GM 31122 INTERPRETATION OF THE 1972 AND 1973 HELIPORTED ELECTROMAGNETIC AND MAGNETIC SURVEYS INTERPRETATION OF THE 1972 AND 1973
HELIPORTED ELECTROMAGNETIC AND MAGNETIC SURVEYS
IN THE EXPLORATION PERMIT AREAS OF QUEBEC
REPORT DATE: FEBRUARY. 1975
Ministère des Richesses Naturelles, Québec SERVICE DE LA DOCUMENTATION TECHNIQUE
Date: 3 i OCT 1975 No GM: 31.1?~,
IRON ORE'COMPANY OF CANADA — TECHNI.AL SERVICES DIVISION
MINING ENGINEERING DEPARTMENT
DEVELOPMENT SECTION — K.L.
REPORT NO. 1975-7 IRON ORE COMPANY OF CANADA
OFFICES: SEPT-ILES, QUEBEC MONTREAL, QUEBEC SCHEFFERVILLE, QUEBEC LABRADOR CITY, NEWFOUNDLAND Engineering Department ST. JOHN'S, NEWFOUNDLAND Development Section P.O. Box 1004 Schefferville, Que.
April 18, 1975
Mr. D.S. Campbell Superintendent Mining Engineering 100 Retty Street Sept-Iles, Que.
Dear Sir:
The attached report is a qualitative interpretation of the 1972 and 1973 airborne geophysical work conducted over the three Exploration Permit Areas of Quebec (Nos. 554, 555, and 556) .
This report includes AEM, AM and VLF-EM contour maps corresponding to the three Exploration Permit Areas. All the interpreted anomalies are outlined on the AEM contour maps.
Several of the recommended anomalies were investigated by ground follow up work during the summer of 1974. The results of the surface exploration work are presented in a separate report.
E. Horne Development Supervisor
EH/cg
encl. ACKNOWLEDGEMENT
This is a Development K.L. Report
REPORT NAME: INTERPRETATION OF THE 1972 AND 1973 HELIPORTED
ELECTROMAGNETIC AND MAGNETIC SURVEYS IN THE
EXPLORATION PERMIT AREAS OF QUEBEC
REPORT NO. 1975-7
REPORT DATE: FEBRUARY 1975
SUBMITTED TO: E. HORNE - DEVELOPMENT SUPERVISOR - K.L.
SUBMITTED BY: MAURICE SEGUIN - CONSULTING GEOPHYSICIST
T. BALAKRISHNAN - DEVELOPMENT GEOLOGIST - K.L.
CHECKED BY: J. DEVON - SUPERVISOR MINING ENGINEERING - K.L.
R.E. ARNDT - DEVELOPMENT SUPERVISING ENG. - K.L.
SIGNED: Maurice Seguin
T. Balakrishnan
E. Horne
J Devon
R.E. Arndt
PROJECT REPORT NUMBER NUMBER !975-7 PAGE i
TECHNICAL SERVICES FORM 1212-On ABSTRACT
During the year 1972, a heliported electromagnetic
(AEM), magnetic (AM), and very low frequency electromagnetic (AEM)
survey was conducted in the vicinity of Schefferville, to locate
high grade taconite deposits. This survey included the "Swampy Bay
Area", which forms part of the Exploration Permit Area # 556. A
total of approximately 120 line miles were flown over the "Swampy
Bay Area".
During the year 1973, a similar heliported EM and
magnetic survey, was conducted over all the Exploration Permit Areas
(E.P. II 554, E.P. 4f 555, and E.P. # 556), excluding the "Swampy Bay
Area" of E.P. # 556. A total of approximately 565 line miles were
flown. Both of these surveys were conducted by Sander Geophysics of
Ottawa.
A qualitative to semi-quantitative interpretation
of all the survey data was made. Based on the interpretation,
several AM and AEM anomalies with a potential for high grade taconite
were outlined in the three Exploration Permit Areas.
PROJECT REPORT NUMBEF NUMBER 1935-7 PAGE ii
TECHNICAL SERVICES FORM - 1212-06 DISTRIBUTION LIST
CAMPBELL, D.S.
COLLINS, P.
HORNE, E. LANCASTER, J.G.
FINK, R.P.
RAJU, S.S.
ARNDT, R.E.
BALAKRISHNAN, T.
ENGINEERING VAULT - K.L.
PROJEC' REPORT NUMBER NUMBER •-975-7 PAGE
TECHNICAL SERV ICES TABLE OF CONTENTS
REFERENCE PAGE NO.
1.0 INTRODUCTION 1
1.1 Purpose 1
1.2 Contractor 1
2.0 FIELD SCHEDULE 2
2.1 1972 Airborne Survey 2
2.2 1973 Airborne Survey 4
3.0 INSTRUMENTATION 8
3.1 1972 Airborne Survey 8
3.1.1 Data Recording 9
3.1.2 Evaluation of the Instruments 10
3.1.3 Accuracy of the Instrumentation Used 12 3.2 1973 Airborne Survey 15 3.2.1 Description of the Instruments 15 3.2.2 Data Recording 15 3.2.3 Evaluation of the Instruments 16
3.2.4 Accuracy of the Instrumentation Used 16 4.0 CHARACTERISTIC ELECTROMAGNETIC RESPONSE CURVES 17
4.1 Curve Response for Special Geometric Model 17
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE iv
TECHNICAL SERVICES TABLE OF CONTENTS (continued)
REFERENCE PAGE NO.
4.2 Effect of Frequency, Coil Separation,
Height, Direction of Flight and Magnetite
Content, on the E.M. Response Curves 21
4.3 Effect of Permeability and Conductivity
on the Electromagnetic Response Curves 21
5.0 PRESENTATION OF DATA 23
5.1. 1972 Airborne Survey 23
5.2 1973 Airborne Survey 24
6.0 INTERPRETATION PROCEDURES 25
6.1 Qualitative Interpretation of the 1972
Survey Data 25
6.2 Results 26
6.2.1 Keough Lake Band 27
6.2.2 Lac Therese Band 27
7.0 INTERPRETATION OF THE 1973 SURVEY DATA 28
7.1 Results 29
7.1.1 Exploration Permit Area No. 554 29
7.1.2 Exploration Permit Area No. 555 30
7.1.3 Exploration Permit Area No. 556 30
7.2 Summary 31
PROJEC REPORT NUMBER NUMBER 1075-7 PAGE v
TECHNICAL SER TICES
LIST OF FIGURES
Characteristic Electromagnetic Response Curves Page No.
A. Vertical Permeable Thick Sheet 18
B. Vertical Conductive Thick Sheet 18
C. Vertical Conductive and Permeable Thick Sheet 19
D. Horizontal Permeable Slab 19
E. Horizontal Conductive Slab 20
F. Horizontal Conductive and Permeable Slab 20
PROJECT REPORT NUMBER _ NUMBER ).975-7 PAGE vi
TECHNICAL SERVICES
LIST OF MAPS
MAP NO. TITLE
1. Index Map at l": 8 Mile Scale, Showing Areas of 1972,
1973 Airborne Geophysical Surveys. (In Pocket)
Maps Accompanying the Report. (In Book Form -'2 Copies)
,2. 1972 Airborne, E.M., VLF-EM and Magnetic Survey, -
"Swampy Bay Area".
3. 1973 Airborne EM and Magnetic Survey.
Exploration Permit Area No. 554
Exploration Permit Area No, 555
Exploration Permit Area No. 556
PROJEC" REPORT NUMBER NUMBER 1975-? PAGE vii
TECHNICAL SERVICES
LIST OF TABLES
PACE NUMBER TABLE NO. 1 Compilation of Data for Qualitative Interpretation of the Heliported Magnetic and Electromagnetic 34 Surveys - 1972. Swampy Bay Area. (E.P. No. 556)
TABLE NO. 2 Priority Anomalies, based on A.E.M. and A.M.
Data, Swampy Bay Area. 49
TABLE NO. 3 Assessment of A.E.M. and A.M. Anomalies
1973 Airborne Survey. 52
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE viii
TECHNICAL SERVICES DEFINITIONS
CONDUCTIVE:
Material having a.substantial conductivity.
CONDUCTIVITY:
Electrical conductivity is the inverse of the resistance to the passage of electrical current multiplied by a geometric factor which is proportional to the cross-sectional area of the conductor.
DIPOLE:
Oscillating magnetic moment with two directions or poles.
FOUCAULT (EDDY) CURRENTS:
These are secondary currents or current cells in a conductor which result from electromagnetic induction. The number of currents generated will generally depend upon the number of conductors present.
GEOMETRIC MODELS CONSIDERED:
a) Vertical thick sheet (two dimensions of which are larger
than the third).
b) Sub-vertical thick sheet
INDUCTIVE:
Permeable.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE ix
TECHNICAL SERVICES SUSCEPTIBILITY:
The ratio of the induced magnetization to the strength
of the magnetic field causing the magnetization.
