S2Je9NE*et2 CLAW LAKE

RECEIVED010 JUL 1 l 19/7

MINING LANDS SECTIO.V

A COMPARISON OF AN AIRBORNE

GAMMA-RAY SPECTROMETRY ANOMALY

WITH GROUND FOLLOW-UP SURVEY

RESULTS IN THE CLAW LAKE AREA

BARRIE F. JOSE

Queen's University, Kingston, Ontario. 1977.

a thesis submitted in partial fulfillment for the degree of B.Se. Honours, Geophysics.

ABSTRACT

The Geological Survey of Canada and Atonic Energy of Canada

Ltd. have produced a high sensitivity gamma-ray spectrometer for

airborne radiometric mapping of the Canadian Shield, Airborne

data collected with the system in northern Ontario during the

summer of 1975 indicated very anomalous values in the area off.

Claw Lake. A Oetailled ground study involving geological tapping

and ground scintillometer surveys within a group of 12 contiguous

claims was compared with the airborne profiles and contour nap*.

Most of the area is covered with glacial overburden and the

few granitic outcrops within the claim-group did not possess

unusually high count rates. Some of the highest*reading ample*

from outcrops were assayed for U,O., ThO., and K and the ResultsJo 2

were found to be very low. The hills of boulders and boulder field*

within the claim-group may have provided an important contribution

to the anomalous signal. It is likely that the boulder* are a lag, . . . ( .t . , s

deposit resulting from the removal of finer detritial material by

glacial meltwater.

Variations in terrain clearance, changes in the temperature

of the photomultiplier tubes and temporary radiation sources such214 i as cosmic ray bursts, atmospheric Bi, andavnthetic particle*

in the atmosphere do not provide a satisfactory explanation of the -. "

anomaly. The possibility that the principal source lies north of the

claim-group is supported by the airborne profiles, aeromagnetic

data, and the possibility of a fault or shear zone along a lineament

north of the property. Correlation between airborne and ground

data in the area of the claim-group is very poor.

C

ACKNOWLEDGEMENTS

The author is most grateful to his adviser, Dr. E. Farrar,

for his invaluable advice and critical reading of the original

manuscript.

My sincere thanks are extended to Noranda Exploration Company, Limited through Dr. R.S. Woolverton, who made the field

study possible, and Mrs. S. Dublin for her assistance in

preparation of the final copy.I would especially like to thank Miss J. Murray for her very

capable assistance in the field work.

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TABLE OF CONTENTS

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5aje9NEwi2 CLAW LAKE 010CABSTRACT

ACKNOWLEDGEMENTS

TABLE OF CONTENTS

LIST OF FIGURES, TABLES, AND MAPS

INTRODUCTION

PART A-REVIEW OF AIRBORNE THEORY

INTRODUCTION

l SOURCES OF RADIATION

1.1 NATURALLY OCCURRING RADIOELEMENTS IN ROCK AND SOIL

1.2 SECONDARY GAMMA RADIATION FROM COSMIC RAYS

l. 3 ATMOSPHERIC AND TERRESTRIAL CONTAMINATION

(i) Gaseous Radioelements(ii) Radioactivity of Natural Particles

In Atmosphere and Precipitation

(iii) Radioactivity of Synthetic Particlesin the Atmosphere .- ASSOCIATED v/trtt Tic Derecrof

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/.tJ, -f2 FACTORS AFFECTING SIGNAL STRENGTH

2.1 SOURCE CHARACTERISTICS

(i) Activity of Surface Materials Contributing to Signal

(ii) Individual Radioelement Concentrations

(iii) Thickness of Source and Absorption

(iv) Geochemical Halos

(v) Weathering of outcrops and Overburden

(vi) Effect of Overburden

(vii) Vegetation

(viii) Precipitation

(ix) Effective Radiating Area

2.2 AIR CHARACTERISTICS

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DETECTOR CHARACTERISTICS >

(i) Compton Scattering , 5(ii) Detector Crystal Volume . to

(Hi) Spectrometer Stability H

(iv) Sampling Rate /i

3 OPTIMIZATION OF SURVEY PARAMETERS H

4 DESCRIPTION OF AIRBORNE SYSTEM FLOWN OVER THESIS AREA IZ

5 DESCRIPTION OF GROUND INSTRUMENTS USED IN THESIS AREA /5"

PART B-COMPARISON OF AIRBORNE SURVEY RESULTS WITH GROUND FOLLOW-UP DATA

6 DESCRIPTION OF CLAW LAKE /7

6.1 LOCATION AND ACCESS rt

6.2 TOPOGRAPHY AND VEGETATION /7

6.3 REGIONAL GEOLOGY 17

l AIRBORNE DATA 39

9 DISCUSSION AND CONCLUSIONS

8 GROUND DATA J5

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_PRODUCTION

In the summer of 1975 an airborne gamma-ray spectrometer

survey was conducted in northern Ontario under the joint Federal-

Provincial Uranium Reconnaissance Program by the Geological

Survey of Canada and the Ontario Division of Mines. After the data were released in 1976, 12 contiguous claims were staked by

Noranda Exploration Company, Limited near Claw Lake on an anomaly

which was thought to be a very good exploration target. A brief reconnaissance into the area proved inconclusive in determining

the source of the anomaly.A more detailed study was undertaken by the author from the

22nd to 29th of August, 1976, in an attempt to provide further

information and conclusions.This thesis consists of two main parts:

A - a detailed review of airborne gamma-ray spectrometer surveys,

B - a comparison of airborne and ground results in the Claw Lake

area.

PART A - AIRBORNE THEORY

INTRODUCTION

Airborne gamma-ray spectrometry provides a method of

estimating the abundance of potassium, uranium, and thorium in

surface materials beneath the aircraft.40 Potassium is measured directly from K which emits photons

at 1.46 MeV so'disequilibrium is not a problem. The radioactive

decay of uranium and thorium is more complex though and proceeds214 through many successive steps. Bi with photons of energy

1.76 MeV and 2 08T1 with photons of energy 2.62 MeV, intermediate

decay products within the uranium and thorium decay schemes, respectively, are used to measure indirectly their parent element

concentrations.214Bi and Tl were chosen because they are relatively

abundant, high in energy and are also most easily descriminated

from other gamma rays in the spectrum.

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rays over 0.1 MeV emitted by thorium and uranium in equilibrium

with their decay products. Measurements are only correct if the decay series is in equilibrium forming a closed system.

Radium and radon gas are intermediate decay products in the21 (j

uranium decay scheme. In an open environment B i may be

spatially separated from its parent uranium through migration

of intermediate decay products such as these. There is less

evidence to suggest that disequilibrium may be a problem in the Th decay series but measurements for both are commonly written

"eU" and "eTh" meaning equivalent uranium and thorium.

l SOURCES OF RADIATION

This section is devoted to four main sources of radiation which have been suggested by Gregory (28).

