•qj/i vqv.^yd s:-i3ynos:-im - ontario · rock, r-p.d geothermal zones. a vertical conductive slab...
TRANSCRIPT
:Z6l '
Aq
•QJ/I VQV.^YD s:-i3ynos:-iM
010A3N1IHM
42A06NE0046 2 . S833 WH l TNE: Y
010C
Fi: '..-r; r.-1 at i on
2-4
5
5
i x
rt b y P .('. Fra-;.-r "Hi;.-ju-n Survey of South Porcupine Area, Ontario,^vt.^.h.-r 26, 1977. D. 78.
MAPS
1.
A :.,-': .'' - y -l r:.. - ' ./, y ';. y ii: ' . .n Ltd. was (. a i r i ud out in - 'Uth.-rn Whitney
: ...•'.'p in .'•. ,: t .''/7 .-.r i:..- : - -. : .\-A\O K -AU .-;CKS CANADA i.,D. i-ioi^in-s. rhis
s;::-vi-v v.i:j .-^ n t :\u: t , " l b v C : 'M I Ni.'O T.t j . vlio at the t i in.? were wnrking on the RoSARiO
:, ' l '. ' . / s . A : . r ; !'. :: ,'f :!iii ; : i r v..-r;.. j i'.;rv..-y (•...T.-.TH- t J cs only) w.is s:ih::;i t t ed in
.h' '.r i-'// i.. y . ". '. J i"., r . : ' - : /:it croiiit nil the Alanio * [ -orLion of the cl.ihr.s.
F;:.' i . -• 1 ---i- ,r.,-v i: -i w : -:" :.. '. (. : - - d h.-n-in giving v!ie Di^hen II results over
;- ; rt , .;' :".- A!", r-' :i : . ::y . -.:- \ - 11 ,' i' t h. e A1-..;i.j c l /i l n ;,ri.;i:;5 as well as the
t-nh i]M'.-d 1. l i l ' - '"''i') -::,:i''tie r.-uiits and ri'sistivity nap doriv,-d from the elec-
t : ' . .-! i o i : f, ' : :' :-:-i.
:;:. ( . : ' :! ; , ., l. i. /-) l , : 'i-. :i.U. l'. ^ - r ^ivi:. ; ; a d.-:., r :,-.(. [on of the !u-Uro;-,t.-r
i r. s t.i 11,i t i mi , il.it.-i ;-.roi-.-^ri i nj; ;- roe, -duros , and into rp re tnt i on is included with
this i :ir. r -..hi- t "rv i^-, "ft .
Ala.iio i'l-t r.i h'iiin Ltd., who 11 y ,-vnod subsidiary of Rosario Resources Corporation.
: . - -- I T V
;2,- - l : : : . '.- VI!;.;;; l./ . .'.'.X! O . : i ,/ t. roKai into Lwu groups - the AlU.-rstan option
•. :..; ' 2 ,- ' " ; : ' 'up . i ' r. l y tin 1 .- :- t ,-rn p o rt i .m of the A l l c- r s i o n opt ion 2 as lu-.-n
i '..'i'.-'! Lv t!.,.' -;:r'. ,-y \Jiilo all of the Alamo claims received full coverage. Only
•'.•'..' r' : '.- ~ i :i i 1 - .'-. i l . ; :i oprii'.i that r.-o.-ivi-d r,JVL-r.p i'.io and were ellielble at
;';,:-; ::.,- :".-r i" : i : ' . r . . ;.:.\ .' i .-a ] a '- : -. - ;-,.-n t orcdits are h', 'wn on tile maps
.it ('i,- ^ /k .d" th ; :-; ;-.-p.'rt. All of the Alano v'roup is shown on the naps although
' i ' i!..; : L-,- 10 o ...-,'-r \ '.* . .- "i l i '.; ib 1 1- for furi.li.-r ;v:-opl!v s i ..-a l orcdits, }'iT:sure-
...-iiis of liu? l Sai.- uiles uv,-r cauh block give 15.69 miles over the Allerston claims
.-.nd 47. ~'i r) r .Mi--; ov.-r ;';.- Alam-v claims.
..M :, r:.; i n r; i.,i : ,s
nili-s x 40/21 elms -- 29.9 d ays per c Ira per parameter
IP. '..g'lU
P. 4.!'"J
P. 4.'
P. 42i
P. 42(
^. 421
P . 4.y..H
l'. 4.!! ''18/4
P. 42uf';s5
P. 42UOS6
P. 42UUH7
P. 443580
P. 4.VJ58H
:'.:rv.-y (a-, -d i ts
.V).9
29.9
J9.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
Higlic-n KM Purvey Gr.'d i us
Allowable CreditsRemaining
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
29.9
15.5
15.5
15.5
15.5
15.5
15.5
15.5
15.5
15.5
15.5
40
40
15.5
15.5
l LI O'Jl l S'/'
Sill L1 D:i e 101
1 1
1 1
1 1
1 1
1 1
1 1
I 1
II
I 1
II
II
It
1 1
(l
I 1II
II
II
1 1
M
I l
II
II
II
I l
II
II
l l
I l
II
ii 11 11 1t 11 11 11 11 ii n M 11 n 11 M nM
II
l l
I l
II
M
II
II
l l
I l
II
II
II
II
69
•d•d•d•d•c! 'd 'd "d
'd•d•d 'd 'd 'd•d 'd 'd•d 'd 'd "d "d 'd•d•d
•d "d 'd 'd
l l
K
l l
l l
M
1111l!
a'd 'd Pd 'd 'd
"'.•: ills .-i ',he ~;i.h'-:p. if .y--, t -..a ;-.nd i n t i- rp r L- t a L i 0:1 are v;iveii in the following
r. -p. .rt ;.y D. C. Fra-.er
r..;i, l M'.iu-S
i'::.' a ! r' 'i', ,- i X - ; :- . .-y '..:; . •.-; ! l i ;.,-d v. ir;. M;S -- u l ph i J, --ox i de i r--n fo r;:;:i t i ons
whirl! ;:, -y st-i'Vi'- a. i a ^uu'.e Lo base r.ieLal or precious netal deposits within
or p- : ra]k-l to the ii'di ! o r... .1 L i on horizons. Major folds within so'ith central
W'.: i i :..-v i. ill a;-r- h,- tr:c,-il fro:'i the airborne data.
Ri- -pec. t fill ly -.;ubrri L ted ,
-- - : - '
R.S. M idd le r onK:-.p l orat :' on Manager, Canada.
R.M/1.J
REPORT f!o. D73
DIGHFH SUMY
OF
SOU Hi POP.OJPINE ARB, OrlTARIO
Linm
BY
(.w\\m
TORONTO,SEPTEI'BER 26, 1977
D, C, FRASER PRESIDENT
SUMMARY
.IIA DK;H;:M airborne electromagnetic/resistivity/
magnetic survey of 254 line-miles was flown for
Coininco Lira i t eel in /uigtist 1977, in the South Porcupine
area of: Ontario. A considerable number of conductors
wen? detected, some of which v;ere recognizable only
on those channels which have geological noise stripped
off. Several discrete targets were identified.
LOCATION MAP
8I"00'
Scale l : 250.000
Figure 1. The survey area.
I Ij PRODUCTION
i A DlGHi-iM survey of 254 line-miles was flown with a 400-
foot line-spacing for Coininco Limited on August 9th, 1977,
in the South Porcupine area of Ontario (Figure 1). The
Alouette II jot helicopter C-GNQX flew with an average
airspeed of GO nph and EM bird height of 110 feet. Ancillary
equipment consisted of a Geometrics 803 magnetometer with
its bird at an average height of 160 feet, a Sperry radio
altimeter, Ceocam sequence camera, 60 hz monitor, Barringer
8-channel hot pen analog recorder, and a Geometrics G-704
digital data acquisition system with a Cipher 70 7-track
200-bpi magnetic tape recorder. The analog equipment recorded
six channels of KM data at approximately 900 hz and one of
magnetics and radio altitude. The digital equipment recorded
the KM data with a sensitivity of 0.2 ppm/bit and the magnetic
field to an accuracy of one gamma.
The Appendix provides details on the data channels,
their respective noise levels, and the data reduction procedure.
The quoted noise levels are generally valid for wind speeds
up to 20 mph. Higher winds may cause the system to be
grounded because excessive bird swinging produces control
difficulties in piloting the helicopter. The swinging
results from the 50 square feet of area which is presented
by the bird to broadside gusts. The DIGHEM system nevertheless
can be flown under wind conditions that seriously degrade
other AEM systems.
