GM 46677 GEOPHYSICAL OVERVIEW OF THE AERODAT AIRBORNE GEOPHYSICAL SURVEY ON THE MCIVOR LAKE PROPERTY 'MMietin de Meryl" it des BeuQnrap 110 Service de Is Oéolnformatlon Ode i5 JINN 1988 No GAL 4.6677
L GEOPHYSICAL OVERVIEW
OF THE
AERODAT AIRBORNE GEOPHYSICAL SURVEY
ON THE
MACIVOR LAKE PROPERTY
FOR
SHEAR EXPLORATION LIMITED
R.J. Meikle Exsics Exploration Ltd April 22, 1988 TABLE OF CONTENTS
Page INTRODUCTION 1
AIRBORNE SURVEY 1
SUMMARY AND RECOMMENDATIONS 3
LIST OF MAPS
Map #1 Interpretation Map #2 Calculated Vertical Magnetic Gradient Map #3 VLF-EM Total Field Contours Map #4 Total Field Magnetic Contours Map #5 Calculated Vertical Magnetic Gradient Contours. & Colours
APPENDICES
Appendix A Geophysical Report on Caber Project Aerodat survey INTRODUCTION
The writer has been contracted to review and assess a recent airborne Mag, VLF and HEM Survey flown by Aerodat over a 165 claim group lotted in Daniel Township, Quebec. Claim status, location etc., has been dealt with in a report by R.E. Norman,
Feb 10, 1988.
This brief report deals specifically with the results of the airborne survey and the correlation with the limited amount of previous work done on the property. Technical specifications for the airborne survey are included. They are taken from a report on a larger survey of which the Maclvor Lake Property comprises a part of the eastern block.
AIRBORNE SURVEY
The airborne results show several interesting features. The most noteable is a NE trending diabase dike which is well defined on the Total Field magnetometer map as well as the vertical gradient map. From the government map M306 it is evident that there are numerous copper and zinc showings on or in close proximity to the dike, northeast of the property. the structural significance of this intrusive is not known at this time.
- 1 - However, there is an offset in the centre of Maclvor Lake. This offset would support the possibility of a NW structural fault which would correlate with:
1. A pronounced NW straight NE shoreline of Macivor Lake.
2. A NW flexture in the western tributary of the Allard
River and a NW trending bay to the SE on the main river
course.
3. There is a coincident NW trending resistivity low shown
on the Aerodat calculated apparent resistivity contoured
map.
4. Fourth, but probably the most important; this proposed
structure is parallel to and west of a major NW fault
shown on government maps. This feature forms the south-
western flank of a felsic unit to the SW on which there
are several mines in close proximity to this
felsic/mafic volcanic contact, the Matagami Mine being
one of the larger ones. This NW structure continues to
the NW through the Allard River, Wabassi Lake and the
Gouault River. The current Aerodat survey covers a
portion of this structure and shows a coincident NW
trending resistivity low.
Only the Calculated Vertical Magnetic Gradient Map is
available to the author. This map does not show any
clear evidence to support the NW fault.
- 2 - There are several airborne EM anomalies mainly clustered around the east and SE shore of Maclvor Lake. From the compilation files it appears that there is a felsic unit between
Maclvor Lake and Wabassi Lake. This felsic unit was encountered in two drill holes. It should be stressed that this work was carried out in the late 1950's and early 1960's. The geophysical work appears to have consisted of Vertical Loop Surveys. Also, the thrust of their early exploration programs was base metal orientated. It appears that favourable gold-bearing geology was not recognized and gold assays were not commonly run.
Other than the aforementioned structural features, the
Airborne Survey suggest that the geology consists of interbedded volcanics striking EW to northeasterly. This being the case, the stratigraphy which hosts the New Hosco Mine, 4 km to the east would continue on to the property.
SUMMARY AND RECOMMENDATIONS
The property is well situated geologically and has a very limited smount of work done on it. The NW structures described appear to be economically important on a regional scale. The NW structure in the vicinity of the Matagami Lake Mine cari be extrapolated northwestward through Daniel Twp., La Gauc:hetiere
Twp., Grasset Twp., Subercase Twp., and Caumont Twp., using surface topographical expressions. Also, there are numerous gold showing along this structure in each township.