1.1 NATURALLY OCCURING RADIOELEMENTS IN ROCK f, SOIL

The only geologically significant radio-isotopes that have

gamma photons capable of penetrating through the air to the

altitude at which the airborne detectors are flown are certainA Q

members of the uranium, thorium decay series and K. These

elements may occur separately or together in various proportions,

depending on the geochemical nature of the source.

1.2 SECONDARY GAMMA RADIATION FROM COSMIC RAYS

When high energy cosmic particles pass through the atmosphere

they produce a radiation complex that includes gamma photons.

The exact nature of cosmic gamma flux is not completely under

stood but it is believed to contribute a relatively constant

low background flux which does not vary significantly below

altitudes of 50,000 feet. Some cosmic ray bursts are known to

occur which have produced significant, non-reproducable, positive anomalies of short duration/ (Gregory (28)).

Secondary radiation effects resulting from cosmic ray ir

radiation of rock are negligible as sources of gamma flux, Hess

and Roll (32) .

1.3 ATMOSPHERIC AND TERRESTRIAL CONTAMINATION

Three principal sources of contamination are as follows:

{i) Gaseous Radioelements

While gaseous radioelements existing in the atmosphere may

contribute to the general radiation background, they are con

sidered to be of little importance as parents of air turbulence

and precipitation. It is not known by the author if a full

evaluation of the gamma effect from uranium decay products ac

cumulated under temperature inversion conditions in the atmosphere

has been attempted. However, from measurements taken on seven

different days at the calibration pads at Uplands Air Force base,

near ottawa, Darnby and Grasty (26), found that uranium counts

showed a variation of up to 20%. They believe a significant

part of this was due to atmospheric radon content.

{i i) Radioactivity of Natural Particles in Atmosphere

and Precipitation

214 The variability of atmospheric Bi is due to changes in

atmospheric composition stemming from environmental factors

such as porosity and composition of ground, recent rainfall,

wind strength, pressure gradient, surface saturation or deep

continuous snow cover, etc., (Darnley, 11). Under fine summer214

weather conditions, he observed that the Bi content measured

at an altitude of 125m is normally at a maximum in the early

morning and commonly diminishes by 10-151 as the day progresses,' 214owing to atmosphering mixing. Variations in the Bi background

of the order of ID-20% have also been noted occassionally in the

early morning within neighbouring parts of a valley.

Charbonneau and Darnley (3) have observed an unusually high

uranium count of 5 times background which was apparently the

result of a heavy rainstorm. They attributed this to a high214

prqportion of Bi associated with dust particles being deposited

on the ground.

(iii) Radioactivity of Synthetic Particles in the Atmosphere

The radioactivity of synthetic particles (i.e. fallout) in

the atmosphere may cause important intensity variations. It is

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possible that such material could cause sharp, intense anomalies

or broad, irregular anomalies depending on the size of the con

taminated air mass.

1.4 RADIOELEMENTS ASSOCIATED WITH THE DETECTOR

Wrist-watches and aircraft instruments which contain radium

luminized dials must not be used.FACTORS ::r"V::;V"

^ FACOTRS AFFECTING SIGNAL STRENGTH

The interrelationships between factors affecting signal strength are complex. The parameters involved may be best

described under source, air, and detector characteristics.

2.1 SOURCE CHARACTERISTICS

(i) Activity of Surface Materials Contributing to Signal

Practically all soil and rock types tend to-exhibit with a surprising degree of uniformity a chacteristic intensity of

gamma radiation.

Kellog et al (31), Gregory (28), Russel (44) and others have

described the relative activities of some common materials.

(ii) Individual Radioelement Concentrations

The primary spectrum from an aggregate of radioelements in

the source is the summation of the separate spectra for each of the radioelements present.

Uranium series, thorium series, and potassium differ

greatly in their activities and signal variation is complexly

dependent on their ratio.

(iii) Thickness of Source and Absorption

Gamma-rays are attenuated in the surface material as a

result of self-absorption which is dependent on^density. The

relationship between depth, density, and effective gamma flux

received has been explored by Gregory and Horwood (30) and their

results are summarized in Table 1.

TABLE l ABSORPTION OF GAMMA-RAYS IN SOURCE AS A FUNCTION OF DENSITY

ROCK TYPE DENSITY gm/cm^

DEPTH REQUIRED FOR GAMMA RADIATION cm

TOTAL

granitedry overburden

2.71.5

15 - 2: 30 - 4!

(iv) Geochemical Halos

Although radioactivity measurements are only representative

of a relatively thin surface layer, one should not assume that more deeply buried ore bodies could not be detected. Airborne spectrometry, like many geochemical exploration techniques, relies on primary and secondary dispersion halos. Transportation

of material in solution and vapour form, precipitation of radioactive salts at the surface, movement due to hydrostatic gradient, and evaporation of fluids in rock may occur at or near buried ore to enrich the surface material.

(v) Weathering of Outcrop or Overburden

Geologically recent weathering and removal of uranium may

be quite common but does not necessarily pose a problem. Aslong as residual radium, intermediate in the decay scheme

214 between uranium and Bi, has not migrated beyond distances

of 50-100m removal of uranium is of little consequence. No evidence has been found for migration beyond these distances which are of the order of magnitude of spatial resolution of

airborne systems.

(vi) Effect of Overburden

The Canadian Shield is a prime target for airborne methods

because of its large area and relative inaccessibility. Sur face cover is dominated by overburden, swamp, or lakes with only a small percentage of bedrock exposed.

Overburden must be locally derived or residual in order that the results of the survey be meaningful. A detailed study by Darnley and Fleet (13) covering a variety of rock types rep resentative of the Canadian Shield revealed that the pattern

of radiation from shallow overburden is similar both in in tensity and distribution to that of exposed bedrock. It was concluded that to characterize a rock type it is not necessary to be dependent solely upon the radiation from occasional out

crops.

T{vii) Vegetation

Background variation between areas may be affected by the

presence of trees and brush which themselves contain a small

amount of radioelements (Cannon and Kleinhampl (1)).

(viii) Precipitation

Conditions of surface saturation or deep snow cover screen

radiation from the detector.

(ix) Effective Radiating Area

Since the airborne gamma ray spectrometer acts as a passive

sensor measuring gamma radiations from a surface of infinite

areal extent, the source may be represented as a continuous distribution of point source emitters of various intensities.

