A Geochemical 

Exploration for 

Antimony in 

Southeastern Alaska 

MINERAL RESOURCES OF ALASKA 

- - 

GEOLOGICAL ' SURVEY BULLETIN 1024-N 

The a@/icutitm of geochem icol 

techniques in e~hration 

far untimofly wes 

II' - 

ASSAY OFFICE 

ANCHORAGE, AlASm 

- 

UNITED STATES GOVERNMENT PRINTING OFFLCE, WASHINGTON I 19Sf 
WNlTED mATE8 DEPARTMENT OF THE INTERIOR . . . . 

* -. -. 

Fsed A. Seaton, Secretaty -; 24- , .--L : - s 

I' ... " '. 

-)----.--- - - . *. . .L * - +__-.-._ 

GEO-ICAL SURVEY 

. - - - - . . ,I .,,, 

I .: . .. . ,- . . *.. ,.. I.. . ," ... 

... * ". -,- 

8.. ", '.. 
CONTENTS 

Abatract-,,,,,,,,,,-*-------------------------------ll--r-------,,--- 

In~~ctfm,,~",,~,,*,,---,,-----~-----~~~---------~*------~~~-~ 

Areal geol~gy,,,--,,,--------**~------,-,-----,,---~----"---,,---- 

Geochemical ~Ioratim--,,,-,,------------------------------------- 

Phyeiaal charaaterhtica d soil--- - ------- ,,--------- - --, --- --- --- 

Method of colIection d samph- ,,,,,,---,,,,,------------

?rlethodeofchemicalanalyeis---,-,,,,+,~---------,,-------~~,~~- 

Lateral dhtribution of antimony in r~fduum -,--,,,--,---------

Preliminary orimtstian travnrsea -,,,,,-----------------+---, 

Reconn~ssmcetra~erllea----,--------------,~-------------- 

Detaildlat~&es--~-,------------,--------------------*---- 

Vdoal distribution of nntimtlny in soil prome ,,---------------

M~tribution of antimony in fluvial Bedimenta ,,-,,,---,,,,,,--,,,, 

Distribution of antimony in bedrock -,,,,,----,,-,--,---,,, 

Interpretation of results- - -, -- -, -, ** - ,, - - - ,,, - - - - - , = - -- - --, - -, -- 8ubquent exploration---, ,- - - ,,- - -- -- - - , - -- - , , - - - -. -- - -- - - -- - ,, - - Concluai~ne----------+---+-----------,-----,,,,,--~--------------- 

Recommendations for future work at Caammo Point ,,,,,,,,,,-,-----, 

prsta !&=In met1 

pess Smm 2Q. View of e muakeg-cevered arrta at Caemano Point,, , , -- Faces 166 

a. Map of preliminary noil Barnple lines. 

Map &owing reltbtionship of physical explo~tion to geochemioal anomalies, Rlackhmd Claim. 

Ro~ 21. Index map showing location of antimony proape&, Caamano 

Point ,,---,--,-,-,--,----------------164 

22. &etch map of Clcvelrmd Peninsula ~howing geology and 

recomaissanoe linea of mil samph, 1953 ---------,,,,,,, 166 

33. GeoloAio map of 44-foot level. shaft 2, Tillicum Mining Co. 

property ,m,-,--,,,,,,------------,- 175 

Pam 

TABLE 1. Bpeotrogrsphia ana1ysia of antimony orea from Caamano Point, 

Alaska_ --------,-- ,_-,----------,,,,,----,,,,,,,-,-,166 

2. Antimony content of preliminary soil and plant aemples----, - 169 

3. Antimony content of aoiI sampIea from mconnaismnoe traverses- 171 

RESOURCES OF ALASKA 

A GEOCHEMICAL EXPLORATION FOR ANTIMONY IN 

SOUTHEASTERN ALASKA 

BY C. L Smmmm 

kBmm 

Prellmlnfmy -cal mng by tbe U. 8. GeoIaglml8umey wue 

tfodmt in IRK2 in muakeg-covered ground at Casmena PohL Cleveland Penlnmle, 

Ah&& In an dart to delimit mesa of stibnlte concentratfon. It waa conducted 

&I aid. ii pos~Ib4 an eBploratlon project of the Defense Mherale Explomtton 

AdmMutmtioa &mpIw were mlleeted from sol1 and deeomp~sed limestoneanddst bedmwk at depths ranging from 18 ta 80 indm by means of a pipe 

WRftb an interlor gInnger. 

MU aamplln@ was IOU& by detailed samgling d the ereas whew the 

rtntlmogy crmtent of the 90th cw8lrrtently everaged more than 300 ppm. Them 

em of major soil coneentmtlons were pmapectd by mace trenchhg aria 

permmfon drlllfng to depthe of 20 feet ; this proved the existence of stlbnlte ore. 