- 3 A favourable place to concentrate exploration efforts would be the intersection of this NW structure with other structures such as the diabase dike on Macivor Lake.
The following recommendations are based on a compilation of the available Aerodat Maps, Government Maps and Compilation Maps.
1. A grid should be cut to cover the entire property. The baseline should be orientated at 090 degrees TN with cross lines at an azimuth of 180 degrees TN at a spacing of 100 meters. This would seem to be the optimum direction to couple with the different structures described in this report.
2. A detailed magnetometer survey should be carried out on the entire grid at a 12.5 meter spacing utilizing a recording base station.
3. A two station VLF-EM survey should be conducted on the entire grid utilizing Cutler Maine and Anapolis Maryland.
4. The entire grid should be mapped in detail.
5. A "Gradient Array" IP survey should be carried out to cou»»+ the more interesting geological areas of the grid and any important anomalies located by the Mag/VLF survey.
Yours truly,
R.J. Meikle
Exsics Exploration Ltd
- 4 APPENDIX A.
The following data is taken from a report entitled
"Geophysical Report on Caber Project Aerodat Survey" by
R.J. de Carle, Nov 25, 1987. The full report is not available
because it covers both the Shear Exploration property as well as
Newmont Exploration of Canada Ltd's property.
2 - 1
2. SURVEY AREA LOCATION
The survey area is depicted on the index map as shown. It is centred at Latitude 49 degrees 47 minutes north, Longitude 78 degrees 00 minutes west, approximately 27 kilometres west-northwest of Matagami, Quebec, (NTS Reference Map No. 32E/16 and 32F/13) . The eastern portion of the survey block is in the confines of Lac Macivor while the western portion is in the proximity of Riviere Subercase. The area is accessible by helicopter or float plane from the Town of Matagami.
The terrain is generally flat, with elevations in the order of 850 feet above sea level. Two large hills, located to the southwest of Lac Macivor, are approximately 1150 feet high.
78°00'
Lac La Coucheliiri
Lae t41PPP, ~au Rat ouauil ra446 Lac Lac < y 5 Alacivor ô Warm ~!^
~_~_...~~~.. 4 49°45' ► ~ d +~, r ~i ~ h
, \ç.0
—19 ti~ l 3 - 1 3. AIRCRAFT AND EQUIPMENT
3.1 Aircraft An Aerospatiale A-Star 350D helicopter, (C-GJIX), owned and operated by Ranger Helicopters Limited, was used for the survey. Installation of the geophysical and ancillary equipment was carried out by Aerodat. The survey aircraft was flown at a mean terrain clearance of 60 metres.
3.2 Equipment 3.2.1 Electromagnetic System The electromagnetic system was an Aerodat 3-frequency system. Two vertical coaxial coil pairs were operated at 935 Hz and 4600 Hz and a horizontal coplanar coil pair at 4175 Hz. The transmitter-receiver separation was 7 metres. Inphase and quadrature signals were measured simultaneously for the 3 frequencies with a time constant of 0.1 seconds. The electromagnetic bird was towed 30 metres below the helicopter.
3.2.2 VLF-EM System The transmitters monitored were NLK, Jim Creek, Washington, broadcasting at 24.8 KHz for the Line Station and NAA, Cutler, Maine, broadcasting at 24.0 kHz for the Orthogonal station. 3 - 2
3.2.3 Magnetometer The magnetometer employed a Scintrex Model VIW-2321 H8 cesium, optically pumped magnetometer sensor. The sensitivity of this instrument was 0.1 nanoTeslas at a 0.2 second sampling rate. The sensor was towed in a bird 12 metres below the helicopter.
3.2.4 Magnetic Base Station An IFG- 2 proton precession magnetometer was operated at the base of operations to record diurnal variations of the earth's magnetic field. The clock of the base station was synchronized with that of the airborne system to facilitate later correlation.
3.2.5 Radar Altimeter
A King Air radar altimeter was used to record terrain clearance. The output from the instrument is a linear function of altitude for maximum accuracy.
3.2.6 Tracking Camera
A Sony video tracking camera was used to record flight
path on VHS video tape. The camera was opèrated in continuous mode. Fiducial numbers and time reference marks, for cross reference to the analog and digital data, were encoded on the tape.