This distribution can be expressed as a function D (x,y) which

gives the intensity at any (x,y) co-ordinate position. Wh-n

this surface (ground) distribution of source intensities is viewed from the air, what the detector measures is modified by

the effects of distance R from the source and the absorption coef

ficient u of the air. The response of the detector can be ex

pressed as a point-detector function relating detector responseto distance. Them attenuation of intensity with distance is the, .. - function: e f

s

Source -

Thus, for an ideal source-detector geometry with a point

detector at an altitude h feet above an infinite plane, the

intensity measured at a certain point by the detector is the

product of the value of the point-detector function and the

value of the surface intensity distribution function at each

8.

c*Fan infinite number of points on the ground. The value re corded on the radiometric profile is the sum of all these

products.Thus the radiometric profile is the convolution of two

functions: the surface radioactive intensity distribution function, and a point detector function relating detector re sponse to distance. Mathematical descriptions have been given

by Pierson and Franklin (38), Duval et al (19) , and more re cently by Clark et al (6) as follows:

where R ^ x + y + h

e radiometric profile function~ ground distribution of radioactive

source intensities;i,k /**K ^ constants:k describes the constant factors affecting 'the count rate

of the particular system including detector efficiency:;j is the absorption coefficient

It is apparent that the size of an exposure with high

specific surface activity will affect the distribution function;

D (x,y) , by contributing to the source flux measured at the detector. Similarily topographic relief will affect the dis tribution function by increasing the surface area of the source

and may vary the solid angle subtended by the source at the detector. Flight lines should also be chosen approximately normal to the geological strike to provide maximum resolution

of geological features.

2 . 2 AIR CHARACTERISTICS

The amount of attenuation of the signal in the air is principally dependent upon the air density and the distance

between the source and detector. Since the signal strength is proportional to e - ^ y the effect of distance is apparent. The absorption coefficient, p , is a function of density. and con trols the relative attenuation of various photons.

The density of the air may vary with air pressure/ temperature, and humidity. The relative flux attenuations

is U, Th,and K. With increase in air distance, K and Th

fluxes increase in prominence relative to U flux.The principal advantage of flying at lower terrain clear

ance is in increasing spatial resolution. Disadvantages of flying at a low elevation are that it is more hazardous/ navigation is more difficult, as also is track recovery, and more line miles are necessary tq cover a given area. It is

important that terrain clearance be monitored and taken into account. A 50 foot change in terrain clearance may produce a 1C^ change in count rate from a large area source. For a small area source the change in count rate will be even more severe.

2.3 DETECTOR CHARACTERISTICS

(i) CoTipton Scattering

It is well known that high energy gamma-rays produce a certain fraction of scattered photons of lower energy which contribute to count rates in lower energy photopeaks. This effect is called Compton scattering. The scattered photons

may be produced inside the crystal detector itself or outside by scattering within the source material or in the air. In creasing the size of the crystal increases the fraction of photons which are totally absorbed in the crystal thereby also increasing the number of counts in the photopeak.

The contribution ratios, also referred to as stripping ratios are defined as:**"s counts in the "u"-channel per count in the "Th"-channelft - counts in the "K"-channel per count in the "Th"-channel

](** counts in the "K"-channel per count in the "U"-channelThe corrected count rates are given by the following

equations {after Darnley, (11)):

/o.

NTh

Nu

corr

corrNkcorr "

where NTh ,

BGO

N

N

Th

U

NK

NU'

- BCDi- BCD

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Thcorr " NNy e count

. backg rt

rates in

)und count

Ucorrthe Th, U, X channels

rate in a particularchannel indicated by a subscript

corr ** subscript referring to corrected countrates

The stripping ratios are dependent on the geometry of the

source as well as the window width employed and the size, num ber and spacing of the radiation detectors. The coefficients,

•i, /i, and if should be determined under natural survey con ditions. Since it is impossible to know the geometrical

shape of the source, a homogeneous source of effectively in

finite size is the most suitable model for calibration pur

poses. To this end, the Geological Survey of Canada has built five calibration pads 2.5 feet by 25 feet and 18 inches

thick, spiked with different amounts of uranium and thorium. The aircraft or helicopter mounted spectrometer may be taxied over the pads and calibrated. A detailed description of the procedure along with computer programs for determining tj-, f , and X are given by Darnley and Grasty, (25).

{i i) Detector Crystal Volume

The detector volume should be large enough to pick up

anomalous areas on the ground of the desired dimension. If

the detector volume is too small for its intended use either spatial or radiation intensity resolution will suffer. In .

theory it is not possible to have a detector volume which is

too large for a particular application. In practice, however,

there is an upper limit to volume arising from the fact that

although count rate increases, resolution decreases because of

self shielding effects. To make ratio measurements useful a

high count rate is required.

lJ J.

(iii) Spectrometer Stability

Since drift of "energy windows" causes large fluctuations

in count rate, spectrometer stability must be carefully control

led. To minimize instablility caused by drift in the high

voltage supply and temperature dependent variations in the

gain of the photomultiplier tubes, some spectrometers make use

of automatic gain adjustment using an isotope of known energy

as a monitor. The two isotopes most commonly employed areOAT l *^7

Am which is an alpha emitter and Cs, a gamma emitter.

Recently Co has been advocated to avoid some of the dis- .

advantages inherent in the other two.

It has become common practice to maintain the whole de

tector system at a constant temperature by means of a thermostatically controlled heating jacket.

(vi) Sampling Rate

The rate at which measurements are taken should not be confused with count rate previously discussed. Ideally, to

fully define the shape of an airborne radiometric profile,

the sampling rate should be made as high as possible. In pr^^tice this leads to very poor counting statistics which

introduce high frequency variations in the radiometric profile.

l OPTIMIZATION OF SURVEY PARAMETERS

Since the airborne radiometric profile given by equation

(1) is a space-varying function which can be considered to be

composed of different frequency (wavelength) components, the size of an anomalous zone can be related to its obporved wave

length, A , on the radiometric profile.

Since the contribution to the transform of the exponent

^in - equation (1) has been shown numerically to be negligible, Killean et al (33) have approximated the Fourier transform of

the point detector function by:

f ' 7 ' l

where is the wavelength of the spectral component of the anomaly, The function of equation (2) can be considered to be the fre

quency response of a smoothing function (i.e., the point de- tc 2tor function) which operates on the ground intensity dis-

1Z.

function to produce the radiometric profile. A plot

of the point detector transform versus frequency (or wavelength)

for any chosen altitude falls off as the wavelength decreases.

