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QEOLOGIC&REPORT ON PEKO GOLD MIW:d.s.~NNANT CREEK GO~~
SUMMARY
INTRODUCTION
N.T.
by
J.F. IV3nac.
CONTENTS
HISTORY AND PRODUCTION
GENERAL GEOLOGY
ECONOMIC GEOLOGY
Lodes
St ructural Control
Secondary Enrichment
Diamond Drilling
Geophysical Investigation
Prospects
PLATES
Surface Geology 62 foot level 120 foot level 170 foot level 210 foot level
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Cross and Longitudinal Sections
1tt = 40 ft. 1" = 20 ft. in = 20' 1" = 20' 1" = 20' itt = 40'
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Page
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GBOtOGIQ,AL REPORT ON PEKQ GOLD 1m, TENlfAN'I' CBm
'{"tD-FULD a If. t. by
J. F. Ivanac.
SlJMIARY.
1. The Peko lode lies in the north limb of a west p1ung1ng anticline.
2. GoJd is the economic mineral above the 210 ft. level; gold and copper on and below the 210 ft. leve1.
3. A new orpshoot has been discovered by the BureaU of Kineral Resources.
4. A repetition pattern for overshoots is suggested.
I1TRODUCT Inlf.
A Geological Survey of the Peko Gold Mine waS conducted as part of the field activit.ies of the BureaU of Mineral Resources in 19,0. !he objects of the survey were to study the factors 1ocali21ng the ore, to suggest possibilities for the discovery of new orefhoots, and to plan a diamond drilling campaign to test these possib1lities. J. F. IVanac and B. P. Walpole mapped the geology of the mine. The pI ane tabl~ survey of the surface outcrops was carried out by E. M. Bennett.
The Peko Gold Kine is situated 6l miles from Tennant Creek township en a magnetic bearing of 114 degrees, It is reached by fol1owing a well-formed sealed road from th~ township to the No. 3 Government batter,y for I m11e and thense due east along a fire-rloughed road for six miles. The road 1s tr'versable for most of the year, but is unpassable for a short period during the annual wet season, from December to February.
Thp .ine is owned by Peko Gold .ines No L1ab111ty and is managed by .~. W. MacDonald.
RISTOR! Alm...fB9wm,nN,
The Peko Gold Kine was discovered in 1935 and mn'\.g operations wp,re commended in that year. Activ1ties were tera1neted in 1942 by World War II and since that date there hac been no producti'D. A co~any, Peko Gold Kines Bo L1ab111t,r, was formed in 1947 and has reoently started to dewater the mine as a pr~liminary step towards further mining activity. The Company has cOllDlenced to erect its own treatment p'ant for the extrFlct10n of gold and copper f'r CJIl the ore.
In 1936, a Ifagnetoaeter survey waS conducted by the Aerial, Geological and Geophysical Survey of Horthern Austra1 ia.
At the conc1us1on of the Geological SUl'Yey in 195o a didond dr111 hole ,29 teet in 1 ength was nut down by the Bur~aU of Mineral Resources.
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Production figures of the mine are' isted :in the table below:
Tonn- kecovery age. by Amal- Tailings
Date Long g amat ion dwt. per ToIlS • awt. per ton.
~oDI
1st July 1935' - 30th June 1.936 173., I., " 1936 " 1937 1571.0 3.~ Reported to n 1939 " 1940 304 6.0 3. be about 12 n 1940 " 1941 710.0 3.5' dwt. per ton.
Total 55'00.5 3.1
Th.~ 'ow Tf'CO~:r-y by amalgamation is reported to be ~ue to the v~ry f1nF! grainsi ze of the gold and to the read1nes s of thf' orp to ,,~, ill~". T~ tailings Were cyanidp.d by Central ao1d M11l1ng Company, but rpcords of thE'se operations have been lort. The reported figure of l~.O dwt. per ton was ~upp' t~d hy lll". J. Riggins.
The ~urface and underground p lanr "iccompany1ng th1. s report show thp posit1.:)n of workings. All levels, exoept the 21.0 ft. were acces~ibln at the time of thp. survey.
On sane of these 'eVels native timbers, carbeen, snappy gum and mulga havp bef'n llsed as supports. At the time the ~urvey was carried out they wer0 in excellent condition. on the 1. ~o ft. 1 f've' these t imb€l"s 'veN' supporting the \11- ight of t111 wh.1 ch extends up to 62 ft. level.
GENEIAL ClOI.OGY.
The Peko gold "mine lies in a part of the extensivE! a1luvial plain wh1ch OOVers large area~ of the Tennant Creek goldfield. This fl at-lying area is alma st complete1 y devoid of rock outCT'OPS end extends for ~()me distance in a" directions a round t he mine.
ft.. body of massive quartz hf-'matl te is the on1y outcrop on the lN~!p, but subsequentlY, sedjm~nts were exposed by open cutting on the northern edge of the lodp.
The s~~iments consist of interbedded, red, ffi'>d1umgrpjned sandstone, TPd, finp-greined sj'ic~ous sandstone, tuffaCAoUs sandstone, s l' ty c'ayst()n~ end sandy sha] es. The total sed:llIlpntary thicmes s exposAd '1 n tbf' open cut is 46 ft, j.nc'u~ing:- sandst"ne, ~2 ft; silty claY8tone, 3 ft; shale, 31f
Underground development headings have penetrated the country l"ock 1n BE'veral places. Sandston~ and narrow lenses of mUdstone a1'e the pl"~dom1nant rock types exposed. on the 120 ft. 1 eve' , a ~s(6Ittie be.d containing negative pyrite crystals can be tl"8ced fro. 8~, 58'! to 8S, 75'W. Th.ts bed/las a maximua w:1cth of ?~ ft. Th~ negative pyrit(" crystals l"a.nge in size fl"om i inch to i inch.