3.2.7 Analog Recorder An RMS dot-matrix recorder was used to display the data during the survey. In addition to manual and time fiducials, the following data were recorded:
Channel Input Scale CX11 Low Frequency Inphase 2.0 ppm/mm CXQ1 Low Frequency Quadrature 2.0 ppm/mm CX12 High Frequency Inphase 2.0 ppm/mm CXQ2 High Frequency Quadrature 2.0 ppm/mm CPI1 Mid Frequency Inphase 8.0 ppm/mm CPQ1 Mid Frequency Quadrature 13.0 ppm/mm VLT VLF-EM Total Field, Line 2.5%/mm VLQ VLF-EM Quadrature, Line 2.5%/mm VOT VLF-EM Total Field, Ortho 2.5%/mm VOQ VLF-EM Quadrature, Ortho 2.5%/mm ALT Altimeter 10 ft/mm MAGF Magnetometer, fine' 2.5 nT/mm MAGC Magnetometer, coarse 25 nT/mm MAGN Magnetometer, noise 0.025 nT/mm 3 - 4
3.2.8 Digital Recorder
A DGR 33 data system recorded the survey on magnetic
tape. Information recorded was as follows:
Equipment Recording Interval
EM system 0.1 seconds
VLF-EM 0.5 seconds
Magnetometer 0.2 seconds
Altimeter 0.5 seconds
Nav System 1.0 seconds
Positional information was recorded at 1.0 second
intervals on a DAC/NAV I. 4 - 1
4. DATA PRESENTATION
4.1 Base Map
A topographic base at a scale of 1:10,000 was prepared from an
enlargement of a 1:50,000 topographic map.
4.2 Flight Path Map
The flight path for all blocks was derived from the Mini-
Ranger radar positioning system. The distance from the
helicopter to two established reference locations was measured
several times per second and the position of the helicopter
calculated by triangulation. It is estimated that the flight
path is generally accurate to about 10 metres with respect to
the topographic detail of the base map.
The flight path map showing all flight lines, are presented on
a Cronaflex copy of the topographic base map, with camera
frame and navigator's manual fiducials for cross reference to
both the analog and digital data.
4.3 Airborne Electromagnetic Survey Interpretation Map
The electromagnetic data were recorded digitally at a sample
rate of 10 per second with a time constant of 0.1 seconds. A
two stage digital filtering process was carried out to reject
major sferic events and to reduce system noise. 4 - 2
Local sferic activity can produce sharp, large amplitude events that cannot be removed by conventional filtering procedures. Smoothing or stacking will reduce their amplitude but leave a broader residual response that can be confused with geological phenomena. To avoid this possibility, a computer algorithm searches out and rejects the major sferic events.
The signal to noise ratio was further enhanced by the ap- plication of a low pass digital filter. It has zero phase shift which prevents any lag or peak displacement from occur- ring, and it suppresses only variations with a wavelength less than about 0.25 seconds. This low effective time constant permits maximum profile shape resolution.
Following the filtering process, a base level correction was made. The correction applied is a linear function of time that ensures the corrected amplitude of the various inphase and quadrature components is zero when no conductive or permeable source is present. The filtered and levelled data were used in. the interpretation of the electromagnetics.
An interpretation map was prepared showing peak locations of anomalies and conductivity thickness ranges along with the 4 - 3
Inphase amplitudes (computed from the 4600 Hz coaxial re- sponse) and conductor axes. The anomalous responses of the three coil configurations along with the interpreted conductor axes were plotted on a Cronaflex copy of the topographic base map.
4.4 Total Field Magnetic Contours The aeromagnetic data were corrected for diurnal variations by adjustment with the digitally recorded base station magnetic values. No correction for regional variation was applied. The corrected profile data were interpolated onto a regular grid at a 25 metre true scale interval using a cubic spline technique. The grid provided the basis for threading the presented contours at a 5 nanoTesla interval.
The contoured aeromagnetic data have been presented on a Cronaflex copy of the topographic base map.
4.5 Vertical Magnetic Gradient Contours The vertical magnetic gradient was calculated from the gridded total field magnetic data. Contoured at a 1 nT/m interval, the gradient data were presented on a Cronaflex'-copy of the topographic base map. 4 - 4
4.6 Apparent Resistivity Contours The electromagnetic information was processed to yield a map of the apparent resistivity of the ground.
