INIS-mf—9688

URANIUM DIVISION

PNOC ENERGY COMPANIES BLDG.PNPC COMPLEX, MERRITT ROAD,FORT BONIFACIO, METRO MANILAPHILIPPINES

f l

1980

I

I• • vlSE»mFIC ILfBftAR) ».»*

URANIUM GEOCHEMICAL EXPLORATION

( IN NORTHWESTERN LUZON

nCT13198*I1 GABRIEL SANTOS, J R .

AND

I LOURDES FERNANDEZPHILIPPINE ATOMIC ENERGY COMMISSION

I AND

MANUEL OGENA AND GEORGE TAULIPNOC-EDC . • • .

II ABS1HACT

I A reconnaissani.. geochemical stream water and sediment survey

• which was conducted in northwestern Luzon was able to detect '•.

(10) uranium anomalous areas. These anomalous areas are located

I along a north-south trending zone of Miocene marine e l a s t i c s and

sedimentary rocks with tuffaceous sediment in te rca la t ions . In

§ general , northwest Luzon has low radioac t iv i ty except for two anoira-

- lous areas which have 3 to 6 times background rad ioac t iv i ty . Radon

anomalies occur in sparsely sca t tered locat ions .

The anomalous zones appear to be re la ted to major north-s-. . .

faults and secondary northeast-southwest trending structures.

.• - Geochemical corr jlations between uranium and other elements

such as copper, lead, zinc, manganese, silver, cobalt, .and nickeJ

I are generally very poor.

II

I

_ It is suggested that the intermediate intrusives iv the

• Cordillera Central are possibly the principal source rodcs of

W uranium in the survey area.

rr

ii

iiiiiii

i

- 2 -

II•

URANIUM GEOCHEMICAL EXPLORATIONIN NORTHWESTERN LUZON

II

BY

GABRIEL SANTOS, J R .AND

LOURDES FERNANDEZPHILIPPINE ATOMIC ENERGY (EMISSION

I AND

MANUEL OGENA AND GEORGE -TAULIPNOC-EDC

II INTRODUCTION

I The first indication of possible uranium occurrences in

• Solsona, Ilocos Norte, Northwestern Luzon was detected by an

airborne gamma spectrometer survey which was carried out by

I Huntings Geophysics, Lixl. of London in 1954. Subsequent ground

follow-up geologic and radiometric surveys in Solsona area fo<

I nearly two decades failed to pinpoint the possible location of

m the airborne radiometric anomaly. i

* In 1978, it was decided that the northwestern Luzon region

including Ilocos Norte, Abra and Ilocos Sur be explored systematical-

II ly. for uranium using geochemical methods. The exploration was

undertaken jointly by PNOC-EDC and PAEC, with the latter providing

II personnel, technical planning and analytical support. The work- which was essentially an orientation survey was covered by a non-

II

II

exlusive one year exploration permit from the Bureau of Energy

I Development (BED), Ministry of Energy and includes all lands in| Luzon bounded on the South by latitude 16°45' West and on the

East by longitude 120o52'30" North and elsewhere by the Luzon

T

II1

Sea.

i The objectives of the orientation survey were to determine

the best sampling medium which could be used effectively in a more

F intensive reconnaissance survey for pinpointing the presence of

i possible uranium mineralization; and to locate the airborne radio-

metric anomaly which was detected in 1954. The results of the

I orientation survey were submitted as a report to BED in 1979. The

results of the survey indicated that the stream water as well as

} the -80 mesh size fraction of the stream sediments were the best

. sampling media in the geochemical survey. Radon measurements in

' stTeam waters would also be useful in the evaluation of the geoche-

I mical results. Heavy mineral concentrates were considered less

effective in outlining uranium geochemical anomalies than the

| -80 mesh stream sediments fractions.

* The main purpose oe this paper is to describe the results

I of the reconnaissance geochemical exploration for uranium in

northwestern Luzon.

I- 2 -

ILOCATION

IThe survey area is located in the northwestern part of

• Luzon as shown in Fig. 1. The expanded non-exclusive exploration

'"» permit area is bounded in the east by longitude 121°00' North and

in the south by latitude 16°20' West; and elsewhere by the Luzon

I Sea. The area of interest covers.the provinces of Ilocos Norte,

most of Abra, Ilocos Sur, Eenguet, La Union and some sections ofI Mountain Province. Accessibility to the project area is moderately

'-_ easy owing to the presence of well-maintained national and provincial

• roads as well as the i iierous barrio roads and trails. The main

I road, Route 3 to the area from Manila runs along the western cc. .

line passing through San Fernando (269 km.) in La Union> Vigan

I (408 km.) in Ilocos Sur and Laoag City (486 km.) in Ilocos Norte.