TELLURIC CURRENTS
Natural (ionospheric in origin) currents in the ground.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE xi
TECHNICAL SERVICES FORM - 1212-05 LIST OF SYMBOLS
A.E.M. : Aeroelectromagnetic
A.M. Aeromagnetic
Q Conductivity
D.T.W.R. Davis Tube Weight Recovery
Ay Residual Total Magnetic Component
y Gamma (s)
h : Height of the Coils above the Ground
K Volume Ferromagnetic Susceptibility
Kt Susceptibility-Thickness Product
s Transmitter - Receiver Coils Separation
U Magnetic Permeability
p Dip of Formation
P.P.M. Parts per Million
p Electrical Resistivity
Pc Electrical Resistivity of Cherty Iron-Formation
Pm Electrical Resistivity of Magnetic Iron-Formation
R+ Positive Real Component
VIm Quadrature Vertical Component
V.L.F. Very Low Frequency
VRe Real Vertical Component
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE xii
TECHNICAL SERVICES 1.0 INTRODUCTION
This report represents a qualitative interpretation
of the heliported electromagnetic and magnetic surveys conducted over
the Exploration Permit Areas # 554, 555, and 556 during the years
1972 and 1973.
During 1972, only the "Swampy Bay Area" of E.P. # 556
was surveyed using a heliported magnetometer, V.L.F. - E.M. and
electromagnetic units. During 1973 the rest of the three areas
were surveyed using a heliported E.M. and magnetometer units.
1.1 Purpose
The purpose of this geophysical survey is to locate
high grade taconite deposits in the three Exploration Permit Areas
and to determine which deposits warrant additional exploration work.
1.2 Contractor
These two airborne surveys were conducted by Sander
Geophysics Limited, Ottawa, Ontario. During the 1972 airborne survey,
the personnel consisted of Thomas Moore, technician; Edward Beaumont,
pilot; George Sander, owner and his two sons Henry and Stephan.
In 1973, the personnel consisted of Frank Kiss,
technician; Ray Garbout, electrician; Brian Wilson, pilot; Bruce
Wyatt, mechanic; and George Sander, owner.
PROJEC'' REPORT NUMBER NUMBER 1975-7 PAGE 1
TECHNICAL SERVICES FORM - 1212-06 2.0 FIELD SCHEDULE
2.1 1972 Airborne Survey
The survey was flown from June 22nd through June 25th,
1972, but actual surveying days for "Swampy Bay Area" alone were
June 22nd and June 24th. The following is a log of the contractor's time from mobilization to demobilization.
Monday, June 19: Demobilization from Labrador City. The pilot flew the helicopter to Schefferville while the Sander Geophysics group moved their equipment from the Lorraine Camp to the Wabush airport for transport to Schefferville via Quebecair.
Tuesday, June 20: The Sander Geophysics group and M. Seguin flew from
Wabush to Schefferville. The equipment was not sent until the following day.
Wednesday, June 21: The A.E.M. equipment arrived on Quebecair, and was assembled and installed in the helicopter.
Thursday; June 22: The installation of the equipment was completed in the morning and was tested in the afternoon. The survey work began at 3:00 P.M., and four short test lines (Numbers 47, 48, 49 and 50) were flown in the Howells River Area. These lines had been flown with a similar
A.E.M. system by Lockwood Corporation in 1971. The majority of the Swampy
Bay area was also flown; this represents a total of approximately 100
PROJECT REPORT 1975-7 2 NUMBER NUMBER PAGE
TECHNICAL SERVICES line miles. The weather was favourable for flying; the sky was clear and sunny; visibility excellent and the winds light.
Friday, June 23: Excellent weather, clear and sunny, good visibility.
The entire Iron Arm (Labrador) area was flown between 2:00 P.M. and 8:00 P.M. for a total of approximately 130 line miles.
Saturday, June 24: Excellent weather, clear and sunny, good visibility.
The eight lines remaining in the Swampy Bay, (E.P. ##556) Anomaly No. 145,Knob
Lake and the Wishart Creek areas were flown. The altimeter and the in-phase trace of the A.E.M. unit were not working properly over the
Knob Lake Ridge and Wishart Creek areas.
Sunday, June 24: Good weather. Warm, slightly windy, partly overcast.
The Knob Lake Ridge and Wishart Creek areas were reflown between 5:00 P.M. and 7:00 P.M. This completed the survey in the Schefferville district.
Monday, June 26: Demobilization of equipment.
The weather conditions during this period of time were exceptionally favourable for the heliported survey, and it is recommended that future airborne surveys in the Schefferville region be conducted in mid-June.
PROJECT REPORT NUMBER NUMBER ) 975-7 PAGE 3
TECHNICAL SERVICES
2.2 1973 Airborne Survey
The following is a log of the contractor's
time from mobilization to demobilization.
Monday, September 3rd: Roy Garbout, electrician and Frank Kiss drove
the EM bird and the electronic equipment from Ottawa to Sept-Iles; they
slept in Tadoussac.
Tuesday, September 4th: They drove the EM bird and ancillary electronic
equipment from Tadoussac to Sept-Iles; they contacted Northern Wings
Helicopter of Quebecair in Sept-Iles and started to install the
geophysical instrumentation into the helicopter.
Wednesday, September 5th: They continued to install the electronic
instrumentation in the helicopter, then contacted Quebec North Shore
and Labrador Railway Co. to freight the EM bird to Schefferville.
Thursday, September 6th: They continued to install the instrumentation
in the helicopter and shipped the EM bird on the train to Schefferville.
Friday, September 17th: They continued to install the instrumentation
in the helicopter in the forenoon. Frank Kiss and Ray Garbout flew on
Quebecair from Sept-Iles to Schefferville. George Sander flew from
Ottawa to Schefferville and Seguin from Labrador City to Schefferville.
The pilot Brian Wilson and the mechanic Bruce Wyatt, flew Nothern Wings
PROJECT' REPORT NUMBEF NUMBER 1975-7 PAGE 4
TECHNICAL SERVICES FORM - 1212-05
helicopter (Bell G-4A Standard) from Sept-Iles to Wabush airport where they stayed overnight. The EM bird arrived at the railway station in Schefferville where it was picked up in the afternoon and trucked to the airport.
Saturday, September 8th: Installation of the EM bird and electronic instrumentation. Meeting with George Sander in the forenoon.
Sunday, September 9th: Installation and calibration of electromagnetic and magnetic electronic equipment.
Monday, September 10th: Continued installation and calibration of
EM electronic instrumentation. After the calibration was finished, a first flight test was tried but without success. The EM bird was unstable due to absence of fins that were removed to install the horizontal coplanar coil system. The fins were reinstalled.
Tuesday, September 11th: Finished installing the fins; rained in the afternoon; no flying; flew using the horizontal coplanar with 4000 Hertz frequency emission on the Howells River test site between 4:30 and 7:00 P.M.
Wednesday, September 12th: Changed configuration from coplanar horizontal to coaxial vertical in the forenoon; flew the Howells River test site with coaxial vertical and 4000 Hertz between 3:50 and 6:00 P.M.
PROJEC" REPORT 1975-7 5 NUMBER NUMBER PAGE
TECHNICAL SERVICES Thursday, September 13th: Changed configuration from coaxial vertical
at 4000 Hertz to coplanar horizontal at 1000 Hertz; flew the Howells
River test site with coplanar horizontal at 1000 Hertz between 4:30 and
7:00 P.M.
Friday, September 14th: Flew the southwestern limb of Exploration
Permit Area #555 from line 118 to line 35, in two sorties between 11:00
A.M. and 5:00 P.M. On the way to the Harris Lake - Helluva Lake -
Eclipse Lake area, 5 lines were flown with the horizontal coplanar
configuration at 1000 Hertz. These 5 lines correspond to Nos. 2, 6,
8, 12 and 14 flown in 1972 with the same system using the coaxial -
vertical configuration at 1000 Hertz. A total of 110 line miles were
flown this day.
Saturday, September 15th: Used the same configuration and same frequency
of emission as on the 14th. Total line mileage was approximately 160. miles.
Flew 39 lines of Exploration Permit Area #556 - east limb in the Lac Le Fer
area and part of the east limb of Exploration Permit Area #555.
Sunday, September 16th: Flew the east block of the Swampy Bay area
of the Exploration Permit Area #556 and finished the northern section of
Exploration Permit Area #555 to the north of Eclipse Lake for a total of
approximately 110 line miles.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 6
TECHNICAL SERVICES FORM . 1212-08 Monday, September 17th: Flew all of Exploration Permit Area #554 in
the Bird Lake - Hurst Lake region and the 11 northernmost lines of the
Lac Hayot region of Exploration Permit Area #556 for a total of
approximately 110 line miles.
Tuesday, September 18th: Finished flying the southernmost part
(the last 36 lines) of the Lake Hayot region of Exploration Permit Area
#556 and flew the Annabel Lake region of Exploration Permit Area #556
for a total of approximately 60 line miles.
Wednesday, September 19th: Demobilization day. Removal of EM and
magnetic instrumentation from the helicopter which then left
Schefferville for Sept-Iles.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 7
TECHNICAL SERVICES FORM 1212-06 3.0 INSTRUMENTATION
3.1 1972 Airborne Survey
Description of the Instruments
- A Proton precession magnetometer, accurate to ±1 y was mounted in the bird to measure the total field.
- A Scintrex fluxgate magnetometer, accurate to ±10 y was mounted on the body of the helicopter to measure the vertical component of the earth's magnetic field.
- An Electromagnetic system was mounted in the bird having the following specifications:
1. Coaxial vertical coils with maximum coupling.
2. Coil separation of 23 feet.
3. Frequency of emission equal to 1,000 Hertz.
4. Measures the In-Phase and Out-of-Phase components of
the induced magnetic field.
