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TIN - TUNGSTEN - BASE METAL MINERALIZATION

ASSOCIATED WITH

THE BEN LOMOND GRANITE BATHOLITH

111 27M/77

ABERFOYLE DISTRICT

~ORTHEAST TAS~~IA.

~ __ SL11NO~S,

Snll10NS GEOSERVICES PTY. LTD.

JULY, 1983.

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TABLE OF CONTENTS

SUMMARY

INTRODUCTION

GEOLOGY OF THE BEN LOMOND BATHOLITH

A. LITHOLOGIES

B. GEOCHEMICAL CHARACTERISTICS

C. COMPARISON WITH THE BLUE TIER BATHOLITH

D. CONCLUSION

MINERALIZATION

A. MINERALIZATION ASSOCIATED WITH THE BLUE TIER BATHOLITH

B. MINERALIZATION ASSOCIATED WITH THE BEN LOMOND BATHOLITH

C. GREISEN POTENTIAL IN THE BEN LOMOND BATHOLITH

D. TUNGSTEN-TIN-COPPER-SILVER/LEAD/ZINC

ZONING POTENTIAL ASSOCIATED WITH THE BEN LOMOND BATHOLITH.

EXPLORATION RATIONALE

A. RANK OF DEPOSITS

B. STRUCTURAL CONSIDERATIONS

1. JOINTS, FAULTS Au~D VEIN ORIENTATIONS

2. SUB SURFACE GRAu~ITE XORPHOLOGY

3. DISCUSSION

PROSPECTS Au~D Au~OMALIES

489002

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489003(i)

SUMMARY

The Ben Lomond Granite Batholith shows a strong mineralogical and geochemical

affinity with the fractionated granitoids of the Blue Tier Batholith, and has

itself been fractionated from a calc-alkali granite (biotite granite) to an

alkali granite (inferred biotite/muscovite granite).

The inferred biotite/muscovite granite shows a strong geochemical correlation

with several muscovite/biotite granites ("tin granites") in the Blue Tier

Batholith.

Five primary associations of mineralization occur in or related to the Ben

Lomond Batholith, namely:

(i) Exogranitic quartz vein systems (strike extent:> SOOm);

(ii) Exogranitic quartz vein systems (strike extent --'( 100m) and

fracture stockworks;

(iii) Endogranitic quartz veins and greisen veins;

(iv) Endogranitic fracture stockworks and greisen pipes;

(v) Aplite and greisenized aplite bodies.

The potential occurrence of large greisen sheets (eg. Anchor deposit) is con-

sidered to be minor, and the potential for massive "greisens" (Ardlethan type)

even more remote.

The pot~ntial for zoned W-Sn-Cu-Ag/Pb/Zn mineralization is indeterminate on

present knowledge, and several possibly relevant features in the area require

evaluation.

Structural considerations involving mapped defects, and gravity based sub-

surface granite morphology imply major NW (and probably ~E) trending linears

influenced both the granite/aplite intrusions, and the subsequent primary

mineralization.

iIIiiIIIIII,)IIII111

489004(ii)

Several major residual Bouguer gravity anomalies exist in the area, and

appear similar in status to the Aberfoyle and Storeys Creek aplite bodies.

The primary mineral deposits in the Rossarden area have been ranked according

to inherent tin metal content, probability of occurence, assumed metallur

gical character. and the suitability for various mining methods.

The three highest ranking categories of mineralization are exogranitic quartz

vein systems. aplite/greisenized aplite bodies, and exogranitic veins in

association with fracture stockworks.

Consolidated Mineral Lease 27M/77 covers an area of 2500 ha in northeast

Rossarden, Ben Lomond and Sphinx Bluff.

48900~)1/.

INTRODUCTION

mines. At present the transfer of ML27M/77 to H. J. Stacpoole is in the final

stages of preparation.

Tasmania, and includes the town of Rossarden which is approximately lOOkm

by road from Launceston.

The lease boundaries are shown on Mines Department Mineral Charts Mt. Rex,

operated the now abandoned Storeys Creek (tungsten) and Aberfoyle (tin-tungsten)

The lease was previously held by Aberfoyle Ltd. and Rossarden Mines Ltd. who

III

Amongst the large number of authors who have contributed to the knowledge of

the geology of the Rossarden area are the following: Blisset (1959), Clayton

(1981), Edwards and Lyon (1957), Groves (1972, 1977), Groves and Taylor (1973),

IIII

Hellsten (1979), Henderson (1935, 1936, 1946), Keid (1954), Kingsbury (1965),

Lyon (1957), Nye (1941), Reid and Henderson (1929), Scott (1929, 1934) and

Urquhart (1966, 1967).

In the Rossarden area. aplite cupolas have long been recognized as having an

important, but generally unspecified role in the formation of large (hydrothermal)

exogranitic quartz vein systems (eg. Aberfoyle and Storeys Creek deposits).

I The limited exploration conducted in the area has consequently been directed at

I locating additional vein systems, with apparently minimum effort made to establish

Ithe porential of the Ben Lomond Granite to host other types of mineralization,

such as occur in the adjacent Blue Tier Batholith of north east Tasmania.

II1

Thisreport attempts to inte;;rate all previous geological studies in the area,

with the object of comprehensively re-appraising the 3rea represented by ~L 27~/77

for its remaining mineral p(Jtenti:ll.

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Previous work by the author in a report entitled "Preliminary Report on

Tin-Tungsten Mineralization in ML 27M/77", concentrated mainly on the

Lutwyche-Kookaburra prospects, and should be read in conjunction with the

present report.