A Bhait and drifts made tn the mwt favorable area found di~~emfnated snbnlte 

ore to ai 60 iaet 

ThEs geachemlml wmk of mil aampling to bdim~b biddm ore bodtm h R 

tggIcal Mask811 maskeg area la belleved to be the firat appllcatlon fn Blaska of 

mch khniqnea In active ore esplorntdan. TM rmdts mow the mmlc Zeaeibulb of mhemical exploration as a Atst gtep h extmdlng the known bmdarfea of mlnedbd areas and h dfrecffng Mthl physical explmatlon toward 

the moet favorable areas of nmmace ore Wiea. 

Peta are presented to establish values of eoll conhht of antlmmy that may 

lm dderea normal fn thin t3rpe of terra- 

~ODTJC~ON 

In 1953 the UwZogical Survey mdad gemhsmid explaratioa 

& an antimony prmpect at Caamano Paht on the southwestern tip of 

Clevaland P&ula, ahut 14 airhe miles northeast of Keizhikan, 

which is #EI nmmt town (jig. 21 ), The pmspeet was formerly known 

ldj fb~ the Val ram antimony mine. ]Exp~orata~ work before 

1952 cm&d of two shallow shafta st the site of tbe original dismverg and saml hmch and &allow cnts h bedrwk, none of which 

glidoaed additional sbibnite ore. In 1950 the prospect was quired 

by the Wicam Wig Co., and in 1952 the Defense Minerals Exploration Adninkbtion mgotiated a contrwt with bt company for 

lmmzhing and anMace expl~mtim 

163 
Although the pFhspect at Caamano Pbt had been mspped,plogi- 

,.p&~: tho debils of the structural mritrols oX ore deposition were 

imy?erlactly, hown. mck Vegetation obd the structure of the 

'berdr&c and made &ace exploration slow; Sdt, and &Iy. Such 

qIoratian was haphazard bemum the locationqof bche wd9 influend. mom by the distribution of bedrock .and ehtn, &cia] dq&ta 

' than by the geulogic evidence of the existence of om bodies, fir 

the Sway devised a field method for determining lmm amocints of 

antimony in mils and plants, geochemicaI methods were applied to 

the pmpect at Cmmmo Point befom the mmpq began surfw 

'md 'mkurfm qlonrtion, The purpose was twofold : . - 

*Roblwon, 0. D., IW, Tha hmmmo Point mtlmong. depmit, Qwelatld PemLnwln. 

wathesmtem Alnmka: Yimsa rept h mw at U. B. QeolMcaI Burvw. 
a mmChL EWRA'120N FOR AN=- W BE. AU@WA 1% 

. -1. To obin htual cribria on the gewhemical bhsviior of an-= 

ay .in a typical Aldm of hmvy ddl and thick wta-. 

tioa 

a, To deli& if that were psilble by &emid m&oda, thorn' 

areas Jhly t~ contain bdmck amcantrations of antimony, thusfacilitating the lmtion of trenches in favorable areas, which would. 

. result in a eaving of Government funds. 

To accomplish this pmpoq the writer Pisit. the pmqmt ia 

Septembe~ 1952 and collected 76 soil samples, epd as shown on 

plata 21. The dta of this pprsliminarg sampling ware enoonraging, 

hence more ssmples were coUacted in March 1953, lis a dt, two 

arms -with an abnormally high concentration of mhy in the soil 

were delimitad. Subsqumt trenching and drilling under the Defense 

Mind9 Exploration Administration contract prwed the existsnee 

of stibnjh ore in both areas. During the mer of 1953 the ZSZEicum Mining Ca mIlected ~amples at the mitar" qu& and found 

another ~bm of high sntimony mcentwtion. Surface drillbg 

ahoweif that atibnita om underlies the soil in this ama (ore zone 4 on 

pl. 21). 

~Ehief~of~reportiatopresanfthe~tsoftha 

gemhemical exploration. The writer wishm to howledge the 

wmksis extended to him by krge B. Roberts, general manager, 

Tillim Mkmg Co., and the mistance of William Hibberd, Tirlicnm 

Mining Co., and R. C. Rowe, Bssayex for the Territorisl Department 

of Mines. All samples were anal* in the laboratory of the U. S. 

GeoIogicral Smy, Denver, Colo. 