Such a plot is given by Killean et al (34), who have also

arbitrarily defined a cutoff value \ e , by a value of 1/e of the maximum amphitude component of the point detector trans

form function. This yields a practical lower limit of wavelength resolvable at altitude, h, and is given by:

X - k /Z l J]It should be recalled from section 2.3 (iv) , a practical

limit exists in the sampling rate because of high frequency variations in the radiometric profile. The sampling rate also

determines a minimum resoluable wavelength/ called the Nyquist wavelength, X* , given by:

X. . z vA-t [41where A t ~ length of sampling time in seconds i

v = aircraft speed in ft. /sec.A compromise yielding the best counting statistics for a

given flight altitude is given by equating X* and X* . This

yields an optimum sampling time of:

where h is the altitude associated with a chosen value of ^* . cTo resolve a particular wavelength of anomaly in the radio

metric profile, the maximum flight altitude is fixed at twice the critical wavelength desired. Alternate choices of sampling

time and velocity exist depending on the desired accuracy of

the counting statistics. A large detector volume will permit the use of higher speeds and lower sampling time. Counting

statistics for a particular airborne system can be determined

by. trial flights over areas of known radioelement concentrations.

The economics of detector and flying costs must be balanced with

the counting statistics, target size, and survey parameters.

i DESCRIPTION OF AIRBORNE SYSTEM FLOWN OVER THESIS AREA

The Geological Survey of Canada and Atomic Energy of

C

, Limited have produced the high sensitivity spectrometer

system which was flown over the study area of this thesis.

The G.S.C. was responsible for initiating the program, setting

performance targets, selecting and organizing field test areas

and trials, and undertaking complimentary geological, geophysical and geochemical investigations. A.E.C.L. was responsible for

design and construction of the components, operating the equip ment in the field, computer programming, and derivation of quantitative data from the airborne measurements.

The system eventually chosen so as to guarantee a more

than adequate count rate had twelve 9 inch diameter by 4 inch deep (22.86cm x 10.16cm) Na (I) Tl crystals.

Four 3 inch diameter phototubes were found experimentally

to be more efficient than one 12 inch diameter phototube.

The individual crystal and photomultiplier combinations have

been found to possess a resolution of 12t. The -crystals and

photomultipliers are encapsulated in a 0.019 inch thick

stainless-steel container. Each crystal assembly is packaged

in a metal canister lined with approximately l inch of

polyurethane foam which is molded to accommodate the crystal

and form a container for it. It was found feasible to wire the

corresponding electrodes of the four tubes in parallel without any significant loss of resolution. This greatly simplified

gain matching adjustment of the 48 photomultiplier tubes. Each crystal is maintained at a constant temperature of 100OF by

means of an electrical heating element attached to the wall of

the canister. The individual canisters are grouped in sets of

six inside an aluminium box which is filled with polystyrene

foam insulating material. There are, therefore, two containers

each approximately 4.5 x 4 x 2.5 feet in size.

TABLE 2 ENERGY WINDOWS AND ATTENUATION COEFFICIENTS FOR SKYVAN SYSTEM

(AFTER DARNLEY, (II))

ELEMENT ISOTOPE ANALYSED USED

K 4 0K

0 2 14B1Th ' 2 08T1

f- RAYENERGY (MeV)

1.46

1.72

2.62

ENERGY WINDOW (MeV)

1.36-1.56

1.66-1.82

2.42-2.82

0.4 -2.82

AIR ATTENUATION COEFFICIENT., (ftr'^i' x 10 *#)

2.3

1.7

1.7

2.0

J4.

tTable 2 shows the energy windows and isotopes used by the

\. S.C. system. The air attenuation coefficients as determined

by Darnley (11) are also included. Three single-channel

analysers accept energy from each of these spectral windows

, while a fourth single-channel analyser accepts a band ofradiation which virtually represents the total or integral

count rate from the whole energy spectrum. Associated with

each analyser is a scalar which totals the counts and sub

tracts a pre-determined background in each case for a time

which can be pre-selected. Provision is included for sampling

the output from the integral count analyser more often than the other three by a factor whjjh can be pre-selected on the

timer.

An incremental digital tape recorder is used to sequentially

record the following information at the end of each sampling

interval:

- accumulated total count less background- accumulated K count less background

- accumulated U count less background- accumulated Th count less background- sampling time intervals

- average height in feet over preceding sampling interval

- elapsed distance along flight lines- deviation normal to flight line

- date- flight line information

- operator code numberAn anomaly presentation of the data is provided in flight

by means of a strip chart recorder. The associated navigational

aids include a Bendix ALA-51 radioaltimeter and a Bendix Doppler

navigational system for providing elapsed distance along pre determined flight lines, together with deviations normal to the

line. The navigational system is usually supplemented by a

conventional track recovery camera or TV-video tape recording

system. The digitized information enables a print out of all

A? required parameters corrected as necessary for altitude and

Compton scatter and to produce contoured geochemical maps.

Grasty and Darnley ( 25) have determined the stripping ratios from seven completely independent Skyvan calibrations

as follows:

** - 0.348 0 .015 (4.3^)

fi ~ 0 .331 ± 0.044 ± (13.31) y = 0.560 ± 0.102 ± ( IS.2%)

It should be noted that "S the most critical coefficient,

is the most accurately determined. The total weight of the

spectrometer is 1600 Ibs. A Skyvan was found most suitable

as the survey platform because of its STOL performance, low

control speed, and high rate of climb.

5^ DESCRIPTION OF GROUND INSTRUMENTS USED IN THESIS AREA

Two different instruments were used in the ground follow-

up operations in the thesis area.

The Exploranium model GRS-101 portable gamma ray scintil

lometer is a total count instrument which measures all gamma

radiation above 0.05 MeV. The instrument includes a threshold

setting which automatically triggers an audio tone when the

meter exceeds a preset value. A 1.25" diameter x l" thick

(3.18 x 2.54cm) sodium iodide crystal with a total volume of

1.23 cubic inches (20.1cm ) is employed in the instrument.

The other instrument used was the McPhar model TV-1

three threshold scintillometer. This instrument uses the same

size detector crystal as the Exploranium scintillometer. In

addition to the meter, a speaker provides a variable pitch

output with changing radiation levels. The three threshold

positions are as follows:

Tl at 0.2 MeV - measures the total count across the entiregamma energy spectrum for maximum sensitivity

T2 at 1.6 Mi-V - measures characteristic uranium and thoriumradiations

T3 at 2.5 MeV - measures diagnostic thorium radiation's only

^^ In the total count threshold, Tl, a fast or slow time

cmistant (i.e. sampling interval) may be selected at l or

10 seconds. For T2 and T3 the time constant is set at 10

seconds.

The counts due to U and Th are determined as follows:

counts due to Th ^ C 3r1l = C 3 - C3g counts due to U ^ C^u ^ C Z (Ufrll) - 3 .5 CJr*

~ (CZ - C28 ) - 3.5 (C, - C^)

where the subscripts are defined as: B = background; 1/2,3 channel in which count observed.U, Th, = source of count.

17.

