Fox 2-Record No. 2524

Transcription

1 F HELICOPTER E.M. AND MAGNETOMETER SURVEY OVER THE FOX CLAIMS, OMINECA MINING DISTRICT BRITISH COLUMBIA ON BEHALF OF OWNER MR. MIKE BOYLE Claims: Fox l-record No Fox 2-Record No Location 126' 22' W Longitude 57' 6.5 kilometers north of the confluence of the Finlay and Obo Rivers. December 10, 1980 Vancouver, British Columbia Apex Airborne Surveys Ltd. Ronald F. Sheldrake, B.Sc.

2 TABLE OF CONTENTS Page No. 1. INTRODUCTION LOCATION AND ACCESS GEOLOGY 2. DATA PRESENTATION GEOPHYSICAL RESPONSES DISCUSSION OF RESULTS 4-1, 5. CONCLUSIONS AND RECOMMENDATIONS SUMMARY 6-1 FIGURE I - CLAIM LOCATION MAP - FOLLOWS TABLE OF CONTENTS PLATE I - E.M. AND MAGNETIC ANOMALY MAP - IN MAP POCKET (shows claim location) APPENDIX I - INSTRUMENTATION * APPENDIX II - FLIGHT CHART - IN MAP POCKET CERTIFICATION - FOLLOWS APPENDICES c P '.4 BIBLIOGRAPHY - FOLLOWS APPENDICES STATEMENT OF COSTS - FOLLOWS APPENDICES

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4 c INTRODUCTION This report describes the results of a combined helicopter borne magnetic and electromagnetic survey flown over five test traverses on the Fox Claims. The purpose of the survey was to test if the mineralization reported in the area was responsive to geophysical techniques., The five test traverses totalled 3.5 kilometers over terrain ranging from 1,300 to 1,950 meters in elevation. A Bell 206 B helicopter, supplied by Northern Mountain Helicopters, was used for the survey. Aircraft positioning was controlled from a 1:10,000 topographical map. Terrain clearance of meters for the e.m. sensor was maintained where possible and monitored with a radar altimeter.

5 1-2 The Geonics 33-1 Electromagnetometer is a solid state system especially designed for helicopter transport. It consists of two coaxial coils, one serving as a transmitter and the other as a receiver, which are mounted 6 meters apart, in a rigid "bird" with their axes horizontal and in the direction of flight. The bird is towed 30 meters below the helicopter by means of a suitable cable which also carries the electrical signals 'md power to and from the bird. The system operates at 918 hertz. Changes in the alternating magnetic field at the receiver coil, caused by eddy currents in.the subsurface rock, are recorded. These changes are expressed in ratios of the normal undistorted primary field. They are so small as to be expressed in parts per million or p.p.m. The magnetometer used on this survey was a Geometries 803. It is a total field nuclear precession instrument which measures the magnetic field strength with a sensitivity of one gamma. The sensor is torczidal and is positioned half way between the helicopter and the E.M bird. Appendix I gives details of the geophysical equipment used for this survey.

6 1-3 LOCATION AND ACCESS The Two Fox claims each contain 10 units for a total of 20 units, are located in the Ornineca Mining Division at latitude 57' 43' N, longitude 125' 22' Won N.T.S. sheet 94E/9. The claims are 490 km NNW of Prince George, B.C., and 45 Km WNW of Ware, the nearest settlement. They are in the Ruby Range and are located 6.5 kilometers north of the confluence of the Finlay and Obo Rivers. Access to the claims was by helicopter based at Mackenzie, B.C.

7 c 1-4 GEOLOGY The regional geology consists of a northwesterly trending belt of Cambrian and Ordovician Kechika Group of limestone, phyllite and calcareous shale, and Lower Cambrian Atan Group of limestone, siltstone, dolomite, quartzite, shale, sandstone and conglomerate.

8 DATA PRESENTATION Plate 1 at a scale of 1:25,000 shows the position of the traverses (flight lines) and displays the location of the anomalies. The details of each anomaly are listed on the map sheet. A copy of the analogue chart that was acquired during the survey is included with this report. (see map pocket)

9 c GEOPHYSICAL RESPONSES Both magnetic and Electromagnetic Maps can reveal areas underlain by different rock types and lineaments which could indicate fault zones. Magnetic maps can reveal the location of orebodies which contain higher percentages of magnetite or pyrrhotite than the surrounding rocks. Conductivity thickness is the "parameter-pair" measured with the electromagnetometer. Materials which conduct electronically, metallic sulphides and graphite, have higher conductivity-thickness values than electrolytic conductors such as clays (in overburden) and ion rich rivers or lakes, however there is considerable overlap. The electromagnetic responses encountered by an electromagnetic survey are of four main types.

