Helicopter ZTEM-Magnetic-Radiometric Surveys FOR ...sableresources.com/wp-content/uploads/2018/03/Legault_Sable-Baker...(After Hoschke (2011), Geophysical Signatures of Copper-Gold

Helicopter ZTEM-Magnetic-Radiometric Surveys FOR EPITHERMAL SULPHIDATION GOLD

over BAKER-SHASTA PROPERTY, Toodoggone Region, North-Central BC

.

Presented at Geotech Roundup Mini-Symposium, BCIT, Vancouver BC, 26-January, 2018

By J.M. Legault (Geotech) and Bill Yeomans (Sables Resources Ltd.)

OUTLINE

• Baker-Shasta ZTEM, Magnetic & Radiometric results.

• Multi-parameter Geophysics vs Stream Sediment Geochemistry Results

• Geology and Mineralization at Baker-Shasta.

• Conclusions & Recommendations

• Introduction

• ZTEM Basics

• Geophysics of Epithermal Gold Systems

Baker-Shasta ZTEM Survey

AEM OVERVIEW

Highlighting Three Main Airborne Electromagnetic Systems and Platforms available for Mineral Exploration.

AIRBORNE ELECTROMAGNETICS

Helicopter AEM Systems VTEM TIME-DOMAIN EM

Impulse FREQUENCY DOMAIN EM

ZTEM NATURAL FIELD (PASSIVE) EM


ZTEM BASICS

Parameters ZTEM

Transmitter Not required (Passive)

Receivers Airborne: Hz (Horizontal)

Base (Ground): Hx & Hy (Vertical)

Rx coil diameter Mobile = 7.2m

Base = 3.5m

Nominal Rx

Height

50-100m (Relatively unnaffected

by Receiver height)

Sampling Rate A/D = 2000 Hz

Output = 2.5Hz (~10m/sample)

Frequencies

(Hz)

18, 25, 37, 75, 150, 300 Hz (+/-600)

22, 30, 45, 90, 180, 360 Hz (+/-720)

EM Skin Depth

Penetration

~1km-5km for 1k Ω-m Host rocks

~300m-1.5km for 100 Ω-m

~100m-500m for 10 Ω-m

ZTEM is a Passive EM system Measures EM fields in audio-frequency range (22-720Hz) from distant thunderstorms for deep (>1km) Resistivity Mapping.


C) ZTEM Base Station Receivers

ZTEM BASICS

ZTEM

Tipper Equation


MagnetoVariational (MV) Dataset

along North (X), East (Y) & Vertical (Z)

( Arora et al, 1998)

ZTEM Measures 3 components (xy-z) of EM fields from Plane wave current flow in/around Conductive and Resistive geology, detects anomalous Vertical fields (Tipper).

ZTEM Basics

(after Sattel and Witherly, 2012)

In Phase (IP)

Quadrature (QD)

(modified after Castels, 2006)

ZTEM


Showing ZTEM frequency range in AMT natural field spectrum and Typical ZTEM response over Strong (left) and Weak (right) Conductive Tabular Bodies.

In Phase (IP)

Quadrature (QD)

XIP-075Hz YIP-075Hz

IP_DT-075Hz IP_TPR-075Hz

ZTEM Basics ZTEM 2D Inversion Results

ZTEM 3D Inversion Results

ZTEM Data

3D Resistivity Voxel 2D Resistivity Section

Showing typical ZTEM data types and Resistivity sections and volumes obtained from 2D & 3D Inversion Modeling over Copaquire Porphyry Copper deposit, Chile

Baker-Shasta ZTEM SURVEY

EPITHERMAL GOLD DEPOSIT DISTRIBUTION

(After Taylor, 2007)

Showing Location of Baker Shasta Deposits and Distribution of Selected Epithermal and Intrusion-related Au Deposits in North & Central America.

Baker-Shasta LS


Geophysics of Epithermal Gold Systems

Mesothermal Deposits

Porphyry Deposits

Epithermal Deposits

(After Williams, Towards a multidisciplinary integrated exploration process for gold discovery, In “Proceedings of Exploration 97” )

• Epithermal gold deposits are fossils of geothermal (hot springs) systems and occur above intrusions and/or porphyry copper deposits that form at greater depth.

• Low and High sulfidation (LS) epithermal systems host mix of alteration minerals that create favourable Resistivity Contrasts (Silica=Resistive / Clays=Conductive) with Host rocks.

• Epithermal deposits sometimes lack sufficient sulfides for detection with induced polarization, which makes Resistivity & EM methods favourable tools for their exploration.