RT B - COMPARISON OF AIRBORNE SURVEY RESULTS WITH GROUND

FOLLOW-UP DATA

i DESCRIPTION OF THE CLAW LAKE AREA

6.1 LOCATION AND ACCESS

The 12 claims are located in the Thunder Bay district,

58km northwest of the town of Savant Lake which is situated

on highway #599. The property was found most readily ac

cessible by taking a float plane to Claw Lake where a base camp was established. The claim group was about 2.5km east

of Claw Lake at latitude 50O 42'N and longitude 90O 10'W,

NTS 52J-9.

6.2 TOPOGRAPHY AND VEGETATION

Most of the claim group is covered in glacial debris which

varies from unsorted till to material primarily composed of

boulders with little or no fine material interstially.

The boulder-rich debris may be found as long sinuous

hills or boulder fields. Many of the glacial features trend

in a southwesterly direction.

Spruce trees comprise essentially all of the forested

areas. Alder swamps containing scattered spruce trees are

common in most of the low areas.

6.3 REGIONAL GEOLOGY

Three published geological maps (37, 42, 45), which in

clude the thesis area are of limited value. No work had been

done in the vicinity of Claw Lake owing to the large scale

reconnaissance nature of these mapping projects.

The study area lies within the English River Subprovince

of the Superior Province. Archean splutonic masses of variable

dimensions and areal extent which are composed of a wide variety

of granitic rock types dominate the subjrovince. Six miles

to the west of the claim group lies the northern tip of the

Savant Lake greenstone belt which is mainly comprised of fine

INTEGRAL

MAP 2 TO

TAL C

OU

NT

CO

NTO

UR

S

500-

250

500-

'J? v"o

t.

Ou500-

POTASSIU

M(D

CO

NTO

UR

S10

IQUIYALENT URANIUM MAP 5"

eqiv. UR

AN

IUM

ppm

CO

NTO

UR

S

MAPS

EQIVALENT THORIUM-MAP 7

eqiv. THO

RIU

M ppm

. CO

NTO

UR

S

MAP 8

EQUIVALENT URANIUM l EQUIVALENT THORIUM RATIO MAP 9

eU/eT

h CO

NT

OU

RS

MAP ,o

EQUIVALENT URANIUM X POTASSIUM RATIO MAP H

EQUIVALENT THOmUM-X-.LO.tASJMUM— ——— ~IS

ELEVATION MAP 15

- AEROMAGNETIC MAP MAP 16

GROUND SCINTILLOMETER SURVEY

"EXPLORANIUM" TOTAL COUNTS PER SECOND

MAP 17

GROUND SONTILLOMETER SURVEY MAP 18

"McPHAR" T l READINGS — COUNTS PER MINUTE

GROUND SCINTILLOMETER SURyEY

T2 READINGS COUNTS PER MINUTE

"MCPHAR" T3 READINGS - COUNTS PER MINUTE

OUTCROP DISTRIBUTION

AND

ASSAY RESULTS

massive to foliated, chloritic, mafic, metavolcanics

a few narrow units of felsic metavolcanics and meta-

sediments.

;7 AIRBORNE DATA

The airborne gamma ray spectrometry data (maps 1-15)

are compiled from the preliminary geophysical series maps

produced by the Ontario Division of Mines and Geological Sur

vey of Canada (39), (40). North-south flight lines at 5km

spacings were flown at a mean terrain clearance of 400 feet

at 190kmXhour.

The data for three of the flight lines are presented as

enlarged composites of the ODM-GSC profiles (40), for integral

count, potassium equivalent uranium and equivalent thorium

concentrations, the eU/eTh, eU/K, and eTh/K ratios, and survey

altitude. These profiles have been superimposed.on a base map

to show the relationship to water covered areas. The data

have also been presented as enlargements of computer contoured

maps (39) for each of the seven radiometric parameters. Uranium,

thorium, and potassium counts were measured over 2.5 second

intervals; integral counts over 0.5 second intervals. The

data have been corrected for background, height variation and

spectral scattering. Computer programmes used to produce

the contour maps and profiles are described by Grasty, (22).

This programme tends to distort the contours in the direction

perpendicular to flight lines. The profiles provide a more

accurate means for locating anomalies. Factors relating

airborne measurements to element concentrations were determined

by relating the corrected airborne count rates over test strips

in the Ottawa area to known ground radioelement concentrations,

(Gr'asty and Charbonneau, (25)).

Map 16 is an enlargement of part of an aeromagnetic survey

conducted for the Ontario Division of Mines (39).

i GROUND FOLLOW-UP DATA

8.1 SCINTILLOMETER SURVEY

Maps 17-20 show the results of a ground scintillometer sur-

within the study area. Eight lines were surveyed using a

compass and 30m chain for a total distance of 3270m stations

every 30m, four readings were taken including total count with

the Exploranium model GRS-101 scintillometer and total count,

, characteristic uranium and thorium, and diagnostic thoriumreadings with the McPhar model TV-1 scintillometer. Vegetation,,

degree of ground saturation, and nature of surficial material

were also noted during the survey.

8.2 GEOLOGICAL MAPPING

The property was mapped by pace and compass technique with

the assistance of airphotos. The chained and flagged scintil lometer grid greatly aided the precise fixing of outcrop position,

The geology of the area is shown on map 22 (back cover). An attempt has been made to show the major glacial and topographic

features. Map 21 shows the results of some assays taken from outcrops in the area. The outcrop distribution can be seen

more easily on this map than the geology map.

C

41.

DISCUSSION AND CONCLUSIONS:~

Examination of the airborne spectrometry data would suggest

that this area provides excellent prospects as an exploration

target. Flight line 5 passed directly over the claim-group

( 00 the airborne and ground result* should correlats well.

The eU counts display a broad anomalous region 8 miles in

diameter with count rates up to seven times background. The eO

anomaly is centred in the northern half of the claim-group as i*

a good eU/eTh ratio and excellent eU/t ratio. The eTh/Xratio i*

average for the region which.is a favourable indication that

preferential enrichment of uranium rather than thorium may b* '

responsible for the anomaly. While the eTh and total count data

suggest the centre of the anomalous son* may lie about on* syll*

north of the claim-group, count rates are still anomalous over the

area of the ground study.

Upon close examination of the total count , K, and eTh profiles

and contour maps, a striking similarity is apparent. This would

strongly suggest a very geochemically sympathetic relationship

exists between Th and K. Owing iito the similarity of the X and

eTh profiles, the eU/eTh and eU/K profiles should also be very

similar. This is easily verified by even a cursory examination.

The eU/eTh and eU/X data, although similar to the K and eTh data,

ahow a stronger .resemblance to the el) data. From an exploration

viewpoint this is desirable and may indicate preferential enrichment

of uranium within the area.

