Uncertain – possibly Steep Southeast

Known Geology is based on drilling Along a Narrow Corridor, with Little Known Outside that line.

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DISCOVERIES

Case History: Wheeler River

2-D Synthetic Modeling

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DISCOVERIES

Water 100 – 2 000 m

Alteration 50 -20 000 m

Graphitic Metapelite <1 -50 m

Psammitic (Felsic) Gneiss 5 - 100 k m

Fault

Unconformity

Lake seds 100 - 500 m

Sandstone 2 000 – 5 000 m

Granite 10 - 100 k m

Overburden 10 - 100 k m

Metapelite 50 -1 000 m

Contact

UC

(from Witherly, 2005)

GEOPHYSICAL PROPERTY MODEL for ATHABASCA-TYPE URANIUM DEPOSITS

300m -

1000m -

UBC 2d SyntheticForward Model Data

2d Reference Model

Note: 1500m (n=10)Current extensions

C) Extended TitanPole-dipole Arraya=150m / n=0.5-33.5

6.75 km Total array length

150m A-spacing

10-10kohm-metres

0 500m

300m -

1000m -

UBC 2d SyntheticForward Model Data

2d Reference Model

B) Extended TitanPole-dipole Arraya=100m / n=0.5-29.5



100m A-spacing

10-10k ohm-metres

0 500m

3000 ohm-m

300m -

1000m -

UBC 2d Synthetic Forward Model Data

2d Reference Model


A) Extended TitanPole-dipole Arraya=50m / n=0.5-33.5


50m A-spacing

10-10k ohm-metres

0 500m

1000 ohm-m

3000 ohm-m

5 ohm-m100m

1000 ohm-m

3000 ohm-m

5 ohm-m100m

1000 ohm-m 5 ohm-m

100m

3000 ohm-m

Titan Multi-Array DC Survey 2D DC Forward Models

Note: Gp response onlyat base of pseudosection, i.e.,50m a-spacing likely providesinsufficient penetration

Note: Gp response in middle,i.e., 100m a-spacing likely providessufficient penetration and focuswithin Sandstone and Gp

Note: Gp response in upper 1/3,i.e., 150m a-spacing possiblyexceeds required penetrationlacks and focus within Sandstone

2d DC ResistivityPole-pole Array

Range

10 to 10kohm-metres

500m -

1000m -

0m -

C)

0 500m

1500m -Loke 2d Inversions using Res2dInv (Loke and Barker, 1996)

2d DC ResistivityDipole-dipole Array 500m -

1000m -

Range

10 to 10kohm-metres0m -

A)

-300m Unconformity

-300m Unconformity

2d DC ResistivityPole-dipole Array

500m -

1000m -

0m -

B)

Range

10k to 10ohm-metres

Multi-Array Survey 2D Synthetic DC Inversions

-300m Unconformity

Note: Dpdp provideshigh resolution but possibly lacks depth penetration

Note: Pldp providesgood balance between resolution and depth penetration

Note: Pldp providesbest depth penetrationbut possibly lacks deep resolution

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DISCOVERIES

Case History: Wheeler River

DC/IP Field Tests along L100S

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DISCOVERIESROAD

M-Z

ONE

M-Z

ONE

0 1km

POW

ERLINE

L100S

L100S

Range

10 to 10k

ohm-metres

Pole-Pole Array Pole-pole Array

Range

0 to 30

milliradians

(a=100m / n=0.5-27.5 / 0.73A avg) (a=100m / n=0.5-17.5 / 0.73A avg)

N=27.5 -

- N=17.5

Range

10 to 10kohm-metres

Pole-dipole Array Pole-dipole Array

Range

0 to 30

milliradians

(a=100m / n=0.5-33.5 / 0.51A avg) (a=100m / n=0.5-19.5 / 0.51A avg)

N=33.5 -

- N=19.5

Line 100S Titan DC Survey 2D DC/IP Pseudosections

0 500m

1160 of 1166 total pts(>99%) retained for Inversion

785 of 1166 total pts(68%) retained for Inversion


571 of 1150 total pts (50%) retained for Inversion

Apparent Resistivity Pseudosections(Max 10% Vp error shown)

IP Phase Pseudosections(Max 3mrad error shown)

Dipole-dipole Array Dipole-dipole Array(a=100m / n=0.5-28.5 / 0.55A avg) (a=100m / n=0.5-17.5 / 0.55A avg)

Range

10 to 10kohm-metres

Range

0 to 30

milliradians

N=28.5 -

- N=17.5



?

?