- A V.L.F. system with the coils located on the body of the helicopter and oriented in a horizontal plane both perpendicular and parallel to the flight direction. The V.L.F. system operated at a frequency of
17,800 Hertz and measured both the real and imaginary vertical components of the field induced by a remote radio station (NAA Station, Cutler,
Maine, U.S.A.).
PROJEC1 REPORT NUMBER NUMBER 3975-7 PAGE 8
TECHNICAL SERVICES
3.1.1 Data Recording
The data generated included eleven traces on a
digital-analogue recorder (photosensitive paper) and twelve channel
magnetic tape. These traces are:
Trace No: Parameter Being Recorded
1 Bonzer radar altimeter flying height.
2 In-phase A.E.M. component.
3 Out-of-phase A.E.M. component.
4 Reference V.L.F. horizontal field (Href).
5 Real vertical component (VRe) of the V.L.F.
6 Quadrature (imaginary) vertical component (VIm) of the V.L.F. field.
7, 8, &9 Three magnetometer traces for the proton
precession magnetometer (units of 1,000 y,
100 y, and 10 y).
10 Pitch of the Helicopter.
11 Vertical component of the Scintrex fluxgate
magnetometer.
All these traces were recorded on a time-sharing
recording unit using a single uniformly unrolling photosensitive paper
and a magnetic tape. A twelfth trace recording the roll of the helicopter
was obtained on the magnetic tape.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 9
TECHNICAL SERVICES A continuous 16 mm strip camera generated frames at an average 200 foot distance without overlap, which covered a terrain width of approximately 300 feet. The fiducial marks were co-ordinated through a quartz crystal clock, and at every interval of 5 frames, a mark was fed into the digital system. At every 50, 100 and 1,000 camera exposures, a specific digital code was used on the digital-analogue recorder and on the magnetic tape.
3.1.2 Evaluation of the Instruments
Magnetometers
The magnetometer maps were compiled from the total field proton precession magnetometer. These data were satisfactory, except that the range of the nuclear precession magnetometer was such that it could not record intensities greater than approximately 8000 gammas above the normal total geomagnetic field. The relative intensity values of the magnetic anomalies therefore could not be obtained over all the iron formation bands.
The Scintrex fluxgate magnetometer was included in the survey to record the intensities of those anomalies that were off scale for the proton precession magnetometer. The fluxgate magnetometer was a ground survey instrument which was adapted to the heliported survey.
The ammeter that indicated the field intensity was removed from the fluxgate magnetometer and was replaced by a digital meter.
PROJECT REPORT NUMBER NUMBER 1 9 7 5-7 PAGE 10
TECHNICAL SERVICES 7.0 INTERPRETATION OF 1973 AIRBORNE SURVEY RESULTS
Prior to the surveying of the Exploration Permit Areas, a test grid was chosen and flown in the Howells River (Labrador) iron formation band (where detailed surface exploration work had been carried out) to optimize the magnetic permeability response of the A.E.M. system used.
This study has shown that a horizontal coplanar coil configuration with a frequency of emission of 1000 Hertz offers a better coupling with the permeable bodies than does the coaxial vertical coil configuration, which was the system adopted for surveying "Swampy Bay Area" (EP 556) in 1972.
Hence, all the three Exploration Permit Areas were surveyed using a horizontal coplanar system.
The results of the assessment of A.E.M. and A.M. anomalies of the three Exploration Permit Areas are presented in detail in Table 3. The average in-phase response (in P.P.M.) of all the anomalies encountered in the Howells River Area, which corresponds to an average grade of 21% magnetite by Wt, is + 175 P.P.M.
It was decided to retain all A.E.M. anomalies having an intensity of >+175 P.P.M. of the in-phase component. Such selected anomalies are underlined in Table 3.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 28
TECHNICAL SERVICES 7.1 Results
All the anomalies with an in-phase response of +175 P.P.M.
or more are outlined in the A.E.M. contour maps. The dimensions of the
areas outlined are based on the shape of the A.E.M. and A.M. anomalies.
Anomalies recommended for further investigation are listed separately
for each area. Anomalies of smaller dimensions, which are due to thin
iron formation bands are not recommended for further work. Since the presence
of remanent magnetism is suspected in this area, several A.E.M. anomalies
without a direct coincident magnetic anomaly are also recommended for
further exploration.
7.1.1 Exploration Permit Area No, 554
In this region, the three A.E.M. anomalies of map
sheet AA-2 (No. 1, 2 and 3) and Anomaly No. 8 on map sheet AA-4 are recommended for investigation.
PROJECT REPORT NUMBER NUMBER 1975-% PAGE 29
TECHNICAL SERVICES
7.1.2 Exploration Permit Area No. 555
In this region, the distribution of the A.E.M.
anomalies to be investigated within specific map sheet are the following:
MAP SHEET NO: ANOMALY (A.E.M.) NO:
H-3 1 and 2
I-4 4, 5, 6 and 7
I-5 9, 11, 12, 13 and 14
J-4 17, 18, 19, 20 and 21
J-5 23, 24, 25, 26, 27, and 28
J-6 29 and 30
K-4 34
K-5 35, 36, 37, 37A, 38, 40, 41, 42 and 43
K-6 44, 45, 46, 47 and 48
L-5 50, 51 and 52
L-6 53.
7.1.3 Exploration Permit Area No. 556
MAP SHEET NO: ANOMALY (A.E.M.) NO:
I-6 1
H-7 3, 4, 5, 6, 8 and 9
H-6 11 and 14
F-5 15
PROJECT REPORT 1975-7 NUMBER NUMBER PAGE 30
TECHNICAL SERVICES 7,2 Summary
This qualitative interpretation of both the 1972 and 1973 airborne survey results shows that very few anomalies of economic interest for high grade magnetic taconite bodies are present in Exploration Permit
Areas No. 554 and No. 556. On E.P. No. 554 only the area containing anomalies 1, 2 and 3 on map sheet AA-2 warrant further investigation.
On E.P. No. 556 only the area containing anomalies: 3, 4, 5, 6, 8 and
9 on map sheet H-7, and anomalies: 19, 20 and 21 on map sheets H-6, and
G-6, and anomalies 22 (15) on sheet F-5 need further investigation.
E.P. Area No. 555 is far more interesting, in particular the areas covered by map sheets: 1-4, I-5, J-4 and J-5 containing anomalies
4, 5, 6, 7, 9, 11, 12, 13, 14, 17, 18, 19, 20, 21, 23, 24, 26, 27 and 28 as well as the areas covered by map sheets K-5, K-6, and L-5 containing anomalies 35, 36, 37, 37-A, 40,'41, 42, 43, 44, 45, 46, 47, 48, 50,
51, and 52 should be investigated.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 31
TECHNICAL SERVICES REFERENCES:
1. Landry, J. (1972) - Theoretical Models for the Interpretation of
Airborne Electromagnetic Data. Report No: 1972-22, September 3rd.
2. Seguin, M. K. (1971) - Proposal for an Airborne Electromagnetic and
Magnetic Survey of Taconite Areas in the Vicinity of Schefferville,
P. Q. 24 pp. Report No: 1971-5, July 20th.
3. Seguin, M. K. (1971) - Preliminary Quantitative Interpretation of
the Heliported Electromagnetic and Magnetic Surveys on the Howells
River Magnetic Iron Formation Band, 57 pp. I.O.C.C. Report, August 11th.
4. Seguin, M. K. (1971) - Finalization of the Quantitative Interpretation
of the Heliported Electromagnetic and Magnetic Surveys on the Howells
River Magnetic Iron Formation Band, 21 pp. I.O.C.C. Report,October 2nd.
5. Seguin, M.K. (1971) - Summary Report on Aeroelectromagnetic Survey
for Permafrost Prediction, 2pp. I.O.C.C. Report, December 13th.
6. Seguin, M. K. (1971) - Quantitative Interpretation of the V.L.F.
Results Obtained from the Heliported Electromagnetic and Magnetic
Survey on the Howells River Magnetic Iron Formation Band, 12 pp.
I.O.C.C. Report, December 15th.
PROJECT' REPORT NUMBEP NUMBER 1975-7 PAGE 32
TECHNICAL SERVICES 7. Seguin, M. K. (1972) - Continuation and Extension of the Former
Report Related to Quantitative Interpretation of V.L.F. Results
Obtained from the Heliported Electromagnetic and Magnetic Survey
on the Howells River Magnetic Iron Formation Band, 7 pp.
I.O.C.C. Report, April 14th.
8. Seguin, M. K. (1972) - Comparison of Success to Failure Ratios when
Searching for High Grade Magnetic Taconite on the Western Side of
the Howells River, 5 pp. I.O.C.C. Report, April 16th.
9. Seguin, M.K. (1972) - Interpretation of the 1972 Airborne Electro-
magnetic and Magnetic Survey in the Knob Lake Area, 103 pp.
I.O.C.C. Report, June.
10. Seguin, M. K. (1973) - Semi-Quantitative Interpretation of the 1972
Airborne V.L.F. (Very Low Frequency) Survey, 26 pp.
I.O.C.C. Report, August 17th.
11. Seguin, M. K. (1973) - 1973 Heliported Magnetic and Electromagnetic
Surveys, 4 pp. I.O.C.C. Report, September 19th.