H*ving dicussed some of the interesting aspects of the airborne

data,a comparison should be drawn with the ground results. The

geology map, (back cover), attempts to show the topographic and

glacial features in addition to the outcrop geology. ft variety.,

of granitic rocks were found in the area. These include biotite-

and (or) hornblende- quarts-feldspar gneiss, hybrid granite gneiss,

pegmatite, and a few, small, low count rate, migmatised cones

V ' bearing mafic rich lenses up to 10 feet in length which are most

likely xenoliths. Typical ground scintillometer values in areas of

outcrop were of the order of 90-140 cps. with some local high counts

^ up to 240 cps. which is not unusual for granitic rocks, four samples

which were assayed were taken from widely spaced outcrops which had

above average count rates. The 00 , ,ThO , and X assay result* vex*38 *

i" low and are shown on nap 21. Mo uraninite stain or other

precipitate was noticed on the outcrops. The outcrops did not appear

extremely weathered so their is no direct evidence suggesting that

disequilibrium in the decay scheme could bs a problem* Tn* ground

scintillometer results (maps 17, 18, 19, 20), show tt* low

background count rate that is characteristic of the area, The

lower readings at the southern end of lines 2, 3, and 4 are due to

the swampy nature of the area.

Airphoto examination reveal* an area of sandy glacial outwash

to the north of the Claw Lake anomaly. It seems likely that the

boulder fields and boulder hills noticed within the area are a

lag deposit resulting from the removal of finer detritial material

by glacial meltwater. Readings taken of the boulders throughout the

study area gave values similar to those of the outcrop. The

similarity in lithology between the boulders and outcrop suggests

that the overburden is residual or locally derived.o

The glacial trend in the area is N20 B whereas the structural

trend, as determined from regional lineaments, is about N35 B.

Attempted correlation between radiometric, structural, and glacial

trends proved inconclusive in determining whether the anomalous

sons is structurally or glacially controlled.

Variations in aircraft height can be eliminated as a potential

source for the observed anomaly. Prom map 15 it can bs seen that

terrain clearance was maintained extremely well along flight line 5

within the area of concern. The highest topographic feature in

the area is a drumlinoid structure at the northwest end of Claw

Lake. The feature was examined and found to have a very low

background count rate.

Equation 5 yields 0.58- seconds as the sampling time for

optimum counting statistics. Since integral counts were takem at

0.5**eoond intervals and owing to the large detector volume of the

spectrometer system, count rates were high enough to avoid problems.

It should be noted that the ground measurement* should be

nore reliable than the airborne observation*. Problem* such as

unknown source and air attenuation are eliminated In ground work,

While the background total count rate for the airborne measurement*

was approximately 5 tines that of the ground measurements, the

integrating time of the ground measurements were greater by a

factor of 20.

Change* in the temperature of the photomultiplier tubes or

instability in the spectrometer system resulting in Spectral

window drifting would not satisfactorily explain the anomaly

since it can b* followed between lines 4, 5, and 4.

The only plausible explanations for the anomaly seem to be

that either a temporary radiation source, such as was dicussed

in section* 1,2 and 1.3, cau**d the anomaly or that some source

north of the area studied, possibly combined with the effect*

of the boulders within the claim-group, produced the anomaly.

Although the exact nature of the effects of cosmic ray bursts

are not completely understood it can be ruled out a* the source

of the anomaly unless it* effect we* local l iced in the area

covering all three flight line* over the period they were flown.

It i* extremely unlikely that temperature inversion, causing

concentration of gaseou* radioelement*, could produce *uch sharp

effect* over an area a* small a* the anomaly'214

Bi in the atmosphere can produce largo end variable change*

in the background radiation, affecting both the absolute count

rate and the value of the apparent height coefficient. Increased

Bi in the atmosphere would contribute photon* only to the

U-channel and through Compton scattering to the K-chennel. Since

the airborne indicated Th was also anomalous in the area,

(map* 7 and 8), Bi i* an unlikely explanation "of the anomaly.

Synthetic particle* in the atmosphere could cause intense

anomalies such as the one discussed but verification is not

possible.

Temporary sources of radiation do not satisfactorily explain

the anomaly in the authors opinion.

44.

The possibility of the anomaly being the result of a lag

1 deposit in conjunction with a source north of the ci aim-group

poses some interesting problems which cannot be resolved without

further ground work. Since the claia-group was covered in some

( detail during the mapping and ground scintillometer surveys, it

is very unlikely that any significant exposure within its

boundaries was missed. The contribution of the boulder* is no

doubt more significant than that of the outcrop but it is debatable

that it could cause the observed seven-fold increase above

background observed in the eU-channel. The possibility exists

that the source of the anomaly lies north of the property. Most

of the profiles suggest the anomaly is composed of severs! peaks

of various amplitudes. These peaks are more prominent on some of

the profiles north of the property than within it. The computer

contoured maps may be somewhat misleading because of their smoothing

function. There is some support for s more northerly source

provided by the regional geology and the aeromagnetic anomaly

pattern. The anomalous zone lies within a 3-mile wide, relatively

undisturbed, ENE-WSW trending aeromagnetic belt. To the north

and south of the anomaly the area is magnetically disturbed.

Both the relatively undisturbed band and its surrounding magnetically

disrupted areas have similar average magnetic readings which would

suggest deformation rather than variations in lithology to be

responsible for the bands.t (These magnetic liniaments are likely

shear cones or faults. The northern magnetically disturbed belt

iShOf particular ir,terest. It is alligned with lineaments produced

by the pinching out of the Savant Lake Greenstone Belt, (42).

If this is a fault sons, enrichment along it micht explain many of

the peaks north of the claim-group with the lag deposit accounting

for many of the peaks in the profile near the claim-group. .

Airphoto examination does not reveal t fault but if one exists it

may well be covered by the sandy outwash in that are*.

t

45.

In conclusion, correlation between ground and airborne results

is at best confusing in the Claw Lake area and many questions

remain unanswered. Since the purpose of airborne surveys is to

provide a more efficient means of arriving at "ground truth"

it appears that the airborne system may have fallen short of this

objective at least in the area of the claim-group. It must be

emphasized that gamma-ray spectrometer profiles are not a

panacea and.it is extremely important to interpret them whenever* '*'' ' '

possible with all forms of complimentary evidence.

As technological developments progress and detectors capable

of better energy resolution become available, the advantages of

recording the complete gamma radiation spectrum on magnetic tape

may be realised. This would eliminate many of the problems

discussed.

C.

REFERENCES

Cannon, H. L. and Kleinhampl, F. J.1955: Botanical Methods of prospecting for uranium; Paper

509, Int. conf. on peaceful uses of atomic energy,Geneva.