- 2 -
DATA PRESENTATION
D'lGHEM electromagnetic responses fall into two
general classes, discrete and broad. The discrete class
consists of sharp well defined anomalies from discrete
conductors such as sulfide lenses and steeply dipping sheets
of graphite and sulfides. The broad class consists of wide
anomalies from conductors having a large horizontal surface
such as flatly dipping graphite or sulfide sheets, saline water-
saturated sedimentary formations, conductive overburden and
rock, r-p.d geothermal zones. A vertical conductive slab with
a width of 200 m would straddle these two classes.
The vertical sheet {half plane) model is the most
common model used for the analysis of discrete conductors. All
anomalies plotted on the electromagnetic map are interpreted
according to this model. The following section entitled
Discrete conductor analysis describes this model in detail,
including the effect of using it on anomalies caused by
broad conductors such as conductive overburden.
The conductive earth (half space) model is the most
suitable model for broad conductors. Resistivity contour maps
result from the use of this model. Resistivity contour maps
should be prepared when the EM responses predominantly are of
the broad class. A later section entitled Resistivity
describes the method further, including the effect
of using it on anomalies caused by discrete conductors such
as sulfide bodies.
D i ^cvrr^e c o n d u c t o r jaji '"\ly_s_is_
The EM anomalies appearing on the electromagnetic
map are interpreted by computer to give the conductance
(i.e., conductivity-thickness product) in mhos of a vertical
shoot model. DIGHEM anomalies are divided into six grades
of conductance, as shown in Table I. The conductance in
mhos is the reciprocal of resistance in ohms.
Table I. EM Anomaly Grades
A no ra a 1 y Grade
654321
Mho
5020105
Ranae
^ 100- 99- 49- 19
9^ 4
The mho value is a geological parameter because
it is a characteristic of the conductor alone; it generally
is independent of frequency, and of flying height or depth
of burial apart from the averaging over a greater portion
of the conductor as height increases.* Small anomalies
from deeply buried strong conductors are not confused with
small anomalies from shallow weak conductors because the
former will have larger mho values. ;
* This statement is an approximation. DIGHEM, with its short coil separation, tends to yield larger and more accurate mho values than airborne systems having a larger coil separation
Conductive overburden generally produces broad EM
responr.es which are not plotted on the EM maps. However,
patchy conductive overburden can yield discrete-like anomalies
with a conductance grade {cf. Table I) of l, or even of 2 for
highly conducting clays. The anomaly shapes from the multiple
coils often allow surface conductors to be recognized, and
these are indicated by the letter S on the map. The remaining
grade l and 2 anomalies could be weak bedrock conductors. The
higher grades indicate increasingly higher conductances.
Examples: DTGHEM's New Insco copper discovery (Noranda, Quebec)
yielded a grade 4 anomaly, as did the neighbouring copper-zinc
Magusi River ore body; Mattabi (copper-zinc, Sturgeon Lake, Ontario)
and \\histle (nickel, Sudbury, Ontario) gave grade 5; and DIGUEM's
Kontcalrn nickel-copper discovery (Timmins, Ontario) yielded
a grade G anomaly. Graphite and sulfides can span all grades
but, in any particular survey area, field work may show that
the different grades indicate different types of conductors.
Strong conductors (i.e., grades 5 and 6) are
characteristic of massive sulfides or graphite. Moderate
conductors (grades 3 and 4) typically reflect sulfides of
a less massive character or graphite, while weak bedrock
conductors (grades l and 2) can signify poorly connected
graphite or heavily disseminated sulfides. Grade l conductors
may not respond to ground EM equipment using frequencies
less than 2000 hz.
- 5 -
The presence of sphalerite or gangue can result in
ore deposits having v;eak to moderate conductances. As an
example, the three nill d on ton lead-zinc deposit of
Restigouche '-lining Corporation near Bathurst, New Brunswick,
yielded a well defined grade l conductor. The 10 percent
by volume of sphalerite occurs as a coating around the
fine grained massive pyrite, thereby inhibiting electrical
conduction.
On the electromagnetic map, the actual mho value
and a letter are plotted beside the EM grade symbol. The
letter is the anomaly identifier. The horizontal rows of dots,
beside each anomaly symbol, indicate the anomaly amplitude
of the flight record. The vertical column of dots gives
the 'estimated depth. In areas where anomalies are crowded,
tlie id'.-nt i f i crs , dots and mho values may be obliterated.
The KM grade symbols, however, will always be discernible,
and the obliterated information can be obtained from the
anomaly listing appended to this report.
The purpose of indicating the anomaly amplitude
by dots is to provide an estimate of the reliability of
the conductance calculation. Thus, a conductance value
obtained from a large ppm anomaly (3 or 4 dots) will be
accurate whereas one obtained from a small ppm anomaly
(no dots) could be inaccurate.
The absence of amplitude dots indicates that the
anomaly from the standard (coaxial maximum-coupled) coil is
5 ppm or less on both the inphase and quadrature channels.
Such 5-,mill anomalies could reflect a weak conductor at
the surface, or a stronger conductor at depth. The mho
value tiiid depth estimate will illustrate which of these
possibilities best fits the recorded data. The depth
estimate, however, can be erroneous. The anomaly from a
near-surface conductor, which exists only to one side of
a flight line, will yield a large depth estimate because
the computer a:; r, nmo s that the conductor occurs directly
beneath the flight line.
Flight line deviations occasionally yield cases
where two anomalies, having similar mho values but
dramatically different depth estimates, occur close
together on the same conductor. Such examples illustrate
the reliability of the conductance measurement while
showing that the depth estimate can be unreliable. There
ara a number of factors which can produce an error in
the depth estimate, including the averaging of topographic
variations by the altimeter, overlying conductive overburden,
and the location and attitude of the conductor relative to
the flight line. Conductor location and attitude can
provide an erroneous depth estimate because the stronger
part of the conductor may be deeper or to one side of the
flight line, or because it has a shallow dip.
- 7 -
A further interpretation is presented on the EM
map by ir.oans of the line-to-line correlation of anomalies.
This provides conductor axes which may define the geological
structure over portions of the survey area.
Tlie majority of massive sulfide ore deposits
have strike lengths of a few hundred to a few thousand
feet. Consequently, it is important to recognize short
conductors which may exist in close proximity to long
conductive bands. The high resolution of the DIGHEM system,
and the l.i no-to-1 ine correlation given on the EM map,
are especially important for a proper strike length
e Veil nation .
DIGHEM electromagnetic maps are designed to provide
a correct impression of conductor quality by means of the
conductance grade symbols. The symbols can stand alone
with geology when planning a followup program. The actual
mho values are plotted for those who wish quantitative data.
The anomaly ppm and depth are indicated by inconspicuous
dots which should not distract from the conductor patterns,
while being helpful to those who wish this information.
The nap provides an interpretation of conductors in terms
of length, strike direction, conductance and depth. The
accuracy is comparable to an interpretation from a ground
EM survey having the same line spacing. '
- 8 -
hii KM anomaly list attached to each survey report
provides a tabulation of anomalies in ppm, and in mhos and
estimated depth for the vortical sheet model. The anomalies
are listed from top to bottom of the map for each line.
The EM anomaly list also shows the conductance in
mhos and the depth for a thin horizontal sheet (whole plane)
model, but only the vertical sheet parameters appear on the
KM map. The horizontal sheet model is suitable for a flatly
dipping thin bedrock conductor such as a sulfide sheet
having a thickness less than 50 feet. The list also shows
tile resistivity and depth for a conductive earth (half
space) model, which is suitable for thicker slabs such as
thick conductive overburden. In the EM anomaly list, a
depth value of zero for the conductive earth model, in an
^^rea of thick cover, warns that the anomaly may be caused by
conductive overburden. Since discrete bodies normally are
the targets of EM surveys, local base (or zero) levels are
used to compute anomaly amplitudes rather than true zero
levels. The use of local base levels may distort the
horizontal sheet and conductive earth parameters. True
zero levels, however, are used for resistivity mapping,
discussed below.
Resistivity mapping
t
Areas of widespread conductivity have been encountered
while surveying for base metals. In such areas, anomalies
- 9 -
can bo genera t cd by decreases of only 20 feet in survey
altitude, as well as by increases in conductivity. The
typical flicjht record in conductive areas is characterized
by inphase and quadrature channels which are continuous
ly
active; local peaks reflect either increases in
conductivity of the earth or decreases in survey altitude.
For such conductive areas, apparent resistivity contour
maps
can aid the interpretation of the airborne data. The
advantage of the contour maps is that anomalies caused
by
altitude changes are considerably reduced, and the cont
ours
reflect mainly those anomalies caused by conductivity c
hanges,
In areas of widespread conductivity, many anomalies on
the
KM map ;:,ay be caused by altitude variations. The majority
of those "anomalies" are flagged by S or S? (see map legend) .