The eastern part of the area could be reached via Route 2 up to

Bontoc (396 km. from Manila).

TOPOGRAPHY

The project area forms a part of the western limb of the

Cordillera Central Mountain Range down to the lowlands and the

coastal area of northwestern Luzon. The mountain range and the

*. " ids are parallel »o each other in the north-south direction.

About 30% of the area is characterized by high relief elevations

ranging from 1,500 to 2,000 m. and moderate relief with 1,000 m.

- 3 -

GEOLOQY OF NORTHERN LUZON

\ VIZCAYA \t

METASEOIMEMf

TERRAIN V * ^ « f

f i t . I. LOCATION OF NORTHWESTERN LUZON SURVEY AREA, SHOWINSPHYSIOCRAPHIC AND STRUCTURAL PROVINCES OF NORTHEASTERNLUZON, AFTER OURKEE AND PEDERSOS, l t d .

II

elevation on the average. Several high peaks can be found, notably,

I Mt. Cavitian (2568 m.) and Mt. Clawit (2668 m.) both in Mountain

| Province; Mt. Buguias (2841 m.) in Ifugao and Mt. Pulog (2928 m.)

in Benguet, the highest peak within the project area.

IDRAINAGE

IThe survey area is drained by five major river systems aiii

I their numerous tributaries. These drainage systems include Laoag

• and Vintar Rivers in Ilocos Norte; Abra River in Abra; and Amburaya'

River in La Union and Bued River in Benguet. They all discharge their

I loads westward into the Luzon Sea (South China Sea). Chico River

on the east side discharges its load into the larger Cagayan River

I which drains the entire Cagayan Valley. About halfway of the down-

'. stream reaches of the Laoag and Vintar Rivers, the water gradient*

' are low and the rivers are braided with wide flood plains.

These rivers have large discharge specially during the wet

1 months from June to October. The rest of the year is dry. Accord-

ing to Fernandez and Pulanco (1964), the Ilocos Coastline is an

} emerging shoreline and that most of the stream has probably main-

tained its original course.

Geologic structures generally control the trends of the

major river systems and their numerous tributaries provide excellent

•p

- 4 -

opportunities suitable for conducting regional geochemical

stream sediment surveys.

GENERAL GEOLOGY

Previous works on the geology of northwestern Luzon include

those of Corby et. al. (1951)f Irving (1952), Durkee and Pederson

(1961) and others. The fieological Map of the Philippines compiled

in 1963 by the Bureau of Mines is a good source of the geology of

northern Luzon. The paper of Fernandez and Pulanco (1964) whid:

describes the regional geology of M Luzon as well as the recent

geological survey report under the Philippine-Japan Project (1979)

are excellent sources of geological information regarding the

project area.

The survey area includes more than half of the Cordillera

Central and most of the Coastal Folded-Belt, Vigan-Abra High and

Laoag Embayment of Durkee and Pederson (1961). Fig. 1 shows the

physiographic and structural provinces of northern Luzon and

Fig. 2 shows the geological map of northwestern Luzon.

The Cordillera is composed principally of Eocene to Earl)

Miocene bedded volcanic rocks and thick post-Middle Miocene sedimen-

tary rocks. These rocks have been intruded by Early to Middle

Miocene quartzdiorite rocks which resulted in a geanticlinical

- 5 -

I

mountain range, trending in the north-south orientation. The

major structural lines ulso have a similar direction and in some

places, these fault zones are loci of gold and copper mineraliz; V::ns.

[Durkee and Pederson (1961); Fernandez and Pulanco (1964); RP-

Japan Project Report (1979).3

The Coastal Folded Belt which is located west of Cordillera

Central is a region of highly folded and faulted sedimentary

rocks trending in the north-south direction. The belt is charac-

terized by north-south trendLng anticlines and major faults as

well as northeast-southwest secondary fault systems.

The Vigan-Abra high is a topographic high which is composed

of thick meta-sedimen'*'1 and bedded volcanics with mafic intrusives.

The eastern boundary and probably the western margin are controlled

by north trending faults, Durkee and Pederson (1961).