The course grained (cg.) biotite granite occupies the largest volume,with

the fine grained (fg) porphyrite granite variably present within or surrounding

the former.

EoLlowill% some. detalled !.u-vesL!.gatiana in. r.ec..eIll:. years (Hell sten L979 •. and

Clayton 1981), data on the Ben Lomond Granite has increased considerably.,the main granitoid types in the Rossarden area are:

1. Coarse grained, variably porphyritic biotite granite;

2. Fine grained porphyritic biotite granite;

3. Fine/medium grained quartz-muscovite-tourmaline rock(QMT);

4. Microgranite;

5. Aplite;

6. Pegmatite;

7. Quartz-feldspar porphyries.

JI111.IIII1111IIJIIIII

A. LITHOLOGIES

3/.

GEOLOGY OF THE BEN LOMOND BATHOLITH

489007

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The tourmaline Leucogranite [QMT]) outcrops mainly between Tasmania and

Nisbet Creeks northwest ofAberfolye. Minor intrusive phases are represented

by microgranite.aplitepe~~atite,and porphyry dykes; the aplite also occurs as

stocks of cupolas emanating from the main granite body, and the latter variably

enveloped by a carapace of microgranite.

B. GEOCHL~ICAL CHARACTERISTICS

Typical elements used as indicators of increasing fractionation in granitic

rocks are Mg, Ca, Sr, Ba, Li, Na, K, Rb, Sn and W. The depletion of Na(+K)

and the alkaline earth elements is accompanied by increases in Li, Rb, Sn, Wand

F. The conventi0nal method of presenting fractionation trends in grallitic

rocks is to graph the ratio of ~lg/Li versus the [3tio K/Rb, such thilt

rock.

Anchor mine).

elements with common fractionation trends in the following rati"s:

substitution of these elements seemed likely), it was decided to combine all

489008

indicate a trend toward the alkali

porphyritic granite, microgranite (dyke),

- decreasing values of this ratio confirmed the K/Rb trend, but

greisenizcd aplite, and th~ granites.

also emphasised a major gap between the group of Q-M-T rock. dplite and

K + NaLi+Rb1.

progressively lower values for both ratios

to the high values in the greisenized aplite (? similar to the greisen at the

Excluding the microgranite data, the trends of increasing Ll and decreasing Ba

sequently, (because of the anomalous Mg and Ca values, and because isomorphous

4/.

the aplite, whereas the trends of decreasing K and ~a imply the opposite. Con-

quartz-muscovite-tourmaline rock, aplite, and greisenized aplite (II Level

biotite granite to microgranite to Q-M-T rock to aplite to greisenized aplite.

granites.

The trend of increasing Rb suggests that the Q-M-T rock is a differentiate of

anomalously low Ca, and erratic Li values from the microgranite and the Q-M-T

However, the limited analytical data, combined with some anomalously high Mg,

Aberfoyle).

and Na also follows the K/Rb trend, but the trend of Sr is erratic, due partly

rock, meant that the Mg/Liratio in particular was not a useful discriminant

namely eg. biotite granite, f.g.

of fractionation. The high Mg values probably reflect the formation of second-

ary tourmaline, while the low Ca reflects the absence of fluorite in the Q-M-T

The K/Rb ratio showed a distinct trend from f.g. porphyritic granite to c.g.

The chemistry of six granitic rocks from the Ben Lomond Granite were studied,

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and biotite in excess of muscovite.


Geochemical analyses of the Ben L0~ond granitoids indicate strong affinities

Sheoak Hill, Little Mt. Horror and Constable Creek. These latter sheets of

4890095/ .

description of the geology etc. of the

- progressively declining values of this ratio also

microgranite (7), aplite (4.6), greisenized aplite (4.1) and Q-M-T rock

(3.5).

Mg+Ca+Sr+BaLi+Rb

values, ie: e.g. porphyritic granite (13), e.g. biotitegranite (13),

confirmed the K/Rb trend and also indicated three groups of similar

2.

evidence suggests a single magmatic fractionation series, from granodiorite

to adamellite to calc-alkali granite to alkali granite.

grained or porphyritic. They form large homogenous steep sided plutons,

1. The Blue Tier Batholith consists of a suite of calcalkaline granitic rocks

granite are characterised by the presence of tourmaline, lack of fluorite

2. The adamellite and clac-alkali granite interval of this series is

3. The alkali granites are represented by muscovite-biotite granite,

typically fine ~edium grained, with a general sheet like form; they are

Blue Tier Batholith, from which the following salient features are taken:

occupy 2 vol% of the Blue Tier Batholith .

All muscovite/biotite granites are younger than the e.g. biotite granite", and

related but slightly different sheets of biotite-muscovite granite occur at

Main examples are the Mt. Paris, Mt. William, Mt. Cameron and Lottah sheets;

represented by biotite granites/adamellites which are typically coarse

Li, Rb, F and Sn, and decreasing Fe, Mg, Ca, Sr and Ba. The geochemical

strongly fractionated with low K/Rb, Mg/Li, Sr and Ba, but high Sn, Wand F.

Groves (1977) gave a succinct

and collectively account for> 50 vol% of the Blue Tier Batholith.

which show a normal fractionation trend characterised by increasing Si, AI, K,

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~~~ with granitoids from the Blue Tier area. based on petrological and geochemical

characteristics (particularly Mg/Li. K/Rb. Sn. Li. Sr, Ba).J

. . 11(i) The Ben Lomond c.g. biot~te gran~te~very similar to the Boobyalla and

Poimena (adjacent to the Anchor mine) granite plutons;

(ii) The tourmaline leucogranite (Q-M-T rock) is very similar to the Mt.