W-& geologg of the soathem part & GhmiIand Peninsula ia 

discud by G. D. Robh ' and the geology shown in figure $23 ia -, hm Bobim7s report, with minar additions by the wrihr. 'Ilhe 

Caammo Paint prospect 0cx:urs in limestone interbedded with limy 

slate and subordinata phyllita of M-ic ag& The poc3rs, isoclinally folded and overtlulled to the west, generally fie northwestward - 

and dip northeward, but local wariationa am common, aspeeid1y in -- 

the limestone near the pmspt, Thee structural features are common 

to each area of Btibnite deposition 3 (1) inbnse bmxistioa of limestone, (9) partial dolomitizn tion of limestone and dew tion of appm 

eiable silica in fractures and by replament of limestone breccia, ad 

(3) minor steep faults striking northwestward to northward. The 

stibnite WM deposited by replacement of k&ne and as dismte 

vehlets in-hfractum, Stibnih is thsdy me min~1al. .It~bx~~cep~ 

tionally pnre md contains only tnwa of 5&c, ag shown by the 

qmtmgxaphio analpia of three typical are mmples, 

*Bobhsan. 0. Ih. op. ak 

QEOCHEMICBL EXPLORATION 

The Ethic portion of the sod in the vicinity of the prospect is derived 

h part from reworked marine ( l) glacial till and in part from 

weathered material of the underlying bedrock. The proportion of hhe 

two source rnaterirtls varies from place to pl~ce. In the areas of limestone bedrack the major part of the soil wnsists af insoluble matmiel 

derived from the limestone, overlain by organic matter derived from 

decaying vegetat,ioon Boulders of glacial origin most commonly am 

found only in stream channels or in holes in limestone. Most of the 

boulders and pebbl~ in the present streambeds are flattened and have 

been derived from dynnmically metamorphosed conglomerate t,hat 

occurs in the metasdirnentttry rocks. A few pebbles or boulders of 

quartz diorite, and local awns of blue clny, give eridence of reworked 

glncial material. The soil profile, however, whee observed jrnrnedintely above lirnestona bedrock, consists of rr. layer of decayed orgnnic 

matter grading downward into a yellow to red clay which contains 

quartz fragments derived from the underlying rock, and thence dawnward into lim-ne. At other placers a till zone mum between the 

humus and the yellow day zone which overlies the bedrock. Xo glacial 

deposits are exposed in the banks of the dreams in the vicinity of the 

prospect, and where mch deposits are suspected they are restricted in 

areal exht, nowhere exceeding a fern tens of yards. Muskeg and peat 

hgs seved feet deep have formed an larger flat ,tare and are espcinlly abund~nt in those areas oaf snqected reworlred glaci~l rnatsrid, 

where drainage is: pmr (pl. 20). Most samples collectad from such 

areas came from the yellow day zone ahva bedrock, althougl~ at a 

few places bedrock was below tlia mch of the 6-fmt sampling tube, 

Norm Jly, a guide to the absence of glacjaI material was the abundance 

of quartz fragments in the soil. Thm fragments, us~ially somewllat 

porous ~nd completely unabrrtded, indicated that no glacial debris 

occurred in the soil profle. The muskeg layer rangea in depth from 

an inch or less to 8 feet, and the yellow to red clay zone normaTly 

ranges in thickness from 2 inches to almost a foot, This slight reddish 

color probably mpmn& an initial concentration of iron, or the primnry stnge of the formation of a lnkrjt,ic mil. Bedmk crops out 

sporrrdially on knells and humps, and creek bttoms expose continuoas bedruck. 

If silicification mre restricted to the nrens near ore bodies only, the 

pmee of abundant quartz fmpmts in the residual soil might he a 

pide to further prospwting. EIomever, fine qurtrtz-calcite-dolomite 

veinlets are common in joints in the slaty limestfine wherever they 

crop out, and quartz fragments may be obtained from residual soil 

40626GB7-2 
away from the laown ore WEB. The 1imeatone.ne.ar dl ore Miappears to be 'Lnassive breccia: as pointed out by Robin80n.B Thh 

massive breccia remains a guide to further pmpecting even though 

it probably is the mlt of fracturing of silicified and dolomitied 

hastone rather than of the Muring and bmiation of rnasive 

limestone u~yes" in the enclosing slaty Jimmne. 

, Samples wem wllecbd by using a thm+qu&-inch pipe htu 

I which was ingerted a wooden rod or plunger. The pip, from which 

the plunger extended slightly, was pusbed by hand into the yellow 

day zone. The plunger was then relead and the pip wae pushed 

'. farther into decomposed bedrock or residual maeriaL Tbe pipe 

was then raised nnd the plunger was ud to eject the sample. Three 

or four samples were colIected fmm diflerent holes at each station. 

By this method a sample was taken from the lmmt soil ms and was 

not contaminated by the overlying soil because no material could 

fall into the hole. Each station wss marked by a red flag baring 

the station number. It was not net-q to sumay stations with a 

transit becau~ favorabls areas were hted by physical exploration 

immediately after the samples were taken. 