Propyllitic Alteration

Silicification in Center of Vein System

Hot Spring Silicification Mushroom At Surface

Illite-Sericite Below Mushroom Cap at surface

Very High Resistivity Mushroom at Surface

Very Low Resistivities below Mushroom cap

Very High Resistivities in Center of System

Lower Resistivities in Surrounding Rocks


Geophysics of Epithermal Gold Systems

TECHNIQUE HIGH SULFIDATION EPITHERMAL

LOW SULFIDATION EPITHERMAL

EM/Resistivity

Magnetics

Radiometrics

(After Hoschke (2011), Geophysical Signatures of Copper-Gold Porphyry and Epithermal Gold Deposits – Implications for Exploration” )

Resistivity Signatures over Porphyry & Epithermal Au systems will vary according to the Erosional Level.

• Resistivity Low from Clay Alteration (Typical)

• Resistivity High also Possible (Deep Erosion or Silica Flooding into Permeable Units)

• Magnetic Low (Typical for Magnetite-Depletion)

• Mag-High at Depth also Possible (Intrusive source)

• Potassium High (Adularia-Illite alteration)

• Resistivity High from Silica Alteration (Typical)

• Resistivity Low Also Possible (Deep Erosion or Strong Clay Alteration)

• Magnetic Low (Typical for Magnetite-Depletion)

• Mag-High at Depth also Possible (Intrusive source) • Radiometric Low (Acid Leaching)


Epithermal Gold Examples

(After Hoschke (2011), Geophysical Signatures of Copper-Gold Porphyry and Epithermal Gold Deposits – Implications for Exploration” )

Martabe HS – North Sumatra

Resistivity highs

Pajingo LS – Queensland AUS

Resistivity high Trend

“The resistivity response in LS epithermal systems will vary greatly depending on the level of exposure/erosion. High in the system will be complex (i.e., conductive or resistive). Lower in the system, veins and alteration will be easier to identify with resistivity (Hoschke, Newmont/Newcrest, 2011).


Waihi LS – New Zealand

Resistivity high

Resistivity Low

Yanococha HS – Peru

Resistivity highs(mainly)

Resistivity Lows(also)

ZTEM IN-PHASE TPR (180Hz)


TOTAL MAGNETIC INTENSITY (TMI)

• Radiometric High due K-alteration at Dolly Varden (but Felsic Volcanics too). • Local Magnetic Lows due to Depletion with Larger Mag High over DV deposits (Deeper Intrusives) • ZTEM Resistivity High due to K-alteration (but Felsic volcanics too) NW & NE Structures also visible

ZTEM AT DOLLY VARDEN LS EPITHERMAL Ag

(after Walker et al., 2017)

RADIOMETRICS – EQ POTASSIUM

K-HIGH

MAG-HIGH

LOCAL MAG-LOW

RESISTIVITY HIGH

TOODOGGONE DISTRICT REGIONAL GEOLOGY

Kemess

Toodoggone District

• Mesozoic Toodoggone district is located in north-central BC along the eastern margin of the Intermontane Belt

• The Intermontane Belt represents a succession of volcanic arcs and accretionary complexes formed by subduction of oceanic plates under the North American plate. The Stikinia Terrane is part of the eastern Intermontane Belt

• The Toodoggone district comprises Upper Triassic to Lower Jurassic Hazelton Group Toodoggone Formation volcanic and sedimentary rocks which unconformably overlie island-arc volcanic/sedimentary rocks of the Lower Permian Asitka Group and Middle Triassic Takla Group • Major structures are oriented northwest to N-S and are offset by northeast structures. Most faults are steeply dipping normal faults. Strike slip and thrust faults are less common

• Mesozoic Toodoggone district of the Stikinia Terrane hosts Au-Cu-Mo porphyry and Au-Ag HS -LS epithermal deposits


Regional Geology The Toodoggone District is comprised of 4 Groups:

Early Permian Asitka marine sedimentary and volcanic rocks

Mid Triassic Takla basalt

Late Triassic to Early Jurassic Hazelton volcanic and volcaniclastic rocks include Lower and Upper Members

Cretaceous Sustut conglomerates and interlayered mudstones, sandstones and ash-

tuff

Upper Triassic to Lower Jurassic mineralization associated with plutonism

Black Lake calc-alkaline plutons and dykes intrude the Asitka, Takla, and Hazelton Groups

North Kemess and South Kemess Au-Cu porphyry deposits intrude into the Takla basalt

Geotech VTEM survey outlined in red

SOUTH TOODOGGONE DISTRICT GEOLOGY


Baker-Shasta Property Geology

Baker Deposit Geology

Past producers Baker and Shasta Mines are low sulphidation epithermal Au-Ag deposits which formed in the Toodoggone district between (ca. 192 to 162 Ma.)