Paris muscovite-biotite granite sheet, but also has affinity with the Sheoak

Hill. Little Mt. Horror and Constables Creek biotite-muscovite granite

The poimena biotite granite forms part of the fractionated series of granitic

rocks mentioned previously. and is intruded by the muscovite-biotite granite

(alkali or "tin granite") of the Lottah sheets.

The Mt. Paris muscovite-biotite granite sheet intrudes both Mathinna Beds.

and the western edge of the Poimena granite,and both the Lottah and Me. Paris

sheets host important primary tin deposits.

D. CONCLUSIONS.

1. The sequence of crystallization of the Ben Lomond granitic rocks appears

to represent the· calc alkali to alkali granite end of a normal granitic frac-

tionation series, as follows:

(i) f.g. porphyritic granite [chilled margin of (ii)]

(ii) c.g. biotite granite (major phase of Ben Lomond Batholith)

(iii) Microgranite

(iv) f/m.g. biotite/muscovite granire (inferred, and now altered to quartz

muscovite-tourmaline rock).

(v) Aplite (and probably pegmatite, quartz-feldspar porphyry)

?~) Creisenization of the biotite/muscovite granite + aplites.

2. A major geochemical hiatus occurs geneally about the same time as the

intrusion of the microgranite dykes.

3(i) A strong mineralogical and geochemical affinity exists between the Ben

Lomond c.g. biotite granite and the Poimena biotite granite;

biotite-muscovite granite.

(inferred) biotite/muscovite granite is a younger intrusive body, enplaced

5. In common with the primary tin mineralization in the Blue Tier Batholith,

A strong geochemical affinity exists between the Ben Lomond (inferred)

4890117/ .

and the Mt. Paris muscovite-biotite granite;

the Sn-W-Sulphide minerals present in the Aberfoy1e etc. quartz veins.

the Ben Lomond (inferred) biotite/muscovite granite and the aplite (cupolas etc)

made (in point 3 above) with the Blue Tier Batholith, suggest the Ben Lomond

3(iii) A less significant mineralogical and geochemical affinity exists between

the Ben Lomond (inferred) biotite/muscovite granite and the Constables Creek

near the top of the older Ben Lomond biotite granite.

fluids that were eventually to greisenise both rock types, and to precipitate

4. The sequence of crystallization (points 1,2 above) and the correlations

appear to be the penultimate crystallized portions of the residual magmatic

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biot/mus granite

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It ·'is considered appropriate. in view of the mineralogical and geochemical

affinity of the Ben Lomond Batholith with portions of the Blue Tier Batholith,

to review the primary mineralization in the latter. in order to fully assess

the mineral potential of the Ben Lomond Batholith.

Primary mineralization occurs in three groups. Sn + W. Cu + Ag-Pb-Zn. and

Au. Au-Ag deposits.

1. Tin - Tungsten

This mineralization (cassiterite and wolframite) shows a close spatial rela

tionship with the muscovite-biotite granites. although small lodes occur in

the Constables Creek sheet (biotite) muscovite granite) and in the Poimena

pluton (biotite granite).

The main modes of mineralization are exogranitic quartz-wolframite-cassiterite

veins, and cassiterite in fractures, and endo granitic greisen veins, pipes

and sheets, and quartz-wolframite (t molybdenite t bismuthinite) veins.

2. Copper and Silver-Lead-Zinc

This mineralization is exemplified in the Scamander area where it is part of

a zonal sequence associated with the Constables Creek biotite-muscovite granite.

The zonation appears to follow the classic hydrothermal sequence, namely from

the contact aureole outward the zones are W(tMo~i). Sn, (Cu(-As-Zn-Pb). and

Ag-Pb-Zn [-As-Cul). The genetic association of the latter zone with the Con

stables Creek granite is conjectural, and it may be related to a granodiorite

porphyry dyke.

3. Gold and Gold-Silver

This type of mineralization occurs to the west of the zonal sequence described

above, and is probably associated with the Pyengana granodiorite.

4890128/.

MINERALIZATION

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C. GREISE~ POTE~TIAL IN THE BEN LOMOND BATHOLITH

Actual and potential primary mineralization associated with the Ben Lomond

Batholith is detailed in Table 1.

The valiuity of these greisen models (thick and thin "tin granitE's'), cannot

be disproven at present and if geochemical similarity is any guide, the in

ferred Ben Lomond "tin granite", by analogy with the Mt. Paris "t in granite".

vh~uld ,-lppcar only t,l h,1\'8 the plJtt:~ntial to torm gro:=ist:~n veins.

4890139/.

exogranitic quartz vein systems (strike extent>" 500m) ;

exogranitic quartz vein systems (strike generally ~100m),

and fracture stockworks;

endogranitic quartz veins, and greisen veins;

endogranitic fracture stockworks(minor) and greisen pipes;

aplite and greisenized aplite bodies.

3+8A

4+8B

6+8D

Although 13 categories are shown in this table, there is considerable over

lap between the groups, such that 5 main primary associations can be recog

nized:

1A

1B+2

The formation of greisen sheets requires a minimum of roof rock fracturing

and Groves (1977) suggested that provided the roof rocks were not fractured,

greisen veins were associated with thick muscovite-biotite granites (eg. Mt.

Paris), and that greisen sheets were associated with thin " t in granites"

[ego Lottah sheets, Anchor deposit etc.]).