:Eco,Qlrc G'PdQI,OGY.
Lode.
The surface explosure of the Pe'kO lode is a quartz ... hpmat1tl' bodv s imi1 ar t.o other ".odes Q1 the Tennant Creek go1df1p1d. . It may be considered as tVJO lenticular bodies joined at 00,00. Thp axis of the l:::,rgf'r mass strikes at 77 aeerpf.>s mAgnptic ~nd is 210. ft. in length, that of the smaller, 121 d~gre~ts magnetic and 130 ft. in 1ength. The 10de at the surface ha~ D. maximum width of 80 ft. t at the wint where the two ~ent1cu'ar masses join, it is 30 ft. wide.
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- 3 -'!'he quartz-hr>mst1te is a J;~:rd mass1v~ blvl;>-b" ack
val' j ety jn thEo P8stE'T'n port:1on nncl bec~\mps more quartzosp. towards the Wf'stern extremity, where numberous quartz ve1n1ets parallel to thE' long axis of 'the lenses cut thro1llh the qUftrtzhemet1te.
Tht::' lode has been ~eve'oped by fOllr 'pv~'.s, the 62, '20,170 and 210 ft. levels. On the 62 ft. level the 8verage width C'f the lode 1. 6'5 ft. and 1 ength 210 ft. The fUll length has not been exposed but it is probably about 290 ft. The enriched section extends tram 00,3&1 to 20N, 38£, with a maxlau. width of 20 ft. The strike of the lode changes abruptly fro. east- to north-west neAT the eastprn E'xtrp.mity.
On the 120 ft. Jeve1 (P'ate ) the "ode ha~ bE'~n inter-sected OVer a 1ength of 220 ft. and a width of 95 ft. The are extends fl'. om 30N, ~7W to 33N, 89E, a length of 116 ft. and hal an a~er8f,e width of 14 tt. Prom 7111, 42W to 66. J 8", 8 8ma11 ore~hoot has been mined over a horizontal w1dth ot 8 feet and by inc'1ned sto ing overhead Et an eng~e of 50 ct(!'gr~EI!s. Thf'!il 'ri~e was continued 1nto th@ main stope but no 0l'"P. WAS 1nt~:rRected abOVe 16 ft.
Develo':.ment hE'adjngs have :inte!'sected some ore on the , 70 ft. levrl over a 'I?ngth of 50 ft. and a w:(dth of 30 ft. Further dev~'topJllE'nt wi'.' probab' Y Yeveal a much greater 1 ~m(7th of ore. No. 3 d:fa12ond drilJ hole of thf" Aerial GeoloR1cal and Ceophys1cal Surveys of Northern Au~r~11a intp.rsected a north cros~-cut at 94N, 70W. S1udgp from '68-- 186 ft. assayed 16.8 dwt. pAr ton.
The 210 ft. , eve1 ',,"Jas 1nacces~jb1E' at the time the survey was carried out but old mine plans show that the width of the 'ode has decreased to 47 ft. However the width of 40 ft. of OTe 1s the grf"at~st Intereected in the mine and may probab17 be due to spreading out of va'ues in the water table zone.
AboVA the 210 ft. level the mineralogical comp!')si tion of the Jode material j~ very sirn11s'r on all l~v~ls. It 1s yel1 0w, red, black or white, soft, high'y Weathered, brecciated and iron-impregnrtted sedimpnts intE'rmixed w1th hArd b1ue-black hematite. The sediments werr> prob~bly interbedded sha'es and se~dy shales, highly crushed and fo'ded. The sorted portions of the lode contain the high values, and the harder sections an~ edges of th~ 'ode whjch :nert1y constst of very hard massive hemat! te 1 enst" s are ' ow grade. 'he proportion of mas si ve hemat1 te , enSaS 1ncr ease!! towardS'the edges of the lode.
The gold has an extremely fine g~Rjns1~e and thus does not ama1gamate very Rucces~ful 1y. Bi smuth I:linel"8J s and sericlte 9r~ present, end erA furthel" dp.te~rents to successtul alla1 ,amat1on. Van~anese oxide 1 ~ vr~ry common ~nd is b~'. ieved to be an indicator of sec0ndary pn:richment.
BelOW the 170 ft. 1 evel there 1s a ma rked change in the charact~r of' thf1 lo(lp. A1th0ugh the 210 ft. level work1ngs were inaccessible a review of old mine plans showed that the lode had split lnto dominantly copper-r1ch and dom1nan t'T.y goldr1ch sections. The cupr1terous section forms the northern side of the lode and the auriferous seot1on, the southern side. Spec-1mens collected trOll the dump showed that the copper minerall were nat1ve copper, cupr1te and somE' malachite. Assays 1n this sect10n are reported to be as high as 2~ copper, a p~rcentage 'eveJ which is undoubtedly du~ chjefly to secondeTY enrichment. Gold assays are also generally much h:tgher on this level than on the lev~lS above.
D1amona drilling ~esult! from the primary sulphide zone show that the lode miners's consist of gOld? magnetite, hemetlte, chalcopyrite, pyrite, quartz and a little calcite. Chalcopyrite is the host for tne gold.