North of the Vigan-Abra high is the Laoag embayment filled

with Miocene-Pliocene sediments. Pre-Jurassic crystalline schists

and quartzites as well as Cretaceous ultramafic rocks are found in

the northern part, in the Suyo area, Ilocos Norte. The older

rocks may possibly represent remnants of a continental landmass.

A major fault trending in the northwest-southeast direction extei. i.."i,

from the Cordillera separates the Miocene limestone of the" northern

part of the Laoag embayment.

- 6 -

FIELD AND LABORATORY TECHNIQUES

The sampling pattern was designed to collect one set of

sample of stream sediment and water from each sampling site, from

a stream draining 20-30 sq. km. area. During the orientation phase,

sampling was done along easily accessible tributaries. Figure 3

shows the location of the sampling sites.

At each sampling site, 1-2 kg. of stream sediment was

collected. (Mineral coi :ntrates were also obtained by panning

the sediments using a wooden pan during the orientation survey.)

Two stream water samples contained in 150-ml. plastic bottles were

initially collected. Radicmetric measurement was also taken around

the sampling area. The radon content of the stream water was

determined as counts per minute employing a portable radon detector

RD 200 and a degassing system model RDU 200 manufactured by EDA

Instruments Inc. (See Figs. 4 and 5)

The stream sediment samples were sun-dried and prepared in

the field and the minus 80 mesh fraction was separated and sent

to the laboratory. During the orientation survey, the following

size fractions were separated; -35 m, +80 m, -80 m, +200 m. The

mineral concentrates were treated by removing the magnetic minerals

and the non-magnetic fraction was separated from the siliceous

gangue utilizing heavy media separation.

- 7 -

Uranium analyses were done at the PAEC laboratory using

the method developed by Smith and Lynch (1969) employing a Jarrell-

Ash model 26-000 fluorometer. The sensitivity or limit of detection

of the method was about 0.2 ppm and 0.1 ppb uranium for the stream

sediment and waters, respectively.

Other trace elements such as copper, lead, zinc, manganese,

silver, cobalt and nickel were determined in the uranium leach

solution by atomic absorption spectrometry. The limit,of detection

for copper, lead, cobalt and nickel was 4 ppm; for zinc and manga-

nese, 2 ppm and for si. sr, 0.4 ppm.

- 8 -

RESULTS AND DISCUSSION

A total of 522 sampling sets consisting of

stream sediments and water were collected over the 15,000 sq. km.

survey area. Die results of the uranium and trace element analyses

of stream sediments and waters were treated statistically to

determine the background and threshold values using the method

of Lepeltier (1969).

On the basis of geology, the rock units were grouped under

sedimentary and volcan. . rocks; and intrusive. Table 2 shows the

average background and threshold values of uranium, copper, lea..,

zinc, manganese, silver, cobalt and nickel.

From Table 2 it can be seen that the uranium background

values is below the detection limit of 0.2 ppm (ND) for the method.

The background and threshold values for uranium in stream waters

are ND and 0.55 ppb, respectively.

Uranium in Stream Sediments and Waters

Shown in Figs. 6 and 7 are the uranium distributions in

stream sediments and wattvs, respectively. At least one large

contiguous stream sediment anomaly zone was outlined in Batac-

Badoc area, Ilocos Norte. Other lesser anomalies were indicated

in Sinait-Cabugao, Ilocos Sur; Burgos, I.locos Norte and Malibcong-

Ikmin River area, Abra.

- 9 -

Table 2 : Average Background and Threshold Valuesof Uranium and Selected Elements inGeological Units in Northwestern Luzon.

Parts Per Million

U Cu Pb Zn >4i Ag Co Ni

Bkgd Th Bkgd Th Bkgd Th Bkgd Th Bkgd Th Bkgd Th Bkgd Th Bkgd Th

Sedimentaryand VolcanicRocks N D 0.4 32 220 17 60 60 200 630 1350 0.4

No. ofSamples

No. ofSamples

451(3) 452(2) 454 454 454

2 21 47 12 120

454 454 454

Intrusiverocks N D 0.4 45 250 15 ]10 57 580 430 2400 0.35 1.55 IS 40 9 41

68 64 68 68 68 68 68 68

CompositeUnits(Sed., Vol-canic §Intrusive)

No. ofSamples

N D 0.4 40 330 16 45 60 220 600 1350 0.36 1.65 21 47 9 105

519(2) 517(4) 521 521 521 521 521 521

Note: Bkgd - BackgroundTh - Threshold( ) - E x c l n ^ High • •iues

Isolated anomalies were also found in Pagudpud, Ilocos Norte and

Sabangan-Bontoc, Benguet. Uranium value as high as 1.4 ppm was

recorded in Sabangan.