Categories 5 and 7 are considered either too small, or to have insufficient

grades to be of economic interest. It is apprent that the modes of primary

W-Sn-base metal sulphide mineralization are virtually identical between the

Blue Tier and Ben Lomond batholiths, the main difference being the apparent

absence of greisen sheets (8C) and disseminated cassiterite in granite (5).

~~~ B. MINERALIZATION ASSOCIATED WITH THE BEN LOMOND BATHOLITH

l

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489014TIll!.!': I

ICTlJU. 1:-11) 1'IJTI:N rHI. \Il'iI':It\!. I Z I 1'1 Il"i .ISSIJClATf:D 'II nil 'rilE !l&'" lAlMllNH llATllllLITlI

!~II "iEll"L ILl l'luN TYPE (JltE ,IIINElnIB G\NGUf: MP,mHA!.S GIW>E SIZE (TONNES) EXAlO:'LES

EX,J(;ILINIl'TeLA. (juartz Veins Cs Wf (Cp 5p Gn) Qtz Apy Py 1.~14 2.1dgb (UG) Aberfoyle (actual proLluc tion)

(>-500m strike) ?0.1-0.5%<:14 10dO (01') AberfoyleLll. :)uartz Veins Cs (Wf Mol Qtz 0.4-0.~So ~50 000 (00) Brock., FlabertysPlummers

( ~lO()m)(!Qtz Z 3.5xl06 (OP):.!. rrae ture S toekworks Cs (Cp Sp) py) 0.25~So (Great Pyramid), Ilrocks

Storey. Creek

f\'k Hilt IN I 1'1 t:

3. liuartz Veins Wf (Mo Cs Ili Cp) (tz Tm Muse Py Apy 0.7~Sn 5-50 000 ~UG) U-th, Ben Lomond TungstenI, • r",c turc Stockworks Cs :l:Muse, Kaol) 0.25-1.O:'So ~ 150 000 UG) Rex !Jill (see 8B)5. (jraui tf" Cs Qtz Feld Muse Biot ? ? (Lottah Sheet)&. Aplite Wf Cs (Sp Mo) Qtz KFelLl Ab ~ 0.20-0. 5O%Cld 10xl06 (01') Aberfoyle7. l'egllUt ti te Cs Qtz Feld Tm \!usc Top ?0.05~n ? Ivanhoe (Ransome)Ii. (ire i ~f'n

A. Vt'lU!i Cs (we) Qtz Muse Tm t'l Py O.02:'Sn 75 000 (UG) M..-othKROI

Sp Cp Cs (Gn) Qtz Muse Py Apy t'l 0.4~n 500 000 (UG) Royal GeorgeTill KRol

Cs Qtz Musc 1m Fl Py 5:'Sn ,< 10 000 ~UG) Ben Loraond TioIJ. Pipe Cs II tz (Musc) FI '1m Kao I 5.~Sn $' 15 000 UG) Great Republic

Sp,Gn Cp Cs Wf Qtz (Musc) Apy Fl 0.25-1.O:'Sn ~150 000 (UG) Rex Hill (Carpathia)Chi Py

2xl06 (01')C. Sheet Cs Cp Mo(Wf Sch Gn) Qtz Muse FI O.2%Sn (Anchor)lJ. Cupo 16 Wf Cs Sp Mo Qtz Musc Chi Kaol '- O. 20-0 • 5%<:1d 10xl06 (01') Aberfoyle1:. ,\luss ive Cs(Wf Mo fli Cp Sp) QtZ Muse Chi Tm Kaol 0.5-0.7~Sn 0.5-2xl06 (01') (Ardwest, South Wild Cherry)

,\ I.l.liV L\L'l. Streum Placer CS INA ? ? Storey. Creek

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489015- . ....... .- ·,,1' - - -

T,UILE I NOTES ANI) U:GI':.'I[[)

( i )( i i )( ii i)(IV)(V)( vi)

LEGEND

All size data refers to in situ tonnea~e8.

UG - in situ tonneage amenaLJle for untlerground extraction.UP - in situ tonneaj!;e wuenable for open pit extraction.Tonneage nnL! graue "nta in Catej(ory 2 mineralization refer to the Great Pyrllll1id.Extlmples shown in hrackets tire not a8~'iOciated with the lien Lomond Granite but have a eimilar hydrothermal origin.01 - Sn + W03%.

ow;Hi:Cp:Ca:Gn:\10 :

Seh::01':IV r:

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Bismuthini teChal eopyri teCassi teri teGalenaMolybdeni teSdleel i teSphaleri teWolframite

l;.l~GlJI:;

.\b:Apy:iHo t:Chi:Ft-} d:KFeld:Kao 1:~tUIJC :

I'.y:'i tz:Top:TID:

"I \fElL\LSAl bi te.\rsenopyri teilioti teChlori teFeluspllrPotassium feld~par

Kaol inMuscovitePyri teQuartzTopazTourmal ille

in the western and southern areas.

to a quartz-muscovite-tourmaline rock.

assessment of greisen sheet potential;

hydro-

48901612/.

1. The present western and southern margins are characterised by primary

3. The northeast area, on present knowledge, appears to be characterised by

pipes, (see Table 2).

thermal alteration and may not be a true greisen.

the effects of mineralizing fluids traversing the older granite en route to a

to have a similar probability of occurence to that of the greisen veins and

have been more deeply eroded that the north east area.

the Ben Lomond Batholith, namely the western and southern sides of the granite

2. There is an apparent absence of muscovite-biotite granite ("tin granite")

mineralization in the form of greisen veins (3+BA) and greisen pipes (4+BB),

exogranitic quartz veins, and fracture stockworks; this implies that both

high level (and now totally eroded) "tin granite".

incipient (lB+2) and extensive (IA) fracturing occurred in the Mathinna Beds.

Accordingly the potential occurence of greisen sheets in the north east portion

category in Table 1, although it is characterised by low temperature

The following features of the Ben Lomond Batholith appear relevant in the

formed by the alteration of e.g. biotite granite and f.g. porphyritic granite,

of the Ben Lomond Batholith can not be precluded, and statistically would appear

These features are interpreted to indicate different degress of unroofing of