After each sample was collected, the pipe was cleaned by scraping 

the inside with a flattened stick. To determine the degree of pcwi- ' ble accidental "enrichment" if a high-pde sample was f ollowd by one 

of low grade, the following method was used: mother sample was 

collected in soil of low antimony conc8ntmtion, and the pipe wp 

cleaned again. A second sample W&B then wllected in soil of high 

antimony concentration and thia pipe was recleaned. i4 third was 

taken where the first test sample had hen mllwbd. The reglzlts 

showed nagligible contaminations. 

The methods of analpig used in thia work were devised by the 

Geologicsl Sumey and are described in Circular 161 and in an openifle report entitled "Additional field methods usad in gmchemid 

prospecting by the G~ological Survey." Them methods are simple 

to perform ; they call for reagents and apparatus that are cheap and 

. readily available and require a minimum of technical trainii. The 

analyaes are precise to a plus or minus 30 percent Therefore, small 

differences in valum obtained by thw methods ~huuld not be regarded as ignificant. 

Roblnmn, O. D., OP- dt., P 4. 
a OEOCHEMICAL EXPLORATION FOR ANTIMONT XN 8Fl, AM- 169 

PrsZimimy hteh trcwmm.-The initial. step was the -tablbmt of a preliminary raw of values to indicate normal and 

anmalow concentrations of antimony in the soil. Adingly, 71 

sail samples were taken in hes rts shown on plate 21, mme radiating 

from the main prospect, and some dong the strike of the limestone. 

Thew lines also were intended to be true prospect lines indicating 

pmib1.e extensions of the ore zone. In the analysea of the initial soil 

sampl- no determinations greater than 2,000 ppm of antimony were 

made becaum this conmritmtion seemed sufficiently diagnostic to 

indicate om (table 2). 

 TAB^ a.-dnlimng c-t of prtlimitswy roil ad planl wmph 

(See pl. 21 for location d mil amp lea) 

tbllalm : a E. cmm, mu ; ~nd WW, p~mti 

1 hmples from inner bark of hemlock tme. 

Boil lampl- Soil namplea loll umplsl 

Bgmp3e no, W (ppm) 

Line 1: 

I-- -u ----- 2-..---+*-., 

3--------- 

4----,---- 

6. - - - , - - - - 

, lamla ma 

The ?-Con. 

7- - - - - - -- - 

8 - - - - - - . -- 9--------- 

Line 8: 

120 

180 

50 

50 

20 

88 (p~m) 

Line 4; 

1 ---------- 

2 ----+----- 

3 ---"-----. 

4 ++-------- 

5 -------.-- 

8ammn1e no. 

60 

40 

80 

fi ------- *.. 

7,-,------ 

8 - , -- - - - - 9 - - - -, - - - 10 - - - - - - - - - lI--------- 

12--,------ 

13 - - - -- - +, - 14- - ------- 15- - -- ----, 

Line 2: 

1- - -- ,--, - 2 - - - - , - - - - 3 - - , -, -- - - 

600 

80 

20 

To 

30 

8b (ppm) 

10 

30 

20 

20 

10 

10 

20 

ZW) 

20 

no 

80 

6 ---,,----- 

7 ,--_------ 

---------- 

Line 5: 

1 ---------- 

2 --,------- 

3 ---------- 

4 +++------- 

5 -_--..---,- 

6---------- 

7, _ - - - - - - - - line^: 

I-+-+------ 

2 ----,-,-,- 

3 ---------, 

4*--------- 

5 ---------- 

6 ----+..++-- 

7,_-,--,--- 

Line 3: 

1 ,,,,-----, 

2 --------,- 

3 --------,- 

4 ----*---,- 

5 ---------- 

6 --_--_---* 

4 - - - - , -- -, 

5--------- 

6*-------+ 

7 - - - - - - - - - 8 -,,------1 

Line 3 : 

1 - , -- , - - - - 2 - , - - - + - - - 3 - - - - , -- - - 4-, - - , -- - - 5 - - , -, - - - - 6 - .. - _ - - - - 

go 

60 

300 

80 

a 

40' 

40 

20 

40 

80 

20 

4-----.*.. wH)O b,*-* ,.,,. 6 -.----,-- 

T--------- 

coo 

GO 

So 

250 

fO 

30 

MK, 

80 

SO 

60 

40 

30 

20 

70 

120' 

40 

>a, 000 

80 

140 

8 --------- 

0--* ------ 10 --------- 11- * ------- 

I Control 

samples: A -- s ---------- 

C ---------- 

Dm ---- * ---- 

80 

60 

100 

40 

1,200 

>2,m 1,800 

4 50 

Plant sarnplm 

E- I., - - - - - - - - R-----,,-,- 

P .-,,,,,,,, I 

F -.,,.,,,,, 

B ---------- 

0 ,,,,---,,, 

N ,,,,-,---- 

R ,,.,------ 

4.5 

3. 5 

23 

2. 6 

.6 

.4 

1. 5 

.8 
' The mdts proved the f e~sibiIity of &ding ore- hongh geochemieal mdhods by showing a high concentration of' antimony in the 

mil near ore mes in comparison with the lower7 or background, 

values obtained elsewhere. Two amas of apparently h@ antimony. 

concentration in soils that could not be related to known ore zona 

were found during the preliminary studies. 