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strugtural <Cpnt7:ol.
fhe geolo,ica1 SUl"Yey of the Peko Gold II1ne hal revealed 8~veral :Japortent structural controls, 1'0 expla1n the set-up some t.terence is necessary as development headings have not proceeded ver" tar beyond the 88d of the lode.
Relional geological studies have showa that the Peko gold .ine probably lies on the north 11mb ot-a west plUJlling anticl:!ne. '.l'he pitch in this sect ion ismkl'lown, but is believed to range f:ro. 30~O dEtgrees west.
~ . I j,,' ,...,' ,;,../ , -!... ''':'''; I ;. : I .... ~ ,~~t' '. I,!" ./', frv.l.j / ~~f~'(" ... ,."'".: #r. '::.
'!'he beds expo'ed by open cutting en the Mrth sid. of the lode and by underground develop.ent dip north at anglel which range from 65' degrees to almost vertical. Generally the beds strike due east but at 321, 40E on the 170 ft. level there 1s a possib'e change in strike to north-east.
Strike and dip of tracture cleavage almost parallels the bedding. The angle of 1otersection of bedding and cleavage is natl and the .1ne area represents a marked flattending of p tch in the general wpst pitching structure.
Th1s marked change of pitch, with steepening ot the bec1d:lng and the interbedded nature ot cOllpetent and inco.petent sandstone has led to crump11ng and brecciation of the sedimpnts prior to the introduction otJllneral1z1ng solutioDJI. The lode is of the replacement type and shows a djstinct banding, which is a refleot10tt of selective repJacement of different , 1 thol og ic a1 hor i zons •
To the east the lode appears to botta. oa a taul' which dips to the north-west at 30 deKrees, and is probably syapathetic with a st.11ar possible b~dd1ng-ltrike ehange. In cross section ,O~, the flattening of the lode points to the pos~ibi1i~ ot a flattening ot the dip of the bedding with development ot a shear aero •• the flattened portion.
The control ot thp ores hoot in the lodes is not .. obvious bUt is possibly due to selective replace.ent ot a Ihal. horizon lying above a co.patent sandstone horiaon. The oresboot lies ctmtrally in the lode and has thtl' aame general dip aad pitch· although there is a possibility that the ere pitchel steeply east in the upper levelS and then revprsel to a west pitch in the lower worldals.
~condarY Enr1gh1eDt,
EVidence obtained trom underground investi,ation and dia.ond dri'11ng indicates the possibility ot cons1derable secendary enriclment in the Peko lode. Th. lone of surface 1IIp_erishaent tro. the surface to a point above the 62 tt. level and the apparent absehce of visible copper minerals above the water table le~el support this assumption. How~ver, on present evidence, this enrichaent does not appear to affect the mater1al alsay value of the ore a8, above the water table it averages about 1, dwt. per ton (based on previous records~, and belOW it may average - Gold, 13.3 dwt. per ton and c'pper 7.3 per cent. per ton (figures based on core a8sa1s trom the Bureau of Kineral Resources Diamond Drill hole.)
However, there 1s a marked variation in size of the oreshoot above and belOW the water table level and there is sOlIe su«gestion (with present evidence) of gold values spreading out above the 210 ft. level. Enricnment has therefore probablY taken the tora or !ub!traction of cupriteroU8 aiDeraII and pyrite gangue with subsequent increase in the width of gold ore above water table level. Copper minerals subtracted froll the lode above water table 1 eve' , have been deposited in the water table zone.
-,-DltMe' nrlll1p.c itsUltl.
Exploratory diaaond drill1nc to test a possible neW ore occurrence, wss commenced on the 2,th A11Iust, 195'0, under the supervision of Bureau of lI1.neral Resources. Intew>retatioll of structural and 1Itholopcal features of the lode and country rook pointed to the oonolusioll that the lode ., ruld probably steepen in dip below the flat section. !his lode COincIded with aa,aetic ano.aly .0. 1 discovered by the Aerial Geological and Geophysical SUrve·y ot lorthern Australia.
!he exuination of the present lode showed that ore il .ade an the steeply dipping sectionl, and Diamond Drill Hole 10. 1 wal de.igned to interseat this possible steep section of tbe lode. The position of thil hole is shown Oft Plate 4; the bearin, was trUe north or 176 degrees magnetic; the depression was 76 degrees south.
~. J. Green Was foreman dr111er and he was assisted by Mr. C. White and Jr. B. Billings.
!he results are as tollowsl-
PRO GOLD MIll DIAIOID DRILL BOLF. 10.1.
'. no
root .... !oR,coyen
ft. ins. De!.cript1.oa "'II
~ 2 8 Pale butt .aOO1 shale t fine
5'0 90 10
90 100 2
110 120 9
120 130 4
130 140 1
140 15'0
2
15'6 170 13
170 180 6
aDd aedina grained turfaaeous sandstone.
o '. Pink, yellow and grey shale . wi th sandy bands. leddill, flatly dipping.
6 ), Pale butt fine and aediWi gra1ned sandstone and shale.
6 0.4' fine mediua grained sandstone - shaly ill part. 4 -9'6" pink sandy slate wi th sOBle aediUJI grain" sandstone.
o . 0..6" pale purple sandstone. 6"_2'0" pale purple sandy .hale. 21 0"_3'6" waBdstone 3 r6"-4'0" sandy slate.
8 '. 0-8" pale purple tine grained sandstone. 8"-1'8" sandy slate.