The Ard1ethan type mineralization (BE) has also been included in the greisen

4. The inferred "tin granite" in the north east area has been greisenized

The greisen veins and pipes typical of the western side are thought to represent

(presumably both are equivalent to the older granite in the Rossarden area).

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However, kclOlin is not uncommon in both the Blue Tier and Ben L.lmond batholith::,

\eg. categories 4, 6, HA, 8B, 8D) <lnd the potentLil for "massive greisens" to

13/. 489017

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"'" I'I'I1111IItlIII IIIIIIIII

\,\>~. occur in association with categories SA, B (and? C) requires further evaluation.

At present, because of the speculative staus of this type of mineralization

(in NE Tasmania), its probability of occurence must be low C'< 0·01), [see Table

21 •

D. TUNGSTEN-TIN-COPPER-SILVER/LEAD/ZINC ZONING POTENTIAL ASSOCIATED WITH THE

BEN LOMOND BATHOLITH

The mineralogical and geochemical affinity of the Ben Lomond (inferred) biotite/

muscovite granite with the Constables Creek biotite-muscovite granites has

been mentioned in the preceding sections; this latter granite is associated

with a W-Sn-Cu-Ag/Pb/Zn zoned sequence of mineralization in the Scamander area.

Minor, localized zoning occurs in the greisenized muscovite-biotite granite of

the Lottah sheet (Anchor deposit), and consists of successive partly overlapping

Mo, Sn and Cu rich intervals.

The potential for a zonal sequence of mineralization to be associated with the

Ben Lomond Granite is difficult to assess, mainly because of the lack of

exploration east of the Lutwyche deposit. The available data for the Rossarden

area is as follows:

1. ~ineralogical zoning in the Aberfoyle deposit (and to a lesser extent in

the Storeys Creek deposit) is well documented, with Sn increasing and W decreasing

with distance from the granite/aplite.

2. The composition of wolframite in the Aberfoyle and Storeys Creek deposits

shows a depletion in Mn with distance from the granite/aplite. Wolframite from

the W zone in the Scamander area show a similar trend with distance from the

Constables Creek Granite.

3. Late stage sulphides (typically Zn rich) occur within a SOm radius of the

aplites in the Abderfoyle and Storeys Creek deposits. In addition, some of the

quartz veins at Storeys Creek have been replaced by masses of galena sph;llerite

and chlorite.

4. There is a crude mineral zonation in the Rossarden area from the greisenized

(inferred) "tin granite" in the vicinity of the Mammoth deposit hosting W (tMo

tSntBi) mineralization outward to the Aberfoyle-Storeys Creek line of deposits

hosting Sn-W (tCutZntPb) mineralization.

5. Soil geochemical work by Aberfoyle Ltd. in the Rifle Range area (IS00m NE

of Aberfoyle and approx 2000m from the nearest granite), located coincident Cu

-As-Zn anomalies; this area is also noted for the lack of Sn-W mineralization.

However, the Lutwyche vein system (Sn-W) is located only SOOm SW of Rifle Range.

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14/. 489018

The intermediate rankings are represented by greisen sheets, greisen veins

and massive greisen, and the lowest rank by greisen pipes.

Additional factors considered relevant in the ranking of these associations

for exploration priority include the probability of occurrence, the metallurgical

character and mining methods (cut off grades etc).

The resultant rank values correlate with the tonneage (contained Sn) ranking

for the three most prospective targets, namely exogranitic quartz veins,

followed by aplite/greisenized aplite stocks, followed by exogranitic quartz

veins and fracture stockworks.

489019lSI.


A. RANK OF DEPosrts

In addition, the gross dimensions of the deposit were considered in terms of

suitability for open pit extraction using an arbitary scale of probabilities

ranging from low (10% chance) to medium (50% chance) to high (100% chance).

Application of the foregoing parameters is shown in Table 2,

The probability of occurrence of a given category of mineralization can only

be estimated from the 21 recorded deposits associated with the Ben Lomond

Batholith, whilst the metallurgical characteristics are largely assumed, and

based on limited data from Aberfoyle Ltd. Pre-concentration factors are a

measure of the quartz vein content of the deposit.

The categories of mineralization shown in Table 1 were combined in to the five

main associations, and then initially ranked according to the contained (in

situ) tin metal as shown in Table 2. Grades used in this calculation were as