PROJECT REPORT NUMBER NUMBER 1975-'7 PAGE '33
TECHNICAL SERVICES
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 34
THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. ##556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
1-E 749.2 105' -11 550' -20 550' 0 0 760.5 130' -16 500' -14 600' 0 0 776.3 130' -105 650' -34 800' +1,000 +500 780.0 145' -117 900' -36 , 850' 0 0 790.1 105' -42 600' -51 500' 0 0 792.2 125' -30 400' -39 500' 0 - 0 -798.3 115' -43 500' -30 500' 0 0 806.5 135' -77 900' -38 950' +2,000 +1,500 815.0 120' -178 1,000' -68 850' +3,500 +3,000
2-W 840.9 135' -92 1,200' -32 1,100' +2,000 +1,500 846.2 145' +52 1,400' -18 - +8,500 +11,000 850.1 155' -46 ' 1,000' -21 - +1,500 +1,000 855.3 115' -48 400' -30 500' +500 0
3-E 863.1 145' -58 700' -28 600' 0 0 866.7 135' -47 650' -24 500' 0 0 872.7 115' +85 1,600' + 4 _ +7,500 +10,000 880.6 135' -94 1,400' ; -17 1,000' +500 0
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 35 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
4-W 908.1 145' -81 1,300' -28 1,100' .0 0 913.1 105' +80 1,800' +4 - +7,500 +13,000 920.0 200' -37 1,100' -7 - 0 0 • 5-E 933.1 145' -56 1,300' -26 1,100' 0 0 936.8 120' +73 800' +4 - .+7,000 +15;000 940.0 140' +10 700' -12 - +6,000 +4,500 942.0 135' +71 750' +5 - +8,000 r6,500 945.6 150' .-72 1,100' -19 1,100' +2,000 +1,500
6-W 981.6 135' -77 1,000' -40 1,000' +2,000 +1,000 985.0 120' +70 1,000' -41 - +7,500 +6,200 987.7 115' -12 , 550' -58 650' +2,000 +2,000 989.9 120' +62 750' -35 - +7,500 +16,000 993.0 145' -68 750' -37 700' 0 0
7-E 1,005.9 115' - - -10 650' +7,500 +12,000 1,011.7 170' - . .- -4 800' +6,500 +6,000 1,016.9 170! -54 ' 800' ; -3 - '+750 _ 0 Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION•OF • Page 36 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic,Response . — Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in fée..t P.P.M. Width in feet Total Field Vertical Field
8-W 1,045.7 160' -50 550' -16 500' +1,000 +1,000 1,049.5 160' +47 700' -3 700' +5,500 +5,000 1,052.6 130' +65 350' -33 - +3,000 +3,000 1,055.0 135' +110 600' -14 - +6,500 +15,000 1,060.0 145' -125 1,100' -54 1,000' 0 0 • 9-E 1,066.7 115' -192 900' -84 1,100'. 0 0 1,069.5 130' -158 750' -61 - 0 0 1,075.0 115' +129 600' + 2 - +7,000 +16,000 1,078.4 135' +56 500' • -10 - +7,000 +6,000 1,082.0 175' +45 800' -4 - +6,000 +5,500 1,086.5 155' -49 500' -36 +450' +1,000 + 500
10-W 1,104.0 125' -20 450' -19 500 • 0 0 1,118.3 135' +118 700' -11 - +6,000 +5,000 1,126.4 135' +56 750' -2 - +8,000 +14,000 1,130.9 125' -150 800' -71 800 0 ~
• •
) . . ._ __ ._._ . . ~ . . 4 . . .. . . _
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 37 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase - Oujt-of-Phase - Intensity in Gammas V No. No. Feet r P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field '
11-E 1,135.6 125' -142 600' -41 - .- 0 1,138.7 115' -164 700' -80 700' +1,000 +1,000 1,142.8 120' +64 800' + 8- 700' +8,000 +9,500 1,151.3 165' +28 550' 0 - +7,000 +6,000 1,154.2 150' -63 550' . -20 600' 0 G 1,158.8 120' -29 300' -18 400' 0 ' 0 •1,167.0 125' -32 400' -24 450' 0 0
12-W 1,170.9 145' -24 400' c-13 400' 0 0 1,177.8 145' -64 350' -45 ' 350' 0 0 1,185.0 155' +60 650' -7 - +7,000 +6,500 1,191.8 100' +51 500' -6 - +8,000 +16,000 1,196.9 120' -13a 450' -64 - 0 0
13-E 1,198.2 115' -200 1,500. -120 1,500' 0 0 1,206.0 105' -89 350' -60 350' 0 0
1,208.0 125' -80 .350' -58 400' 1,000 +50G 1,211.2 95' +150 .600' ,. -4 - +8,000 +18,000 1,220.8 170' +50 900' -7 600' +8,500 +7,000
1
0
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION. OF Page 38 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
--_ E.M. Response Magnetic Respinse Line Fiducial Altitude In-Phase Out-of-Phase ' Intensity in Gammas No. No. Feet P.P.M. JJidth in feet P.P.M. Width in feet Total Field Vertical Field
13-E 1,225.0 135 -46 500' -18 - .0 0 1,228.1 135 -36 400' -23 350' 0 0 1,235.4 150 -62 650' -31 700' 0 0
14-W 1,243.9 175' +4 900' 0 900' , 0 0 1,248.7 165' -71 550' -26 1,000' 0 - 0 .1,252.3 120' +75 600' 0 - +4,000 +4.000 1,255.5 135' +14 650' +2 600' 0 0 1,258.2 125' .-32 500' -37 550' +1,000 +500 1,261.0 115' +42 1,000' 0 ' 900' +8,000 +11,000
15-E 1,272.8 135' -100 1,100' -28 - • 0 0 1,279.3 155' -38, 350' -20 450' 0 0 1,282.1 145. +10 - +3 - +6,500 +6,000 1,292.0 155' '+25 550' +2 - . +6,500 +5,500 1,295.2 125' -74 .450' -24 - 0 0 1,297.6 125' -57 400' -41 400' 0 0
16-W 1,307.9 125' -38 450' -31 400' ' 0 0 1,317.3 125' . -54 500' • -47 600' 0 0 1,320.0 145' -75 550' -32 500' •0 0 •
•
4 —
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF . Page 39 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response — Line Fiducial Altitude_ In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in féet P.P.M. 'Width in feet Total Field Vertical Field ~. . 16-W 1,325.4 145' +80 1,200' -10 - +6,500 +6,500 1,333.0 135' -25 550! -30 600' 0 0 1,337.6 145' +45 1,000' +4 - +8,000 +14,000 1,342.4 140' -30 350' -20 450' 0 0
17-E 1,345.3 145' -78 450' -31 500' +1,000 +500 1,348.2 125' -79 550' -27 500' 0 0
1,356.0 .105' -65 550' -35 600' +1,000 +500 1,358.0 125' .+42 700' +2 - +8,000 +13,000 1,361.3 130' +11 500' +1 ' . - +3,500 +3,000 1,363.5 125' -38 450' -34 500' 0 0 • 1,370.0 185' +13 1,000' -4 - +6,000 +6,000 1,374.3 105' -171, 500' -80 600' +1,000 0
18-W 1,397.2 155' -78 600' -18 750' 0 0 1,400.8 155' +46 650' -6 - +8,000 +7,000 1,403.2 145' , +44 600' -5 - +6,000 +5,ü00 1,411.3 140' +27 650' +7 - +7,500 • +6,500 1,415.5 145' -28 350'. -13 600' . 0 0 , •
,p ..
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION-OF Page 40
THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas _ No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
19-E 1,428.0 130' -48 650' -30 700' . +5,000 +4,000 1,431.1 125' +31 650' +1 +8,000 +10,000 1,441.3 120' +68 550' -2- 600' +6,000 +5,000 1,444.4 160' +41 900' -7 +8,000 +6,000 1,449.0 135' , -98 1,000' -38 1,100' +1,000 . 0 ' 1,460.0 135' -57 ' 550' -29 700' + 0 ' 0 •1,489.0 145' -111 600' -43 900' +1,000 0 1,491.1 145' -52 -21 +8,000 +9,000 1,492.8 145' •+29 750' +7,000 +6,000 • 20W 1,497.4 195' -34 500' -7 . +1,500 +1,000 1,506.2 130' +50 700' +8,000 +12,000 1,509.8 155' -50 650' -21 700' 0 0 1,531.4 180' -21 450' -2 0 0 1,542.1 150' -90 1,000 -32 1,150' +1,000 0 1,546.1 130' +73 900' -11 850' +8,500 +8,500 1,555.6 145' +25 800' +3 800' +8,000 +10,000 1,559.1 135' -58 500'... -31 600' +1,000 +500 1,565.4 145' . -12 _ -$ _ +2,000 0
~ ' H.