2. Charbonneau, B. W.1973: Ground Investigation of the Mont Laurier airborne

radioactivity survey; in Report of Activities, Part A, Geol. Survey Canada, Paper 73-1, pt. A, p. 67-78.

3. Charbonneau, B. W. , and Darnley, A. G.1970: Radioactive precipitation and its significance to

high sensitivity gamma-ray spectrometer surveys; in Report of Activities, Nov. 1969 to Mar. 1970; Geol. Survey Canada, Paper 70-1, pt. B, pp. 32-36.

4. Charbonneau, B. W. , and Darnley, A. G.1970: A test strip for calibration of airborne gamma-ray

spectrometers; in Report of Activities, Geol. Survey Canada, Paper 70-1, pt. B, pp. 27-32.

5. Charbonneau, B. W., Richardson, K. A. , and Grasty, R. L.1973: Airborne gamma-ray spectrometry as an aid to geo

logical Tapping, Township No. 155 Elliot Lake area, Ontario? in Report of Activities, pt. B, Geol.

Canada, Paper 73-1, pt. B, pp. 39-47.6. Clark, R. B., ^ -al Jr., J. S. and Adams, J. A. S.

1972: Computer simulation of airborne gamma-ray spectro-t meter; J. Geophysics Res., 77(17): 3021-3031.

7. Darnley, A. G.1968: Helicopter tests with a gamma-ray spectrometer;

Can. Min. J., v.89, no. 4, p. 104-106.8. Darnley, A. G.

1970: Airborne gamma-ray spectrometry; Can. Min. Me tall, ; Trans., v.73, p. 20-29.

9. Darnley, A. G.1972: Airborne gamma spectrometry survey in areas of Elliot

^ Lake, Ontario and Fort Smith, Northwest Territories;in Report of Activities, Part A, Geol. Survey Canada,

:. Paper 71-1, pt. A, p. 48-49.10. Darnley, A. G.

1973: The use of total Radioactivity measurements forreconnaissance airborne surveys; Geol. Survey Canadh,

? Paper 73-1A.11. Darnley, A. G.

1973: Airborne gamma-ray survey techniques present and future V. in Uranuim Exploration Methods. IAEA Vienna, p. 67-105.

12. Darnley A. G., Brislow, Q. and Donhoffer, D. K.1969: Airborne gamma-ray spectrometer experiments over

the Canadian Shield, in Nuclear Techniques and Minerali Resources, International Atomic Energy Agency, Vienna, l p. 16 3-186.

(

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24..

25.

Darnley, A. G. and Fleet, M.1968: Evaulation of airborne gamma-ray spectrometry in

Bancroft and Elliot Lake areas, Ontario; in Report of Activities, part B, Geol. Survey Canada, Paper 68-1, pt. B.

Darnley, A. G. and Grasty, R. L.1971: Mapping from the air by gamma-ray spectrometry, Can.

Inst. Min. Met., Spec, v 11, p. 3-12.

Darnley, A. G. , G rasty, R. L. , and Charbonneau, B. W.1969: Airborne gamma-ray spectrometry nnd ground support

operations; in Report of Activities, Part B, Geol.Survey Canada, Paper 69-1, pt. B, p. 10.

Darnley, A. G., Grasty, R. L. and Charbonneau, B. W. 1970: Highlights of G. S. C. airborne gamma spectrometry in

1969; Can. Min. J. April, p. 98-101.

Darnley, A. G., Grasty, R. L. and Richardson, K. A.1972: Regional variations in radioelement cor.tent within

the Canadian Shield; 24th Int. Geol. Con-jr. Montreal,Sect. 9, Exploration Geophys. , p. 14.

Darnley, A. G., Richardson, K. A. , and Grasty, R. L.1972: Experimental airborne gamma-ray spectrometry surveys;

in Report of Activities, Part A, Geol. Survey Canada,Paper 72-1, pt. A, p. 46-49.

Duval, J. S., Cook, B. and Adams, J. A. S.1971: Circle of Investigation of an airborne gamma-ray

spectrometer. J. Geophys. Res., 76(35): 8466-8470.

Exploranium1975: Portable gamma-ray scintillometer model GRS-101

data sheet.

Geological Survey of Canada1954: Prospecting for uranium in Canada.

Grasty, R. L.1972: Airborne gamma spectrometry data processing manual,

GSC Open File No. 109.

Grasty, R. L.1973: Gamma-ray scattering corrections for the airborne

measurements of uranium; in Report of Activities, Part A, Geol. Survey Canada, Paper 73-1, pt. A, p. 82.

Grasty, 1975:

R. L.Uranium stripping determination au natural for air borne gamma-ray spectrometry; Geol. Survey Canada, Paper 75-1, Part A, p. 87.

Grasty, R. L. and Charbonneau, B. W.19/4: Gamma-ray spectrometer calibration facilities; in

Report of Activities, Part B, Geol. Survey Canada,Paper 74-1, pt. B, p. 69-71.

48.

Grasty, R.L., Darnley, A.G.1971: The calibration of gamma-ray spectrometers for

ground and airborne use; Geol. Survey Canada,Paper 71-17.

27. Grasty, R.L., Holman, P.B.1974: Optimum detector sizes lor airborne gamma-ray sur

veys; Geol. Survey Canada, Paper 74-1, Part B, p.72-74.28. Gregory, A.F.

1960: Geological Interpretation of Aeroradiometric Data Ceol. Survey Canada, Bull 66.

29. Gregory, A.F., Fournier, A.L.196-: The effect of temperature on response of scintil

lation counters; Geophysics, v.25, No.6, p.1288-1290.

30. Gregory, A.F., Horwood, J.L.1961: A labratory study of the gamma-ray spectra at the

surface of rocks; Minos Br., Dept. Mines Tech. Surv., Ottawa Research Rep. R110.

31. Kellog Bartlett Kessler etc.

32. Hess, V.F., and Roll, J.D.1948: New Experiements Concerning the Surplus Gamma

Radiation of Rocks; Phys Review, vol.73, pp.592-595.

33. Killean, P.G. and Carmichael, C.M.1970: Gamma-ray spectrometer calibration for field analysis

of thorium, uranium, and potassium; Can. J. Earth Sci., v.7, no.4, p.1093-1098.

34. Killean, P.G., Hunter, J.A. and Carson, J.M.1971: Some effects of altitude and sampling rate in airborne

gamma-ray spectrometric surveying; Geoexploration, v.9, no.4, p.231-234.

35. Killean, P.G., Hunter, J.A., and Carson, J.M,1975: Optimizing some parameters for airborne gamma-ray

spectrometric surveying; Geoexploration, v.13, p.1-12.

