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42C02SE0385 ESQUEGA32 ESQUEGA 010

FALCONBRIDGE LIMITED

DIGHEM III SURVEY

WAWA 0/V CLAIMS

ESQUEGA TOWNSHIP

DISTRICT OF ALGOMA, ONTARIO

(C

(CR.L. Kenny Falconbridge Limited Winnipeg, Manitoba April 10, 1984

42C02SE0305 ESQUEGA32 ESQUEGA 010C

JH TABLE OF CONTENTSw Page

1.0 INTRODUCTION l

2.0 LOCATION AND ACCESS l -

3.0 PROPERTY DESCRIPTION l

4.0 PREVIOUS WORK l

5.0 GENERAL GEOLOGY l

6.0 DETAILS OF THE SURVEY 4

7.0 ASSESSMENT DAYS CREDITS 5

8.0 RESULTS 5

9.0 CONCLUSIONS AND RECOMMENDATIONS 6

i 10.0 REFERENCE . 6

l Statement of Qualifications - R.L. Kenny 7

,/--. Statement of Qualifications - H.F. Keats 8

l Appendix I - List of Claims 9jl Appendix II - Technical Specifications of DIGHEM III System 10i

Appendix III - Report of Assessment Work 13

Appendix IV - Data Interpretation Method 16

Appendix V - EM Anomaly List 44

Figure l - Location Map 2

2 - Location of Claims 3

Maps (in envelope at back of report)

1 - DIGHEM III Survey - Electromagnetic Anomalies

2 - DIGHEM III Survey - Magnetics

3 - DIGHEM III Survey - Enhanced Magnetics

'i 4 - DIGHEM III Survey - Resistivityi c -

1.0 INTRODUCTION

During the period April 19-20, 1983, a DIGHEM III airborne electro

magnetic/magnetic survey was completed for Falconbridge Limited on the

company's claims in Esquega Township, District of Algoma, Ontario.

The survey was carried out as part of a regional survey over most of

Esquega Township and parts of Corbiere, Musquash and Michipicoten Townships.

This report describes the survey and the results obtained.

2.0 LOCATION AND ACCESS

The claims covered by the survey are located some 3.5 miles west

of Hawk Junction and 9 miles northeast of Wawa, Ontario (Figure 1).

Access to the claims is via the Algoma Central Railway spur line from

Hawk Junction to the Helen mine as well as a private road from Highway

101 to the Sir James and Lucy iron mines. .

3.0 PROPERTY DESCRIPTION

The area covered by the survey comprises 58 claims which are presently

held by Falconbridge Limited, Box 40, Commerce Court West, Toronto, Ontario.

The claims are shown on Figure 2. A listing of the claims is provided

in Appendix I.

4.0 PREVIOUS WORK

Prior to the airborne geophysical survey, no work had been completed

by or for Falconbridge Limited on the claims in question.

5.0 GENERAL GEOLOGY

A geological map by Sage et al. (1982) indicates that the central

and western portion of the claims are underlain by a northeast-trending,

north-facing, monoclinal sequence of massive, tuffaceous and fragment,?'

mafic to felsic metavolcanic rocks, with minor intercalated iron formation.

The eastern part is underlain by quartz and quartz feldspar porphyritic

" HAWK JUNCTION

Approximate Locationof C ontre o fClaim Group

- '

D A - O&^

HAWK JUNCTIONAUXMA DOTTUCT

ONTARIO FIGURE l - Location Map NTS: 64C/2

hhlilililTUli

SCALE: 1" - 1 /

TWR2S RANGE 2S

LOONSK1N LAKE ]

M X ^*fe

ML. j ML

JUNCTION

*c~lktf-

5^S3/l r ^ 1"!""^^ l T i rt i { l a

iZfli^/j^

FALCONBRIDGE CLAIMS

W2^

Intrusive rocks which represent the border phase of the Hawk Lake Granitic

Complex.

6.0 DETAILS OF THE SURVEY

The geophysical contractor was DIGHEM Limited of Suite 7010, l First

Canadian Place, Toronto, Ontario. The survey was carried out with an

Aerospatlale Lama turbine helicopter (C-GDEN) flying at an average airspeed

of 81 mph (130 km/h). The equipment consisted of:

1) an electromagnetic bird containing 1 vertical coaxial transmitter-

receiver coil pair and 2 horizontal coplanar transmitter-receiver coil

pairs;

2) a magnetometer bird containing a Geometrics G803 magnetometer;

3) a Sperry radio altimeter;

4) a Geocam sequence camera;

5) a Barringer 8-channel hot pen analog recorder;

6) a Sonotek SDS 1200 acquisition system; and

7) a DigiData 1640 9-track 800-bpi magnetic tape recorder.

The average heights of the electromagnetic and magnetometer birds were

98 ft. (30 m) and 148 ft. (45 m), respectively. The average line spacing

was 656 ft. (200 m).

The analog equipment recorded four channels of EM data at approximately

900 Hz, two channels of EM data at approximately 7200 Hz, two ambient

EM noise channels (for the coaxial and coplanar receivers), two channels

of magnetics (coarse and fine count), and a channel of radio altitude.

The digital equipment recorded the EM data with a sensitivity of 0.20

ppm and the magnetic field to one nT (le., one gamma). The technical

specifications of the DIGHEM III system are provided in Appendix II.

7.0 ASSESSMENT DAYS CREDITS

A total of 128.6 miles (207 km) were flown during the regional survey.

Of this amount, 25.44 miles (40.9 km) were flown over the Falconbridge

Limited claims.

Because two kinds of instruments were carried on a single flight

(1e., electromagnetic and magnetic), the survey counts as two surveys

! for assessment purposes. Total assessment days credits are 2,035.2 days (eg.,ll 40 days/mile x 25.44 miles/survey x 2 surveys).

Since airborne geophysical work must be equally distributed over

the claims covered by the surveys, 35.1 days were apportioned to each

j of the 58 claims in question. A photocopy of the report of assessment

work filed on March 16/84 with the Algoma Central Railways Mining Recorder

is provided in Appendix III.

;(C 8.0 RESULTS

\ The survey data were interpreted by S. Kilty, a geophysicist and

operations manager with DIGHEM Limited. A report, as well as a set of

electromagnetic, magnetic, enhanced magnetic, and resistivity maps, were

provided by DIGHEM Limited.

That portion of the DIGHEM report containing background information

on the method of data interpretation is contained in Appendix IV. A

listing of the EM anomalies on or immediately adjacent to the claims

in question is provided in Appendix V; copies of the maps can be found

at the back of the report. A brief description of the more important

EM anomalies is provided below.

Anomaly 1050A-1140xC is a grade 2 and 3 anomaly with associated

x-type responses. This anomaly coincides with the Loonskin Lake Fault

*'"~" shown on the geological map by Sage et al. (1982).