Note: Coincident DCLow + IP High over Gp

Note: Weaker DC Lowand No IP high over GP

Note: Strong but Wide DC Low + No IP

high over GP

2d DC ResistivityPole-dipole Array

500m -

1000m -

0m -

B)

Range

10k to 10ohm-metres

-400m Unconformity

2d DC ResistivityDipole-dipole Array

500m -

1000m -

Range

10 to 10kohm-metres

0m -

A)

2d DC ResistivityPole-pole Array

Range

10 to 10kohm-metres

500m -

1000m -

0m -

Loke 2d Inversions using Res2dInv (Loke and Barker, 1996)

C)

-400m Unconformity

-400m Unconformity

0 500m

Line 100S Titan DC Survey 2D DC Inversions

Note: Dpdp provides high resolution but lacks depth penetration

Note: Pldp provides best balance between resolution and penetration

Note: Plpl provides most depth penetration but possibly lacks resolution

Range

10 to 10kohm-metres

2d DC Resistivity 500m -

1000m -

0m -

Range

0 to 50milliradians

2d IP Chargeability 500m -

1000m -

0m -

2d PW MT TM-TE Resistivity

Range

10 to 10kohm-metres

500m -

1000m -

0m -

1500m -Quantec PW2dia Inversions based on algorithm by de Lugao and Wannamaker (1996)

Loke 2d Inversions using Res2dInv (Loke and Barker, 1996a)

Loke 2d Inversions using Res2dInv (Loke and Barker, 1996a)

Line 100S DC, IP & MT2D & 3D Inversions

0 500m

Alteration Zone

Alteration Zone

Gra

phite

Gra

phite

Alteration Zone?

-400m Unconformity

-400m Unconformity

-400m Unconformity

Gra

phite

?

Granite-Metasedim

ent Contact?

Granite Contact?

Granite Contact?

3d DC Resistivity

3d IP Chargeability

Loke 3d Inversions using Res2dInv (Loke and Barker, 1996b)

Loke 3d Inversions using Res2dInv (Loke and Barker, 1996b)

Alteration Zone

Gra

phite

Alteration Zone?

500m -

1000m -

0m -

500m -

1000m -

0m -

Gra

phite

Granite Contact?

Granite Contact?Note: 2d DC suggests W-dipfor M-zone

Note: M-zone poorly resolved

Note: M-zone alteration appears well resolved but conductor dip andcontrast differs w DC

Note: 3d DC indicates steeper dip

Note: 3d IP resolves M-zone

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DISCOVERIES

A) Z=20mZ=50mZ=100m

Note: Powerline Visiblein Near Surface

Z=150mZ=200mZ=250mZ=300m

Note: Alteration Visible100m above UC

Z=350mZ=400mZ=450mZ=500m

Note: Graphite Visiblein Basement

Z=550mZ=600mZ=650mZ=700mZ=750mZ=800mZ=850mZ=900mZ=950mZ=1000mZ=1050mZ=1100mZ=1150mZ=1200mZ=1250m

Note: Migration of GraphiteConductive Zone to NW

Z=1300m

WHEELER M-ZONE – 3-D VOLUME of 2-D SMOOTH DC RESISTIVITY

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DISCOVERIES

Z=20mZ=100m

Note: PL+Road+NoiseVisible in Near Surface

Z=300m

Note: Alteration in IP low above UC?

WHEELER M-ZONE – 3-D VOLUME of 2-D SMOOTH CHARGEABILITY

Z=500m

Note: Graphite IP High?

Z=700m


Z=900m


Z=1100m


Z=1400m

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DISCOVERIES

WHEELER M-ZONE – 3-D VOLUME of 3-D SMOOTH RESISTIVITY

Z=20mZ=100m

Note: Powerline correlateswith near surface DC low

Z=300m

Note focused DC resistivitylow 100m above UC

Z=500m

Note: Graphite wellresolved in basement

Z=900m

Note: Absence of NWmigration in Gp signature

Z=1300m

Note: Absence of NWmigration in Gp signature

Z=1400m

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DISCOVERIES

WHEELER M-ZONE – 3-D VOLUME of 3-D SMOOTH CHARGEABILITY

Z=200mZ=100m

Note: Layer-like IP-High zone in sandstone?

Z=300m

Note widespreadpresence of IP highlayer in sandstone

Z=500m

Note: Well definedIP high along DC low

(except on north lines)

Z=900m

Note: Well definedIP high along DC low(also on north lines)

Z=1300m

Note: Well definedIP high along DC low(also on north lines)

Z=1400m

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DISCOVERIES

Study Findings

• Field surveys corroborated our initial 2-D DC synthetic modeling studies, i.e., Dpdp offered best resolution but poorest penetration; Plpl had greatest penetration but poorer resolution; Pldp had better combination of resolution, penetration and economy.

• MT data quality excellent – not hindered by ground contacts or Powerline effects – confirms all season capability.

• DC resistivity data quality and survey productivity greatly improved current injections (>0.5A avg), thanks to more powerful GDD Tx – suggests >2-3 season capability for DC/IP.

• Multi-parameter DC-IP-MT results show remarkable similarities and contrasting behaviour (i.e., DC vs MT; 2D vs 3D).

• DC resistivity results do not appear to be significantly hindered by powerline effects, but IP significantly more affected (acceptable).

• Coincident DC+MT resistivity low and IP high confirmed over graphite > additional tool for geologic mapping & discrimination.

• 3-D inversions simplify, improve understanding of responses.

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DISCOVERIES

Titan-24 DC Resistivity Results at Wheeler River

Thank You

CAMECO CorporationSaskatoon, SK

DENISON MINES CorporationToronto, ON

Japan-Canada UraniumTokyo, Japan

Toronto, ON

KEGS- EXPLORATION 07 SYMPOSIUM GEOPHYSICAL CONTRIBUTIONS TO NEW DISCOVERIES 1 Synthetic Model...

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