10 Bedrock conductors: including formational graphitic responses and massive sulphides targets. 2. Surficial conductors: overburden and lake responses. 3. A combination of 1 and 2: When a conductive material overlays a bedrock conductor the response due to the bedrock layer is superimposed on the response of the overburden or ldke response. Depending upon the conductivity contrasts, and the thickness of the overburden, some bedrock conductors can be recognized through the surficial layer. 4. "Negativerr magnetic effects: When conductors are also magnetic the electromagnetic responses can become distorted. The distortion tends to decrease the inphase response, often reversing the sign of the E.M. anomaly. Apparent depths and conductivity-thickness products, in this case, are generally not representative.

11 4-1 DISCUSSIONS OF RESULTS The geophysical survey has revealed electromagnetic anomalies on two of the five traverses flown. (see Plate 1) Although the data is limited in its coverage, the anomalies suggest that there are two subparallel conductors that &e in close proximity to the mineraliztion reported to outcrop along the ridge.* The anomalies on L2 are the most interesting from an exploration point of view for they indicate conductive targets coincident and contiguous with a magnetic response; a significant characteristic since it may indicate that metallic sulphides give rise to the responses rather than graphitic rocks. The magnetic anomaly is evident on L3 and L4 as well. *personal communication/mr. Mike Boyle.

12 5-1 CONCLUSIONS AND RECOMMENDATIONS Tine survey has revealed anomalies that provide a target for massive sulphide mineralization. Although the responses indicate only moderate conductances the proximity of surface mineralization and the coincidence of the magnetic response gives these anomalies added priority. It is recommended that a combined ground magnetometer and E.M. survey (horizontal loop, 1,000 hertz) be undetaken to delineate the extent of the magnetic and conductive rocks. A drill target ought to be identifiable from that data.

13 6-1 SUMMARY The geophysical survey was successful in identifying magnetic and electromagnetic responses in the area of the known minderalization. If the relationship between the reported mineralization and the geophysical response can be correlated, the survey data may indicate that the mineralization could extend for several hundred meters either side of L2., Respect fully submitted APEX AIRBORNE SURVEYS LTD. c "b

14 APPENDIX I INSTRUMENTATION Electromagnetic Instrument QPe: Helicopter mounted in-phase - quadrature instrument manufactured by Geonics Limited, Toronto, Ontario. Coils: The transmitting and receiving coils are co-axial 6 meters apart in a towed bird 30 meters below the helicopter. The coil axis is in the direction of travel. Frequency: 918 Hz Noise Level: Approximately 1/4 ppm (0.6 second time constant). Magnetometer Type: Proton precession model G803 manufactured by Geometries Corporation, Toronto. Cycling Time: 0.3 second. Sensing Head Design: 5 inch diameter Toroid.

15 APPENDIX I (Continued) Ancillary Equi pm ent : UDAS Digital Acquisition System with recorder. Geocam 35 mm Flight Path Camera Hoffman Radio Altimeter Geometries G806 Magnetic Base Station and recorder. Helicopter: Bell 206 B supplied by Northern Mountain Helicopters Ltd., Prince George, B.C.

16 I CERTIFICATION I, RONALD F. SHELDRAKE, of the City of Vancouver, Province of British Columbia, F hereby certify as follows: I r- 1. I am President of Apex Airborne Surveys'Ltd. a company incorporated under the laws of the Province of British Columbia. 2. The Vancouver Office of Apex Airborne Surveys Ltd. is located at Suite Howe Street, Vancouver, British Columbia. 3. I received by B.Sc., in geophysics from the University of British Columbia in May I have practised my profession since that date. 5. I did not examine the claims area, but I am not aware of any conflict and belikve that the data presented herein is reliable. 6. I have no interest, direct or indirect, in the mineral claims discussed in this report, nor do I expect to receive any. 7. I consent to the use of this report in or in connection with a prospectus or in a Statement of Material Facts..onbb. Sheldrag Geophysicist December 10, 1980

17 BIBLIOGRAPHY Geology G S C O.F. 483 Personal Communication Mr. Mike Boyle

18 ! P February 6, 1981 STATEMENT OF COSTS Type of Survey: Helicopter Electromagnetic and Magnetic Date(s) of Fieldwork: October 9, day Survey Kilometers: 3.5 kilometers Cost per linear kilometer: $ Additional Charges: Total cost of Survey: $2,500.00

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