Fmr samples of hedock inner bark also were collected to ascertain 

whet,her this pies of tree showed greater antimony content near the 

ore. The hemlock bark ~ucrnples showed an increase in antimony 

concentration nertr the ore zone, rand the writer blieva that geobotmnical sampling could have ken applied mcmsfully in this area. Soil 

,gamples were pmfemd, however, because they offerad a water 

contr& in tatal antimony content. 

Recm&sance traverrrex.-In 1953, additional mnnaismnce hawarms mted the regional distribution of antimony in soils overlying 

+&verse rock types (fig. 22 and table 3). A signifidant variation in 

antimony content of the soil in relation ta the composition of the 

underlying rock is apparent. The soil in the am trav0d by lines 

A, B, and C (fig. 22) contains a relatively low mncentmtion of anhtirnony. Samples 1 and 2, line d, were collected from soil overlying 

limestone bed* and the remaining samples in 1in~ A were taken 

from soil overlying metamorphmed clastic sediments. The decrease 

in mtimorry content to 10 ppm corresponds with the lithalogjc change 

in the bedrock. All the samples in line B were collected from soil 

overlying schist, conglomerate, or metahsalt, and these smples also 

-aPel~~rinal~timonycontent. LineCbeginsinlim&oneorlimy slate, 

-rind then traverses alternating thin bands of schist and limy slate. 

into metamorphosed clastic wdimenta. The soil concentration of antimony again apprs to decrease abruptly with the lithologic change 

from limestone to schist. Similar variations were apparent in line D.' 

Limestone is the predominant bedrock underlging the mil in the 

prea traversed by lines E and F, and the antimony cantent of the soil 

in these Iinas is considerably greater than that in the other lines. The 

median value of 31 samples taken from soil overEying limestone bedmclc in lines E and F is about 60 pprn, and the ~bmrnger mtimony content, excluding as anornaIous those vahs that are more than 120 ppm 

.j(i. e,, mors thnn twice as large as the median), is about 37 ppm. 

bi Antimony eontent averages about 11 ppm in 30 samples hkan in 

lines A, A', and C, excluding one anomalous value of 150 pprn of 

tkntimony obtained from soil overlying limestons near the prospact. 

detailed studies.-At the request of the writer, the Tillicum Mining Co. collected an additional 65 samples in a grid on nhut 15-foot 

canters in the most favorable area indicated by the samples on line 

8 of tha preliminary orientation traverses. Almost a11 thew snm- 
plea ~~ &re thsn the average of 37 ppm of antimoony obtained 

for the limeatone ae a whole. Valu~& in excess of 10,000 ppm of anti- 

&ny were ob&hd Prom many of tbw smpleu& Their relationship to sukquent physical. explorartion by trenching, drilling, or 

singiag of shafts is disc4 later in thia report. 1. 

"fwelve groups of mur~plea ware taken b dehfmhm the vertical 

dktribution of antimony in the so2 profilk The rdta of thin 

aamphg indicate that two mnea of antimony mnmhtiop tend to 

mur : one jmmdiatelgt omlying bedrock and one st &the base of the 

hmm layer, both aepmtd by a zone of lowermtlcemtra,tio~ T%e 

wri- hlim that thii would dwt an enrichment of the mil at 

the base of the haus cad by the decay of vegetation conhining 
L 

1172 I :. .:- ~~ORCEB..O~ -,., . . I! 

,: &nhbng and an eohment .bf the mil imm~lly.omr1~~~

- rock caused kthwmIution of .lime~tmend n resulting m~~mtratian 

A of th&-l~solabEe aantimohy. The zone of lower mncenimrtion m- 

. p& an ka d:f lewhind' by capiuary' watk kd mta. Sliia 

i fragments and needles of stibxlita could be panned from bdk mnples 

. of decornpd material overlying bedmk in araa containing 10,OW 

a ppm of ahtimony ; this indimtea that the stibnita i0 mlstively Imert. . 

' 7% occurrence of small kapents of !atibnite in the sail is der 

:indication that the sail immediately overlying hdrock is composed 

: of the insolubb rasiduea left from the +mlutim of' limeetme or slaty 

' hestme. me high antimony cahtent. of mils throughout the lime- 

: stone areas can be explaind by wsuming that the insolubla material 

(especially gtibhita, kernmite, or stibiconite) has been concentratad 

in the clay and dmmposed mdterial overlying bsdrocg during the sohi tian of a considerable thickness of limestone containing its little .as 

2 ppm of antimony. The solution of limestone w~ probably acceler- , ated by the distinctly acid surface wabr normally derived from ms- 'I ,;keg areas in Alaska. 