A more quantitative approach is to prepare a resistivity
contour map. Such a map improves the interpreter's ability
to differentiate between conductive trends in the bedro
ck
and those patterns typical of conductive overburden.
Discrete conductors will appear as narrow lows on the c
ontour
map and broad conductors will appear as wide lows.
Conductive overburden diminishes the ability of
an EM s;ystem to effectively explore the bedrock. For
cxiimple, the lower the resistivity of the cover, the
more active the EM channels, and the less the likelihoo
d
of recognizing that a particular anomaly might be cause
d
by a bedrock conductor. As a general rule of thumb, the
effectiveness of the DIGHEM system for base metal
- 10 -
explorat i cm is given in Table II
Table II. Influence of Conductive Cover
On Base Metal Surveys.
Resistivity
> 300 ohn-m
100 to 300
30 to 100
^ 30
Exploration effectiveness
at 900 hz
excellent
good
moderate
poor
Apparent resistivity r?.aps should be constructed
when the exploration effectivenss ('/"'able II) is moderate to
poor, because the contour patterns can be helpful in
differentiating between bedrock and overburden conductors.
Wide resistivity lows nay be caused by broad (e.g., f latly
dipping) bedrock conductors or by conductive overburden.
The two can only be differentiated on the basis of the
resistivity contour patterns coupled with knowledge of the
geology. For example, a wide east-west resistivity low
might .suggest the existence of a bedrock conductor in an
area of flatly dipping stratigraphy which strikes east-
west, whereas it would be suspect if the geological
strike was north-south. -
- lOa -
X t vi'1 P el ec t r o m an p. otic responses
DIGI1EM naps contain x-type EM responses in addition to
KM anomalies. An x-type response is below the noise threshold
of 2 ppm, and reflects one of the following: a weak conductor
near the surface, a strong conductor at depth (e.g., 300 to 400
feet below surface), or noise. Those responses that have the
appearance of valid bedrock anomalies on the flight profiles
are mentioned in the report. The others should not be followed
up unless their locations are of considerable geological interest.
The thickness parameter
TT . ,U1GHKM " can provide an indication of the thickness of a
steeply dipping conductor. The ratio of the anomaly amplitude
of channel 2-I/channel 22 generally increases as the apparent
thickness increases, i.e., the thickness in the horizontal plane.
This thickness is equal to the conductor width if the conductor
dips at 90 degrees and strikes at right angles to the flight line.
This report refers to a conductor as thin when the thickness is
likely to be less than 3 m, and thick when in excess of 15 m.
Thick conductors can be high priority targets because most
massive sulfide ore bodies are thick, whereas non-economic bedrock
conductors are usually thin. An estimate of thickness cannot be
obtained when the strike of the conductor is subparallel to the
flight line, when the conductor has a shallow dip, or when
the anomaly amplitudes are small.t
R o du c t i o n ^o f c o n d u c t i v e o v erburden response
The DIGHKM system yields four channels which generally
- lOb -
are free of the response of conductive overburden. These
are the i nphase differences channel 33, the quadrature
difference:; channel 34, and the two anomaly recognition functions
of channels 35 and 36. Channels 35 and 36 are used to trigger
the conductance channel 37 which identifies discrete conductors.
Discrete conductors usually occur in the bedrock, such as
sulfides or graphite, rather than in the overburden, such as
conductive clay. Only discrete conductors are plotted on the
EM nap. Broad (i.e., non-discrete) conductors are not plotted
on this i.'.ap, but are identified by lows on the resijjtivity
contour raap.
Magnet itc produces a form of geological noise on the inphase
channels of all KM systems. Rocks containing as little as lL%
magnetite can yield negative inphase anomalies. When magnetite
is widely distributed throughout a survey area, the inphase EM
channels may continuously rise and fall reflecting variations
in the magnetite percentage, flying height, and overburden
thickness. This can lead to difficulties in recognizing deeply
buried bedrock conductors, particularly if conductive overburden
also exists. However, the response of magnetite generally vanishes
on the inphase differences channel 33. This feature can be a
significant aid in the recognition of conductors which occur
in rocks containing accessory magnetite.
- 11 -
Kaqne t i os
The existence of a magnetic correlation with an
EM anomaly is indicated directly on the EM photomosaic,
An EM anomaly with magnetic correlation has a greater
likelihood of being produced by sulfides than one
that j s non-magnetic. However, sulfide ore bodies
may be non-magnetic (e.g.. Kidd Creek near Tiirjnins,
Ontario) as well as magnetic (e.g., Mattabi).
The magnetometer data are digitally recorded in
the aircraft to an accuracy of one gamma. The
digital tape is processed by computer to yield a
standard total field magnetic map contoured at 25
gamma intervals. The magnetic data also are treated
mathematically to enhance the magnetic response of the
near-surface geology, and an enhanced magnetic map is
produced with a 100 gamma contour interval. The
response of the enhancement operator in the frequency
domain is shown in Figure 2.
The enhanced magnetic map bears a resemblance
to a ground magnetic map. It therefore simplifies
the recognition of trends in the rock strata and the
interpretation of geological structure. The contour
tJ o
ID-" io- J
CYCLES X FOOT
Figure 2 Frequency response,- of mbgnetic operator
- 12 -
Interval of 100 gammas is suitable for defining the
near-surface local geology while de-emphasizing deep-
s e a t e d reg i onal f c' a tu res.
7\part from the difference in the contour interval,
the enhanced magnetic map and the standard magnetic map
are Identical when magnetic basement rocks underlie
several thousand feet of non-magnetic cover. The
difference between the two maps increases with the
amount of magnetization of the near-surface geology.
Tiie presence of a magnetic coincidence with an
EM anomaly can result because the conductor Is magnetic
or because a magnetic body occurs in juxtaposition
with tlie conductor. Tne majority of magnetic
conductors represent sulfides containing pyrrhotite
or magnetite. However, graphite and magnetite In close
association can provide coinciding EM-magnetic anomalies.
The truly magnetic conductors tend to follow closely
the contoured magnetic highs. Such coincidence may
be more evident on the enhanced magnetic map than on
the standard magnetic map because of less disturbance
from regional magnetic features. The enhancement,
therefore, provides data maps which contribute to the
evaluation of EM anomalies.
- 13 -
CONDU CTORS^ INJTHE SURVEY 7*.REA
The DTGHKM map provides an interpretation of conductors,
as to Lhoir length, strike direction, depth, and conductance
quality or conductivity-thickness product in rihos. There
remains only to correlate these conductors with the known
geology to provide the next step in the exploration program.
When studying the KM map for followup planning, consult
the anomaly listings appended to this report to ensure that
none of the conductors are overlooked. Conversely, the original
nap may be printed with topography burned out, leaving only the
anomalies which then will be clearly visible.
The survey area was fairly active due to cultural features
and to the abundance of bedrock conductors and conductive
overburden. The resistivity over bedrock conductors was as
low as l ohrn-m, sharply contrasting with the overburden
resistivity of 300 chru-m.
The KM map indicates which anomalies are believed to be
caused by cultural and surficial sources. Generally, such
anomalies are not commented on below, as the discussions are
directed to identifying bedrock conductors.
Tlie field followup should not completely ignore anomalies
interpreted to be of a possible cultural source. If the
followup shows that culture does not exist near suc.h an anomaly,
then the conductor probably occurs in the bedrock.
Knomaly 19D
Groups 6 , 7
Anoma l i os 28C, 3 CD
Group 8
Group 9
- 15 -
A single-line grade 2 bedrock conductor, with
a 20 gamma magnetic correlation, occurs on
strike with group 5.
These groups reflect huge conductive zones
with widths up to 700 feet. The zones are better
defined by the resistivity map than the EM map
because of the considerable thicknesses involved.
The enhanced magnetic map clearly defines the
associated magnetic properties of these zones,
and suggests that group 8 is an extension of
group 6.
These single-line grade l conductors may have
their computed mho values degraded by conductive
overburden. They may reflect a widening of the
huge conductive zone of group 7. There is a
possibility, however, that they are isolated
from this zone. They appear to have a weak
magnetic correlation.
A short strong conductor exists with a 150 gamma
magnetic correlation. The EM responses on the
south end (lines 11 and 12) are subtle. Both
conduct^lnce and thickness increase to the north.
Lines 9, 13 and 14 converge on a conductor having
a grade 2 conductance. It occurs in an area
of intense electromagnetic activity and is
largely masked by neighbouring strong conductive
and magnetitic EM responses. Its apparently
isolated nature suggests that it may be an
interesting target.