Baker veins occupy ENE striking ,steeply dipping structures that cut the Takla Group volcanic rocks (basalt / andesite / rhyodacite); alteration includes epidote-chlorite-calcite+/-pyrite

Felsic dikes and porphyritic stocks intrude Takla Group

Skarn alteration occurs in Asitka limestones(blue) proximal to Duncan Granodiorite located 200m SW of the Baker deposit

The Baker deposit demonstrates a strong genetic link between epithermal and magmatic ore fluids

Total production A and B veins 77,500 tonnes yielding 1,168 kg Au and 23,085 kg Ag, with reserves of 50,000 metric tonnes containing 20.1 g/t Au and 177 g/t Ag


Baker-Shasta Property Geology Shasta Deposit Geology

Shasta deposit is an adularia-sericite type epithermal deposit in which deposition of metals coincided with the transition from quartz to calcite dominant gangue

N-S oriented stockwork breccia zones dip 60 degrees west while SSE oriented veins dip 70 degrees NE

Mineralization is associated with stockwork breccia zones associated with strong, hydrothermal potassic alteration of dacitic lapilli tuffs and flows of the Saunders Member of the Lower Toodoggone Formation. Hydrothermal alteration envelopes are <50m wide

Mineralization includes pyrite, sphalerite, chalcopyrite, galena, acanthite, electrum and native silver

WNW and NNE striking brittle-ductile faults cut and off-set the veins at Shasta

Total reserves estimated at 1,600,000 metric tonnes grading 2.84 g/t Au and 132.2 g/t Ag


ZTEM FLIGHT LINES AND DIGITAL ELEVATION MODEL (DEM)

BAKER MINE

SHASTA MINE

BAKER-SHASTA GEOLOGY & ZTEM LOCATION

Showing Location of Baker-Shasta Claims over Regional Geology and Flight lines over DEM •Baker Mine in northwest corner (topo high), Shasta Mine in southeast (topo low).

ZTEM SURVEY RESULTS

BAKER MINE

SHASTA MINE


• 982 line-km at 150m + 1.5km ties • ZTEM-Magnetics-Radiometrics • August 17-23, 2017.

REDUCED TO POLE (RTP) MAGNETICS (Corrects for Mag Inclination/Declination)

BAKER MINE

ZTEM SURVEY RESULTS

SHASTA MINE SHASTA MINE

ANALYTIC SIGNAL OF MAGNETIC FIELD (Corrects for Magnetic Remanence Effects)

BAKER MINE

Showing Regional and Local Magnetic Signatures across the property. •Baker and Shasta Deposits are located in well defined, local magnetic lows.


RADIOMETRICS – EQ POTASSIUM % (Maps K-Mineral Distribution & Alteration)

BAKER MINE

ZTEM SURVEY RESULTS


RADIOMETRICS – Th/K RATIO (Corrects for Overburden/Bedrock Effects)

BAKER MINE

Showing Regional and Local Radiometric Signatures across the property. •Baker and Shasta lie in local Potassium highs that lie along by NE-trending K-lows


IN-PHASE 180Hz TOTAL PHASE ROTATION (TPR)

BAKER MINE

ZTEM SURVEY RESULTS


IN-PHASE 180Hz TOTAL DIVERGENCE (DT)

BAKER MINE

Showing Both Types of ZTEM Data Representations – both Map Apparent Conductivity: •TPR (left) highlights Regional Geology; DT (right) shows more Structure & Local Geology •Both images enhance Major NW-SE conductive trend, cross-cut by NE-SW trends.


ZTEM IN-PHASE DT (720Hz) (Shallow Depth Penetration)

BAKER MINE

ZTEM SURVEY RESULTS


ZTEM IN-PHASE DT (30Hz) (Greater Depth Penetration)

BAKER MINE

Showing ZTEM Results for Shallow (high frequency DT) and Deep (Low frequency): • Shallow Data (left) enhance NW & NE trends, these extend to depth (right). • Baker & Shasta Occur along NE trending splays away from Main NW trend.


ZTEM 2D RESISTIVITY (-100m) (Shallow Depth )

BAKER MINE


ZTEM SURVEY RESULTS


ZTEM 2D RESISTIVITY (-500m) (Greater Depth)

BAKER MINE

Showing ZTEM 2D Inversion Results at Shallow (left) and Deep (right) Levels: • Baker & Shasta lie in NE conductive trends away from main NW conductive Structure • Other NW and NE conductive trends are also visible.