One large stream water anomalous zone was delineated in

Dingras-Badoc, Ilocos Norte. Smaller anomalies were indicated in

Burgos, Ilocos Norte. Several isolated anomalies in Narvacan.-

Candon, Ilocos Sur, Bacnotan and Naguilan, La Union were also

outlined. A high 7 ppb U found in Sinait, as well as those obtained

in San Fernando and Caba maybe due to sea water contamination.

However, these anomalies would still warrant a brief closer

examination.

In general, there is a very good correlation between the

stream sediments and water uranium anomalies in Batac, Burgos and

Pagudpud areas in Iloco; Norte and Sinait, Ilocos Sur.

Radon Radioactivity Measurements

Shown in Figures 4 and 5 are the radon and radioactivity

maps obtained during the orientation phase of the survey. Four

widely separated point anomalies were delineated, three,in Ilocos

Norte (Burgos, Sta. Praxedes and Nueva Era) and one in Cabugao,

Ilocos Sur. The highest radon measurement (45.3 cpm) was recorded

in Burgos.

- 11 -

Six anomalous radioactivities corresponding to 3 times

background were measured in Dingras-ffercos-Batac, Ilocos Norte

and Malibcong, Abra. Exploration Model GRS-101A and Me Phar TV-5

portable scintillometers were used to take the radioactivity-

readings.

The uranium anomalies appear to be preferentially situated

in areas underlain by Miocene marine elastics overlain with tuff-

aceous sediments. In Batac-Badoc area, two major northeast trending

faults probably control the extent of the uranium dispersion. Inter-

secting north-south an^ northeast trending moderate faults apparently

contribute in localizing the uranium anomalies in Cabugao.

In the Malibcong-Ikmin River area, the uranium anomalies

are closely related to the Miocene quartzdiorite rocks and northea-

southwest structures. The Narvacan-Candon and Bacnotan uranium

anomaly in waters are related to strongly folded tuffaceous sand-

stone shale.

It may be noted that the uranium anomalies are predominant!

distributed in the Coastal Folded Belt and Laoag Embayment. It is

believed that the possible principal uranium source rocks are the

intrusive intermediate rocks, mainly quartdiorite found in Cordillera

Central. The Cordon syenite complex (Baquiran, 1975, Khittel, 1979),

located in the southeastern part of the Cordillera is also a

possible source rock of uranium in the project area.

- 12 -

1

Si The summary of .significant correlating geochemical and

ij geophysical anomalies in Northwestern Luzon are presented in

Table 3. The anomalous areas are arranged in their order of \.. .^i-

ij tial for finding possible uranium mineralization.

fi It is interesting to note that the regional background and

threshold values for copper and zinc obtained in the present work

1 is partly similar to the RP-Japan Project (Phase 1 ) , 1979 as shown

m in Table 4.

(Table 4. Comparison of Regional Background and

Threshold Values Obtained on the RP-Japan Project (Phase 1) 1979, and thePresent Work.

| Cu (ppm) Zn (ppm)Ba

II

Back- Thres- • Back- Thres-ground hold ground hold

Present Work 40 3 3 0 5 0

RP-Japan Project 32 125 58 120

It can be seen in Table 4 that even though the geochemical

extraction procedures used were different, the results obtained

for the regional background are rather closely similar. The

thresholds correspond to abscissas at 2.5% probability for Cu anc

Zn. The large differences in the threshold values are probably

due to the variety of rock units covered in the present womk

as compared to the RP-Japan Project. (Please see Fig. 8.)

- 13 -

Table 3 : Summary of Correlating Geochemical andGeophysical Anomalies in Northwestern Luzon

1.

2.

3.

4.

5.

6.

Area

Batac-Badoc

Cabugao-Sinait

Maiibcong-Ikmin River

Narvacan-Candon

Bacnotan-San Gabriel

Pagudpud

Uranium inStream Sediments

Large

^derate

Small clusters

Background

Small

Small

Uranium inStream Waters

Large

Moderate

Background

Large

Moderate

Small

Radon(cpm)

-

Small

Background

Background

-

Background

Radioactivity(cps)

3 x background

Background

Up to 8 xbackground

Background

Background

Background

Geology

Marine Clastics(N2 to N3)

Marine ClasticsCM2 - %)

Quartz diorite(Upper Miocene)

Marine Clastics(N2 " % )

Marine Clastics(N2)

Marine Clastics0*2)

7. Burgos Small Small Small Background Marine Clastics,limes tor" (N2)

Uranium and thu Trace , -ments

The other trace elements such as copper, lead, zinc,

manganese, silver, cobalt and nickel were also determined in the

stream sediments to investigate whether any of these could serve

as possible indicator or pathfinder element for uranium.

