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.