36. McPharModel TV-1 three threshold scintillometer instrument manual.

37. Moore, E.S.1927: Savant Lake Gold Area, map no.37j, District of Thunder

Bay, Ontario, Division of Mines.

38. Ontario Division of Mines1960: Neverfreeze Lake Area, Thunder Bay District,

aeromagnetic map 920G.

39. ODM-GSC1976: Airborne gamma-ray spectrometric survey, Sioux

Lookout sheet contour maps, Districts of Kenora and Thunder Bay; Ontario Division Mines, Prelim, Maps P.1112-1118, leophys. Ser., scale 1:250,000. Survey and compilation for OD?, and GSC, 1975.

49,

ODM-GSC1976: Airbotne gamma-ray spectrometry survey profiles of

integral, K, U, Th, (U/Th), (U/K), (Th/K), height, Sioux Lookout Sheets, Districts oi ienora and Thunder Bay; ODM Prelim Maps P.1119-1146, geophys. ser, scale 1:250,000. Survey and compilation for ODM and GSC, 1975. :

41. Peirson, D.H. and Franklin, E. ' \1951: Aerial prospecting for radiometric minerals. Br. !

J. Appl. Phys., 2:281-291. ]

42. Pye, E.G., Davies, J.C. and Pryslak A.P.1966: Sioux Lookout - Armstrong Sheet, G.C.S., Ontario

Division of Mines, M.2169.

43. Richardson, K.A.1973: Airborne radioactivity measurements over the

Canadian Shield, Geol. Survey Canada, Paper 73-1, Part A, p.94.

44. Russel, W.L.1944: The Total Gamma-Ray Activity of Rocks as indicated

by Geiger Counter determinations; Geophysics Vol.9, pp.180-216.

45. Sage, R.P., Breaks, F.W., Stott, G., and Mcwilliams, G. andBowen, R.P.1974: Operation Ignace-Armstrong-Pashkokogan-Caribou Lakes

sheet, District of Thunder Bay, Ontario Div. Mines, Prelim. Map P.962. Geol. Ser., scale l" to 2 miles, neology, 1973.

Ministry ofNaturalResources

Ontario

b

CLAW LAKE 900

78 02 07

Kr. Harry L. Bellining Recorder

Ministry of Natural Resources Box 669 Court House Sioux Lookout, Ontario POV 2TO

Your file:

Our tile: 2.2447MINISTRY OF NATURAL RESOURCES

RECEIVEDFEB101978

RESIDENT GEOLOGIST'S OFFICE SIOUX LOOKOUT

Dear Sir:

Re: Mining Claims Pa. 376378 et al, Claw Lake Area File 2.2447^,^..^^^,.^,,^.^.,^^^—^,^-.

The Airborne Geophysical (Radiometric) and Geological assess ment work credits as shown on the attached statement have been approved as of the above date.

Please inform the recorded holder cf these mining claims and so indicate on your records.

Yours very truly,

McGinn, Director sfnds Administration Branch

Whitney Block, Room 1617 Queen's Park Toronto, Ontario M7A 1X1 Phone: 416-965-6918

DN/mw

cc: Noranda Exploration Company, Ltd. Thunder Bay, Ontario Attn; Mr. R. S. Woolverton

cc: Noranda Exploration Company, Ltd. Toronto, Ontario

cc: Resident GeologistSioux Lookout, Ontario

r *

Ministry ofNajuraiResources

Ontario

LandsAdministrationBranch

Projects Unit Technical Assessment

Work CreditsFile 2.2447

Recorded HolderNoranda Exploration Company Limited

Township or AreaClaw Lake

Type of survey and number of Assessment days credit per claim Mining Claims

GeophysicalElectromagnetic

Magnetometer.

Radiometric — 10

Induced polarization

Section 86 (18)^.

Geological ——— 10

Geochemical.

.days

.days

.days

.days

.days

.days

.days

Man days D

Special provision O

Airborne bil

Ground C3

Hotte* of Intent to b* is*u*d:

CD Credits have been reduced because of partial Coverage of claims.

O Credits have been reduced because of corrections to work dates and figures of applicant.

O No credits have been allowed for the following mining claims as they were not sufficiently covered by the survey:

Pa. 376378 to 81 inclusive

376390 to 93 "

436403 -04

436415 - 16

Jfc - .'if "V The Mining Recorder may reduce the a')ovo credits if necessary in order that the total number of approved assessment days recorded on

' tl'MCh claim doe* not exceed the maximum allowed as follows: Geophysical — 80; Geological —40; Geochemical — 40;

Ontario

Ministry of Natural Resources

GEOPHYSICAL - GEOLOGICAL - GEOCHEMICAL TECHNICAL DATA STATEMENT

File.

TO BE ATTACHED AS AN APPENDIX TO TECHNICAL REPORTFACTS SHOWN HERE NEED NOT BE REPEATED IN REPORT

TECHNICAL REPORT MUST CONTAIN INTERPRETATION, CONCLUSIONS ETC.

Type of Survey(s) GEOLOGICAL SURVEY———————— Township or Area CLAW LAKE AREA M. 2134————— Claim Holder(s) NORaNDA EXPLORATION COMPANY, LIMITED

BOX 45. COMCRCE COURT VI., TOBCNTO

Survey Company NQRflNDA EXPLORATION COMPANY, LIMITED

Author of Report BARRIE F. JOSE______________Address of Author BOX 2656. THUNDER BAY, CNTARIO

Covering Dates of Survey AUGUST 21-SEPIEMBER 2, 1976( [incoming to office)

Total Miles of Line Cut ___________________ ! -

SPECIAL PROVISIONS CREDITS REQUESTED

ENTER 40 days (includes line cutting) for first survey.

ENTER 20 days for each additional survey using same grid.

Geophysical

—Electromagnetic.—Magnetometer^—Radiometric——

DAYS per claim

-Other.Geological 2Q On each of

12 claims Geochemical______——

AIRBORNE CREDITS (Special proviwon crediu do nol ipply to airborne lurveyi)

Magnetometer. .Electromagnetic.(enter dayi per claim)

DATE- JULY 5' 1977 SIGNATURE:,

. Radiometric

Res. Geol.. Q.. a lifirr.,innc ^3' l f Q*

Previous Surveys File No. Type Date Claim Holder

JUL i l

MINING CLAIMS TRAVERSED List numerically

PA 376378(prefix)

PA 376379(number)

PA 376380

PA 376381

PA 376390

PA 376391

PA 376392

MINISTRY OF NATURAL RESOUi

R EC SJ-V ED!l1sioux LOOKOUT

PA 376393

PA 436403

PA 436404

PA 436415

PA 436416 '

TOTAL CLA1MSJ2.

*.N

feU

t-

*Y

^f

K

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