Anomalies 1090D-1120A, 1140xB-1160A and 1190B-1210B are grade 3

to 5 anomalies which reflect an Intermittent conductive horizon associated

with a long, curved magnetic trend. The direct magnetic coincidence

suggests that the conductor may be an Iron formation.

Anomalies 1230B-1240A, 1270A-1310A, 1330A-1340A and 13760A are grade

2 to 5 anomalies which reflect a conductive bedrock horizon associated

with a long formatlonal magnetic high. The direct magnetic coincidence

suggests that the conductor may be an Iron formation.

9.0 CONCLUSIONS AND RECOMMENDATIONS

The DIGHEM III airborne electromagnetic/magnetic survey detected

a number of bedrock electromagnetic conductors on the company's 58 claims

1n the Wawa area. One of these coincides with the Loonskln Lake Fault

and two are thought to be due to Iron formation. The cause of the remaining

conductors 1s not known at the present time. A program of geological

mapping Is recommended in order to determine the probable cause of these

conductors.

10.0 REFERENCE

SAGE, R., REBIC, Z., ABERCOMBIE, S., NEALES, K., MCMILLAN, D. and CABERT, T. 1982: Precambrian Geology of Esquega Township, Wawa Area, Algoma District, Ontario Geological Survey Preliminary Map P2440, Geological Series Scale 1:15,840 or l""1/4 mile.

Respectfully submitted.

R.'.. Kenny

Ib

C

STATEMENT OF QUALIFICATIONS

I, RICHARD LOUIS KENNY, of the City of Winnipeg, Province of Manitoba,

DO SOLEMNLY DECLARE THAT:

1. I have obtained a B.Se. in Geological Engineering (1975) and Master's degree 1n Natural Resource Management (1981) from the University of Manitoba, Winnipeg, Manitoba, and have practised my profession since graduation 1n 1975, a period of seven years; and

2. I am responsible for the writing of this report.

Dated at Winnipeg, this 12th day of April, 1984,

WITNESS:

R.L. Kenny Falconbridge Limited Winnipeg, Manitoba

8

STATEMENT OF QUALIFICATIONS

I, HARVEY FRANKLIN KEATS, of the City of Winnipeg, Province of Manitoba,

DO SOLEMNLY DECLARE THAT:

1. I am a member of the Association of Professional Engineers for the Province of Manitoba.

2. I am a MSc Graduate of Memorial University of Newfoundland, and have practised my profession since graduation 1n 1970 for a period of 14 years.

3. I am responsible for the supervision of the geophysical survey covered by this report.

4. I am a Fellow of the Geological Association of Canada.

Dated at Winnipeg this 12th day .of April, 1984.

WITNESS:

C

H.F. Keats Falconbridge Limited Winnipeg, Manitoba

LIST OF CLAIMS

(C

Claim No.

AC10471 AC10472 AC!0473 AC!0474 AC!0475 AC10476 AC10477 AC!0478

.AC! 0479 AC!0480 AC10481 AC!0482 AC!0483 AC!0484 AC 1 0485 AC10486 AC!0487AC10488ACT 0489AC!0490AC10491AC10492AC!0493AC!0494AC!0495ACT 0496AC!0497AC!0498ACT 0499

REGISTERED HOLDER:

Date Recorded Claim No.

March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 27, 1983March 23, 1983 March 23, 1983 March 23, 1983 March 23, 1983March 23, 1983March 23, 1983March 23, 1983March 23, 1983March 23, 1983March 23, 1983March 23, 1983

Falconbridge LimitedBox 40Commerce Court WestToronto, OntarioM5L 3B4

AC10500AC10501AC10502AC10503AC10504AC10505AC10506AC10507AC10508AC10509AC10510AC10511AC10512AC10513AC! 051 4AC10515AC! 051 6AC! 051 7AC10518 AC10519 AC! 0520 AC10521AC10522AC10525AC! 0526AC10527AC10528AC10529AC10530

APPENDIX I

Date Recorded

MarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarchMarch

23, 1983 23, 1 983 23, 1983' 23, 1983 23, 1983 23, 1983 23, J 983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27, 1983 27. 1983 27, 1983 27, 1983 27, 1933 27, 1983 22, 1983 22, 1983 22, 1983 27, 1933 27, 1983 27, 1983

ACR Prospector's Licence #260

i C

APPENDIX III

REPORT OF ASSESSMENT WORK

(filed on March 16/84 with the

Algoma Central Railways Mining Recorder)

42C02SE0305 ESOUEGA32 ESQUEGA 900

ALGOMA CENTRAL RAILWAYMINES DEPARTMENT

REPORT OF ASSESSMENT WORKTO THE RECORDER OF AIGOMA CENTRAl RAILWAY

A itpoieU form li* r*- qvlrtd for rocX lyp* of work lo tx iKordrd I.*. on* for (itorhyiicot, enotKtf for (rielopicol, onoltitr fei drilling, t it.

s

(Nom* of Rvtorcftd Holdtr)

..-...-.,.40jL..C.p.i^.e-r;-ce -C-p-uj't--jJestJ- , -Torpntp t Ontario(Foil Offiu Add..11)

do hereby report the performonce of .. ... i.. Z+Q3S-2...................

not before reported to be opplied on the following contiguous eloims:

MSL 1B4NoJ

i/iu) rx

doys of ..g.?.9PlMl?.?C?.lflrp* of WorV)

Note: Cloim No.

AC.1.Q471 ACI0472

All cloim number* must be shown in full.Doyi Cloim No.

ACJOAZ2

AC1 0.4.7.4 AC1D.47.5 ACWiZfi

..35.1

..35.1

.35*1

ACJJMTg

A.C.1Q.4JRQ AC10481 'AC10482

Doy*

35,135,1

3JLJ 35.J 35.1

Cloim No.

AC.iP.484 AC 1 04 85 ACi486

AC l 0488 35.1

O tt

o zh-nr Orx

tu I

II

Ill

IV

All of the work was performed on Mining Cloim(s) . .--5.ee..fl.ttaCJlEd..5.hee.t..j[ar:-.?.ddltJj)na.L.C].a.iniS (In the cose of geological or geophysical survey(s) where more than 18 claims ore involved show oddi- ~" lionot eloims ond respective "Doys" on bock of this sheet) Reod Carefully; The Following Information Is Required By The Mining Recorder.

l For Manual Work, Stripping, Opening Op of Mines, Sinking Shafts or Other Actual Mining Opera tions Names ond addresses of the men who performed the work ond the dotes ond hours of their employment. Deloiled sketches of all work must be submitted In duplicate.For Diamond and Other Core Drilling Total Footage, Number of holes. Diameter of core. Nome ond address of owner or operator of drill. Dotes when drilling was done. Signed core log ond profile sketch In duplicate for each hole. Also sketch plan in duplicate showing drill hole locations with res pect to claim poili, direction of hole, length, etc.For Compressed Air or Other Pov/er Driven or MocKcnicol Equipment Type of drill or equipment. Names ond addresses of men employed lo operate equipment and the dates ond hours of their emp loyment. Detailed sketches In duplicate showing the work performed.For Power Strippin0 Type of equipment. Nome ond address of owner or operator. Amount of money expended. Dotes on which work was done. Proof of actual cost must be submitted to Mining Recor der within 30 days of recording work. Deloiled sketches in duplicate showing extent ond dimensions of work performed ond its location with respect lo claim posts.