shown in Table 2, except for the following: lA (0.20% Sn), lB (0.50%Sn), 4 +

88 (0.50% Sn), 6 + 8D (0.20% Sn) and 8E (0.50% Sn).

I

1111JIIIIIIIIIIIIIII'IIIIIIIIII

- -- ---- -- -- -- - ~- --.J- .1_1.,.ILJIiJ__ IIIiI _~ _. -,__~.'.I.I

PllhLUlY ,I!NI':lnLl:I~,'l'ION CODE CON rAINED PIWIJAllILITY ME'fALLUHGICAL PROflA!lILITY RAN}{ RMKTIN O~'

,,,,n .• n~'O OF lx2x}x4 5,,6(l'ONNES) OCCUlUlliNCE (% ) PltE-CONN HECOVliliY(:') OPEN PIT

FACTOR POTENTIAL (:' )1 2 3. 4 5 6 7

~xog,nud lie quartz Vt!:lns 1,\ ~u 000 2ti 3. 70 100 11 7&0 11 7(,0

Aplit~/gre18enized upl i te & .. HD 20 000 20 1 ~50 100 2 000 2 000cupola

:-'lH:-i~iv~ /!,rt'isen HI~ 10 000 11 11 170 100 70 70

Exog-raui LiC {!uurtz VP llUI III .. 2 'J 000 12 !:: 1 '1(50 75 'j40 4o'j(inti frac ture s tockworks ~

t:(in·j~en ~ht'et 8C I, oot) 18 1 ~JO 100 1&0 1(,0

Elldugranl tic quartz veins 3 .. HA " 'joo 23 1.2 65 10 449 45-and grel~el\ veins

Elld()l!:rauJtic frac ture I, .. HIl 1 000 B I 165 10 52 'j:-l tOl:kworks &. greisen pipe

o

The faults are normal resulting in horst and graben structures, and in the

Rossarden area the NW set appear to pre date the NE set.

Faults in the Mathinna Beds (Rossarden area) essentially match those in the

granite, as follows:

(i) NW set - bedding faults, dipping 60-80° SW (eg Kookaburra Fault)

(ii) ~-~~E set - dipping 40-70 0W (eg Aberfoyle faults)

(iii) ~E set - vertically dipping 45' NW and 90°

(c) Vein Orientations

Mineralized quartz veins occur in three groups:

(i) Aberfoyle type - strike ~-,,~E, dippingj)-700W

(ii) Lutwyche type - strike ~·i. dipping 45-70'5W

(iii) Batterv t\'rc - strike ,E, Jippin>; appr"x. 90'.

The country rock Mathinna Beds have been folded along generally NW trending

folds, which are tight, symmetrical and similar in style. Slaty and fracture

cleavages are axial plane to the major folds, which plunge gently to the SE;

axial planes dip steeply to the SW.

(a) Joints

Joints in the Ben Lomond Granite trend NNW, NE and ENE, and are regarded as

pre-Permian in age. Joints in the Mathinna Beds trend WNW, NNW and NE are

best developed in quartzite rich units, and are considered to be fold related

(ie. pre-granite).

(b) Faults

Faults in the Ben Lomond Granite are sinuous and generally trend NW to NNW

(Castle Carey Fault) and NNE to NE (Burns Marsh, Aberfoyle I, 2 and 3 Faults);

they were considered by Blissett(1959) to have both pre and post Permian move

ment, with most of the displacement occuring in several post-Permian episodes (ie.

Jurassic and Tertiary).

II

'IIII

rlII11JIJIJIjljlJIJIJIJIJIII

17/ .

~~\)B. STRUCTURAL CONSIDERATIONS

1. JOINTS, FAULTS AND VEIN ORIENTATIONS

489021

dykes have generally similar orientations to the quartz veins,I ~~\,Aplite

18/ .(489022

IIIIIIIIIIIIIIIIIII

while some microgranite dykes trend ENE.

2. SUB-SURFACE GRANITE MORPHOLOGY

The gravity survey of part of the Rossarden area by Leaman (1974) indicated

that this was the most useful method of geophysical exploration, following the

failure of seismic and electrical methods. Interpretation of Mathinna Beds

isopachs allowed the construction of sub-surface contours on top of the granite,

with the following results:

(a) Faults - orientations ranging from NNE-NE to NW and thus confirming the

NNE-NE trending Burns Marsh and Aberfoyle faults. However, a previously un-

recognised NW trending fault, (termed the Eastern Hill Fault), was located,

and is a major feature.

(b) Regions of steep gradients on the granite surface, which trend NW, NE

and ENE, and defining the following:

(i) A NW trending "plateau" containing the Storeys Creek deposit, in

which the aplite cupola is similarly orientated;

(ii) A NE trending "peninsula:' containing the Aberfoyle deposit, but in which

the aplite cupola is apparently orientated ~E;

(iii) A NE trending "peninsula" (?horst) originating near the junction of the

Eastern Hill and Burns Marsh faults. The Aberfoyle West gravity anaomaly,

(Table 3) is located at the SW end of this feature, termed Egans Peninsula;

(iv) A very prominent rectangular "peak" (? aplite stock) offset from the

~E extremity of Egans Peninsula. It is termed the Golf Course West gravity

anomaly, (Table 3).

(v) An ENE trending "plateau" containing Brocks Prospect at its northern

margin. This feature is termed Brocks Plateau, and is bounded to the west by

the BurnS Marsh Fault, and the east by the Aberfoyle No.3 fault. The northern

margin of this plateau trends similarly to one of the joints in the granite.

I

3. DISCUSSION

19/. 489023

IIJ]

]

J]

]

IIIIJIIIJI]1JIJI