ZTEM IN-PHASE DT (180Hz) MAGNETIC ANALYTIC SIGNAL (ANSIG)

RESULTS AT BAKER MINE RADIOMETRICS – EQ POTASSIUM %

NW-SE STRUCTURES

CONDUCTIVITY HIGH

0 1km NE-SW STRUCTURES

WEAK MAGNETIC LOW

WEAK K-HIGH IN K-LOW REGION

Baker is characterized by : Weak Potassium high (K-alteration), in larger NE trending K-low structure; • Weak Local Magnetic Low (depletion), at Intersection between NW and NE Conductive structures. • Consistent with LS Epithermal Au-Ag signatures at shallow-erosional levels (Waihi LS, NZ).


ZTEM IN-PHASE DT (180Hz) MAGNETIC ANALYTIC SIGNAL (ANSIG)

RESULTS AT SHASTA MINE RADIOMETRICS – EQ POTASSIUM %

NW-SE STRUCTURES

RESISTIVITY HIGH

0 1km

NE-SW STRUCTURES

WEAK MAGNETIC LOW

K-HIGH

NE-SW STRUCTURES

NW-SE STRUCTURES

Shasta is characterized by : Strong Potassium high (K-alteration) in larger NE trending K-low structure • Weak Magnetic Low (depletion) and Resistivity high at Intersection between NW and NE structures. • Consistent with LS Epithermal Au-Ag signatures at Deep erosional level (like Dolly Varden)


ZTEM TARGETING ZTEM RESISTIVE ANOMALIES

(from 360Hz DT Image)

SHASTA-STYLE RESISTIVE SIGNATURES

0 2km

ZTEM CONDUCTIVE ANOMALIES (from 360Hz DT Image)

BAKER-STYLE CONDUCTIVE SIGNATURES

0 2km

Showing ZTEM anomalies over 30Hz In-phase DT



Over Magnetic Lows

SHASTA-STYLE ZTEM+MAG SIGNATURES

0 2km

ZTEM CONDUCTIVE ANOMALIES Over Magnetic Lows

BAKER-STYLE ZTEM+MAG SIGNATURES

0 2km

Showing ZTEM anomalies over Magnetic Analytic Signal



Over Magnetic Lows + Radiometric K-Highs

SHASTA-STYLE ZTEM+MAG SIGNATURES

0 2km

Showing ZTEM anomalies over Radiometric Eq Potassium

ZTEM CONDUCTIVE ANOMALIES Over Magnetic Lows + Radiometric K-Lows

BAKER-STYLE ZTEM+MAG SIGNATURES

0 2km


Vectoring VTEM Targets with Stream Sediment Geochemistry

Dec-2017


Showing Cu (ppm) and Au (ppb) Ultra-Trace ICP-MS

BAKER-STYLE ZTEM+MAG SIGNATURES with Stream Sed Anomaly

SHASTA-STYLE ZTEM+MAG SIGNATURES with Stream Sed Anomaly

CONCLUSIONS & RECOMMENTATIONS • ZTEM results have identified Conductive signatures that correlate with Magnetic Low

and Potassium Radiometric signatures that coincide with those observed over the Baker Mine and are consistent with shallow eroded LS Epithermal Au deposits.

• At least 10 correlate with Stream Sediment Geochemistry anomalies that represent follow-up targets for Baker-type LS epithermal mineralization

• ZTEM results have also identified Resistive signatures that correlate with Magnetic Lows and Potassium Radiometric signatures that coincide with those observed over the Shasta Mine & are consistent with deeply eroded LS Epithermal Au deposits

• At least 3 correlate with Stream Sediment Geochemistry anomalies that represent follow-up targets for Shasta-type LS epithermal mineralization

• Our analyses of ZTEM+Mag+Radiometrics and Stream Sed Geochem have identified prospective targets but solely based on Visual correlation of data-based multi-component evidence.


• Additional 3D ZTEM & 3D Magnetic inversions, and more Rigorous 3D Predictive Classification/Neural Network type targeting are recommended in future follow-up.

ACKNOWLEDGEMENTS

Our sincerest thanks to the SABLE RESOURCES INC.

for allowing us to present these results.

Helicopter ZTEM-Magnetic-Radiometric Surveys for Epithermal Low Sulphidation Gold over the Baker-Shasta Property, Toodoggone Region of North-Central BC

Presented at Geotech Roundup Mini-Symposium, BCIT, Vancouver BC, 26-January, 2018

Documents

Helicopter ZTEM-Magnetic-Radiometric Surveys FOR ...sableresources.com/wp-content/uploads/2018/03/Legault_Sable-Baker...(After Hoschke (2011), Geophysical Signatures of Copper-Gold