^ ^ With each of the above types of work (l, II, III i IV) duplicate sketches or legible prints thereof ore re quired and they must show detailed measurement* in feet of the work completed ond Us location to the nearest claim post.For Geological, Geophysical and Geochemical Surveys, Soil Sampling, Assaying, Metallurgical Tests The names ond addresses of the men employed wllh doles ond hours worked. (Technical work to Include report preparation, drafting and typing as well as field work when calculating Assessment credits). Type of Instrument used In the case of geophysical survey.Properly signed reports ond mops In duplicate (prints) together with qualifications of outhor(s) must be filed with the Mining Recorder within 60 doys of record ing the work.For land Survey The name ond address of Ontario land Surveyor together with certificate of qualifica tions. The work requirements, descriptions, necessary drawings, etc. musl comply with Algoma Central Rail-

f ,- - way and Ontario Government Regulations.The Required Information is as follows; (Attach o list if thls'Tpoce IspoJ sufficient),

.Barch.Jfi*JI5Bd__

t ,- -M

Dote ..-

ALGOMA CENTRAL RAILWAYMINES DEPARTMENT

(Sionolvit of Rxor^rtf Hotdtl cr Apint)

CERTIFICATE VERIFYING REPORT OF WORKHarvey Franklin Keats_____ __ ^

Bancroft Bay. Winnipeg, Manitoba(Poll Offic*

hereby cerlifvi1. That I hove a personal ond intimate knowledge of the fjcts set forf

nexed hereto, having performed the work or vvlineited some di/ring2. Thot the annexed report Is true.

Doted .,.......M?-h...?.!L..........--- ^JM..^

jn 1H* report of work an- j *ler

K

5 oIU OC

dfOu.

I

o o

ut i/t

O

15

Addendum to Report of Assessment Work covering airborne electromagnetic and dated March 16, 1984

filed by Falconbarldge Limited magnetic surveys in Esquega Twp.

Claim No.AC10489AC10490AC1Q491AC 104 92AC10493

AC10494AC10495

AC 104 96AC 10497

AC10498AC10499AC 10500AC10501AC 10502AC1G503-

AC10504

AC10505AC10506AC10507AC10508

Days 35.135.135.135.135.1

35.1

35.1

35.1

' 35.1

35.135.1

35.135.135.135.135.1

35.135.135.135.1

Claim No.AC10509AC10510AC 105 11AC10512AC10513AC10514AC10515AC10516AC10517AC10518AC10519AC10520AC10521AC105P2/ .tiO!//.'-

AC 10526

AC10527AC10528AC10529AC 10530

Pays 35.135.135.135.135.135.135.1

35.135.135.135.135.135.135.1A',,\

35.1

35.135.135.135.1

Total of 58 claims covered by the surveys

16

APPENDIX IV

DATA INTERPRETATION METHOD

17

SECTION II: BACKGROUND INFORMATION

ELECTROMAGNETICS

C

DIGHEM electromagnetic responses fall into two general

classes, discrete and broad. The discrete class consists of*

sharp, well-defined anomalies from discrete conductors such

as sulfide lenses and steeply dipping sheets of graphite and

sulfides. The broad class consists of wide anomalies from

conductors having a large horizontal surface such as flatly

dipping graphite or sulfide sheets, saline water-saturated

sedimentary formations, conductive overburden and rock, and

geothermal zones. A vertical conductive slab with a width

of 200 m would straddle these two classes.

The vertical sheet (half plane) is the most commonl

model used for the analysis of discrete conductors. All

anomalies plotted on the electromagnetic map are analyzed

according to this model. The following section entitled

Discrete conductor analysis describes this model in detail,

including the effect of using it on anomalies caused by

broad conductors such as conductive overburden.

The conductive earth (half space) model is suitable for

broad conductors. Resistivity contour maps result from the

itfi' l d

18

l

j

J

I I I

- 11-2 -

use of this model. A later section entitled Resistivity

mapping describes the method further, including the effect

of using it on anomalies caused by discrete conductors such

as sulfide bodies.

Geometric, interpretation

The geophysical interpreter attempts to determine the

geometric shape and dip of the conductor. This qualitative

interpretation of anomalies is indicated on the map by means

of interpretive symbols (see EM map legend). Figure II-1

shows typical DIGHEM anomaly shapes and the interpretive

symbols for a variety of conductors. These classic curve

shapes are used to guide the geometric interpretation.

Discrete conductor analysis

The EM anomalies appearing on the electromagnetic map

are analyzed by computer to give the conductance (i.e.,

conductivity-thickness product) in mhos of a vertical sheet

model. This is done regardless of the interpreted geometric

shape of the conductor. This is not an unreasonable

procedure, because the computed conductance increases as the

electrical quality of the conductor increases, regardless of

its true shape. DIGHEM anomalies are divided into six

n

conoueior j JoeolloB , . t

f - :1-:W; ;7\ ' 7Channel CXI '-'/f \ . X

j : '' : ' : ., 'Channel CPX - S\S\. X 1

W*nJ\, J

Interpretive ^ rj lymbol

f *

Coflductorr '

,, 0 * vertJIM ...thin

' . g e prob cond bet! itror

Ratio of omplltudee CXX/CPU . 4 2

. i , . o . . . .\ A A A A ^^/^\. ̂

r, JV A A A A J V^.1

^ A. . ^ ~ ^ ^v v v y yy

ED TT C R S, H, S E p

1 \ n u o ^jl \ LJ U ——————————— ' ;

leal dipping vertical dipping epherei wide . S i conductive overburden Flight linedlXe thin dike thick dike thick dlk* horizontal horizontal H * thick conductive cover porollel to

j, ,. ,. . or near-surface wide . . able iirtl ribbon, conductive rock unit conductorJ,CtJ ' ' metal roof, large fenced 6 . wide conductive rock gir one •mo" fenced o reo unit burled undtr

yord resistive cover E* t edge effect from wide

- ' 'conductor . jvorloble vorloble variable 74 vorloble '/2 ^/4

i

Figure I -i Typicol DIGHEM onomaly shapes

20

- II--

grades of conductance, as shown in Table XX-1. . The conduc

tance in mhos is the reciprocal of resistance in ohms.