In general there is poor negative (inverse) correlation

between uranium and the selected trace.elements except nickel.

Shown in Table 4 is thr correlation coefficient between uranium

and the other elements.

Table 4. Correl- ion Coefficient between Uraniumand l . trace elements.

ELEMENTS CORRELATION COEFFICIENT

U vs. Cu - 0.06

U vs. Pb - 0.05

U vs. Zn - 0.08

U vs. Mn - 0.13

U vs. Ag - 0.03

U vs. Co - 0.10

U vs. Ni • 0.05

Shown in Fig. 8" is the recommended areas for follow-up semi-

detailed or intermedia/?- density sairjpling surveys. Although the

- IS -

predominant uranium anomalies are widely distributed in marine

I elastics and sedimentary rocks, it is felt that other possible

uranium occurrences, such as vein-type deposits may not be detected

I by low density sampling.

IIIIIIIIIII

- 16 -

CONCLUSION

The reconnaissance stream sediment and waters geochemical

survey which was conducted over a 15,000 sq. km. region in.north-

western Luzon has outlined ten (10) uranium geochemical anomalous

areas. These anomalous zones are mainly located in marine elastics

and sedimentary rocks vith tuffaceous sediments as well as in quartz

diorite.

The radioactivity in two anomalous areas is between 3 - 6

times background. Radon anomalies occur in sparsely scattered

points.

The anomalous zones are associated with major north-south

faults and secondary northeast-southwest structures.

Geochemical correlations between uranium and the trace

elements, copper, lead, zinc, manganese, silver, cobalt and nickel

are generally very poor.

It is suggested that the quartz diorite and silicic tuffs

in the Cordillera Central as well as the Cordon syenite complex are

possibly the principal source rocks of uranium in the survey area.

- 17 -

Ml Unit. ENERGY .

r»rrr

ACKNOWLEDGEMENTS

The authors wish to acknowledge the valuable assistance

and encouragement of Dr. M. C. Berbano, PNOC-EDC.

The chejnical analyses were performed by the staff of

the Nuclear Fuels Research Division, Department of A'uclear

Technology and Engineering of PAEC. The staff also assisted

in the statistical confutation of the geochemical Oata.

REFERENCES

Baquiran, G.B., 1975, "Notes on the Geology and Exploration ofof the Karian Copper Deposits, Cordon^ Isabela", Jour.Ceol. Soc. Phil., Vol. 29, pp. 1 - 1 2 .

Corby, G.W., et. al., 1951, "Geology and Oil Possibilities ofthe Philippines," Rep. of the Philippines Dept. Agric.and Nat. Res., Tech. Bull. 21 363 pp. >

Fernandez, J.C. and Pulanco, D., 1964, "Preliminary Report onthe Reconnaissance Geology of Northwestern Luzon,Philippines", 1 :reau of Mines.

Irving, E.M., 1952, "Geological History and Petroleum Possibili •.., .of the Philippines," Bull. Amer. Assoc. Petrol. Geol.,Vol. 36, pp. 437 - 76.

Knittel, U., 1979, "Petrography and Origin of the Syenite fromCordon, Isabela, Vol. 33, pp. 34 - 42.

Lepeltier, C., 1969, A simplified statistical treatment ofgeochemical data by graphical representation: Econ. Geol.,v. 64, pp. 538-550.

Neville, A. and Kennedy, J., "Basic Statistical Methods forEngineers and Scientists", Pennsylvania: InternationalTextbook Co., 1964.

Report on Geological Survey of Northwestern Luzon (Phase.1),Sept. 1979, Bureau of Mines - Japan InternationalCooperation Agency, 124 pp.

Smith, A.Y. and Lunch J.J., 1969, Field and Laboratory Methodsused by the Geological Survey of Canada in GeochemicaJSurveys, No. 11. Jranium in Soil, Stream Sediment andWater. Surv. Can. Paper 69-40.