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 41 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude T.+-P},ase Out-of-Phase Intensity in Gammas V No. No. Feet P.P.M. Width in feet P.P.M. Width in feet- Total Field Vertical Field ... 21-E 1,573.2 135' -60 750' -38 1,000' . +1,000 0 1,576.1 135' +23 550' +2 +8,000 +10,000 1,585.8 155' +31 550' -8 650' +8,000 + 8,000 1,590.0 125' -72 500' -28 +1,000 + 500 1,592.0 125' -83 350'. -46 550' 0 0 - 1,602.1 150' -23 400' -11 250' 0 •0 _•1,627.0 145' -100 900' . -45 . 900' + 1,000 0 1,631.2 140' +49 800' -3 + 8,000 + 10,000
22-W 1,641.7 185' +22 400' +3 •. 450' + 10,000 0 1,643.9 190' +31 350' 0 400' + 2,000 0 1,651.5 130' +98 600' -9 800' + 8,000 + 10,000 1,656.0 165' -71 500' -21 0 0 1,659.1 115' -60 550' -50 600' 0 0 1,673.2 145' -31 400' -18 350' 0 0 1,674.7 150' -24 350' -13 400' 0 0 1,685.4 115' -132 1,000' -55 1,200' + 1,000 •!- 1,OUu 1,690.0 115' +66 650' . -11 550' + 8,000 + 9,500 1,698.4 155' +24 1,000 ; - - +•7,000 +.8,000 1,702.0 145' -55 750' -35 800' 0 0 p .
Page 42 Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
23-E 1,716.3 150' -55 800' -21 850' 0 0 1,719.0 135' +33 3501 -5 +8,000 +9,500 1,726.5 125' +35 500' -10 +7,000 +66 000 1,729.0 125' +62 750' -12 700' +8,000 +9,000 1,734.0 145' -125 800' -48 750' +1,000 0 1,744.7 145' -51 450' • -26 450' +500 +500 1,747.0 135' -62 450' -35 500' 0 0 1,762.6 155' -49 850' -32 650' +1,000 0
1,768.3 135' .-142 1,200 -62 1,000' 0 0 1,772.0 .115' +61 1.,100' -3 +8,000 +13,000
24-W 1,787.4 -72 800' -42 700' 0 0 1,795.5 -134' 1,300' -57 1,150' +1,000 +500 1,800.0 125' +63 500' -10 +8,000 +12,500 1,808.3 145' +23 650' +3 750' +7,000 +6,500 1,811.9 160' -52 650' -23 700' 0 0
25-E 1,830.6 165' -28 800' -22 1,000' +1,000 0 1,834.0 150' +32 700' - 700' +8,000 +9,000 1,843.2 125' +103 800' -26 800' +8,000 +9,000 1,847.2 115' -142 550' -68 550' +2,000 +1,500
•
t
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 43 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet, Total Field Vertical Field
25-E 1,849.6 135' -115 350' -30 400' +1,000 +500 1,855.6 165' +8 - +2 - 0 0 1,864.0 130' -86 750' -44 800' 0 0 1,881.3 120' -150 1,000' -66 800' 0 0 1,884.8 130' +47 800' -7 +8,000 +11,000
26-W 1,910.4 135' -33 500' -31 450' +5,500 +4,500 1,917.0 115' +63 750' +3 700' +8,000 +8,000 1,922.1 150' -91 500' -26 600' +1,000 0 1,932.1 140' -90 500' -38 0 0 1,936.5 135' -131 450' -64 500' 0 0
1,939.2 130' -82 650' 2. 37 700' 0 0 1,942.0 130' -132 750' -60 800' 0 0 1,948.8 155' +43 800' -9 1,000 +8,000 +10,000 1,957.5 135' +14 0 +8,000 +9,000 1,960.8 165' -55 800' -26 1,000' +3,000 +2,000
27-E 1,970.1 145' -83 650' -34 800' +1,000 0 1,972.0 145' -17 -4 +8,000 +11,000 1,981.4 115' +37 400' -12 500' +8,000 +8,000 1,983.7 115' +78 750' -9 750' +8•,000 +9,000 1,986.9 . 120' -141 350' -68 400' +1,500 +1,000
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF . Page 44 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas — No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field'
27-E 1,990.6 140' -162 600' -65 600.' . +500 0 1,995.6 120' -126 700' -65. 650' , 0 0 2,002.4 145' -92 1,000' -37 800' 0 0 2,0O6.3 145' -24 800' -7 1,000' 0 0 2,009.4 160' -54 800' -34 -. , 0 0 2,014.4 145' -161 1,200 . -58 1,100' 0 . 0 -2,018.4 120' +81 550' -3 - +8,000 +7,000 2,025.6 155' -32 700' -26 850' +7,000 ,-6,500
28-W 2,044.4 140' +78 1,000' -3 1,100' +8,000 +17,000 2,049.6 150' -86 700' -33 650' 0 0 2,053.6 160' -82 700' -28 - 0 0 2,061.1 135' -149 750' -64 - ' +2,000 +1,000 2,063.4 120' ' -108 400' ' -90 400' +1,000 0 2,065.7 135' -25 750' -10 700' 0 G 2,068.5 140' -126 700' -44 - . 0 0 , 2,072.6 125' -150 950' -66 900' +1,500 f^,^00 2,076.3 130' +50 750' -11 - +8,000 . +9,000 2,086.5 140' +16 700' -1 - +8,000 +10,000
'
f . , •
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 45
THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
' E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
29-E 2,099.9 165' -79 1,000' -39 1,100' .0 0 2,105.5 205' -6 - +2 - +6,000 +7,000 2,117.4 135' +33 800' -12- 500' +8,000 +7,000 2,122.8 130' -135 700' -69 600' +2,000 +1,000 2,127.5 150' -92 650' -31 - 0 0 2,130.5 135' -31 550' -11 400' + 500 ' 0 :2,134.8 145' -89 500' -26 - 0 O 2.137.2 165' -80 650' -18 - 0 0 2,144.6 145' --136 500' -42 • - 0 0 2,147.5 145' -140 700' -64 750' 0 0 2,150.6 150' -111 900' -42 800' 0 0 2,154.1 115' +110 900' -15 _ +8,000 +17,000
3u-W 2,185.3 140' +58 1,000 ' -11 1,000' +8,000 +15,000 2,191.7 130' -151 1,000' -59 800' 0 0 2,203.8 125' -117 500' -77 500' 0 0 2,208.2 125' -164 800' -57 600' 0 0 2,212.8 150' -98 750' -43 700' +2,000 +2,000
31-E 2,229.4 155' -108 1,000' -53 900' 0 0 2,242.6 150' +11 350' -3 +6;000 +5,000
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page 46
THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude In-Phase Out-of-PYase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field ~ Vertical Field
31-E 2,248.5, 125' -178 1,000' -83 900' •0 0 2,253.6 130' -180 950' -73 850' 0 0 2,258.0 145' -79 500' -64 450' 0 0 2,261.9 135' -99 750' -69 700' 0 0 2,269.0 140' -141 800' ' -35 - 0 C 2,273.2 130' -157 1,000' -66 800' 0 ' 0 _2,276.8 135' +65 1,000' -6 +8,000 -'-1ç,n00 . 32-W 2,296.3 115' •+76 800' -12 -- +8,000 +11,000 2,300.8 140' -99 700' -26 - 0 0 2,303.7 135' -113 800' -39 0 0 ' 2,313.8 120' -137 450' -50 500' 0 0 2,316.0 140' -129- 500' -41 - 0 0
33-E 2,318.6 135' -71 900' -41 1,000' +3,000 +2,500 2,324.0 135' -145 1,200' -57 1,000' 0 0 2,337.3 135' -144 900' -58 800' 0 0 2,341.8 130'. -176 1,100' -71 850' - 0 0 2,347.3 115' +85 1,000' +8,000 +7,500
34-W 2,373.0 140' +100 850' +8 1,000' +8;000 +11,000 2,385.9 '125' -200 800' -68 550' 0 0 2,387.8 135' -188 700' -42 500' 0 0
Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION.OF Page 47 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response _. Line Fiducial Altitude In-Phase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
34-W 2397.4 155' -68 800' -26 750' +5,000 +5,000
35-E 2,402.1 125' p -61 1,200' -34- - +7,000 +7,000 2,406.0 135' +26 900' -2 900' +8,000 +8,000 2,414.5 130' -84 1,000' -8" 1,000' 0 0
2,418.6 115' -222 1,100' 462 1,100' 0 . 0 2,423.3 145' -163 1,100' -24 1,000' 0 0 2,426.2 135' -205 750' -49 800' +1,000 0 2,429.5 160' -106 650' -3 600' 0 0 2,432.3 140' -188 1,000' . -52 •1,000' 0 0 2,436.0 ' 140' +56 750' +7,000 +8,500 -
36-W 2,450.0 130' +84 700' -18 650' +8,000 +11,000 2,462.2 135' -159 1,100' -48 1,100' +1,000 +1,000 2,467.1 150' +4 500' +2 - 0 0 2,469.0 155' -7 450' -6 - +1,000 +1,000 2,473.0 155' +57 1,100' -9 _ +8,000 +8,506
37-E 2,487.4 125' +76 1,100' -11 800' +7,500 +8,500 2,494.1 145' 421 800' +2,000 +1,500 , 2,498.4 155' -115 4 1,100' -24 1,200' +1.,500 +1,000
I-...___ Table 1. COMPILATION OF DATA FOR QUALITATIVE INTERPRETATION OF Page *48 THE HELIPORTED MAGNETOMETER AND ELECTROMAGNETOMETER SURVEYS (1972)
SWAMPY BAY AREA (E.P. #556)
E.M. Response Magnetic Response Line Fiducial Altitude InyPhase Out-of-Phase Intensity in Gammas No. No. Feet P.P.M. Width in feet P.P.M. Width in feet Total Field Vertical Field
37-E 2,506.2 195' -33 500' '0 0 2,509.6 150' -77 1,000' -20 1,000' 0 0 2,512.6 135' +44 800' -10 +8,000 +11,000
38-W 2,536.8 145' +70 1,000' +5 +8,000 +11,000 2,547.3 135' -120 850' -28 900' +1,000 0 -2,554.0 155' +18 600' +5 500' +7,000 +7,300 2,557.3 155' +14 500' +4 450' +8,000 +9,000
39-E 2,568.0 140' +14 750.' +2 +7,000 +8,000 2,571.0 145' +12 700' +4 +4,000 +3,000 2,579.3. 145' -103 1,000' -66 1,000' 0 0 2,586.7 165' -5J 450' -15 500' 0 0 2,590.0 135' +62 700' -16 700' +8,000 +14,000 2,592.8 150' +14 600' +2 +2,000 +3,000 2,596.5 110' -59 900' -44 1,000 0 0
40-W 2,602.0 145' -29 600' -18 600' +1,000 +1,000 2,606.4 155' +39 1,200v +8,000 +15,000 2,614.3 135' -135 1,300' -44 1,100' 0 0 2,619.1 150' +24 900. +2 +4,000 +3,000 2,624.0 165' +13 700' +4 800' +5,500 +4,000
Table 2 PRIORITY ANOMALIES, BASED ON A.E.M., A.M. DATA Page .49
1972 - HELIPORTED ELECTROMAGNETIC AND MAGNETIC SURVEY.