Group 10
Group 11
Anomaly 15F
Grouo 12
Group 13
Group 14
' - 16 -
One or rriore conductors strike parallel to
the flight lines, making resolution impossible.
The conductors are only visible on the whaletail
inphase channel 24 and on the resistivity channel
40. The resistivity map shows the general
conductive trend.
A 700-foot long non-magnetic grade l conductor
is isolated from other conductive responses, and
so could be an intei'csting target.
A single-line near-surface non-magnetic conductor
is indicated by a sharp quadrature response on the
standard coil-pair. There is a possibility that it
could reflect an unusual sferic pulse or a
discarded geophysical wire.
A 350 galena correlation exists with a grade l
conductor which has a length of 1200 feet. The
conductor is poorly defined because of geological
noise, and its conductance may be larger than
the computed value.
Two short conductors on lines 22 and 24 may exist,
hidden in geologic noise. Magnetic correlations
of 100 to 450 gammas occur with these questionable
conductors.
The single-line grade 6 anomaly 24E exists only
on the whaletail coil-pair. It correlates with
a 10 gamma magnetic high. There is a suggestion
that it extends northeastward to the x-type response
on line 25. This x-type response also exists only
)
- 17 -
on the vha l etail coil-pair, and is only l ppra
in amplitude. The followup of the conductor may
prove difficult, as it could represent a blind
body at a depth in excess of 300 feet.
Group 15 This group consists of three x-type responses
which strike parallel to the magnetics. They
could reflect a conductor at a depth in excess
of 300 feet.
Group 16 A grade 2 conductor with a 20 y a ram a correlation
(v;hich is visible only on the enhanced map) has a
length of 700 feet. It appears to be an attractive
target as it is isolated from long conductive
7, o n e s .
Croup 17 The anomalies of group 17 are complicated by
cultural features. The conductor usually appears
to be thin over most of its 1.5-mile length.
The zone may widen to include anomaly 43B. The
conductor is generally magnetic , which can best
be seen on the enhanced magnetic map.
Group 18 This grade 3 conductor lies outside of the survey
area. The anomalies may be somewhat mislocated
because the aircraft was in process of turning
towards the next survey line.
Group 19 A moderately wide conductive zone extends for
over one mile before it runs off the map sheet.
It occurs on the southeast flank of a' magnetic
high.
- 18 -
lAnomaly 48C This single-line grade 2 conductor might be
caused by conductive overburden. It has a magnetic
correlation of 150 gammas, with a somewhat thumb-
print-shaped pattern on the: enhanced magnetic map.
Group 20 Two x-t.ype responses could reflect a moderately
strong non-magnetic conductor at a depth greater
t'nan 300 foot.
Anomaly 55D A short non-magnetic grade 3 conductor yielded
a strong anomaly on the whaletail coil-pair and
a weak response on the standard coil-pair. This
.implies that the system f lev; subparallel to the
strike of the conductor. The magnetic map chows
a diabase dike-like feature with such a strike
within 1000 feet of the EM anomaly. The anomaly
certainly should be followed up if previous work
lias not explained its source.
Anomaly 580 An x-type response on an adjacent line correlates
with this non-magnetic grade l anomaly. The
conductor may have a stronger conductance than
indicated on the map.
Respectfully submitted,
Toronto, Ontario Scotember 30th, ]977 /is
Four maps accompany this report
Elec tromagnet ic s
Res i stivity
Magnet ics
Knhanoed magnetics
D. C. Fraser President
l map sheet
l map sheet
l map sheet
l map sheet
- 14 -
The following anomalies may be of interest.
Croup l A conductive magnetic band, with a length 'of
3 miles, runs off the southwest boundary of
the survey area. Conductance grades vary from
l to 6. The zone appears to reflect iron formation.
Croup 2 A cluster of high conductance EM anomalies
coincides with a 900 gamma elliptical magnetic
anomaly in an area of culture. Some of the EM
anomalies may reflect bedrock conductors, but
most appear to be cultural.
Croup 3 A n on-magnetic grade l conductor extends over
a length of 1/2 mile. It is believed to reflect
mainly a bedrock source although some of the
anomalies may be caused by conductive overburden.
Anomaly 14::F A non-magnetic single-line grade l anomaly
reflects a weak near-surface conductor. There
is a possibility that the anomaly is caused
by a local pocket of conductive overburden,
although the resistivity does not support this.
The resistivity gradient shows that the EM
anomaly occurs at a point where overburden
thickness increases rapidly.
Groups 4,5 Group 4 outlines a non-magnetic conductor, with.
conductance grades of 2 to 4, which has a
length of one mile. It runs along the northwest
flank of a magnetic high. Groiip 5 runs along
the southeast flank of the same magnetic high,
reflecting a generally non-magnetic conductor
of grades l to 6.
II
^-JU'-E-IL D I x
THI-^ FI, I r. i i T EKCOPJ3 7\ND PATH RECOVERY
The flicjht record is a roll of chart paper containing the
geouhy L. i cal profiles. Tb.e profiles v;ere generated by computer at
a scale identical to the geophysical reaps. The flight record
contains up to 16 channels of information, as follows:
ChannelNumber_
20212223242528293132333435363740
Parameter
i.-.,v-,nL-t i c sa l L i L ii d estandard" coil-pair inphasestandard coil-pair quadraturev'p. a l L- t ;i i l"-'; ' : coil--pair inphasev/haletail coil-pair quadrature
:.-.LiniLor (standard receiver) i .i en t noise monitor (whalelail receiver)
t:;:i^s function inphase ;-sums function quadrature""**differences function inphasedifferences function quadraturefirst anomaly recognition functionsecond anonaly recognition functionconductaucel op, r esist iv i t y
Scaleun its/mm
1010
1111111111111
.03
gammafeetppmppmpprappmpprappmppmppmppmppmppmppmmhodecade
Noise
2 C-5 fc1-21-21-21-2
00
1-21-21-21-21-21-2
——etpprrpp::ippi.lp p::Pi' :: 'ppiTiPP-"
ppi:ppF
pprrp p L
ppi-
coaxialhorizontal coplanar generally not plotted
The log resistivity scale of 0.03 decade/rnm means that the
resistivity changes by an order of magnetude in 33 mrn. The
resistivities at O, 33, 67 and 100 nun up from the bottom of the
chart are respectively l, 10, 100 and 1000 ohm-m. '-
- 11 -
The fiducial marks on the flight record represent points
on the ground which were recognized by the aircraft navigator.
Continuous photographic coverage allowed accurate photo-path
recovery locations for the fiducials, which were then plotted
on the geophysical reaps to provide the track of the aircraft.
The fiducial locations on both the flight records and
flight path maps were examined by a computer for unusual
helicopter spi.-ed changes. Such changes often denote an error
in flight path recovery. The resulting flight path locations
therefore reflect a more stringent checking than is provided
by standard flight path recovery techniques.
IIThe following brief description of DIGHEM illustrates
the information content of the various profiles.
The DJGi'KM system has two transmitter coils which are
mounted at right angles to each other. Both coils transmit at
approximately 900 hz. Thus, the system provides two completely
independent surveys at one pass. In addition, the flight chart
profiles (generated by computer) include an inphase channel and a
quadrature channel which essentially are free of the response of
conductive overburden. Also, the EM channels may indicate whether
the conductor is thin (e.g., less than 3m), or has a substantial
width (e.g., greater than 15 m). Further, the EM channels include
a channel of resistivity and another of conductance. A minimum
of 10 EM channels are provided. The DIGHEM system therefore gives
information in one pass which cannot be obtained by any other(
airborne or ground EM technique.
- 111 -
V
Fi (jure 3 shows a DIGHEM flight profile over the massive
pyrrhotite ore body in Montcalm Township, Ontario. It will serve
to identify the various channels.
The two upper channels {numbered 20 and 21) are respectively
the nagnetics and the radio altitude. Channels 22 and 23 are
respectively the inphase and quadrature of the coaxia
l coil-pair,
which is termed the stanclarcl coil-pair. This coil-pair is equivalent
to the standard coil-pair of all inphase-quadrature a
irborne EM
systems. Channels 24 and 25 are the inphase and quadrature of
the additional coplanar coil-pair which is termed the
whaletail
c o i l - p a i r .
Channels 31 and 32 are inphase and quadrature sums functions
of the standard enid whaletail channels; they provide a condensed
view of the four basic channels 22 to 25. The sums channels
normally are not plotted.
Channels 33 and 34 are inphase and quadrature differences
functions of the standard and whaletail channels. The differences
channels are almost free from the response of conduct
ive overburden.