(a) The gravity defined faults and regions of steep gradient in the granite

surface (See Plan) have trends which can be entirely correlated with the

known regional defects (joints, faults) in both the Ben Lomond Granite and the

Mathinna Beds.

(b) The Ben Lomond Batholith is elongate in the direction of the regional

trend of the Mathinna Beds (NW-SE). and it is likely that~ of the aplite

bodies are controlled by this orientation. Additional controls on aplite

orientation are likely to be those exerted by the original granite morphology,

and which can be inferred from the trend of defects in both the Ben Lomond

Batholith and Mathinna Beds. (eg. the NE trend).

(c) Reconstruction of the granite topography in the Aberfoyle Graben (during

pre-Permian time). by extending the Eastern Hill Fault to the SE shows that the

Storeys Creek and Aberfoyle aplite cupolas, plus the inferred Egans cupola

(Aberfoyle West gravity anomaly). are all located immediately east of this

fault (See Plan).

(d) The Golf Course West gravity anomaly occurs within a NW trending horst

bounded by the Rifle Range and, extrapolated) Kookaburra faults on the east

and west sides respectively. The Lutwyche vein system is also located within

this horst, including the SE extension, and the location of anomalous strean

sediment samples (SS37, SS26) either in,or draining from,this horst (or its

extension) imply that it has a potential strike of ~5km.

(e) The broad symmetry of the Eastern Hill Fault (with associated aplite

cupolas). and the similarly trending Kookaburra fault (with inferred aplite bodi,"

at Lutwyche and Golf Course West) suggests that these NW trending faults are,

major features; and are probably syn-tectonic with granite emplacement.

(f) Hellsren (1979) showed that abrupt changes in granite morphology (includ

ing aplite protrusions), could act as zoneS of stress concentration due to the

combination of overburden stress modified by granite/aplite shape. and the

high fluid pressure within the granite/aplite.

The intera,'t: ~llll of these stresses results in the differential stress being

maximized along the upper edge of these obtuse angled features, resulting

in a concentration of hydraulic fractures.

(g) Zones of mineralization will follow those hydraulic fractures, and may

be broadly distributed about the primary granite/aplite obtuse angled features;

(i) abrupt change in granite shape _ maximum hydraulic frac turing "

6 (+8D), IA;

(ii) granite shelf, marginal to fault_ moderate hydraulic fracturing~

1B+2;

(iii) granite shelf _ minimum hydraulic fracturing _ 3+8A/4+8B •

8C.

I

1]1].]1'

].]1]1]1]1IIIIII

•I1I

•III

20/ . 48902·1

21/. 489025

Unknown (possibly I) = SS 37.

This bias is interpreted to reveal the likely deeply-buried stdtus of many of

These resul ts, when compared to the probabil it ie s of octlrrence shown in Tab Ie

2, indicate a bias toward category IB + 2, at the expense of category 6 + 80.

PROSPECTS fu~ ANOMALIES

are shown in Table 4. and the possible associations

= Golf Course West, Aberfoyle West (= Egans);

6 + 80 = Nisbet Creek.

=SS 26

IB+~ =SS 45 (see Brocks Prospect)

"

"

"

?

?

?

? Category IA

The area covered by ML 27M/77 contains numerous prospects as detailed

in Table 3,and the Pla~ The 16 known prospects (13 of which are primary)

may be grouped as follows:

Category IA = Aberfoyle, Kookaburra. Lutwyche, Eg~ns;

" I(undiff)= Kookaburra SE. Lutwyche SE. Eastern Hill;

" IB+2 NW Storeys Creek. Brocks. Flaherty-Plummers. McOonnells,

" 3+8A = Mammo t h ;

" 9 = Storeys Creek, Egans Alluvial, Upper Aberfoyle Rivulet;

"unknown = Rif Ie Range.

Gravity Anomalies

are as follows:

Combining the prospects and anomalies gives a mixed total of 20, of which 17

are presumed to be primary in origin. The distribution of the categories of

mineralization in this total is as follows:

IA:- 30%, I (undiff) :- 23%, IB + 2 - 23%, 3+8A:-6%, 6+80:-6%, and 12% unknown.

Geochemical (stream sediment)anomalies are shown in Table 4, with the following

possible associations '

? Category IA =SS 25 (see Kookaburra SE and/or Lutwyche SE)

I \)~~

IIIIIIIIIIIIIIIIIII

Accordingly, the gravity anomalies located in this survey, assume some

significance, particularly the Golf Course West Anomaly.

Thus the previous knowledge of the subsurface granite morphology is incomplete,

and the potential occurence of other blind aplite bodies and quartz vein

systems within ML27M/77 must be considered attractive targets for further

explo~ation.

48902622/.

~'t..~However, it should be noted that the 1974 gravity survey, would have missed