SWAMPY BAY AREA
r Map Sheet No. Line No. Fiducial # In-Phase Out-of-Phase Mag. Anomaly Priority # Anomaly No. P.P.M...., P.P.M. Vertical Field 4
H-6 40W 2606.4 +39 0 15000 3A 19 41E 960.0 +87 -30 15000 2A 42W 937.3 +40 -11 16000 3A 43E 885.0 +49 -20 13000 3A 44W • 862.1 +60 -23 12000 3A 46W 782.5 +52 -14 11000 3A
G-6 39E 2590.0 +62 -16 14000 3A 38W 2536.8 +70 +5 11000 2A 37E . 2512.6 +44 -10 11000 3A 36W 2450.0 +84 -18 11000 2A 34W 2373.0 +100 +8 11000 lB 20 33E 2347.3 ' +85 0 8000 2B 32W 2296.3 +76 -12 11000 2A 31E 2276.8 +65 -6 . 15000 . 3A 30W 2185.3 +58 -11 15000 a" 3A
29E 2154.1 +110 -15 17000 lA 1 28W 2040.4 +78 -3 17000 2A 27E 2018.4 +81 -3 8000 2B
25E 1884.5 +47 -7 11000 3A 21 23E 1772.0 +61 -3 13000 3A , i
Table 2 PRIORITY ANOMALIES, BASED ON A.E.M., A.M. DATA Page 50 1972 - HELIPORTED ELECTROMAGNETIC AND MAGNETIC SURVEY SWAMPY BAY AREA
Map Sheet No. Line No. Fiducial # In-Phase Out-of-Phase Mag. Anomaly Priority # Anomaly No. P.P.M..... P.P.M. Vertical Field , . F-5 2W 846.2 +52 -18 11000 3A 22 3E 872.7 +85 +4 10000 1B 4W 913.1 +80 +4 13000 lA 5E 936.8 . +73 +4 15000 2A 5E 942.0 +71 +5 8500 2B 6W 985.0 +70 - -41 7500 2B 7E 1005.5 +80 16000 lA 8W 1055.0 +110 -14 15000 lA 9E 1075.0 +129 +2 16000 lA. 10W 1126.4 +56 -2 14000 3A 11E 1142.8 +64 +18 9500 3A
9E 1082 , +45 -4 6000 3B 23 lOW 1118.3 +118 -11 6000 1B 12W 1185.0 +60 -7 7000 3B G-5 13E 1220.8 +50 -7 8500 3B 14W 1252.3 +75 0 4000 2B • 16W 1325.4 +80 -10 6500 2B 24
,20W 1546.1 +73 -11 8500 2B 25 21E 1631.2 +49 -3 10000 3A
. '
Table 2 PRIORITY ANOMALIES, BASED ON A.E.M., A.M. DATA Page 51
1972 - HELIPORTED ELECTROMAGNETIC AND MAGNETIC SURVEY,
SWAMPY BAY AREA
Map Sheet No. Line No. Fiducial # In-Phase Out-of-Phase Mag. Anomaly Priority # Anomaly No. P.P.M....,.... P.P.M. ..Vertical Field , G-5 22W 1690.0 +66 -11 9500 3A 25 23E 1726.5 +35 -10 ` ' 7000 3B • 23E 1729.0 +62 -12 9000 3A . 24W 1800.0 +63 -10 12000 3A 25E 1843.2 +103 -26 9000 1B 26W 1948.8 +43 -9 ' 10000 3A 27E 1981.4 +37 -12 8090 . 3B . 28W 2076.3 +50 -11 9000 3A
13E 1211.2 +150 -4 18000 lA 26 14W 1261.0 +42 11000 3A
16W 1337.6 - +45 +4 14000 3A 27 17E 1358.0 +42 +2 13000 . 3A
.
, , •
r ~
Page 52 Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES
1973 AIRBORNE SURVEY Area: E.P. No. 554
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
-1 - . - - - - - No Anomalies.
AA-2 1 61 2131 +310 -6.3 5500 Mainly Magnetic Folded I.D. 2 57 1955 +240 - 5000 Folded I.F., Thin Band. 3 48 1497 +180 - 4500 Thick I.F. Band. '
AA-3 4 22 1563 + 80 -2.5 7500 Magnetic & Conductive Thick. I.F. Band '5 25 1788 + 25 -1.7 6000 Magnetic & Conductive Folded I.F. 6 31 374 +160 -0.2 3500 Good Conductor. Thin I.F. Band.
AA-4 7 18 127,7 + 40 -3.3 7000 Flat Dipping large I.F. Band. 8 9 602 +400 -3.3 12,500 Magnetic, Thin I.F. Band. 9 9 560 + 80 - 5500 Thin I.F. Band. 10 3 179 + 70 -1.3 9000 Magnetic & Conductive, Thin I.F. Band
•
Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES Page 53
1973 AIRBORNE SURVEY Area: E.P. No. 555
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
:I-3 . 114 1145 +320 -1.0 6000 Magnetic & Conductive 112 863 +300 - 5500 Flat lying I.F. Band. 2 109 1033 +180 -0.8 6000 do. 3 105 1233 +160 -2.0 5000 do.
I-4 4 99 1459 +200 -0.3 500 Highly Conductive and Permeable flat lying I.F..Band. . 5 87 1831 +280 -1.4 5000 6 80 84 +520 -0.2 4000 Highly Conductive I.F., Good Target. 7 76 340 +500 -1.0 3500 do.
I-5 8 77 2140 +150 -1.7 8000 Magnetic, Thin I.F. Band. 9 80 1928 +220 -8.6 10000 Magnetic, Narrow I.F. Band 76 2228 +220• -11.3 9560 do. 10 75 2291 '+120 -5.0 10000 Highly Magnetic Narrow I.F. Band. 11 68 3048 +340 -5.0. 10000 do. 12 65 2930 +240 -3.8 3000 Magnetic, Narrow I.F. Band. 13 65 2919 +400 -10.0 3000 do. 14 65 2904 +300 -12.2 6000 do.
Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES Page 54 1973 AIRBORNE SURVEY Area: E.P. No. 555
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
J-4 i5 68 687 +160 -5.0 3000 Magnetic, Narrow I.F. Band. 16 67 732 +145 -5.0 3000 Thin Magnetic I.F. Band. 17 58 1058 +220 -5.0 5000 do. 18 54 1182 +500 - 3500 do. 19 54 1198 +425 -8.5 3500 do. . 20 49 493.5 +185 -5.0 4500 do. 21 , 44 435 +220 -10.6 6000 do. . 22 ' 52 1324 . +110 -5.0 5000 do.
J-5 23 59 482 +200 - 1000 do. 24 63 133 +280 -0.1 2500 do. 25 62 233 +450 -4.8 5500 do. 26 , 63 111 +350 -0.2 5000 Thin Magnetic, I.F. Band. 61 280 +320 6000 27 40 1427 +285 - 8000 do. 42 1379 +160 -3.3 , 7Q00 do. 28 41 1403 +480 -3.3 6000 do.
J-6 29 53 951 +400 -7.4 7000 Thick Magnetic I.F. Band. 30 39 1484 +345 -5.0 6000 do. 17 40 1673 +145 - : 7000 do.
C,
I
Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES Page 55
1973 AIRBORNE SURVEY Area: E.P. No. 555
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
K.4 JA , 35 354 +240 -3.3 3000 Folded and faulted I.F. with 37 375.2 +200 -4.8 4500 large NRM Component. 33 43 435 +160 -12.8 1500 do. 32 44 443.8 +160 -3.3 5000 do.