Table II-1. EM Anomaly Grades

Anomaly Grade

654321

Mho Range

> 9950 - 9920-4910 - 195-9

< 5

(C

The conductance value is a geological parameter because

it is a characteristic of the conductor alone; it generally

is independent of frequency, and of flying height or depth

of burial apart from the averaging over a greater portion of

the conductor as height increases.^ Small anomalies from

deeply buried strong conductors are not confused with small

anomalies from shallow weak conductors because the former

will have larger conductance values.

Conductive overburden generally produces broad EM

responses which are not plotted on the EM maps. However,

patchy conductive overburden in otherwise resistive areas

This statement is an approximation. DJGHEM, with its short coil separation, tends to yield larger and more accurate conductance values than airborne, systems having a larger coil separation.

21

- II-5 -

can yield discrete anomalies with a conductance grade {cf.

Table ll-l) of l, or even of 2 for conducting clays which

have resistivities as low as 50 qhm-m. In areas where

ground resistivities can be below 10 ohm-m, anomalies caused

by weathering variations and similar causes can have any

conductance grade. The anomaly shapes from the multiple

coils often allow such conductors to be recognized, and

these are indicated by the letters S, H, G and sometimes E

on the map (see EM legend).

For bedrock conductors, the higher anomaly grades

indicate increasingly higher conductances. Examples:

DIGHEM's New Insco copper discovery (Noranda, Canada)

yielded a grade 4 anomaly, as did the neighbouring

copper-zinc Magusi River ore body; Mattabi (copper-zinc,

Sturgeon Lake, Canada) and Whistle (nickel, Sudbury,

Canada) gave grade 5; and DIGHEM's Montcalm nickel-copper

discovery (Tinunins, Canada) yielded a grade 6 anomaly.

Graphite and sulfides can span all grades but, in any

particular survey area, field work may show that the

different grades indicate different types of conductors.

Strong conductors (i.e., grades 5 and 6) are character

istic of massive sulfides or graphite. Moderate conductors

(grades 3 and 4) typically reflect sulfides of a less

massive character or graphite, while weak bedrock conductors

22

- II-6 -

Ow (grades 1 and 2) can signify poorly connected graphite or

heavily disseminated sulfides. Grade 1 conductors may not

respond to ground EN equipment using frequencies less thin

2000 Hz.

The presence of sphalerite or gangue can result in

ore deposits having weak to moderate conductances. As

an example, the three million ton lead-zinc deposit of

Restigouche Mining Corporation near Bathurst, Canada,

yielded a well defined grade 1 conductor. The 10 percent

by volume of sphalerite occurs as a coating around the fine

grained massive pyrite, thereby inhibiting electrical

(( conduction.

Faults, fractures and shear zones may produce anomalies

which typically have low conductances (e.g., grades l .

and 2). Conductive rock formations can yield anomalies of

any conductance grade. The conductive materials in such

rock formations can be salt water, weathered products such

as clays, original depositional clays, and carbonaceous

w material.

On the electromagnetic map, a letter identifier and an

interpretive symbol are plotted beside the EM grade symbol.

The horizontal rows of dots, under the interpretive symbol,

indicate the anomaly amplitude on the flight record. The

"ll : 23

- II-7 -

1 vertical column of dots, under the anomaly letter, gives the

estimated depth. In areas where anomalies are crowded, the

j letter identifiers, interpretive symbols and dots may be

obliterated. The EM grade symbols, however, will always be

l discernible, and the obliterated information can be obtained

from the anomaly listing appended to this report.

The purpose of indicating th* anomaly amplitude by dots

is to provide an estimate of the reliability of the conduc

tance calculation. Thus, a conductance value obtained from

a large ppm anomaly (3 or 4 dots) will tend to be accurate

whereas one obtained from a small ppm anomaly (no dots)

could be quite inaccurate. The absence of amplitude dots

indicates that the anomaly from the coaxial coil-pair is

5 ppm or less on both the inphase and quadrature channels.

Such small anomalies could reflect a weak conductor at thef

surface or a stronger conductor at depth. The conductance

grade and depth estimate illustrates which of these

possibilities fits the recorded data best.

Flight line deviations occasionally yield cases where

two anomalies, having similar conductance values but

dramatically different depth estimates, occur close together

on the same conductor. Such examples illustrate the

reliability of the conductance measurement while showing

that the depth estimate can be unreliable. There are a

24

- IX-8 -

number of factors which can produce an error in the depth

estimate, including the averaging of topographic variations

by the altimeter/ overlying conductive overburden, and the

location and attitude of the conductor relative to the

flight line. Conductor location and attitude can provide an

erroneous depth estimate because the stronger part of the

conductor may be deeper or to one side of the flight line,

or because it has a shallow dip. A heavy tree cover can

also produce errors in depth estimates. This is because the

depth estimate is computed as the distance of bird from

conductor, minus the altimeter reading. The altimeter can

lock onto the top of a dense forest canopy. This situation

yields an erroneously large depth estimate but does not

affect the conductance estimate.

Dip symbols are used to indicate the direction of dip

of conductors. These symbols are used only when the anomaly

shapes are unambiguous, which usually requires a fairly

resistive environment.

A further interpretation is presented on the Ef-5 map by

means of the line-to-line correlation of anomalies, which is

based on a comparison of anomaly shapes on adjacent lines.

This provides conductor axes which may def?ne the geological

structure over portions of the survey area. The absence of

25

t. .

l ^ conductor axes in an area implies that anomalies could not

be correlated from line to line with reasonable confidence.

JDIGHEM electromagnetic maps are designed to provide

J a correct impression of conductor quality by means of the

. conductance grade symbols. The symbols can stand alone .

with geology when planning a follow-up program. The actual

l conductance values are printed in the attached anomaly list

for those who wish quantitative data. The anomaly ppm and

l depth are indicated by inconspicuous dots which should not

. distract from the conductor patterns/ while being helpful

to those who wish this information. The map provides an

l (; interpretation of conductors in terms of length/ strike and

dip/ geometric shape/ conductance/ depth/ and thickness (see

\ below). The accuracy is comparable to an interpretation

from a high quality ground EM survey having the same line spacing.

The attached EM anomaly list provides a tabulation of

anomalies in ppm/ conductance/ and depth for the vertical

-** sheet model. The EM anomaly list also shows the conductance

and depth for a thin horizontal sheet (whole plane) model/

but only the vertical sheet parameters appear on the

EM map. The horizontal sheet model is suitable for a flatly

dipping thin bedrock conductor such as a sulfide sheet

having a thickness less than 10 m. The list also shows the

26

- 11-10 -

resistivity and depth for a conductive earth (half space)

model/ which is suitable for thicker slabs such as thick

conductive overburden. In the EM anomaly list, a depth

value of zero for the conductive earth model/ in an area of

thick cover, warns that the anomaly may be caused by

conductive overburden.