Channel 37 is the conductance. The conductance channel essentially
is an automatic anomaly picker calibrated in conducta
nce units of
mhos; it is triggered by the anomaly recognition functions
shown
as channels 35 and 3G.
Channel 40 is the resistivity, which is derived from the
whaletail channels 24 and 25. The resistivity channel 40
yields
data which can be contoured, and so the DIGHEM system yields a
resistivity contour map in addition to an electromagn
etic map, a
magnetic contour map, and an enhanced magnetic conto
ur map. The
•V
. : i ' , i !; - quad -X -~! " - '
: i .v ; - * -'Sums t - -unction
ar.ornaty recugrlition. . - . ':- - -- --^* r- - —
f g i F ight r...-r f/ .i.'cdrn deposit, with line panllel to strike
.se!-'': .:,"- l Jf". d
v^vv-\;v;;::-:\;.\\f' :x\t -" f;' - ;V.SN :r]^-:vrv rvv.p; . --\ '^-
cok;-o;^v-:;;.:.;,v;::;,,;;-: ,:
iv -
c-nhancud magnetic contour map is similar to the filtered magnetic
m,ip d i s jus sed by Fraser.*
Figure 4 presents the DIGHEM results for a line flown
pL'rpi'ndicula rly to the Montcalm ore body. Channel 20 shows the
175 gamma magnetic anomaly caused by the massive pyrrhotite deposit,
For the I'M channels, the following points are of interest:
1. On channels 22-25 and 31-34, the ore body essentially
yjolcls only an inphase response. The quadrature response
is almost completely caused by conductive overburden
(which also gives a small inphase response). The hachures
show tile KM response from the overburden. The overburden
response vanishes on the differences EM channels, as can
be si-en by comparing the quadrature channels 25 and 34.
ThJ s is an .important point to note because DIGHEM. is
the: only r.M system which provides an inphase channel and
a quadrature channel which are essentially free of conductive
overburden response.
2. The whaletail anomaly of channel 24 has a single peak. This
shows that the conductor has a substantial width. If the
width had been under 3 m, the conductor would have produced
a weak m-shaped anomaly on channel 24.
3. The ore body yields a resistivity of 5 ohn-m in a background
of about 200 ohm-m (cf. channel 40). A dipole-dipole ground
resistivity survey with an a-spacing of 50 m showed a similar
background, but the ore body gave a low of only 53 ohm-m
* Cdn. Inst. Mng., Bull., April 1974.
bee,"iiir.e of the averaging effect inherent in the ground
technique.
4. The ore body has a conductance of 330 mhos according to
it::. KM response on this particular flight line. The
conductance channel 37 saturates at 100 mhos, and so the
deposit is indicated by a 100-mho spike.
Figure 3 illustrates the DIGHEM results for a l ine flown
subparallel to the ore body. The ore body anomaly is small on
the standard coil-pair (channel 22) but shows up strongly on the
v.'haletail coil-pair (channel 24).
073 i c y. i r; c o O'lT AljG/77
xA. f, 'O'-', AL Y
1A 'IB1C10IEIF
^Tf/.W co
HEALPPM
56146
1448
DAKDIL
QUADpprjj
307447
12
c c PL Acol
REALPPv
4115
1430
164
':ARL
OIJAOP P M
15570
1528
VERTCI
4
. corjD
. '-'HOS
t
4
3716
1426
. 156
TCALKE
.DEPTH*.FEET .
*,
30 .33 .
124 .137 .RO .43 .
HOR I70NTALSHEET
corjoMHOS
101247
33
DEPTHFEET
142146331328235139
CCNDUCTIEARTH
R ESI S DEOHf-'-M F
2403441141
VE
PTHEET
1062
215?52185121
2A2B2C202E2F2 G
1U73 -
2621
82400
152
04
1602
16015
1414820
283
11
182923
. 15622
2 .52 .
116 .300 .317 .12 .35 .
11575
335
76191306619652105263
733243
75816
045
24153755787
195
3A383C30
838
49
132
1 0
190
36134 '
603
17
725
. 158
. 197
0 .255 .R 5 .11 .
152
3040
141527245110
16311
10338822395
4 A4 B4 C.404E
5A505C505E5F5G
6A686C606E
50597
173
124a6
13
76
25219
18633
23
1212937
21516212
1?0
22225
102
142
171224
67
554018
21415
04
40
3315160
11
81932481
. 1231
119917
4
4
978629
5325
4
,
143
23H
. 173
1.57 ,0 .
97 .133 .161 .
*t
0 .190 .41 .0 .
73 .13? .92 .
A
,
64 .66 .63 .47 .
1P3 .
2413
204
202213
126
4164
32
37141
261293332
16046516297
224350255
278178185156363
1735151 -
9
13328
1492124
H764
121
343n
136264308
131345770
144299203
19773
13895
343
t* E STIMATED DEPTH MAY RE UNRELIABLE OF THE COMOUCTPR MAY RE DEEPER OR LINE, OR BECAUSE OF A SHALLOW DIP
BECAUSE THE STRONGERTO ONE SIDE OF THE FLIGHTOR OVERBURDEN EFFECTS.
078 coi'.itiCQ POHCUPir.r, r, f jT
^TAMHARO c o PL A r: A R^ COIL COIL
LINE X HEAL CHAD REAL SIJAO. , , , , , r ^ ri i* nt ; n ' o P *J!
AKOf-'ALY
8A 88
80 8E 8 F 8G 8 H 81
9 A9 i39C90 9E -
9 F 9G 9H
lOA10B 10Cloo
11 A 118 llC HD HE 11F11G
12A12012C 120 12E 12F
4)
1 . p M,
T5
36
7 3 3
57 16 22
10 225
12 10 14 b 5
466
18 12
109 77 67 2 4
203
1096134 9
18 2
n n
-' r i j .
7 19
20 8 9
40 3
10
2 107
18 4 4 2 4
208 7 6
102 31 28 12 5 86
1453828 7 6 5
1 O (i
r i ;
33 64
10 7 1
154 36 43
8 273
23 23 28 15 14
708
38 31
140 84
119 3 8
485
1373042 18 45 0
RS
i i
16 30
40 17 13 73 0
13
8 118
34a5 5 9
H13 1218
113 35 53 25a
125
1454832 14a6
1 07
AUG/77 I1
. VERTICAL . HORIZONTAL COHDUCTIVE
DIKE -. SHEET EARTH
' cnNC nrpTH*; COND 'OF.PTH RESTS DEPTH ! r.HOS FEET . MHOS FEET CHM-K FEET
4
*. 47 33
4
2 31
36297 44
t
; 23. 33
47
33 70
, 28 13
4
m r Q685
. 45 , 22
*
4
; 23. 53
511 7
. 55 4
4
16. 19
\ Ql fl 12
. 79 1
4
; i3
4
4
0 .0 .
4
0 .
37 .37 . 22 . 116 . 114 .
4
*
9 .Q .
Q Tt~ -J *
66 . 78 . 80 .
150 , 146 .
4
4
0 .61 .71 .105 .
4
*
4
0 .0 . 0 .
28 . 110 . 75 . 69 .
**
0 . 0 .0 .
76 . 90 . 40 .
4
4
0 .
11 9
11 1
10 53 11
6a i2a
15 7 4
162
116
7 13 13 1 2
13 1
5 654
17 1
4
10786
84169 153 113 260 253
210146253180 254 243 358 339
102215217 261
0 97 94 114 29fi 214 249
0 870
241 234181
0
1 2
8087
195 1 1 1
5 2
7023 3 1 4
12
1401b
3 1 1
203 32
1 73
556
12l
313
7
65 48
054 28 80
247 211
146 100 129101200 205 294 260
70110174 206
067 63 7
197 175 116
042 .0
168 200 27
0
13A 88
* ESTIMATEO DEPTH VAY Hf"THE STRONGER PAr?T .
FLIGHT .
D73 COV.IMCO PORCUP
^PrM:R.r.KO A .COIL
LINE X REAL OUAO P ANOMALY PPM P I'M
133 13C 130 13E 13F 13G 13H 131
14A 14B 14C140 14E 14F '
14G 14H 141 14J 14 K
-
*15A 15B 15C15D 15E15F
16A 168 16C 16D 1GE
17A178 17C170
47 5 0 6 7 0
12 17
144 147
52 1 0 2
10 2 0 7
121 6 2
93 170
53 014
7
1210
213
20 9
12 3 4 0 3 3
127 119 1012 1
13 2 5 0 1 4
91 14 1157 268
34 6 2 0 7
969
ia30
Tt, E, OrjT
co PL A r; A R COIL
EAL C'.JAO PPI-}' PPM
275 0
23 15 5
3 3 43
122 115
21 1 2
13 18 7 1
23
117 2 2
Ifll 191
34 0 2
10 19
1370
590
26 19 22 14 10 0 9 1
109 97 1317 17 30 3 9 1 1 7
101 22 1793 922
43 11 8 2 6
16416 4463
f.L'G/77
. VERTICAL . HORIZONTAL . CCMCUCTTVE
. "CIKE . SHEET EARTH
'. rOND DEPTH*; COMO DEPTH RESIS DEPTH . r-HOS FEET . *HOS FEET OH^-v FEET
*
! 29 31
13 16 14 63
. 277m
24 27311 1H2356 2
28
*
! 26 21
41 * ^ A4 1
*
191 2
70 17
t
221
171
*
10 . 33 . 0 .