K-5 35 37 1857 +460 -2.0 4000 Folded and faulted I.F. with large NRM Component. . 36 37 1863 +300 2500 do. 34 2205 +350 ' -2.5 4000 do. 37 30 4200 +280 -1.4 5000 do. 37-A 24 4930 +140 - 5000 do. ' 38 23 5076 +220 -5.0 5500 do. 39 24 4966 +140 . - 5000 do. 40 24 4988 +200 . -5.0 5000 do. 41 26 4634 +240 -3.3 4500 do. 42 34 69 +240 -6.5 3500 do. 43 36 363.5 +260 -5.0. 3000 do.
Table 3. ASSESSMENT OF A'.E.M. AND A.M. ANOMALIES Page 56
1973 AIRBORNE SURVEY Area: E.P. No. 555
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
I ri-b 44 . 37 1891 +240 - 2000 High NRM Component? 45 36 1969 +360 - 4000 do. 46 36 1983 +280. -3.3 -50.0 do. 47 37 1879 +220 -2.5 1000 do. . 48 33 2280 +420 -3.3 0 do. 49 33 2291 +230 -3.3 1000 •do. .
L-5 5'0 12 791 +220 -3.8 5000 NRM Component? highly folded and . faulted thin band. 51 ' 11 852 +220 -5.0 3000 do. I 52 9 1174 +180 - 4000 do.
h L-6 I 53 7 1073 +185 -3.6 7000 do.
•
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Page 57 Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES
1973 AIRBORNE SURVEY Area: E.P. No. 556
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity
H-6 13 ' 24 689 +110 -1.7 9000 Thin magnetic I.F. Band. 14 19 983 +260 -7.8 7000 Thin I.F. Band - synclinal structure.
F-6 ------No anomalies of interest.
F-5 15 1 17 +410 -1.1 15000 I.F. Band anticlinal structure.
E-6 16 1' 1788 +120 -6.0 6500 Thin I.F. Band on NE flank of a plunging anticline to SE. 17 3 1713 +140 - 13000 Thin I.F. Band on SW flank of plunging anticline to SE. 18 13 1238 +110 = — 16000 Definitely due to large NRM Component. 15 1143. +100 '2.1 15000 (MK. SEGUIN).
, •
Page 58 Table 3. ASSESSMENT OF A.E.M. AND A.M. ANOMALIES 1973 AIRBORNE SURVEY Area: E.P. No. 556
Map Anomaly Line Fiducial E.M. Response Mag. Total Sheet No. No. No. Real (P.P.M.) Real/Imag. Residual General Remarks Ratio Intensity I-6 1 12 1258 +220 -3.3 5000 Highly magnetic, Thin I.F. Band 2 7 1431.5 +165 -2.5 9000 do. t 1-7 ------No Anomalies.
H-7 3 29 279 +260 -1.7 Missing Broad I.F. Synclinal Structure- Highly magnetic. • 4 21 530 +220 -2.0 do. do. 5 19 640 +260 -7.2 do. •do. 6 16 792 +280 . -5.0 do. do. 7 16 780 +140 -5.0 do. do. 8 22 . 478 +185 -5.0 do. Narrow Synclinal structure in I.F. 9 31 109 +185 - do. do. 10 14 883 +160 -3.3 do, Broad synclinal structure in I.F.
H-6 11 38 68 +210 -. 6000 Thin Magnetic I.F. Band. 12 27 544 120 - 10000 I.F. Band in anticlinal structure. • The quality of the data recorded with the fluxgate magnetometer is not ideal for the following reasons:
1. The sensor unit was mounted directly on the
helicopter and not in the bird.
2. The magnetometer measures the vertical component
of the field and not the total magnetic field,
thus necessitating additional corrections for the
pitch and roll of the helicopter.
3. The average flying height of the fluxgate
magnetometer was approximately 200 feet above
the ground, while that of the proton magnetometer
was approximately 135 feet. A correction factor
(the inverse square distance law) must be applied
to the fluxgate magnetometer readings to compare
them with the proton magnetometer readings.
V.L.F. and A.E.M. Units
The V.L.F. survey data coincided more or less with the data obtained from the vertical coaxial A.E.M. unit but the number of anomalies s reduced. Hence no separate interpretation of the V.L.F. survey results is made in this report.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 11
TECHNICAL SER'JICES 3.1.3 Accuracy of the Instrumentation Used
Magnetometers
The data gathered with the proton precession magnetometer
are very accurate but the range of this instrument is insufficient to
obtain the maximum intensity values over magnetic iron formation bands.
The data obtained with the vertical component fluxgate magnetometer are
relatively inaccurate but cover a high range of magnetic intensity values.
It is recommended to make use of an airborne fluxgate magnetometer in
future surveys; the Gulf Mark III airborne fluxgate magnetometer has
proven to be very useful for similar surveys.
A.E.M. Units
The instrumentation used by Sander Geophysics was
not as sensitive as that of Lockwood Surveys Corporation used in 1971.
The difference of sensitivity is affected by the separation between the
transmitting and receiving coils. The separation for the Lockwood
system is 31 feet whereas it is only 23 feet for the Sander system. Since
the received signal varies as the inverse cube of the distance; the
signal ratio is only (23)3 / (31)3 =41%. Consequently, an instrumental noise threshold of 2 P.P.M. characterizing the Sander system corresponds
to 2/0.45 =4.4 P.P.M. in the Lockwood system. As the characteristic instrumental noise of thè Lockwood system is only 2 to 3 P.P.M., it
means that it is slightly superior to the one of Sander.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 12
TECHNICAL SERVICES V.L.F. Unit
The permeable and conductive bodies generally show
a signature which is different from that of the solely conductive bodies
with the V.L.F. unit. In the case of permeable (magnetic) bodies, the
reference coil records a decrease in the intensity and a positive leaf
followed by a negative leaf on the cross-over of the real component of
the vertical secondary field. In the case of the conductive bodies, the
reference coil records an increase in the intensity and a negative leaf
followed by a positive leaf on the cross-over of the real component of
the vertical secondary field. The decrease of the reference field intensity
in the presence of a permeable body indicates inverse polarity (instrumental)
since the intensity should increase in the presence of an amplifier like
a permeable body. The polarity is independent of the flight direction
as the primary reference coil has no prevalent polarity in the homogeneous
V.L.F. horizontal plane wave. It is surprising, however, to observe no
significant signal on the imaginary component of the vertical secondary
field. This would be expected for permeable bodies which are not
conductive, since no Foucault currents are present, and thus, no imaginary
component is produced. However, the iron formation bands in the Scheffer-
ville area contain a significant amount of magnetite and are poor to medium
conductors at a frequency of 1000 Hertz. They are thus likely to be medium
to good conductors at an emitting frequency of 18,000 Hertz and the fact
that no imaginary signature is observed is difficult to explain. In the pre-
sence of solely good conductive bodies like the Menihek Slate (which is a good
conductor at 1000 Hertz, the imaginary signature disappears leaving only a
real field component. In the Schefferville area the quadrature-real component
PROJEC'" REPORT NUM BER NUMBER 1975-7 PAGE 13
TECHNICAL SERVICES FORM - 1212.0E ratio over iron formation bands varies between 0 and 0.1 on the average.
One way to explain this characteristic is the following; the response of the real and imaginary components of the secondary field is diagnostic in regions where the parameter 0 = (opw )2
(R2 + x2)2 is small i.e. when 0 (apw )z R with R >>x. The EM response gets saturated when 0 becomes large, or in other words when the imaginary component becomes negligible and when the real component is large
(maximum). Consequently, the large V.L.F. response is due for the most part to the fact that x >>R. For instance, if R = 100m, the ratio of
=1.6 * 106 = 1.6 * 104, since x =1000 miles (1600 Km). This increase of the response by a factor of 104 is largely responsible for the large value of the real component and the small value of the quadrature.
In this case, the value of the real component is always negative and it is impossible to differentiate between a conductive and a permeable body.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 14
TECHNICAL SERVICES 3.2 1973 Airborne Survey
3.2.1 Description of the Instruments
- A Gulf Mark III Fluxgate Magnetometer measuring the total magnetic field with a precision of ± 1 gamma was mounted on the towed "Bird" of the helicopter.
- An electromagnetic system was mounted in the
"Bird" having the following specifications:
1. Horizontal coplanar coils with maximum coupling.
2. Coil separation slightly less than 23 feet.
3. Frequency of emission equal to 1,000 Hertz.
4. Measures the in-phase and out-of-phase components
of the induced electromagnetic field.
- V.L.F. - E.M. unit was not used for the 1973 airborne survey.
- A Bonzer Radar Altimeter to record the height of the helicopter above the ground surface.
- A continuous 16 mm strip camera to record the flight path.
3.2.2 Data Recording
The data generated and recorded are similar to the
1972 survey described earlier, except only the total magnetic field, the E.M. in-phase, out-of-phase traces and the altimeter trace are recorded on a single uniformly unrolling photo sensitive paper.
PROJECT REPORT NUMBER _ NUMBER 1975-7 PAGE 15
TECHNICAL SERVICES 3.2.3 Evaluation of th" Instruments
Evaluation of the A.E.M. unit used in this survey
is omitted because the equipment used here is the same as described
for the 1972 survey.
Magnetometer
The magnetic contour map was compiled from the data
obtained from the total field Gulf Mark III Fluxgate Magnetometer,
which has a very wide range and is well suited for this kind of work.