Since discrete bodies normally are the targets of

EM surveys, local base (or zero) levels are used to compute

local anomaly amplitudes. This contrasts with the use

of true zero levels which are used to compute true EM

amplitudes. Local anomaly amplitudes are shown in the

EM anomaly list and these are used to compute the vertical

sheet parameters of conductance and depth. Not shown in the

EM anomaly list are the true amplitudes which are used to

compute the horizontal sheet and conductive earth

parameters.

X-type electromagnetic responses

DIGHEM maps contain x-type EM responses in addition

to EM anomalies. An x-type response is below the noise

threshold of 3 ppm, and reflects one of the following: a

weak conductor near the surface, a strong conductor at depth

(e.g., 100 to 120 m below surface) or to one side of the

flight line, or aerodynamic noise. Those responses that

27

- 11-11 -

have the appearance of valid bedrock anomalies on the flight

profiles are indicated by appropriate interpretive symbols

(see EM map legend). The others probably do not warrant

further investigation unless their locations are of

considerable geological interest.

The thickness parameter

DIGHEM can provide an indication of the thickness of

a steeply dipping conductor. The amplitude of the coplanar

anomaly (e.g., CPI) increases relative to the coaxial

anomaly (e.g., CXI) as the apparent thickness increases/

i.e.t the thickness in the horizontal plane. (The thickness

is equal to the conductor width if the conductor dips at

90 degrees and strikes at right angles to the flight line.)

This report refers to a conductor as thin when the thickness

is likely to be less than 3 m, and thick when in excess of

10 m. Thin conductors are indicated on the EM map by the

interpretive symbol "D", and thick conductors by "T". For

base metal exploration in steeply dipping geology/ thick

conductors can be high priority targets because many massive

sulfide ore bodies are thick, whereas non-economic bedrock

conductors are often thin. The system cannot sense the

thickness when the strike of the conductor is subparallel to

the flight line, when the conductor has a shallow dip, when

28

- 11-12 -

the anomaly amplitudes are small, or when the resistivity of

the environment is below 100 ohm-m.

Resistivity mapping

Areas of widespread conductivity are commonly

encountered during surveys. In such areas, anomalies can

be generated by decreases of only 5 m in survey altitude as

well as by increases in conductivity. The typical flight

record in conductive areas is characterized by inphase and

(jiimlrfthnrp n)immol n vriiloh n i o until l nu'/uiO y m i\ l y*., l sit*nt

EM peaks reflect either increases in conductivity of the

earth or decreases in survey altitude. For such conductive

areas, apparent resistivity profiles and contour maps are

necessary for the correct interpretation of the airborne

data. The advantage of the resistivity parameter is

that anomalies caused by altitude changes are virtually

eliminated, so the resistivity data reflect only those

anomalies caused by conductivity changes. The resistivity

analysis also helps the interpreter to differentiate between

conductive trends in the bedrock and those patterns typical

of conductive overburden. For example, discrete conductors

will generally appear as narrow lows on the contour map

and broad conductors (e.g., overburden) will appear as

wide lows.

29- 11-13 -

((

The resistivity profile (see table in Appendix A) and

the resistivity contour map present the apparent resistivity

using the so-called pseutio-layer (or buried) half space

model defined in Fraser (1978) 2 . This model consists of

a resistive layer overlying a conductive half space. The

depth channel (see Appendix A) gives the apparent depth

below surface of the conductive material. The apparent

depth is simply the apparent thickness of the overlying

resistive layer. The apparent depth (or thickness)

parameter will be positive when the upper layer is more

resistive than the underlying material, in which case the

apparent depth may be quite close to the true depth.

l The apparent depth will be negative when the upper

layer is more conductive than the underlying material, and

will be zero when a homogeneous half space exists. The

apparent depth parameter must be interpreted cautiously

because it will contain any errors which may exist in the

measured altitude* of the EM bird (e.g., as caused by a dense

tree cover). The inputs to the resistivity algorithm are

the inphase and quadrature components of the coplanar

coil-pair. The outputs are the apparent resistivity of the

Resistivity mapping with an airborne multicoil electro magnetic system: Geophysics, v. 43, p. 144-172.

30 - 11-14 -

91W conductive half space (the source) and the sensor-source

distance. The flying height is not an input variable,

and the output resistivity and sensor-source distance are

independent of the flying height. The apparent depth,

discussed above, is simply the sensor-source distance minus

the measured altitude or flying height. Consequently,

errors in the measured altitude will affect the apparent

depth parameter but not the apparent resistivity parameter.

i The apparent depth parameter is a useful indicator

of simple layering in areas lacking heavy tree cover.

The DIGHEM system has been flown for purposes of permafrost

'C 1111*1/1*1 riy i who r o poult, l vo n|.ipnrnnt; rtupt.hn vmr** nnpfl nn H

, measure of permafrost thickness. However, little quantita

tive use has been made of negative apparent depths because

the absolute value of the negative depth is not a measure of

the thickness of the conductive upper layer and, therefore,

is not meaningful physically. Qualitatively, a negative

apparent depth estimate usually shows that the EM anomaly is

caused by conductive overburden. Consequently, the apparent

^ depth channel can be of significant help in distinguishing

between overburden and bedrock conductors.

The resistivity map often yields more useful informa

tion on conductivity distributions than the EM map. Iny f

31

- 11-15 -

comparing the EM and resistivity maps, keep in mind the

following:

(a) The resistivity map portrays the absolute value

of the earth's resistivity.

(Resistivity - I/conductivity.)

(b) The EM map portrays anomalies in the earth's

rocifitlvity. An nnomnly by definition la a

change from the norm and so the EM map displays

anomalies, (i) over narrow, conductive bodies and

(ii) over the boundary zone between two wide

formations of differing conductivity.

The resistivity map might be likened to a total

field map and the EM map to a horizontal gradient in the

direction of flight . Because gradient maps are usually

more sensitive than total field maps, the EM map therefore

is to be preferred in resistive area.s. However, in conduc

tive areas, the absolute character of the resistivity map

usually causes it to be more useful than the EM map.

C-

The gradient analogy is only valid with regard to the identification of anomalous locations.