The approach taken in computing apparent resistivity was to assume a model of a 200 metre thick conductive layer (i.e., effectively a half space) over a resistive bedrock. The computer then generated, from nomograms for this model, the resistivity that would be consistent with the bird elevation and recorded amplitude for the 4600 Hz coaxial frequency pair used. The apparent resistivity profile data were interpolated onto a regular grid at a 20 metres true scale interval using a cubic spline technique.
The contoured apparent resistivity data were presented on a Cronaflex copy of the topographic base map with the flight path.
4.7 VLF-EM Total Field Contours The VLF-EM signals from NLK, Jim Creek, Washington, broad- casting at 24.8 kHz were compiled. The VLF data were compiled in contour map form , and presented on a Cronaflex copy of the topographic base map. 5 - 4
The northwest trending magnetic feature located towards the southwest corner of Map 4 is thought to be related to the same ultramafic unit as discussed in Map 3. Similar rocks are thought to exist towards the northeast corner of Map 4.
Most, if not all, of the lower magnetic intensity areas within Map 4 are thought to be related to felsic intrusives.
The east-northeast trending magnetic features within Map 5 are thought to be related to interbedding of metavolcanic and metasedimentary horizons. Towards the southeast corner of the map sheet, the circular features could be ultramafic or mafic intrusives. The smaller, circular magnetic features within the lower intensity magnetic area could be related to the same rock type.
The previously mentioned northeasterly trending diabase dyke strikes across Map 6 and continues well beyond the northeast corner of the survey area. Note the middle section of the dyke which displays a much lower magnetic intensity. The writer does not have an explanation for this phenomenon. The magnetic susceptibility is obviously quite different in this area. 5 - 5
Otherwise, the lithology tends to be east-west. The Lower magnetic intensity areas may be related to felsic intrusives, however, for some of the more obvious magnetic trends, metavolcanics may be the rock type. In referring to Map 6, note the relationship of the former New Hosco Mines (off the east survey boundary) to the magnetics. It is generally an area of low magnetic intensity.
5.3. Vertical Gradient Magnetics Towards the western portion of the survey area (Map 1), the computation of the vertical magnetic gradient has clearly shown a rather low magnetic intensity environment which, for the most part, tends to be striking in an east-west direction. Evidence of folding and faulting suggests structural changes
within the lithogical setting.
Structural events have also played a major role in the
geological setting of Map 2. The east-west mafic volcanic horizons towards the northern quarter of the map sheet with boundaries or contacts with the possible metasedimentary rocks are clearly defined. The mafic rock unit is estimated to be approximately 250 metres thick. APPENDIX III CERTIFICATE OF QUALIFICATIONS
I, ROBERT J. DE CARLE, certify that: -
1. I hold a B. A. Sc. in Applied Geophysics with a minor in geology from Michigan Technological University, having graduated in 1970. 2. I reside at 28 Westview Crescent in the town of Palgrave, Ontario. 3. I have been continuously engaged in both professional and managerial roles in the minerals industry in Canada and abroad for the past eighteen years. 4. I have been an active member of the Society of Exploration Geophysicists since 1967 and hold memberships on other professional societies involved in the minerals extraction and exploration industry. 5. The accompanying'report was prepared from information pub- lished by government agencies, materials supplied by Newmont Exploration of Canada Limited and from a review of the proprietary airborne geophysical survey flown by Aerodat Limited for Newmont Exploration of Canada Limited. I have not personally visited the property. 6. I have no interest, direct or indirect, in the property described nor do I hold securities in Newmont Exploration of Canada Limited.
Signed,
Palgrave, Ontario Robert J. de Carle November 25, 1987 Consulting Geophysicist REFERENCES
1. Government du Quebec-Carte Provisoire-ET-8508
2. Cites Mineraux du Quebec-Feuille Lac Waswanipi-32 F
3. North Abitibe Mineral Area-MPH Consulting Limited
4. Aerodat Report on Caber Project Airborne Survey-
R.3. de Carle, Nove 25, 1987
5. Preliminary Mineral Assessment Report on the Lac Maclvor
Property, Quebec-R.E. Norman, MSc., Feb 10, 1988