L <, "- ." , 

;i 1 'mT-Qlr-mmFLm-- ; 

j Eight asmpls. of stream kdkent --taken within a rdina -&f 

ktbqmrtsrs of a mile of the pmspect (k. 22). Four of these 

rsrunples, of sediments derived from limestone Mhmk at and neht the 

.; pros;pect, contain much more mtimony (than the four samplm of 

?sediments derived from limestone-free bedrock (tabla 3). Smples 

$35 and 87-show no .increase of antimony content aver that in the mil 

$from he C; sediment sample 9 and thed samples from the northern 

f part of hs A contain the same amount.af sntimony ; dhmt sample 

:!23 conkah more antimony than the mil samples from line B, probably 

'becam the west fork of the stmm heads near tb prospect ; sediment 

~swnplw 83,84, and 85 contain antimony in about the same cuncmtra- 

: tion as soil samples from lines E md F, a mry diagnoetic inmaw ow. 

lsamplee from lines A-D. Sediment sample 85 is an offshore kli 

i&ent mllwted rrt loH tide at 8 point about 1100 yards from th6 

;mouth of the crwb and indicates a fairly rapid digitma1 of mtirnoq-rkh dim~nta st tide lePel. . .-. 

*I I I I,, Several mmp1ea of bhxk were anal@ for antimmy con* by 

atandd field method. A wple of slaw lhdmne hm the mch 

2 contained 15 ppm of antimony; s smp1e of brerxist&I; 

md dolamitbed bee from shaft 3 mntained 6,000 ppq 

One gampla fmm smaU limestone pods in the metdimentq rock^ near the beach contained 1 pprn of antimony and 
another Contained 2 ppm. A mp1e frmi a schist band 8 ht wide 

new the old ore dump hm ~hft 1 contained 16 ppm of antimony+ 

Although not conclusive, the dts indicata that regionally the 

antimony content of the limestone is about 1-2 ppm, increasing near 

the mineralized mae to about 15 ppm and near om zmea to as much 

as 6,000-10,000 ppla 

Tha samples of slaty and altered Iimdme were cruahd and leached 

dth warm dilute hydrochloric mid and the inmlnble msidnw were 

&ed under the microscop The midue from the slaty limhne 

contained a few dear quartz fragments, small sandy masses mmpd 

of silimua fragments, some graphite, aed a few pyrite c@ds in I 

tha form of pyritohdmns. The residua frod the altered lim-B 

cuntained a greater abundance of quartz hgmmta, similar sandy 

mmw, red oxides of iron, and vary little graphite. 

The writer believea that the brecciateci, silicified, md doIomithd 

limostone was farmed from daty limestone con- sandy ~gmgates by the addition of quartz and the lea of pphih Antimony 

may have aecompmied the silica or iit may have been intmdnd later, 

Evidence from exploration at shaft 1 indicates that some quartz and 

8tibnita were deposited contamporaneonsly. 

Chbin inferences that shonld be WM in htrrre phmiarl 

exploration in this am may be dram with respect rto the antimony 

cantant of the mil of thia district. 

The background content of the lowemmt soil me depends in large 

measure upon the mposition of the underlying bedrock In areas of 

nnmineralized limestone, a background content of 30-40 ppm of sntimony should be assumed, This background content decreesas in 

mil overlying hstane-free mks to less thm 10 ppm, 

Nem minexrtlized areas in limestone, the antimony conbnt of the 

lowsrmast soil zone ranges from 100 to 1,000 ppm. 'I'his range of 

content might properly be termed the "threshold valnk," and mmples 

thst am considered to be indieatin of naar-mrface are bodies ~hould 

cmtain antimony in the range from 1,000 to 10,000 ppm, for in this 

study wampIes den above the om hdies that were trenched or 

drilled mn~ishtly gave such mmlta: An antimony amtant within 

this range definitaly is anomalona. 