JInterpretation in conductive environments

21

- 11-16 -

l

'

l Environments having background resistivities below

30 ohm-m cause all airborne EM systems to yield very

l large responses from the conductive ground. This usually

prohibits the recognition of discrete bedrock conductors.

i

l ' channels which contribute significantly to the recognition"j

! of bedrock conductors. These are the inphase and quadrature

l difference channels (DIFI and DIFQ), and the resistivity and

l depth channels (RES and DP) for each coplanar frequency; see

table in Appendix A.

l i..i The EM difference channels (DIFI and DIFQ) eliminate

l up to 991 of the response of conductive ground, leaving

l responses from bedrock conductors, cultural features (e.g.,

telephone lines, fences, etc.) and edge effects. An edge

l effect arises when the conductivity of the ground suddenly

changes, and this is a source of geologic noise. While edge

l effects yield anomalies on the EM difference channels, they

l"" -* do not produce resistivity anomalies. Consequently, the

resistivity channel aids in eliminating anomalies due to

l edge effects. On the other hand, resistivity anomalies

will coincide with the most highly conductive sections of

J f conductive ground, and this is another source of geologici \

lj

l

33

- 11-17 -

noise. The recognition of a bedrock conductor in a

conductive environment therefore is based on the anomalous

responses of the two difference channels (DIFI and DIFQ)

and the two resistivity channels (RES). The most favourable

situation is where anomalies coincide on all four channels.

The DP channels, which give the apparent depth to the

conductive material, also help to determine whether a

conductive response arises from surficial material or from a

conductive zone in the bedrock. When these channels ride

above the zero level on the electrostatic chart paper (i.e.,

depth is negative), it implies that the EM and resistivity

profiles are responding primarily to a conductive upper

layer, i.e., conductive overburden. If both DP channels are

below the zero level, it indicates that a resistive upper

layer exists, and this usually implies the existence of. a

bedrock conductor. If the low frequency DP channel is below

the zero level and the high frequency DP is above, this

suggests that a bedrock conductor occurs beneath conductive

cover.

Channels REC1, REC2, REC3 and REC4 are the anomaly

recognition functions. They are used to trigger the

conductance channel CDT which identifies discrete

conductors. In highly conductive environments, channel REC2

m 34- 11-18 -

is deactivated because it is subject to corruption by highly

conductive earth signals. Similarly, in moderately

conductive environments, RBC4 is deactivated. Some of the

automatically selected anomalies (channel CDT) aro discarded

by the geophysicist. The automatic selection algorithm is

intentionally oversensitive to assure that no meaningful

responses are missed. The interpreter then classifies the

anomalies according to their source and eliminates thosei

that are not substantiated by the data, such as those

arising from geologic or aerodynamic noise.

Reduction of geologic noise

Geologic noise refers to unwanted geophysical

responses. For purposes of airborne EM surveying, geologic

noise refers to EM responses caused by conductive overburden

and magnetic permeability. It was mentioned above thatj

the EM difference channels (i.e., channel DIFI for inphase

and DIFQ for quadrature) tend to eliminate the response of

conductive overburden. This marked a unique development

in airborne EM technology, as DIGHEM is the only EM system

which yields channels having an exceptionally high degree

of immunity to conductive overburden.

35 - 11-19 -

Magnetite produces a form of geological noise on the

inphase channels of all EM systems. Rocks containing less! 'than H magnetite can yield negative inphase anomalies

caused by magnetic permeability. When magnetite is widely

distributed throughout a survey area, the inphase EM chan

nels may continuously rise and fall reflecting variations

in the magnetite percentage, flying height, and overburden

l thickness. This can lead to difficulties in recognizing

; deeply buried bedrock conductors, particularly if conductiveil overburden also exists. However, the response of broadly

distributed magnetite generally vanishes on the inphase

difference channel DIFI. This feature can be a significant*

A aid in the recognition of conductors which occur in rocks

containing accessory magnetite.

EM magnetite mapping

The information content of DIGHEM data consists of a

i combination of conductive eddy current response and magnetic

permeability response. The secondary field resulting from

j. conductive eddy current flow is frequency-dependent and

consists of both inphase and quadrature components, which

are positive in sign. On the other hand, the secondary

field resulting from magnetic permeability is independent

of frequency and consists of only an inphase component which

36

- 11-20 -

is negative in sign. When magnetic permeability manifests

itself by decreasing the measured amount of positive

inphase, its presence may be difficult to recognize.

However, when it manifests itself by yielding a negative

inphase anomaly (e.g., in the absence of eddy current flow), ..

its presence is assured. In this latter case, the negative

component can be used to estimate the percent magnetite

content.

A magnetite mapping technique was developed for the

coplanar coil-pair of DIGHEM. The technique yields channel

"FED" (see Appendix A) which displays apparent weight

percent magnetite according to a homogeneous half space

model.^ The method can be complementary to magnetometer

mapping in certain cases. Compared to magnetometry, it is

far less sensitive but is more able to resolve closely

spaced magnetite zones, as well as providing an estimate

of the amount of magnetite in the rock. The method is

sensitive to 1/41 magnetite by weight when the EM sensor is

at a height of 30 m above a magnetitic half space. It can

individually resolve steeply dipping narrow magnetite-rich

bands which are separated by 60 m. Unlike magnetometry, the

EM magnetite method is unaffected by remanent magnetism or

magnetic latitude.

Refer to Fraser, 1981, Magnetite mapping with a multi- coil airborne electromagnetic system: Geophysics, v. 46, p. 1579-1594.

37

- 11-21 -

The BM magnetite mapping technique provides estimates

of magnetite content which are usually correct' within a

factor of 2 when the magnetite is fairly uniformly

distributed. EN magnetite maps can be generated when

magnetic permeability is evident as indicated by anomalies

in the magnetite channel FEO.

Like magnetometry, the EM magnetite method maps

only bedrock features, provided that the overburden is

characterized by a general lack of magnetite. This

contrasts with resistivity mapping which portrays the

combined effect of bedrock and overburden.

Recognition of culture

Cultural responses include all EM anomalies caused by

man-made metallic objects. Such anomalies may be caused by

inductive coupling or current gathering. The concern of the

interpreter is to recognize when an EM response is due to

culture. Points of consideration used by the interpreter,

when coaxial and coplanar coil-pairs are operated at a

common frequency/ are as follows:

i t

\\

1. Channels CXS and CPS (see Appendix A) measure 50 and

60 Hz radiation. An anomaly on these channels shows '

38- 11-22 -

that the conductor is radiating cultural power. Such

an indication is normally a guarantee that the conduc

tor is cultural. However, care must be taken to ensure

that the conductor is not a geologic body which strikes

across a power line, carrying leakage currents.

2. A flight which crosses a line (e.g., fence, telephone

line, etc.) yields a center-peaked coaxial anomaly

and an m-shaped coplanar anomaly. 5 When the flight

crosses the cultural line at a high angle of inter

section, the amplitude ratio of coaxial/coplanar

(e.g., CXI/CPI) is 4. Such an EM anomaly can only be

caused by a line. The geologic body which yields

anomalies most closely resembling a line is the

vertically dipping thin dike. Such a body, however,

yields an amplitude ratio of 2 rather than 4.