52 .134 . 367 . 126 . 142 .
4
*
0 . 0 .
20 . 1 .
47 .5 .
126 . 103 . 271 . 240 . 111 .
*
*
0 . 13 . 10 . 7 .
15 .c3 *
*
t
0 . 0 .
133 . 216 . 78 .
*
t
0 . 0 .
36 .0 .
8 130 1 163 1 62 5 2274 324 3 731
14 2^6 50 231
7 0 8 0 1 147 1 711 137 1 29 3 339 6 233
12 550 1 603 7 295
8 0 1 1171 S3
11 392 92 1 116
6 01 88 1 310
15 446 5 260
7 0 1 545 151 1 0
3 86
865 7 9
17 1 1
3 2
97312513an" ifl5 2
20-5 4
2106 2711
140
598
5658 183
1a
3 777
6355
68 52 0
162 253 616 248 267
0 0
33 00 0
24-fl 226 501 374 237
0 13 0
6021 0
00
151 407 192
0 . 0
100 0
6A 125 118 139 166 .20 O .4 OO
^^;'1?^^,^,c;" R""L^Eu^^^PLo^oc^rsio^r?Hf?^^LINE" OR lit CAUSE OF YSHAU.O* DIP OR OVERBURDEN EFFECTS.
D78 CC
4)Wl-lNE X
ANO'-'ALY
18818C180
19A19B
19019 E19F
20A200
2002QE
21A21R21C
22A22Q22C
23A23023C23023E
24A24824C24024E24F
- 24G
j'-'lr.CU
ST ANCO
REALPPM
01010
7311
3275
467
37H
lo'*8
10
IB5
18
2217033
2197685
3
pcuc
DAROIL
QUADr- p M
" ,
35
15
3816
3128
2910
1410
105131
a5
14
1015659
79
1616244
jpir.'E,
CO PLCO
R r A LPP'I
02545
14316
6606
2610
1008
921216
114
32
921768
69
176
2126
ON T
ANARIL
CijADP P f/
69
44
3940
8267
2313
2410
107204
121221
1021161013
322
2322U56
AtjG/7
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
*
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
7
VERTICALD
C 0 N D -'HO S
12910
595
6384
226
764
185
98
194
17
2311243
22953
16235
IKE*
DEPTH*.FEET .
**
2 .flo .43 .
*.
0 .22 .
4
142 .67 .89 .
4
4
0 .40 .
.46 .36 .
4
4
0 .78 .
172 .4
50 ".104 .55 .
4
4
n .20 .29 .
116 .100 .
.*
0 .R6 .29 .21 .
131 .154 .142 .
HORIZONTALSHEET
COfvQ DEPTHMHOS F
173
152
2102
62
181
62
20
525
64111
1721
3112
EET
192251163
85127
346192250
55184
157181
0207355
210266191
110152150285234
58254148126311345336
CONDUCTIVEEAR
RESISOH" -H
5283
14
138
462
56
436
. 162
4361
6567
513
1836080
1466
38851
9556
T H
DEPTHFEET
1619796
5741
227152132
a85
12766
*
0112326
150148133
568823
162119
0201.5628
289198209
* ESTIMATED OEPTH ''AY PFT UNRELIABLE OF THE CONDUCTOR r*AY RE DEEPER OR
LINE, OR "ECAUSE OF A SHALLOW DIP
BECAUSE THE STRONGER PART TO O M: SIDE OF THF. FLIGHT OR OVERBURDEN EFFECTS.
078
9' F- 'A^O.'.'Al
25A25825C
26fl26C26D
27A27827C27027E
28A28B28C28D
29A^98 ^9C29D
30 A3QB3QC
31A3lB3lC3103lE3lF
CO". I f. C 0
ST A?- C
coi
i REAL.Y PPM
142214
131930
14171
10
1254
15 -
82' 38 1623
143240
1512834311150
PORC
A R nL
nUADPPr-l
81818
71925
61
1138
1112163
8721147
141415
1412426251416
UP i r-, r: ,
COPI.CO
R F A LPP^
23532
32697
200
225
42
5106
44
88116 3282
2377
114
12126985613
147
C NT
A r: A RIL
QUADpPV
72731
02556
32
266
17
32420
0
10135 5011
553416
121634ti613728
AIJG/77
4
4
4
t
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
*
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
VERTCI
C 0 N C'-'HOS
121610
231124
47273
24
1132
430
1651 9
146
640
106
101929145
126
ICALKE
DEPTH*FEET
651962
1092
11
6621516
10437
600
1067
015 2144
02
39
4807
453843
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
*
4
4
4
4
4
4
4
4
4
4
4
4
4
4
MOR ISP
connr-'HOs
453
647
111216
311
72
513 3
30
21023
36852
27
ZCriTALEET
DEPTHFEET
240143181
305125115
235509147304136
230102112205
0121 134162
0119146
1920
112146149139
CCNOUCEART
RESISOH" -M
147
15
5l*3
119126954
1561
lib1
51
151
2411
16428
371
T I VEH
DEPTHFEET
16387
113
2436372
18829360
154135
15328
196
008 65
142
082
121
1230
7297 .61
118
.32A 2 . 199
,* ESTIMATED DEPTH f'AY nr UWRFLT /\GLE BF C At-'SE THE STRONGER PftRT! OF THE CONDUCTOR f-'AY RE DEEPER OR TO OT.'E SIDE OF THE FLIGHT
LIfJEi OR BECAUSE OF A SHALLOW DIP OR OVERBURDEN EFFECTS.
80
. .' ,: a L
1J^r.'E sfPo-'ALY
3?B 32C 320 32E
33A 338 33C 330 33E
34 A 34 B 3 't C 3'iD 34E -
35A 3 5 [3 35C 350 3 5 E. 35F
t36A 360 36C 360 36E 36F
37A 370 37C 370 37E
v.:.- i ;, L 'J
S T A f,J C 0R Era,
r- P M
'36
44 16 18
67 2218 1 1 13
27 2718 7
35
29 26 29 15 6 tt
27 30 30 1 3
50
7 11 3
21 97
OAR nI L
0 LI A DPPM
'85
14 14 13
45 12 1 1 13 14
15 12 13 12 25
17 8
13 13 16 12
33 11 9 2 6
24
5 23
18 20
-ij.-lf-L,
CCPL CO
REAL PPM
95 11130 34
15 66 34 39 42
20 19 32 22
1 19
5 21 51 62 7
28
65 2541 1
36 135
13 14 0
35 259
C.;,' T
Af'AR IL
CHADPPM
97 23 28 25
10 34 3125 19
3014 21 26 50
4 7
25 16 35 24
ao10 118
44 50
0 6 5
53 18
AiJG/77
VERTICAL DIKE
4
. COMO
. r.'.HOS
4
*
20 100 13 16
*
24 30 1614 18
4
4
15 25 18 6
354
4
2153 35 33 2 9
9
! 11 42 62
1 7
52*
! 3248 3
10 . 359
4
DEPTH*.FEET .
*
4
0 . 0 .
53 . 72 .
*
4
0 .4n .72 . 12 . 23 .
4
4
0 . 91 . 14 . 57 . 18 .
*59 "
PO .61 . 55 . 20 . 60 .
4
4
0 . R6 . 13 .
116 . 9 .
42 .
.
83 .'111 .102 . 48 . 24 .
HORl^OrjT^L SHEET
COMQ f-1 H OS
6 22 4 5
78 5 4 5
47 5 2 9
6 12 9 9 1 3
4 10 14 1 2
13
8 11 13
68
DEPTHFEET
0 97
187 204
0164 203 145 160
43 233 151 184 121
204 228 1R8 190 113 193
0 226 145 202 132 141
287 299308 156 102
COrjCUCTIVET EARTH
PESISOHtf-M
41
117
3 27
10 6
8 46
27 2
5 1 2 2
94 18
10 2 1
285 23 1
3 2
102 131
DEPTH ' FEET i
0 73
126 147
0 123145 \ 34 '
103
0 184 95 98 86
i
149 187 147 147 13
1 18
0 183 110 114 51
110
226250 153 , 93 92
36A 132 132 150 154 ,* 21 O . 7 O
ESTir/AUn DEPTH f/AY P F UNRELIABLE BECAUSE THE STRONGER PARTOF THE COMOIJCTOR '' A Y pE DEEPER OR TO oriE SIDE 0 F T HF r LIGMTLIME, OR BECAUSE OF A SHALLOW DIP OR OVERBURDEN EFFECTS.