P-U<.'8SiJ.it

^ 3 1

URANIUM GEOCHEMICAL EXPLORATIONIN NORTHWESTERN LUZON

URANIUM DIVISION

PNOC ENERGY COMPANIES BLDG.PNPC COMPLEX, MERRITT ROAD,FORT BONIFACIO, METRO MANILAPHILIPPINES

S E C T I O N 1 !

ND1

45'

ND BATONGMT. MINEXtCu)

Mufi ku/un \ LEPA

I2O°I5'

2 O ° I 5 '30' ' 45*

KM 5 4 3 2 ' 0

SCALE I : 250.0C

J20°00 JO l2l°00 30

3270

3269

3168 • 3268

, 2967) -3067 3167 • 3267 34.i i i ; . i --

I20°00* 30 I2I°OO- 3p

INDEX MAP

SECTION 10

URANIUM EXPLORATIONRECONNAISSANCE GEOCHEM!

NORTHWESTERN

ORIENTATION

MAP

I2I°OO" DATE :

SEPT 1980

ARCHIVE NO.. REPOSANTO

a T

I2I°OO'

-3275^

250.0C

3274

3272

3271

3270

3269

3ZF8

3267 34r

REPOSANTO'

a T

SCALE I : 250,000

KM 5 « 5 2 1 0

5,0 i2i°oo' so iaa«oo'

375 - -3475—so

3274 -3374 • 3474 ~i

• • [ -

3'73 3373 •3473'

3272 • 3372 -3472: 3

3271 3371 • 3471 \

3270 3370 347O

i«°oo'l I '

n̂- 3269 33P.J -3^6 V -Jo'

3168 ' 3268 • 336B^,346a-

2967J -3067 3167 • 3267 3467; I ; . 1 • -s

IZO°QO' 50 rZI°OO' 30 ' I22°OO'

INDEX MAP

URANIUM EXPLORATION PROJECTRECONNAISSANCE GEOCHEMICAL SURVEY

NORTHWESTERN LUZON

ORIENTATION RADON

M A P I SECTION 11

121 °00' DATE :

SEPT. 1980

ARCHIVE NO.: REPORT BY: FIGURE NO.:SANTOS, OGENA 4

a TAULI

15"

I2I°OO' IS0'"

- -3475 I2O°I5'r" ^ - xi i \ \ 11 /

30'\

45

I2O°I5' 30' 45

9o30T

15'-

Pagudpud

15 Bangui

Burgos 15 ; \ / .'

10

10 / /

10PASUOUIN

20

2020

BA ARRA

15

15

20Tomdagai

20.. " . /

-J10

1020 VINTAR

D LAOAG CITY

San Nicolas20 10

Piddi

10

35

Oingras

So sona

S E C T I O N 1 |Currimao

/

30 -

A T A Q _ Marcoi

25 / N

\ Cur nmao

/ , I

SEPT. 1980 a TAU

121 "00'

Pagudpud

•I9°3O'

ORIENTATION RADI

MAP

LEGEND

V tr

X

LOCATION OF STREAM

AND WATER SAMPLE

OPERATING MINE

MINERAL DEPOSITS A

OCCURRENCES

PROVINCIAL CAPITAL

20 SCINTILLOMETER R

COUNTS PER SECOr

BACKGROUND COUNTS -

THRESHOLD COUNTS - 30

NUMBER OF MEASUREMENT \

• ANOMALOUS RAD: (

IECTION 2 /

a i AU itn.

I2I°OO'

RAD)

P

ND-

OF STREAM

R SAMPLE

MINE

EPOSITS A

CES

L CAPITAL

METER R

>ER SECOf-

U N T S -

4TS - 30

UREMEN'i

)US RAD1.

ORIENTATION RADIOMETRIC

MAP

LEGEND

<I9°3O'

LOCATION OF STREAM SEDIMENT

AND WATER SAMPLES.

A OPERATING MINE

X .__ MINERAL DEPOSITS AND

OCCURRENCES

• PROVINCIAL CAPITAL

20 SCINTILLOMETER READING

COUNTS PER SECOND (CPM)

BACKGROUND COUNTS - 10 cpm

THRESHOLD COUNTS - 3 0 cpm

NUMBER OF MEASUREMENTS- 196

• AMOMALOUS RADIOACTIVITY^ <? F T T I fl N 3

I8°OO'

45

30

\

S E C T I O N

\ 8 L

-V,o/o ,

~~-~. I) . \ Lagangilong

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( S E C T I O N 2

IS

S E C T I O N 5