C-l' sandstone 1'-616" pale purple sandy shale with tine grained sandstone band ••
8 ' . pal. butt and pale pink fine ana mediua grained sandstone with 6" ot siltstone.
o White and pale purplish grey tine aDd aediu grairled tuffaceous sandstone with shale bands in part ••
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6 "" ~ 0-1 '6" 12a1e batt s11 tatolle 1 16-.616" Jlediua grained saMstone.
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"-,lootlBI: lrow 'fo Recovery Desgrlpt10n As IllY
180 186 4 0 Banded sandy shale. -.
186 198 7 0 O-lt sandy shale 1 t .6' sandstone 6'-7' sandy shale, in part.
cherty
• 198 210 3 0 0-1'2" reddish brown banded tine grained sandstone. lr2"-3 t pale purple inter-bedded cherty slate and tlne grained sandstone.
210 220 8 7 0-4'10" cross-bedded sandstone with fine cherty slate lenses. 4 110"-7'1" fine grained sand-stone grading into coarse graifted tUffaceous sandstone - pale purpl ish green. 7'1-.8'7" bended cherty slate in the fine grained argillaceous sandstone bands.
220 231 6 0 0-2'4" pale purple cherty 51 ate with fine grained sandstone bands 2'4"-2'8" fine grained tuffaceous 2'8"-6' purple cherty slate.
231 240 0 ; purple slate
240 2;0 0 6 green and purple slate
2;0 260 4 8 0-2' ~ale green banded slate 2'-3' " pale green mediua ,rained tuffaceous sandstone. 3'8"-41 8" slate and sandy slate.
260 270 4 0 0-7" pale green slate. 7"-4' purple cherty slate with some sandstone.
270 ::eO 4 8 0_4';" banded cherty slate with fine grained cross-bedded sandstone. 4' ;".4' 8u light purple slate.
280 292 ; 4 0-4' 3ft pale purple cross-bedded fine grained sand stone and slate Bote at 1', 1/32 lenses and veins of malachite. At 3'4" malachite stringers.
292 300 1 ; pale purple sandy slate.
300 310 7 0 0-1'7" sandy slate with some thin malachite stringers. 1'7"-6'1" fine grained sand-stone grading into coarse grained tuffaceous sandstone with thin malachite stringers. 6'2".6 18" dark green quartz breccia. 618"-7' purple slate with narrow malachite stringers.
310 320 7 0 0-1" purple slate l' -1 to" f:me grained purple green sandstone with some ma1achite stringer!.
ZQotage !rOB to Recoved
1
320 330 2 6
330 340 o
340 350 o 6
350 360 9 4
4 10
369 374 1 9
374 384 2 4
384 391 2 1
319 397 1 10
397 400 3 o
400 409 6
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Description AssaY
1'6"-6 1 sandy Slat. 6 t -7' pink and green mediUll grained tuffaceous sandstone. At 6 1 2", t inch breccia parallel 0 bedding.
0-10" pale green slate 10" -1 f 1" med ium graine~ tuffaceous sandstone. "1"-1'8" pale green sandy !II ate. 1'8"-1'9" medium grained tuffaceous sandstone. 1'9"-2'2" pale green slate with ~inch hematite stringer. 2'2"-2';" medium grained tuffaceous sandstone. 2 t 5'''-2' 6" grE' en che rty s1 ate.
0-8" purp1 ish brown mediumgrained tuffaceous sandstone. 8 f -1 13" hard green cherty slate. l:t 3" -2 t purpli sh green cros I bedded medium gr~1ned sandstone.
green 81 ate
0-6'10" interbedded tuffaceous sandstone and b_nded purple slate 6 110"-9
'4" green cherty s1ate.
0-4tl0" green <lerty slate with occasional quartz stringers.
0-1' 2" grey green mediUll grained tuffaceous sandstone. 1 f 2"-1 r6" brown lode - altered Slate with quartz and (1) hematite stringers and some botr,ylodal Mn02. ,'6"-1'9" green oherty slate.
0-"9" green cherty slate 1'9"-2'4" quartz and magnetite
0-5" pyritic sandstone 5"-1'10" green sandy slate with some quartz and heaati te stringers. 1 t 10"-1 tIl" green cherty slate, pyrite crysta1s and quartz crystal s.
Au Cu dwt/ton %
0 .. 3" green sandy slate 3"-1 t 10" quartz-magnetite (?)pyrite, hematite lode
QUartz, magnetite hemat1 te, pyrite, chalcopy;Jte, lode with a little chlor1~e
Tr.
towards the end of the core Tr.
0-4'5" quartz, chalcopyrite lode. Chalcopyrite later than magnetite and quartz intergrown texture, seg-regations and ve1nlets Tr.
Tr.
Tr.
'rr.
ft. 8.
-t I, .( J
410 420 o
420 42; o
42; 434 3. o
440 6 o
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4,0 460 10 o
460 464 6 o
4)4 471 7 o
471 478 6
478 489 7
489 ,00 1 10
,00,29 12 o
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~eSQr1pt1ga AISay, 4T 5"- '1" massive-magnetite- ~:" -chal cO)JYri te lode - veins ' I .' "
and segregations. 4~ +O9~ 5'1"-5' 8" same as 0-4';", at ;' 7" gl"een sl ate fragments. 1.0 4.0~ 518"_6'5" chalcopyr1te, pyrite, magnetite lode. (?) arsenopyrite. 6 r 3"-6' 5" well formed pyr1te crystals, in wughy 10de
pyrite - magnetite and chalcopyrite lode pre-dominantly chalcopyrite in massive segregations. P,yr1te 1 chalcopyrite and magnetlte lode - w1th the sUlfides in stringers
0-11" chal00 pyrite, magnetite, pyrite chalcopyrite and pyrite in clots. At 4" 425-427 dit colourless zeolite in vugh 3.60 4,1_ 11"-1 '8" massive pyrite, chalcopyrite, magnetite lode, l r8" 3'0" massive pyrite ) lode with a little magnet-) 427-434 d ite. ) 0.6 o. 0-1' massive pyrite lode with a little chalcopyrite and magnetite Tr. 1'-4'6" pyrite, chalcopyrite, pyrrhotite (?), magnetite lode (tow sUlflde) 4'6,,-6'0" same as a"ove but with quartz veins - tendency to form bands.