The operation of the instrument was not entirely satisfactory due to
the lag in the system in following the sharp turns made by the helicopter.
This problem was not serious since the survey lines were straight and
turning points only occurred beyond the surveyed area.
3.2.4 Accuracy of the Instrumentation Used
Magnetometer
The data gathered with the Gulf Mark III Fluxgate
Magnetometer are satisfactory. The precision of the instrument is
1 - 2 gammas, which is quite sufficient for this type of survey;
moreover the wide range of the unit helped to cover a high range
of magnetic intensity values in this area.
A.E.M. Unit
The A.E.M. unit used in this survey is the same
as the one used in 1972. The accuracy of this instrument has been
given earlier in this report.
PROJEC' REPORT NUMBER NUMBER 1975-7 PAGE 16
TECHNICAL SERV'tCES FORM - 1212-05
4.0 CHARACTERISTIC ELECTROMAGNETIC RESPONSE CURVES
4.1 Curves Response for Special Geometric Models
The E.M. response curves of the real and imaginary components of an A.E.M. system are dependent upon the geometry and the physical properties of the bodies causing the E.M. anomalies. Six situations illustrating the response of permeable and/or conductive bodies are presented:
PROJECT REPORT NUMBER NUMBER 1g75-7 PAGE 17
TECHNICAL SERVICES
A) Vertical Permeable Thick Sheet
REAL IMAGINARY
( dog)
B) Vertical Conductive Thick Sheet
IMAGINARY REAL
(cod
PROJECT REPORT NUMBER NUMBER [975-7 PAGE 18
TECHNICAL SERVICES
C) Vertical Conductive and Permeable Thick Sheet
REAL
------IMAGINARY
(0.1-10)
D) Horizontal Permeable Slab
REAL — IMAGINARY /////i ~ (d ' -_ 1~~z1 _ G
(clop.)
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 19
TECHNICAL SERVICES
E) Horizontal Conductive Slab
REAL
.,~ 4040 IMAGINARY .114 . '- --~ -- ~ • % //// • ( dot() // z
(01a1uo)
F) Horizontal Conductive and Permeable Slab
REAL • • IMAGINARY 1 , ; ‘` ~r✓ ~ • ( I ,' l ~ /d ~ ' , Z. _ ;,_
(doPo)
PROJEC",' REPORT NUM BEP NUMBER 1975-7 PAGE 20
TECHNICAL SERVICES
4.2 Effect of Frequency, Coil Separation, Height, Direction of
Flight and Magnetite Content on the EM Response Curves.
The frequency of emission affects the EM response; low
frequencies emphasize the permeability while higher frequencies emphasize
the conductivity of permeable and conductive bodies. A larger coil
separation allows the reception of a larger signal, but on the other hand
too large a separation increases the instrumental noise to a large amount,
so that for all practical purposes one must compromise and a separation of
8 to 10 metres appears to be satisfactory. The detected A.E.M. signal is
affected to a great extent by the height and direction of flight; flight
directions at 90° to the geological strike improved the received signal.
The flight height is a more important factor; the survey must be flown as
close as possible to the ground and height above ground should be known as
accurately as possible. The EM response curves are obviously dependent on
two physical properties, the electrical conductivity and the magnetic
permeability. Both properties are dependent on the magnetite content; the
higher the magnetite content, the larger the A.E.M. signal.
4.3 Permeability and Conductivity
A permeable non-conducting body creates an in-phase EM
anomaly in the direction of the primary field; no out-of-phase component
is produced.
A non-permeable conducting body creates an in-phase EM anomaly
in oposite direction to the primary field; an out-of-phase component is
then present.
PROJECT REPORT NUMBER NUMBER L9/5-7 PAGE 21
TECHNICAL SERV' CES FORM - 1212-OS In the 1972 survey, the iron formations are conductive only
on a few lines and the intensity of the quadrature response is not large
suggesting the presence of a poor conductor. Consequently, for all
practical purposes, the conductive property does not affect the in-phase
EM response significantly.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 22
TECHNICAL SERWCES FORM - 1212-05 5.0 PRESENTATION OF THE SURVEY DATA
5.1 1972 Survey
The magnetic, EM and the V.L.F. data were plotted and con- toured separately on base maps at a horizontal scale of 1" : 1000' using the I.O.C.C. standard grid; the flight lines and the fiducial numbers were also indicated. The magnetic data are presented as contours of the earth's relative magnetic intensity both in total and vertical fields.
The contour interval for the total field is 500 gammas, while for the vertical field, it is 1000 gammas.
The electromagnetic data are presented as the contours of the amplitude of the electromagnetic response of the in-phase component of the secondary field in units of 20 parts per million, measured above and below an assumed datum level. At the peak of the in-phase component, the value of the coincident point of the electromagnetic response of the out-of-phase component is indicated within a circle.
The V.L.F. electromagnetic data, are presented in another set of maps as contours of the horizontal derivatives of the in-phase component, at a basic contour interval of 2 units. (27/100') The base maps covering the entire surveyed area are, F-5, F-6, G-5, G-6 and H-6 at a horizontal scale of 1'1 =1000'.
PROJECT REPORT 1975-7 NUMBER NUMBER PAGE 23
TECHNICAL SERVICES 5.2 1973 Survey
Presentation of the survey data is similar to that of the 1972 survey. During this survey only the relative intensity of the total earth's magnetic field was measured and contoured. The base maps at a horizontal scale of 1": 1000', covering the surveyed area are listed below.
E.P. Area No. 554: AA-1, AA-2, AA-3, AA-4.
E.P. Area No. 555: H-3, H-4, I-4, I-5, J-4, J-5, J-6,
K-4, K-5, K-6, L-5, L-6.
E.P. Area No. 556: E-6, F-5, F-6, H-6, H-7, I-6, I-7.
PROJECT REPORT NUMBER NUMBER 3975-7 PAGE 24
TECHNICAL SERVICES 6.0 INTERPRETATION PROCEDURES
It is M. K. Seguin's opinion that one can make a fully
quantitative interpretation of the heliported electromagnetic data obtained
through surveying of magnetic iron formations. This statement is, however,
not widely accepted by the geophysical and geological community at large
at this moment. Lack of varied model studies and the effect of conductivity,
(of a conductive and permeable body) over the in-phase response which is
not fully evaluated at present, are cited as examples in favour of their
argument against a fully quantitative interpretation. A fully quantitative
interpretation of the airborne magnetic results is also impossible, since no
complete Natural Remanent Magnetism study had been done in these areas.
Hence only a qualitative interpretation of the A.E.M. and A.M. data of the
1972 and 1973 airborne surveys are made. The interpretation of the two survey
results are given separately.
6.1 Qualitative Interpretation of the 1972 Airborne Survey Results
All the survey data generated were carefully studied and
numerically compiled in table form. (Table 1.) This table summarizes
all the data (except V.L.F. - E.M.) obtained from the survey.
As the amplitude of the positive in-phase response reflects
the susceptibility-thickness product Kt, it was decided to establish the
relationship existing between the positive in-phase E.M. response and the
magnetic intensity (vertical field). Hence all the positive in-phase
responses above 30 P.P.M. are tabulated along with the corresponding
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 25
TECHNICAL. SERVICES FORM - 1212-05 out-of-phase values and vertical magnetic intensity values (Table 2).
This table was then used to grade the anomalies according to their priorities. Priorities were established for those anomalies on the following basis:
In-Phase Out-of-Phase Relative Mag. Priority No. P.P.M. P.P.M. Intensity Vertical (Gammas)
lA ->+80 +5 to -15 >13,000
1B >+80 +5 to -30 > 6,000
2A >+60 +5 to -30 -10,000>
2B >+60 +5 to -45 > 4,000
3A ->+31 +8 to -30 > 9,000
3B >+31 +8 to -35 > 3,500
Anomalies occurring together are grouped and their dimensions are outlined in the A.E.M. contour maps.
6.2 Results
Two distinct groups of anomalies are noticed corresponding to the two iron formation bands, one northeast of Keough Lake with a northwest trend and the other southwest of Lac Therese, which is folded with its fold axis in a northwest trend.
PROJECT REPORT NUMBER NUMBER 1975-7 PAGE 26
TECHNICAL SERVICES
6.2.1 Keough Lake Band
Three prominant electromagnetic and magnetic anomalies are outlined in this narrow steeply dipping iron formation band. Anomaly
No. 19, shows groups of 4 -"2A" and 5-"3A" grade anomalies.
Anomaly No. 20 shows 1 - "lA" and one "lB" grade anomaly and 2 - "2A", "2B" and "3A" grade anomalies. Anomaly No. 21 shows 2-413A" grade anomalies.
Among the three anomalies, Anomaly No. 20 is more interesting, as it shows high intensity response in both E.M. and mag.
Even though this band is narrow, the presence of high grade anomalies, makes it sufficiently interesting for further detailed ground work.
6.2.2 Lac Therese Band
Six groups of anomalies outline this iron formation band. Anomalies of high magnetic and electromagnetic intensity occur close to the southeastern end of the band, which constitutes Anomaly No. 22.
This anomaly is more interesting than Anomalies, 23 to 27 which appear to be mostly due to thin iron formation bands. In this area Anomaly No. 22 warrants further investigation.
PROJECT REPORT NUMBER _ NUMBER 1975-7 PAGE 27
TECHNICAL SERVICES