D 7 8 cc,i,co ,.-,,u,!r. E .
ST A': PAR 0 C C PI. f fl| C 0 I L COI
C r IT
f,1 A R L
A u ^ ni
VERTICAL DIKE
HORIZONTAL SHEET
connucTi VEEARTH
i PEAL QUAD REAL PDAO .Y PPM PPy, PPM PPW
. cOfJD DEPTH*. COUQ DEPTH
. VHOS FEET . MHOS FEETRESIS DEPTH OHM-'-" FEET
38B38C330
39 A39B
40A4QB4QC
41A4 IB4iC
42A42.13
43A43B4^V
16172
12023
7112
105174
2016
1254
1611
6110
1 3 64
78
12
11476
1011
1 3138
11
194 1
0x
14 't46
262 '4
7
1 392611
4811
1 3 34
239
5200
16615
177
22
1533510
1916
1 4 30
16a
402413
.,
1872
! 13222
! 18147
3611
! 1918219
P 8 .52 .
319 .**
0 .85 .
44 .88 .15 .
0 . "6 .89 .
*
49 .37 .
0 .1^3 .71 .65 .
1063
616
461
642
93
6463
254191687
0221
201254121
0222265
186183
0459225223
24
19
41
115
126
49
32
214
410D
19
205142570
0188
13219812
0161165
142114
0374169146
44A44B44C44044E
45A45345C
01
15145
0a
19
0677
15
01021
634
2 138
131121
709
220
25
102239
103
16242
*
959
0 .53 .47 .
110 .19 .
f88 .32 ,15 .
31561
323
0212195304122
317164123
148285
94
243819
084
13324222
2166750
4GB 8 IB 12
ESTIMATED DEPTH .V AY PE UNRELIABLE OF THE CONDUCTOR MAY RE DEEPER OR LIME, OR BECAUSE OF A SHALLOW DIP
94
BECAUSE THE ST'TO OKE SICE OF THE FLIGHTOR OVERBURDEN EFFECTS.
13 192
073 CO-INCH l-' fUM.'Pir-. E , OMT AIJG/7
STA':n.V*D CGPLAr.'AR . VER^ COIL COIL . D
AlNf Z H EAL QUAD REAL QUAD ! COND ^TNOr-'ALY PPM PPM PPM ppfj, . f/HOS
*
46C 3 5 2 7 \ 316D 8 9 10 16 . 6^E 6 7 3 0.8
t
47A 7 5 8 3 .' 15 47B 5 Q 8 23 . 3 H7C j 5 10 1 15 . 2 470 14 17 8 9.7
4
40A ^ 3 13 0 .' 78 '*88 6 6 7 4.91480 2526.2
4
49A. 5 6 8 0 ! 13 49B 8 8 2 2.8
t
4
5 OA 4. 6 4 5 ! 5
*
51 A 5 6 6 4 i 7A^iB '5 5 4 6.6^F3 ! 0 8 6 6 6.9
*
52A 6 3 7 0 ! 25S2B 8 5 5 6 . 10
*
53A 9 7 11 9 | 12 53Q 9 7 9 9 . 11
4
54A 9 7 2 3 .* 8
*
55A 8 6 7 8^9
55C 15 7 4 3 j 22 .550 4 3 22 17 . 12
7
TICALIKE
DEPTH*.FEET .
*
62 !29 .
129 .4
136 ,*
58 . 54 . 47 .
*
111 .lOfl .72 .
*
120 [ 92 .
4
t
63 l
4
88 !99 .60 .
*
167 !57 .
4
103 . 02 .
4
115 I*
63 !
so ;106 .
HORIZONTALSHEET
COND DEPTH F-'HOS FEET
1 2552 1752 339
4 344 1 182 1 174 2 133
16 304 3 3031 233
4 337 2 281
2 252
2 2832 2953 247
6 4023 251
3 278 3 256
3 307
3 241
6 245 4 280
COMHUEAR
RESTS 0 H v - M
1073129
10 72
123 24
1 22
172
13 27
49
333921
519
14 16
25
23
5 13
CTIVETH
DEPTH FEET
11279
240
268 75 59 99.
268 213fl7
254 190
132
131185161
330164
201 177
217-
156
185 205
|.* F.STIV A TED DEPTH P A Y P.r UNRFt.T/\BLE RECA'JSE THE STRONGER P A RT .OF THE CCr.niJCTOR f,- A Y .3E DEEPER OR TO ON'E SIDE OF THE FLIGHTLIT.'E, OR flECAUSE OF A SHALLOW DIP OP OVERBURDEN EFFECTS.
D7S PORCUPINE, CtJT AUG/77
STANDARD COPLANAR COIL COIL
VERTICALDIKE
HORIZONTAL CONDUCTIVE SHEET EARTH
LINE S REAL QL'AD REAL RIJAD . COND DEPTH*. COfJO DEPTH RESTS DEPTH ANO'.'ALY PPtf PPM .' PP'Ji PPM . ;-'HOS FEET . MHOS F EET O Hf'-M FEET
56A56B
57 A57B
58A58B58C
99
510
6a4
119
815
1066
86
96
641
134
14H
1919
*
.** ** ***,,
6g
55
3122
40 .36 .
'
55 .ia .
.39 .97 .42 .
23
22
131
184211
203151
164306190
3322
4536
7014
115
87128
9655
5722160
,* ESTIMATED DEPTH f-'AY RE UNRELIABLE BECAUSE: THE STRONGER PART .. . OF THE CONDUCTOR f-'AY "E DEEPER OR TO ONE SIDE OF THE FLIGHT ,
LIME, OR BECAUSE OF A SHALLOW DIP OR OVERBURDEN EFFECTS,
7 "
y r
o
. ——L
' i*
...x... :
...r,-
,- :; -
. ,-^
^,.-
..,.....
, o'"
-- ,,\
j-;"3
"-
^r^
: ' "
l
c.-"
J.
o -
:^
IX
)f*
-
\n,
. .V
,"
\'
'-^l
N^
rxj
\
<C
OD
Y TW
P W
-270
^ z - — - ,0
~"-
.
p
1 V
-' i-
:: ~
"r
-, 0
J--
-r
-- -'
' 0
GO
:'
'-' '-,
--'
LT ^
-, "'
'- '-"
n-J
f .
? '0
- '
-:
.-.
r. ,
^ ^
] P
'' -'r
- :
;:
' o
. —
r
" '
' 0
M
2 ^ -;
. ,
, , -
-1
LJ
" ^
y '"
' :; c
: "- !
±s'
' i' '
01"
'' : ' r i '
;"^
. '
- -
~'-
—i 1/1 t0 :
:'
,
^. .
U:
0 ^
-" C
) n
0.
COri
-'
t.' 0
-ii
"";- : --
•' 'r; C
O n
r;
r;
T:
?:
^
—
-t;
c^;
- -T'
i-' r:
.1: -~'
- :-':
- ^
^,
c '- 1
--i - -
; - -
- : - '
-' -^
'-'i-
T -,--
'
-. .
' .,
r .
) , .
>>
"'
,.^—
-T
— i
,-
- -
"'
' '
" '
^
' .-
-,
' "^
^ -
7, c 1
^
.": —
r^..
"^
:-- ,
., -
-' ; ..,-
-- '"
T-'
' '
* ,
* -
" \l )
( _ ,
" ".
i"~
,."
1;~
-; -' :
"", ^
'J o
•c! 7'
-.,
-i '
i ~
-
TJ
0 :.'
r~ 0 . ' ;"
l
C
0 r. r:; -
r-
—
0
-so
"n
,~G
;.'
r-,
^*
.-,
-i
;r..
vi
-,
r;-~;
' "-
"
- '.".-
'P-
^
--
--'
,-.
^
" ^
,-.'
"" -—
~^
"- C
:•J
t
1.) r:
,n
;r
;. l
. ,
,; A
;~ ^i ' -;
" " '' ! " _
-' in- -1/
l--
x-- ——
——
——
— . —
— -X r'
'' ' '''
;; ;/
^ G
; ;
S\ '. ! ^-^
vV '.