(434 -1438
0.3%
~8nded quartz-aagnetite lode. (prob. some hematite) with !treaks of pyrite,(?). Slightly vughy in part. FrOJII 4'8".,',ft green slate Tr. Tr. brpcc1a. Soft black powdery mjneral in vughs (?Mn02). Some cry stal s of cbalcopyri te,
0-8 16" tow sulphide B'-lOt ditto Trace
B~me. Disseminated pyrite, chalcopyrite? in massive quartz-magnetite lode - Trace pyrite 1n vughs at 464. Trace
Qusrtz.aagnetite lode with some pyrite and cha1copyrite Trace
Same 8S above but with pyrite clots Trace
Same. Wi th pyri te and chal copyrl te
Shetter~d country with some quartz veins.
green sandstone and slate
Trace Au 0.,% Cu.
529 Feet. ,LND OF HOLE. ----------------------------------------------
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The lod~ was intersected from 397 feet to 500 feet ~ d:istAncp of , 03 fpet. Assuming the 10de to have an a~e rage dip at 70 dpg~pes no~th, this intersection would represent a horizontR' width of ,4 feet. Assay of the drill core showed that approximately ?2 feet of ore was intersected of true width 12 feet. The assay resu't~ are as fo11ows17
Au. Cu. From To dwt.J-..P.S: r ton 12~r cent.
405' ft. 409 ft. 1.0 4.0 410 420 25.1.5' 11.1 420 425 5.90 5.3 425 427 3.6 4.1
22 fpet avp.raging IJ.3 dwt. 7.3% ---Assuming 100% extrac tton the va' ue of one tonp. ()f ore
at prices rul ing a t the 4th Janua ry, 19 5'l, may b0 cal C ul ated as fo 11 OW ~ : -
13.3 dwt/per ton 7.3'1 Copper
£10.6. o. per ton £1 5'. 1 3. 10 • per ton.
'rotaJ per ton £25.19.10 A.
---Core recovery was reasonably high eve~ tlllough part
of the drilling was in very soft count~ rock. Dril1ing statistics are shown :In thf'l fo1'owing tab'~:-
Total Core - 2231f 1t. Length of Hoie P~rcentage Recovery 529 ft. RecoVery
66 Length of TJode ~l~
Total Lode Recovery ft. 103 ft • 64%
. ---------From 0 - 200 feet, the high1y weathered char~cter
of the COtUltry rock pre',ented a nigh core rpcovery. However, water rf'tum was, on the whole, t'ery good inthi s section except for the very porous initial 50 f~et. Subsequently this section was cfased.
The lode was extrem1y ham and the jn1.tir31 dri" ing rate of 50 feet per day coul~ not be maintained. Between 410-420 feet and at 427 fef't weter f'Upp] ies were completely lost i.n vughy rock. It was found necessary to cement these pect ions of the hole. From 46o-if 75 feo.t the 10de waS excessively hard and closely ag~gated quartz-hemati te-magnetite with the oons~quence that 01'11' bi ts had to be replaceo every fj Ve feet. The pyrite-Ilagnetite lode was easily dr1' led and usua1ly gave a good oore rpcovery. Pighteen dayr, were spent on the Diamond dri11ing with an avrrage f)f ~9.3 feet per day.
~bl~cal Inv~stigatiQns.
In 1936 the Aerial Geological and Geophysical Survey of Northem Australia discovered a major magnetic anomaly w1th a maximum value of 5,500 gammas. The cent+e of this anomaly is
. 200 feet north-west of the main shaft. The anomaly was partly tested by two diamond dri" holes No.3 and No.6 (Third Report on Magnetic Prospecting at Tennant; Creek, (1937) T •• A. Richardson and J. If. Rayner). In No. 3 hole thE" main lode W[l s in tersected on the 170 foot level and a sludge assay of 16.8 dwt. per ton was recorded froll 168-186 fpet. However, this reosul t was not 'confirmed by corp 8s8a18.e i No. 6 hole ppnetrated _.S91111er-quartz~magneti tp-hemat1 te lode for 35 feet And was then abandoned. The rf"suJ t~ of this dril1 :lnr. aT~ tabu' ated below.
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Locatiop:
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3. 10. 3 DiAmond Drill Hol ••
peko No. 1 Anomaly at 604W/188 80' south of anomaly centre.
»e,eript1on ,of DJjJl-Q0t§':
o .39 r Brown massive slate. 39 43'6" Brown coarse grained slate with occasional
43'6" 72' 7::?' 100' 100 t 120 t 1~0r. l28 t
128 15"0'
186 t
quartz veins. Pale brown fine grm ned ,late. Brown slat~ I.dth hematite end quartz veins. As for 72' - 100'. As fo r 100 t - 115". Hematite Rnd quartz with sott patches,
7'~ core recovery-. Soft friable ferruginous asterial with
occasional bands hard hemati tc and fJ uartz. About 15'% core recovery.