Consequently, an m-shaped coplanar anomaly with a

CXI/CPI amplitude ratio of 4 is virtually a guarantee

that the source is a cultural line.

3. A flight which crosses a sphere or horizontal disk

yields center-peaked coaxial and coplanar anomalies

with a CXI/CPI amplitude ratio (i.e., coaxial/coplanar)

of 1/4. In the absence of geologic bodies of this

geometry, the most likely conductor is a metal roof or

5 See Figure II-1 presented earlier.

39

- 11-23 -

small fenced yard. 4 Anomalies of this type are

virtually certain to be cultural if they occur in an

area of culture.

4. A flight which crosses a horizontal rectangular body or

wide ribbon yields an m-shaped coaxial anomaly and a

center-peaked coplanar anomaly. In the absence of

geologic bodies of this geometry, the most likely

conductor is a large fenced area. 4 Anomalies of this

type are virtually certain to be cultural if they occur

in an area of culture.

5. EM anomalies which coincide with culture, as seen on

the camera film, are usually caused by culture.

However, care is taken with such coincidences because

a geologic conductor could occur beneath a fence, for

example. In this example, the fence would be expected

to yield an m-shaped coplanar anomaly as in case 12

above. If, instead, a center-peaked coplanar anomaly

occurred, there would be concern that a thick geologic

conductor coincided with the cultural line.

It is a characteristic of EM that geometrically identical anomalies are obtained from: (1) a planar conductor, and (2) a wire which forms a loop having dimensions identical to the perimeter of the equiva lent planar conductor.

40- 11-24 -

J

Kll

l l II

6. The above description of anomaly shapes is valid

when the culture is not conductively coupled to the

environment. In this case, the anomalies arise from

inductive coupling to the BM transmitter. However,

when the environment is quite conductive (e.g., less

than 100 ohm-m at 900 Hz), the cultural conductor may

be conductively coupled to the environment. In this

latter case, the anomaly shapes tend to be governed by

current gathering. Current gathering can completelyt

distort the anomaly shapes, thereby complicating the

identification of cultural anomalies. In such circum

stances, the interpreter can only rely on the radiation

channels CXS and CPS, and on the camera film.

MAGNETICS

The existence of a magnetic correlation with an EM

anomaly is indicated directly on the EM map. An EM anomaly

with magnetic correlation has a greater likelihood of

being produced by sulfides than one that is non-magnetic.

However, sulfide ore bodies may be non-magnetic {e.g., the

Kidd Creek deposit near Timmins, Canada) as well as magnetic

(e.g., the Mattabi deposit near Sturgeon Lake, Canada).

41

- 11-25 -

The magnetometer data are digitally recorded in

the aircraft to an accuracy of one nT (i.e., one gamma).

The digital tape is processed by computer to yield a

total field magnetic contour map. When warranted, the

magnetic data also may be treated mathematically .to enhance

the magnetic response of the near-surface geology/ and an

enhanced magnetic contour map is then produced. The

response of the enhancement operator in the frequency domain

is illustrated in Figure II-2. This figure shows that the

passband components of the airborne data are amplified

20 times by the enhancement operator. This means, for

example, that a 100 nT anomaly on the enhanced r.ap reflects

a 5 nT anomaly for the passband components of the airborne

data.

The enhanced map, which bears a resemblance to a

downward continuation map, is produced by the digital

bandpass filtering of the total field data. The enhancement

is equivalent to continuing the field downward to a level

(above the source) which is V20th of the actual sensor-

source distance.

Because the enhanced magnetic map bears a resemblance

to a ground magnetic map, it simplifies the recognition

of trends in the rock strata and the interpretation of

42

LJ Or?H J Q. S

CYCLES

Figure U-2 Frequency response of mognefic enhoncement operolor.

43

- 11-27 -

O geological structure. It defines the near-surface local

geology while de-emphasizing deep-seated regional features.

It primarily has application when the magnetic rock units

are steeply dipping and the earth's field dips in excess

of 60 degrees.

S ZD-140

i {C

'O

COAXIAL [i 900 HZV ANOMALY/ REAL QUAD K.F1D/1NTERP.' PPM PPMl* - 'V Line 1050 (Flight 1)CA 942 8 2feline- 1060 (Flight 1)[p .1095. C .2|L1ne; lb70 (Flight 1)ID 1234 B 0|E 1249 B 1V Line 1080 (Flight 1)i B 1382 B 01 C. 1371 B 0Hine 1090 (Flight 1)r D 1529 D 43bU 1534 S? 0* : .F 1545 D 5

Line 1100 (Flight 1)C 1686 D - 61F 1682 S? 1

};:-G 1681 S 0Line 1110 (Flight 1)A 1828 T 49B 1830 S? 1C 1835 S? 2Line 1120 (Flight 1)

: A 1980 T 16B 1972 S 0Line 1130 (Flight 1)B 2195 B 0C 2219 B 0

7

5

73

21

1164

1934

2336

123

21

COPLANAR 900 HZ

REAL QUAD PPM PPM

5

0

11

00

5538

12600

10520

330

80

5

6

112

32

1413

6

3189

501011

258

53

COPLANAR 7200 HZ

REAL QUAD PPM PPM

14

5

196

.1110

803026

1729

29

1882924

7922

225

19

11

11615

4417

18126

25

22103103

118118112

2480

932

VERTICAL DIKE

COND DEPTH* MHOS M

3

5

11

11

9419

9811

4511

171

61

17

30

013

09

160

33

500

000

90

397

HORIZONTAL. SHEET

COND DEPTH MHOS M

2

1

11

11

1212

2211

811

41

31

143

95

5855

2357

8712

133

501314

491311

6914

12838

CONDUCTIVE EARTH

RESIS DEPTH OHM-M M

69

1035

6761296

912680

1525

55

1539794

2516606

11612

252132

99

0

016

020

740

94

4200

3600

480

955

m2

s:

gt~-zr-t-H

C/)•H

t)

m0*-H

X•c

" n

COAXIAL 900 HZ

ANOMALY/ REAL QUAD FID/INTERP PPM PPMLine 1140 (Flight 1)B 2306 B . - 0C 2295 .S 0Line 1150 (Flight 1)D 2465 D 22E. 2473 S 0Line 1160 (Flight 1)A 2606 D 14Line 1170 (Flight 1)A 2846 B 0Line 1190 (Flight 1)A 3137 P? 2B 3163 D 4C 3173 S , 1F 3186 S 0Line 1200 (Flight 1)A 3310 D 40C 3288 L 2Line 1210 (Flight 1)B 3627 D 81D 3644 S 0E 3650 L 1Line 1220 (Flight 1)A 3779 L 0Line 1230 (Flight 1)A 3885 S 0B 3913 B 0Line 1240 (Flight 1)A 4073 B 2