The ditriding line between a threshold content and m momaloun 

content might be somewhat flexible, depending upon the immediate 

objective of the gemhemica1 work. Here the immediate objwtive was 

to find n-surface ore bctiee within math of trenches and drill holes 

only 90 feet long, but deeper ore Mia might be indicated by twnpJe~l 

with an antimony content as low as 100 ppm, 
* ' The f &ah il& 'not de~crib oEha attempts at pahemica1 pro&: 

gwtrini for the antimony content of mile, oonqaeaitly little informstian is avdable to &bli& the g~~d'' rsnge of antimony in &I8 

Befom any gemheanid methods may be md sucmmrully, it is necaBsary to know the nod cuncenhtion of esch metdic conEltihent 

in the srea. The wrihr believes that the soil-sampling mdta nb 

,Csmana Point dact a*in geologic, geomotphi% and physical 

. rwnditiom' that nmy not be f onnd 'ehwhere, and they am diagnostic 

only of what may be termed an "antimony area: where stibnib 51 

mall amonnta ia widaspread in the limestone badrock, bukperhpe is 1 more restricted in the metaeedimentary and metrwalcanic rocks. No 

attempt waa made to eshblish a mgianal bba-und vdtie more than 

ds from the pmpect at Caamano Point. 

BUBB1QUENT EXPLORbZZOPP 

h 1M8 the Tillimm Mining 4%. trenched and drilled the areas of 

momdous mmntrationa of antimony northwest of the old wor- 

, and mhnd the soil-sampling dts (pL B). A pIot showing 

' the relation of the mil glrmpPes containing unusually large amom* of 

antimony to the pernuasion-drill holes inhmting dimeminatad st!?% 

I nite ore ahm remarkable correlation. The plot outlines the trend 

' of the min~~ zone which is possibly related to the northwestmid-trending fault revealed in surfme trenches and underground 

openings. It is notable that thia mineralid me rmps out in a low 

 addle where mu* and peat have mmuhtd to a depth of 44 

feat. Bhortly after the dhvtwy, Oeerge B, Roberts, ganeral mmapr, Tillicum Mining Co. (writhn communication, 1953), stated that 

h tbe latter diamwerf eaa be medlted XOO peseent U me rwil sampltag, M 

! moet'ot the ore body ED far iwnd la overlnh by 2 to PI ht of maM rW and 

rnnmeg, * * Whether ar not t.bh diemvery proaw 6f mmmamial importan- 

"the way the noU sampm pbcked np th18 ore body, wbich h rn- pockam, 

L aatonbbu. 

. Trenehew md &dl holes in the vioSQ of samplea dl and 62 

hhseckd di~~ atibnite ore. A shaft 16 feet deep, and hob 

' Wed from the bottom of it, proved cuntinuity to h minerslid 

mne of shattered limestone. Prior ia the analyses of the mil samplee, 

B. RoM and William Hibberd found e.P.txmd limestone containing stibnite heath the humus in this &= 

h &fmt shaft and drifts tntdhg 1Ml feet along tbe inferred 

atrike .of fie ore me dhld disseminated stihite om throngho~t 

(fig. 28). The &ibnite occurs as irregular thin repl~mmt hdi- in 

bmiated, dicified, and doIamitiaed limeshe ad a~ thin vein 

fillingg in #B limmtak Tbe antimony mhnt of h ore avmw 
1.8 prcent dthough some drill holes cut zonea a few feat thick thst 

may. as much as 8 pemnt Dimminated stibnite is expod in each 

face of the drifts, The ore zone appears to be hded on the wmt 

by the f salt thst is exposed on the ~urf am and in the 22 west cramcut 

in the north drift of the 40-foot level (fig. 23). Pomibly the ore 

is relatad to ahatbring and rep1acement of the Sirneatone during movement along this fault and to mistriction of hydrothema1 solntiom 

to the footwall by &the gouge $one in lthe f auk Drill halea that cut 

through the hanging wall of the fault pass abruptly from atibnib 

bearing limestone into pyritiferous rock devoid of ~tibnita 7%~ 

amount of movement on the fault is dmm, but tha feult appears 
176 'r . . ~IUL ~~somcas or , . 

A to be tbe mme one that is exposed in the &bed several hundred 

yards northwest of the new ehaft. Stibnibbmring limdne occm 

rjporadicdy along this f adt, and st* one plm schist is halted again& 

!limestone However, the are body originally &scoved at the pros 

peck (mnbining mew stibnite) and the bodies hter di~~)~vared 

~orthwest of the shaft, are not dined along this fault. Therefore 

this fault &ouId not be reerded as tlxe only cbPbnnelg' in the region and future exploration and prospecting should not be mtricted 

to the area djmt to the fault. 

If the mall &t band qsed in the east end of the twnch nod 

bf the shaft is tJ3e same one expad in the south 'drift on the &f& 

'level from the hft, a small drag fold plunging norbmtward is 

jindicated in the datg limwtona. Robinson notes a drag fold at the 

:ore me at hft 1, md believes %ha$ this drag fold influenced ore 

idepclaition. The drag fold at &aft 2 is small, it has been cut by the 

'Yault, and ore om both north and sauth of it. Possibly this fold 

kerted some influence on ora depktion, but such inl8uence is unknown, Drag folds have been observed at my pl- in the slaty 

)im&ne with no mi&d brecciation, dolomitization, or .ocmmrenm 

of stibni-h om. 