19to ; Casing was seated at 13, feet. Water lost at 170 teet and holp. cemen tp.d here.
Wherp corp. recovery was unsatisfactory, 51 udge in additIon to core, ,,~as B.ssayed.
Assay Rp.lYJ,ts:
Cor~ awl,s: Sallp1e 10. 1 .0. 2
39 1 - 43' Brown slate with quarta 72 r6" - 78 r Chocolate-red schist wi th
tite(?) or quartz veins. D " H n
" " " " " " " "
lio. 3 78 t
10. 4 a,t No. 6' 90
r
- 8,' - 90 1
... 9;'
veins ti: hama-
0/2/14 0/5'/21 0/1/7 0/1/12
No.9,' • 0. 7 100' .0. 8 10;· No.9 110' Jo. 10 1",' Ifo. Bo. No. No. lfo. No. 10. No.
11 120' 12 128( 13 13;' 14 138' 15' 141' 16 144 ( 17 1.47 1
18 15'Of
- 100' ... 105" - 11,0' - 115' - 120 1
_ 128 1
- 13,' - 138' - 141' _ 144'
147 I 150'
_ 1,6 1
" " .. " Brown Slate of !chist. "" " "" "
Choco1ate-!'~d ~chist 11 ith h~mat1te(') O~ q~artz veins. Brown slate of schist Dense hematite and quartz
.. " " " " " " "
" " " "
" " " "
" " " "
tr. tr •
0/0/9 0/0/9
0/0/9 tr. tr. tr. tr.
0/0/21 O/O/l~ tr.
No. 19 15'6 1
10. ~o 170' - '7Q' 186 ,
Fragments of hematite and Quartz. Hematite and quartz tr. Fragments hematite and quartz 0/12/1
§) ud..E~fulgm :
Samp'@ A B C 'D T!.': F G. B I J ](
53' 60' 66f
128' 130r. 150' 15'4 f 160 t
16,' 168 1
173'
... 60' 66' 721
130' 135" 1.541 ,60 t
1.62" 16~1 173' 186'
~: 0/0/9 0/0/1, tr. tr. tr. tr. 0/6/2 0/17/21 1/3/12 0/10/15.
6, piamoJld, Drill ru21e 10. 6.
Peko WO. 1. Anoma1y, angle hole at 610"/1.'5'N. Depression 60 from iaorizontal to south, in direct:! on of No. 3 Diamond Drill Hole.
..
•
•
•
- 11 -
De§or1RtiQP of Cores:
0 232' -239'6" -
240
244 .. 25'0' 6" -25', -267' 5''' -
232 239'6tt
240'
244'
2,0'6"
2"r 267' 5'"
271 r
Brown slate or schist Slate or schjst with pseudomorphs after
pyri tee Hematite, ferruginous slate with Quartz
veins and native copper. Grey fine grained slate or sch1st ,.ith
copper stains and o~artz. Siliceous and ferruginous rock (altered
slate ?) with natile coppeT and clacite. Hematite and quartz Hematite and,uartz with native copper and
sulphide (pyrite). D~nse hemat1t~ with some magnetite, qua'tz ,
native copper, pyrite and arsenopyrite(?).
Dri'l1ng was difficu1t and slow in the dense iron-stone, possibly due largely to poor cond i t·ion of the diamonds.
Static watpr leve) appsrp.ntly not reached.
ASSII Results:
Core Samples: .lU& ~
Sample No, 1 232 16" - 239 16" Schists with pseudomorphs after
239'6" -pyri te. .0. 2 240' Hpmatite ferruginous slat~s with qua~tz, veins tr. nQltr. and n ati ve coppe r.
Bo, 3 240' - 244' Grey schi!t w1th copper Tr. no tr stai ns and quartz.
]fo .• 4 244' - 247' Siliceous and ferruginous rock. tr. 7.85.
No. 5 247' -250'6" Siliceous and terrugjnous rock. tr • 1.2~
Ro. 6 259 16" - 252'6" H~matite and quartz tr. -No. 1 252'6" - 25'5" Hematite and quartz tr. Ro • a 255' - 257' Hematite and quartz with
native copper and sulphides 1.7~ a~ some magnetit~. tr.
No.9 257( - 259' .. .. If " tr. 0.68. • 0.10 25'9 ( - 261 t " " " .. tr • l.3)~ !fo.11. 261 f 263' " " " " tr. 1.3~ 10.12 263' 2~5' n " " " tr. 1.2 10.13 26,t - 2 7' 5" 11 " " " tr. no tt 110.14 26?' 5" 271 f " " " .. tr. 0.54
with jnore!!ls1ng JIB gnetite.
al:Bd.l~ Ssamlej:
Bampl~ A 240' - 245' tr. 1.72~ B 245' - 250' tr, no 1z C 2501 - 255' tr. tr. D 25,' - 260' tr. tr. I 260f 265' tr. tr. ., 270' - 271' tr. 0.20_
f1:SUi I2tc;ts.
Prospeots of further discovery lie in a continuation of the ore making structurps down dip and down pitch, and a continuation of the alsay grade. With the discovery of the Wo. 2 ore shoot it is possible to nostulete a further new repetition to the north snd W~!t. Further pxploration of the new oreshoot 1s d~sirab'e, Rnd wh~n the ~xact posit jon and outline of thIs body have been a~certalned, und~rground drilling for another shoot 1s recommended. Surtaoe drilling may be costIy unless perhaps a churn bit is used in the initial stages •
-.. --..... ~.- _ ... -- .