06

63

10

9

1221

193

2734

1

11

1

COPLANAR ' 900 HZ

REAL QUAD PPM PPM

00

370

28

1

2700

694

17001

0

00

1

216

92

15

4

1312

286

6551

2

44

2

COPLANAR 7200 HZ

REAL QUAD PPM PPM

055

511

56

15

51910

m19

28698

4

212

8

1150

938

20

5

28

2410

2842

85759

3

5112

5

VERTICAL DIKE

COND DEPTH* MHOS M

11

731

20

4

32141

444

7716

1

11

1

00

150

23

22

4940635

035

20

42

49

021

34

HORIZONTAL SHEET

COND DEPTH MHOS M

11

81

2

1

1611

51

1111

1

11

1

9914

m0

103

155

14715019952

69130

436

205

103

087

114

CONDUCTIVE EARTH

RESIS DEPTH OHM-M M

8280312

34292

27

1035

3186

10357607

8160

115441035

945

3423340

372

00

920

75

0

107125

00

4972

3300

52

052

77

fi) 3 D.

O O

tn

COAXIAL 900 HZ

ANOMALY/ REAL QUAD FID/INTERP PPM PPMLine 1250 (Flight 2)A 399 L 0Line 1260 (Flight 2)A 523 S 1Line 1270 (Flight 2)A 653 D 26B 658 S? 0C ̂ 660 B 0Line 1280 (Flight 2)B 804 T 38C 796 L'1 0.Line 1290 (Flight 2)C 899 D 60E 909 L , 0F 91.2 B? 0Line 1300 (Flight 2)A 1071 D 31B 1066 S 0C 1063 L 0Line 1310 (Flight 2)A 1156 D 36B 1160 S 1C 1164 L 7Line 1320 (Flight 2)A 1292 B? 1Line 1330 (Flight 2)A 1400 D 11Line 1340 (Flight 2)A 1536 B? 1

8

.3

2699

2710

341510

1435

1657

2

7

2

COPLANAR 900 HZ

REAL QUAD PPM PPM

0

0

3323

761

10530

4320

6452

1

19

0

6

4

2877

475

694

27

2132

2354

1

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3

COPLANAR 7200 HZ

REAL QUAD PPM PPM

0

18

932423

18512

2431465

7978

10498

6

51

12

15

49

559090

8020

9823

248

226027

239611

4

22

17

VERTICAL DIKE

COND DEPTH* MHOS M

8

1

1419

269

3441

3711

5017

1

15

1

27

0

70

32

323

3263

000

90

31

45

18

1

HORIZONTAL SHEET

COND DEPTH MHOS M

1

1

311

71

611

411

711

1

3

1

199

17

8212

109

55155

4912021

7310

157

7712

151

126

no

65

CONDUCTIVE EARTH

RESIS DEPTH OHM-M M

1035

604

236061035

31035

51035715

1110841035

31110160

232

21

390

0

0

5700

410

3400

5100

620

90

93

81

30

T

ri l- x

r.cr"

C.

* Estimated depth may be unreliable because the stronger part of the conductor may be deeper or to one side of the flight line, or because of a shallow dip or overburden effects.

OR DDITIONAL

N FORM ATI ONV APS:

ESQUJLGAJDOSZ*

fis

......... Falconbridge Property

inDIGHEM SURVEY

WAWA J.V. AREA, ONTARIO

ELECTROMAGNETIC ANOMALIES

FOR

FALCONBRIDGE LTD.

1 2Scale 1 = 10,000

O 1 2

J....... ... F:" - -' - ::\~

.K - - . -...... -:. .. -i -O 14

o oox

1 Kilometres

1 2 MilesJOB

175 BDATE

29 JUNE '83

DRAWN BY /?//

wfCHECKED BY

J. H .

Falconbridge Property

ISOMAGNETIC LINESLOCATION MAP

SURVEYDIGHEMWAWA J.V. AREA , ONTARIO

ENHANCED MAGNETICS

FALCONBRIDGE LT

Scale 1:10,000O 1 2SCALE 1*250,000

S D^Jjt.ASER R

Cycles/metre

Frequency r esponse ot magnetic operator

1 4 1 4 1 2 MilesJOB

175 BDATE

29 JUNE '83DRAWN BY /^ CHECKED BY

vT.A.

42C02SE0305 ESQUEGA32 ESQUEGA 210

LOCATION MAP

SCALE 11250,000

in

DIGHEM-SURVEYWAWA J.V. AREA , ONTARIO

RESISTIVITY

FOR

FALCONBRIDGE LTD

1 2

Scale 1MO,000O 1 2

Falconbridge Property

LEGEND

Contours in ohm — m at ten intervals per decade

Flight Line

1 Kilometres

l I

O 14 1 2 Miles

... .ESQUEGA32 ESQUEGA

220 E56IU - 0032^3

301 A

— Fiducial 2120 (Not recovered *rom— Fiducial 2118 (Recovered from film)

Fiducial 2110 (Not recovered from film)

Fiducial 2104 (Recovered from film)

Line number and Flight direction

Note

The numbers face in the direction of increasing value.

JOB175 B

DATE 29 JUNE '83

DRAWN ^/l/ CHECKED BYS. K.

\ V \l\ * ' X ' * l ?-t fi,\\\\"\" s te/u N\A\VT Irm

T

-OO

Falconbridge Property

LOCATION MAP

84045'

84045

SCALE 1*250,000

48=00

III

DIGHEM~ SURVEYWAWA J.V. AREA , ONTARIO

MAGNETICS

FOR

FALCONBRIDGE LTD.

Scale 1:10,000o 1 2 1 K i lometres

1 4

••-i

1 4 1 2 Miles

42CC2SE0305 ESQUEGA32 ESQUEGA 230

Flight Line

lj.

301 A

and

ISOMAGNETIC LINES (total field)

. icoo ———* 1 000 nT

- TOO ———" 100 nT

- 20 ———' 20 n T

- — ———- 10 nT

magnetic depression

Magnetic Inclination within the survey area: 67 N

JOB 175 B

DATE 29 JUNE '83

DRAWN BY.//7 Wj?

CHECKED BY

M.

q

LOCATION MAP II

SCALE h250fOOO

200

DIGHEM" SURVEYWAWA J.V. AREA , ONTARIO

ELECTROMAGNETIC ANOMALIES

FOR

FALCONBRIDGE LTD

1 2

Scale 1^10,000O 1 2

1 4 1 2 Mites