' "'--.. "
'\
x -' - -
. '
. ' .',' '\
'^.
'
'— s " - ~—
~-
.0 .^--'•.i.-:--.,. -
\ .':^-'
n X
VU
^•o ©
\
-" A
:o - ^
^
\.^ \ -
c7x\
.n
•-xV ,.
;;,. G ; 0
i-o1
(.-o /' c, G
dAA
l
Q
Q
,- T3
u, 0
O
C
'r
'c
w ~
F -*
S; .
~o
-*.
-,r
u Fi
A ^
-' "'
f" E '
5 ^
? -
* "
{ ?o
|*fo
2|.
t ^ |
^Q
^--^oi^
S*"
r L ^
- '
O
O
u
t
-
" -
-f"*-
y-gc*,t*-C
",
L fc
Q
U
E
w *
"
cj1
)*jL
c^0
0^—
*.
C'
-- c
J1 - -.
c ~
S ^
j. i
;f-
n""^*^?
t ?
^
4*
fcp
p-^f3
*
* r'
t2
,3*8**!^
2 i. r
"cg^S
f?^^-
a J
m,
7E
j"S
;'02
l^.|ii^-^
•:, . ,
e *- i c ^ -
^ C
^
(rr*~
C
C
^^
t*--
?~Lft
-'"
1un
^O
*
o ?
i S
^
-- g
*
?
'- ,
i e f 5 i f s 2 5 ^ ^ , o
c^tj^
^
- -T !j r,a,ji*
^^~
—^
ii,/- C
Ti'-'
Lfc.
—
*-"
X, 4-
j- J'
oo
^'^
^^°f^
^Q-^
?;^
e^
i^t^^^^^.c^c.-
^-t
0r,cc-
c c,
mi-,
5:i^3
0c-'*
^.5
^''
c,:oc.o.
. o, f
^^*
o ",
L :
9 c
c -
^
,, o
S
o
' ^ "
a S
"-
, fc
? *
^^o
^^o
'-r
^ "
P 3
^c-^-c^r
T'E^'
--
r.
^ i
^•-O
^O
^-fc^
-, ~
~
Il^^ctl-^
^- 0
a
O
^ j
" —
"^ '
*^C
C-O
^;-
of
V ^"c
r^r, p-
S -^
^.;5
C
3"- *
T-
*
o|
: V
z - "
^ ?
'J -^
I '
fj
^G
J
^ C
*f***o
OG
xi j-
,2 c3 ,
i
^
*
-" ^
-
— o
Z ,-
•4
*
^
*
C
P c
^ "
"o f - i * t0
^
0
L
^
- g
^ 1
o
^
o '
r "
r, n
o t
7rr
S '-'
t- X
S
4, C
. Q
J
^ ^
^
J ^
i-^- n
-r-} r?
S f ? r 3 *O
p
'J t
0 ^
r ' ^-
^^
- ,
O
^
J 4J
S ^
*
i
!~
*?:
j, t
c E
''
''
^! t
S *
"V
?-
' ^
H f
——
—r^
*
^ n s - *- s^ ? --- 1 b L -t
0
Q
. C
i -
**
a. t
i
-
c
t
M ^ Ir?^ - - ; i" ^- ^ ^± r
? *
. fc i
t- ±
T
0 f
'o
O
-s^llii ; ^ ,
| . S
" r
0
*- o
| 2
S^
^5*
"— ^-
t-^
S l 8
" S.
" ". *
? io
E
- -
g ;f-
-1-,'-
J 0 '
* i
i"' ^ I -
"*•* -*
c . , . .5
* t
I *
. * j
* *
J
y i
o O
r J o
i H
.
J
- ,
c "5
O^-
Q-X
i'o
^
-o ^
n-"*^?
^^
Eo*
-o*?i-iE
"w
*S
Q—
*
Oc
~-*3;)
•*E
,o
Vo
pc
yu~
D"
0S
C*'-^
5
- S?
5 * f 1 5 fS
'i-els
^l-I
^ •'tif'a
" -^0.0
0
cc**jT
.*
lJ o
^^S
fo^p^T
^q
ij:s
*Q
'L
^)*
C'e
fc
^ 1 5 ?
E * S 1
a ?
S-9
0aoftS
t--.om
aci^
c
S ^ f
SS
^T
, o
5 2
?1J
—
3:*,O
QM
."o
to
OQ
-*
3^^
cc*0
0^3
^0
?^
^'S
c'c
D-
C^^
J''1
if^o
^ ~
c'
c^
I'^
O3
1" ,i^.t.
0-
•- f,
c ^
f
-0 u
t 0
. :r2
0fS
*^5
-!
S
? c
* tt
3 '
S *
5
S E
^o
t-^o
Sa
^o
^-J
*3
.
''-?
•*o
c--^^-^T
no
^
*-
— tp
ni-O
d
^3
00
^ ^^ e i. E o-
5?
E^ls
**.o.S
i ^
OJ-X:)
CQ
'C;'^
'::Q
i.,
^ o
CT
E a
*- -~
- z.
i \\~
|!l
. i il
*
I f
8
*
-
0i
E t
" ;---I
S ?
1 f''^ic^^S
^^i
-
*
Q
C
?
-'"v*~
^S
-"n
'J ^ i
Z
5 i
f
?^"
.-.^o
?"?
3 E
*"^
.,Q
O.li-ii
Q^
^J2c
A
C
CT
\ ,
-t\ f
j- .
' ^9
V o
3
LUccD
C/)UJI oQ
Oo:
en oh-oLU
UJZoQ
Ld
OL.o:oLL
Oo: oCLXh-IDOCO
OrrOUJjUJ
ooo
o
ro
Q QCU
EA
ST
ER
N
DIS
TR
ICT
Drawn by:by
Oil.
Traced by:by
0*1*A
LA
MO
P
RO
PE
RT
Y
DIG
HE
M
SU
RV
EY
E
LEC
TRO
MA
GN
ETIC
SO
NTA
RIO
N.T
S42-A
-6Scale:
lin :
1/4 mi
Date:
Jan
1978Plate:
AE
M-I
FOR
M 210-0870
v
o: 33l Z
1 : i : ? o: i * ^i i s y: i i , * fi i : ! : ' 5 J
1r . ^ ' ! o! , B
i i . J
1 1 '
—————————————— ' ————————— ? H
i S 8 2Q (P
i CT d" cr•x
eno ea(0
3
"
-bi
~ o 21S"
C-o3
5-~j00
•os.o"
>rnS
i-t.
omi S
OZ H >X6
m >2 nx 2 L^ o ^2 I ^o m o m so ^
"DS ^^^00 ^ "D2 2 mm pi 33
2^^H^ o -c:w w•^ro
i>
tm
m >COHm3J2
DCO H 3)
OH
,
DIGHEM SURVEYSOUTH PORCUPINE , ONTARIO
ENHANCED MAGNETICSe P- h o o r e d field)
FOR
COMINCO LIMITED
!, )OO g on-- m o s
?ijO gammasr
!OO
I gne' .r -lepr ess1 l . 4 S . FOP'
e ,5 u e ri c y -esponse
MIL I S
4aA06NE0046 2 .2833 WHITNEY 210
Vi V)*? u w
1
i
if) o0'
3
-t*}
Osft
c.o
5-4 O)
T3af?
mZ
1ro
! ' . '
1 : !
.i,;O"Z.
3)
O
C
m c0) 377 nV) yH 3
^— C/H CX 3
<rr^
•z.HO)^
1^^
10)
Jj c
s"
;
r'
r)a
3
^:iPh
)
5i.i
C7Wf1'JtT
-H
f) fO OO"
t*r~
2O•D3)O•um33H-C
m
COHm
2g01 H
5oH
^^JJ^^•yl
VII42A06NE004
DIGHEM SURVEYSOUTH PORCUP NTAR
RESISTIVITY
FOR
COM NCO L M TED
UJa:DUJX
(DQ
Q.
o
tfl I/I
ff)U
Jz-JuKU
JZO2Om
0
0
E E
E
E0
0
0
O
O-
o
oO
'M
*'
\
\
O
0e
eE
Eo
ac*
rf
rj in
Ji oj
o
\ \
h-
OLUC\-ID
OC
tOCLXh-IDO
CO
enoh-UJZO^^1
^^^
Q
LUI-
LT -J
OLL 0
O1OO
EA
ST
ER
N
DIS
TR
ICT
sy
ON
TA
RIO
AL
AM
O
PR
OP
ER
TY
D
IGH
EM
S
UR
VE
Y
MA
GN
ET
ICS
N.T
.S4
2-A
-6D
ateya
r -9
78
Plate
AE
M - 3