400N ,
aOON I I--------- ---- ---------J
,OON
z Q I-
o o
f;l . CI) OfJ.(BMR N 91 1.950:
I I i
Lenf7th 420 f't. LJepression 70, ,
o ~o. 0 (i\l96 AGGSNA) z
o § CI)
------ I --·-----r---~·l---
lOON
00
100S
[JO.
• (No.3 AOGSIVA.I--"\I
A I 0-- --- .- _______ l __ _
~ .
o o
I . .... .
I I , I I
1
Dump
-.-.-- - -- ----' .. .--~--- -.--- ~ - -- --_._---- _. BUREAU OF MINEIW. RESOURCES. GEOLOGY . AND 6EOPHYSICS FEB. 1952
III o o
... 0 ' 0 1
... g . ... N - ~
P/.lJ!~ .f. ,., 400 N
SURFACE GEOLOGY
PEKO GOLD-MINE TENNANT CREEK GOLD-FIELD
NORTHERN TERRITORY
SCALE
REFERENCE
Quar tz 'hemotite
/ StriAe and dip
~ Shan
r:;/ Inclined shafT
~&arp
rl ['os fean '--'is'
300 N
,OON
/ Yer fica l dip ~ O/amonddnJI hole. inclin~
/ Plunge or pifch • DD Oiamond drill nole.yerf
... o o 1\1
------. - ---+-~ NT1'- 6
w o o ..,
100 N.
00
1005
I
1 ! ,
. \
. ~
• I
z o i=
~ <I) <I)
o a: u
BUREAU
\
LEVEL PLANS
PEKO GOLD MINE TENNANT CREEK GOLD-FIELD
NOR'THERN TERRITORY
:"~~":' /1 69 II
~
11 l'
Ol/t7rlzlfe '.'::
~ o Q
4 0 0 4.0 80 FEET
E[==~~==C==EI ======~==~lt=========~
z ' 0 1 i= 1 u ; \il l <1) 1 I/)
o a: u
w o , r
. 11
621 LEyEL
~ .
Monway to 12.fJ'level
"
~ 0 '
100 N---t------NP.3 OlVt (A,GGSNAJ (Cere Th;vn 1t]8-18(j feel assayed f(j 8 dwts/lon Av)
, "
z o i= u :x <I) I/)
~ U
z o
~ :a o ex: u
REFERENCE Shaft -extending above and
below level
cs;::J H e ad of'rise Dr wmze
o Foot of'r/.se or winze
~ Head oT' inclined winze
/ I nc//ned bedding
/ Yerf/cal b edding
/ Incline d cleavage
/ Inclined ioint
- D,D, Oiamond dr/I/ hole / rClult w /fh d ip
C Economic ore b o undary ..,..,.,7777'r77"77""71
.. , '
-",. ,1
Dense and 50// lode Wlfh partlcles- ~ or unrC'ploced sandstone
I 76 • 1 II
oo -------
i ~ o 52
flo • ~ .... ' l&J 0 -o
---~
I lOON
'9
, ' ,6l!" , ,7- . ,- ' • . ,
, . ·: .~r>y srmd..'!tone . -~.
120 1 LEVEL .:. . . .' 7'5 '.'
/ I \.: :'''':'.
f • ::"/)/nl/c sonJsloat? ~ '- ,~
Z I o 1= ~ <I)
<I) <I)
o ex: u
8- ~ ...
\
OuartZ - hemaf/fe -
Crushed hematde
[?'\'/'):::'/)l Sandstone
~}??!};a Sandstone and shale
0 / 0" (}uartz vein / /
Stoped or!?
l&J o II)-
I.
Au IOdwls.per Ion
~ o ex: u
'{
w,
z o i= u lij
:2 o a: u
l&J o o
w o o
-•
L' Tootlf -11.
- 00
00
00 ' _________________________________________________ ~~-oo
w o 11"1
~ ~ 0"
8 \l)-
•
.,....
" , OF MINERAL RESOURCES, GEOLOGY AN/}
&:
170' LEVEL
CEOPHYS/CS, FEB, /952
l&J o o
NT11-7 AJS
210" LEVEL o
60'level
120'le"el
170'/evel
200
21'0'/evel
V)
a a ~
. ..,
C) C)
" .
% "
" '.
\ \ l'it \ \~
I l,i;~' I ~ '"
"" I. II f SQJ/7o'slo/7e ~/;moo'slo/Je
, • rraceAu .. .. '. ' ... -.
'" :~. sor~ '. ;J '. •
•• ••• 1\ -:::;. ' •• ~ /oole
~.\~ .... -<'- ". ". Q)c- • •
-;;.. . ...)
S 50
#oo//rO"OO
'.-' .. ·7
£)ense lIemOll'ife SOffit' /,n~yrnerlre, co}'~~r
' . of/riTe 4 Sr$"n0%re
: ,r
MAGNETIC':ANIJ'Iv,!xLY N21
. . ..,
, .
. . . . ,
, ."
.
.. . . . -.J: ..
cou/7ky rocK
• I . ' : j .~ /oIw~A{/,4'O%w
.- --".- .. -- --"--._ --~/.)~IA". tt,t%Cu
. . ,," . . .' . .' 1 rraceAu, rn9ce&
: ' .