CONCLUSIONB 

The chief value of the geochemical work on soils done st Cmmano 

oint lias not .in the amount or grade of ore contained in the new ore t nw but in the em with which they were dimversd. Before the 

ropq was acquired by the TiIIicum Mining Co., no ore zones beyond t be origb1 discovery were fund during a 36-pr period. The 

Be0chemica.l work on soils guided subsurfam exploration to three 

p3ditional ore zanm at a total cost of la than $750 in wages for field 

work and chemical malgrses. Thus the available money could be 

lased for qlomtion in favorable areas rather than for haphmwd kd'&dha .&a .dtYTlbg. . . . ., , .,.- .- 

I It is concluded that miim*n~:'ords; p&&arl j stibnih, are dotedbble by soil-smphg methda, at least in residnal mils, hause the 

&ispers?on halo is somewhat restricted in &ant, and rsnomalies in the 

b II lie close to the bdrmk anomaly, or ore mne. ID areas where bad- 

& is a~erlain by thick cover8 of -keg, sobmples may easily lm 

&~Ilected. Rom the .bdroek-soil mtmt by the use of a pipe with an 

k teriwbplunger, and any dispwion halo of atibniEe should be near 

s be&mk sonrce, Reseaf.ch is being done by tha Smoy on the 

bspwaion halos ,of mixed ores containing SWBSI of, antimon~ <h 

&eSeabIiElb the usefubggs of the antimonial constituents in geochemical c. 

:. : 

~obin-, a. D., OP. at.,, P. a . .. 
.Mhg (Hkwkeq EL :E., pknd cmmmicfbbiotl) ." The dth 

.m~y -- jndioate-%kt antimy sulfides can km used to pinpint &de 

that gl.a 1-td initially by Idnc or mppr indiatora The 

-&matam. ~nllable on ageocheaiid pnqeating h' large," but the 

~rit4~' haws of nu publications that dimss the &pp~~CStio& bf thew 

tecbniqnea ta antimony exploration or to antimonial om. 

In addition, results of the ma1ye.e~ of stream sedimmts indicate 

that wch ~~mpzing in an antimony province might, rapidly ddimit 

&amage aregs favorable for prwpecting. 

Considarable kt& wa~ shorn in Wdcal p- Mniques as a dt of the work done at Caamano Point. areas 

of south^&^^^ Al& are covered with muskeg md thin glacid 

d@ta, and mventional metbods of prospecting are slow and 

dy. Geochemim1 propcting offem a new and inqensiva appro& b the prospecting of theae areas. 

RECOMMENllA!lXQNB FOR FUTURE WORK AT 

CAAMeCNO POINT 

The b& method of exploration in this area entails the following 

hp: Soil. mphg ~hould be used to delimit amas with abnormaUy 

high antimony concentration & the soil, a single trench should then 

be mt acmss the mineralized zone Ca determine bdxd relationships, 

and s portable, gssoline-driven ?X-ray'' diamond drill should be used 

to pmb these anomalous zones to depth of 10&150 feet. In this way 

ocarrerice of sbibnih could be tested economicaUy, and mom 

expawive explomtian by ghafts and drifts could km limited to the 

most favorable areas. 

Daring any sqlomtion, linear topagraphic deprcmions should be 

closely inspected to whether they mpy f adt zones and to 

detmnine a Btractural pattern of fracture zones, Particular attantian 

should be given to areas of becciatad and dolomitized limestone, as 

. noted by Robinson, even though stibnita do^ not mur as ooutrrops 

in the%e areas. 

Owkg to the -erne bmxiatioa of tbe limn@ at the shafi 

2 om mne, the ore suTutions cirdatd fr~ely through wide araas. 

If the bmiahd limestone had kn overlain by an impemious bed, 

such as one of the schist hds intmm1atd in the slaty limestone, 

the mlntions might have been confined over a restrictad area, with 

wnquant higber-grade om deposition. It would mrn desirable, 

in future exfloration of the area, to tram stibnite float into the schist 

am to the northwest. Fanlting and f mturing in the %hist would 
0*a-b6~1-13ar&-- DDI~O~ -w 

! gtibnih bpe hmlhmd me~~~naathw& of the $ncurpn pm 

in the fist area, indidkg &at thk part of 1Ewdaad Penirl~ula 

. ptpWy oonttih coosideable snhomy,. StEmptee of $;reom d- . manu mghh iadimta favoaabh dmhsge am~ far prqech8 . 

DEPARTMENT OF MINES 

, RECEIVED . 
40bE.2 o - 56 (~n pocket) MAP OF PRELlMlNA SOIL SAMPLE LINES, TlLLlCUM MINING COMPANY PROWVY, CAAMANO POINT, ALASKA