. . :-,) "
• ...J '0 • .-;
. . .... --- :-~
.... ,
I I
I '.) '. )
" . I '. !
r ----- -- ----- - -'--'-,------ -- -
Z ! a 0 , ""I
Vl a a a
a z a "' S /OO 'dvlum - ,
~ ~ 7 'i -=s"'v.:..r.:.;-rv::,:c:,:e:....:,/e:;r.:.,:e:,:/ ______ ---r H ". HIli/ "" II b
I II" 711 Iv ,." ' :. /\\ /(,',,' , , ' ,
I \ 1,-
CROSS SECTION 50 E
?
: : .... '.' .
~L~ .... #'\\ \I ","'. :..1: __ J.
:." '.
'. '.
Wvter level '.
"'" ,:,.~?"' ... " '." " , ',' "."
".;
B{/REAU or MI#ERAL RESOURCES, GEOLOGY.£ GEOPIIYSICS,JA#UARr I.9S2
PEKO GOLD MINE TENNANT CREEK GOLD-FIELD
NORTHERN TERRITORY
w
100
rocK 2
300
I 400 I - ~
• CROSS SECTION SOW
,
·
. .
showing intersection of lode by Bureau
of Mineral Resources diamond drill hole
N£1 (1:)50) and diamond drill holes NE 3
sao ' - -i · -
and N26 AGGSNA (1935-1936)
I
(Assay values from core samples)
z o a N
... I
2 , 0 , a '<1' ,
N
62'/eye/
120 'level
f70'/ere/
2107eve/
,. ,
4D I
1I=3==~~ 1:':,.' : : :",j
...... -? .....
----
I
I I
REFERENCE
Ore
Sto~eo'ore
(}uOJr/z -Ilematlle
Shv/e
Sa/7o'sloae
£SlaOl/slleo' 00(//70'0'/)/ -,D0s/li0/7 vCcu rvle
LSlaO//slleo' bouao'a/)/ -~osilio/7 a~,oroY/'male
//lrerred probable or iao'e!'l/71le bou/7dvy cO/7cev/O'd
//7 rerrO'o' /aulf
o-oss-secl/o/7 orcrOSS-Cl/t or drive receo'l'a.5' Trom observer
Cross-secf/cm orcross cuI or d//'ye 60lh a~jJroacll/n.5' u/7d receding
. .
· ·
A,66.SJIIA, Areal Geolo,5T1ca/ u/7o' 6'eo~hysicv/ , Svrv6Y' or #orlher/7 Ausrralia
BUR
20 I
o I
Bureav or Uineril/ Resources, 6'eoloj'Y.§ Geophys/cs
Scale 40 , 80
I 120 rUT
I
· • •
I ~ a a N
?
I ~
'. a C) .... :..>
. .
I I ! I I I ) I I
.1----'1--
I
I.... ~ V')
I"<l: :r V')
~ N 01 O.
Z :z
i I i i g II II
I I I I II I
.? ····· .. ····1 :"?"'I I ........ ? .... . ..... II II
:' I I I I ~o.u/6/e ore
: I I I I
I UJ a a ....
;=.31
.. I , ,
I I I fiR/ed-I/} I
.1 .
.. ;
I I
("-- .... -1---___ .!Il...+ __ _ I
I I I I .. , I " , .. ·1······ I I I .: ,..... I ,{/;Ioresllool I I I , :}.:
: ,t,::'-=--=--1:::====='=~~=~,Lfj ,e,.- ~~ .... . :,' I I 0:'
bollom Alp,] divmo/7o' 0'/11/ hole -41. I I I I , • fA,6G.S.#'A.) . I 1 Ii,' ' •
. . ;
'. I I I I,~ : •• •• 1 II IJ~ , '. ,..-------.r, --- (? i1:
I ....... ______ .u.L_I. '\,: , ' . I " . , '. ". . ..' , .................... . + bo/lom IVpo d/"moad o'r/I/ no/O' I fA.6G,S'.#'AJ I , I I , I I , I I
......... :.? ......... ". ." ?' I . .
.' I ?
. ? . .
I / I L __ ~_", _~_J
. 'l;' • . '
'I .• .' .'
w o o N
I I
LONGITUDINAL PROJECTION
?
I I I
I I I I
. I
7 .
. . I ..' Possible oul/i/le IV~.2 oresnoor
I
?
I I I I I I
?
. // : . .., I I
..
I • ",: I • :
?
.L b0l!0m Alg lo'lilmo/7o' dr:11 Ilole (E, M. R .)
. .
.... ~ 4-" I'll'"
..c't
. .
.
V') ~'" Z o "t'"""'C? Z 0 o 0 OIL 0 a .... oza.. IJ') _ l
S -------...:~--------;;,....c;nF-"*1 ~ ~ I I ItJO 'o'alum ,- A. " jj - \I I/l" ~;:-----'------=----':c-------~:;'::'-=::':"'::'-'-'-'- N __________ , /! ~ /,/ I; 1/ \I , I II ~,'7,,"""',~,.,..,..., ~,-,-" __ -"sc=u::..,.:..r;;::.a::,ceo:.-----_____ _
',' 1-1 /1 ".t-:\""""" . " I~ .
62 '/eye/
1'20'/erel
210'/eye/
. "'I":' :.b 'h , , \\ r '. //1 I ",",
... 7 .. ,11' 1/'. •• , • " 11" -,"
\ .:..:.
",,, h~£:;,;..;;~_~~2:...-l..!!' "~"\.:,
II 1 \: :, ~~:::y,:\""~~~~~= ~."
? '.
"
CROSS SECTION 00
PLATE
100'o'v/um E '
62'/eyel
1'20'/eye/
170'/eve/
2Itl'/erel
ONTO SON
"
NT1i-2 W,K ,