the Aberfoyle and Storeys Creek aplite cupolas, (due to the nature of the

survey, in relation to the size of these aplite bodies).

I

l.].J.JIJ.JIJ.J.J.JIJ.J.).J.J.J.J.J.J.I

- - - - - ~ """",-, ,--- -- - - - -- .-I _- -- ..... - ....- --TABLE ')

wm~u LlJTWYCIIL I' l'Y. L I'f). I'IWSI'ECT 'l'MlUL.UIONo'.-:>'Ql

Aili.11t'uYLESurface:

J\uuli.\lIlJIUl\JUll\SO:-iS:Surface:

SI'll! K~~LE~GTII

(m)

>1000

:-i.A.

ZUO

II' Wfll(m)

[JI':I"l'lI lill\IlE(m)

IZu 'I4L.

N.,.. I.:;%Clll

lOu ?

\lIN':''l'YPE

l.A

l.A.

LA.

WOllK CO~lPLi':TEJ)

9 Percussion holesUillin~ of 1895 Tparce l.

U.G. development,diamond drilling,mining etc.

t'act mapping;I diamond hole(Johnsons Veins)

API'ROX.SIZE

10xIOOT(open pi t)

2xlO(iT(open pit)

CO!dWENTS

Good Open PitPotential; veinswarm possiblyclosed to southbut open tonorth throughSpartan Prosp.

Abandoned mine;Production over50 yrs. yielded.t2.hIOu tonnes~ O.91~Sn, 0.2~

WOj'

Open pit potential not assessedstrike extensionto the NW needsevaluation.

RECUMMEND.\TIONS

Grid &. topographicsurvey; Uiamonddrilling, L, S, A;Gravity survey onlUOxl5m grid;cos tean for lJUlksample.

No further workrequired.

Grid & topographicsurvey. Gravitysurvey on IOOxl5mgrid, (NW ofIlattery vein);Costeaning L, 5. A;Viamond drillingL, S, A.

L. <i.: O ').~ )')\1

I)L

./ I.A 2 diwnond holeson 13 Level

O.6xiOll.r(open pit)

UG potentialonly partlyevaluated.

No work at thisstage.

1,

...]

2.

LPIWSPEC l' STltllill WIDTI1 DEPTH (;IlA])E MIN'.' llOftK cmU'LETE]) APPROX. COllMEN'fS RECOl.UlliNJ>"T IONS

1.1-::'>(;['11 (rn ) (ru) TYPE SIZE(m)

1.l/r"YCllE:Bd06TSurfat..:e: )" dlill IdJ-KO lOll ? I.A. ~'liC t mapping

I'J diamond holes (open pit) Open pit potent- Grid & topographicial no t 8s1!tessed. survey; Cos tean,

L, S, A, jDiamonddrilling L,S,A.

t.; .(J. : ., 1~1I 0.1-0.7 ~OO i"1%CM 1•..\. Nw.aerou8 diamond 'lxI06T UG potential No work at thisholes on 12 & 13 considered stage.Levels mar~inal by

Aberfoyle Gp.

KilliK IllUHfl. \ 'jOO 71,0 ? 7 I • Scout mapping ? SE strike exten- Grid & topographicS.1:. sion of Kooka- survey; mapping;

burra vein costeaning, L,S,A;system; mineral- Percussion drillingization open to L,S,A.the S.E.

1.L r,VYCHE 'iOO 7'i0 7 7 I • Scout mapping; ? SE strike exten- Grid & topographics.!·;. Soil sampling; sion of Lutwyche survey; mapping;

Elec trical vein system - costeaning, L,S,A,Aeophysics. mineralization Percussion drilling

open to the SE. L,S,A.

3.

\,1\\1-;\'\,:CT S ,'lllKE WIIll'lI IlEl'l'll (;IUlJE MI~lf WOllK CUlIPLETED AJ'PltUX. COMMENTS RECOMMENDATIONSLE~"TH (m) (m) l'YI'E SIZE

(m)

R11'1.1'; 1l\..~GE JOOO 10 ? ? ? Scout mapping ? No Sn or W Grid & topographic(700m Soi 1 sampl in!!; mineral iza Hon survey; mapping;~/)il :! diamond holes. observed in c08teaning~ LSA;a 1l0llld I y) outcrop, but Percussion drilling,

sulphides LSA.inferred.drilling appearsmisdirected, mayrepresent faultline

E\' l'!:!t~ lilLI, 'iOIl ~lOO" 'i0

? I. Fact mappin/(, 6xl06T Three vein Grid & topograllicSeveral adi ts (open swarms; interp- survey; COBteaningshafts; pit) retatioD com- LSA' Diamond drill-,7 diamond holes. plicated by low ing. L.';A.

angle reversefaul t andinsufficientdri 11 ing.

N.,\'. c; j'IIHI';YS '/ ? ? 'I '11\1+2 4 diamond holes ? Si tua ted X 600m Locate drill 10/4s,ell I '1:1\ : NE of Storeys Scout mapping (pho to-

Creek Wine; scale) andlJrill logs ? 88!o:lessm.ent.unava Hable,minimal data.

~

,'llOSl'ECT STIllKE WIIl'fH !lEPTII Gll.\IlE mN~ WOllK COMJ'LE!'Ell APPROX. CO.lll&EN'I'S H.ECO~(}II::N DA r IONS ..

(Ill) (m).~

U:NI;l'll 'l'YPE SIZE(Ill)

It\\l\IO I'llSurface: !0110 HxO.l 10 0.7"5n 3 ) ract mapping, 75 OOOT ) Type SA No further work

1,00 Hx I '0 10 O.IL>%Sn 8A ) coste8nin~, LSA, ) mineralization required.O.OH;'Sn ) several old pi ts ) actually greisen

) and trenches. ) envelopea llll) ) thick enclosing) ) quartz veins.) ) Uneconomic grade) ) iu granite.) ) Quartz veins) ) volume and grade

U. (;. : < 1.00 HxO.IO ~70 ~O. 7% 3. ) 50 ooor ) not sufficientvpins Sn ) ) for open pi t.

I); \:-.i~: ? SeVf~ rn 1 ? '! ?1.,\. Old cos teans ? Wi ....ral iza tion Grid /l.; topographicVl'lBH possibly assoc- survey; Costeaning0.2 iated with LSA· Percussion,

inferred aplite drill ing LM.cupola.

liIlliChS: »",0 ? /( ",0 0.')% 1.1J+2. Several trenches ? Narrow quaTtz Grid /I< to pog ra ph i cSn and shafts; 20 veins wi th survey; C08te~ning,

shallow <Iiamond irregular but LSA. Percussionholes. rich !In drllling. LSA.

mineralizution.Sn also infractures. ...

00~::;l

owo

5.o

r..,\J(/

PI\(},;PECT S I'ltll-:l': WIDTH DE!' I'll GIL\I)~: IIINlf WORK COMl'LETIill APl'llOX. COMMENTS 1U':COM:11ENUATIONSLI:N(;'1'1I (m) (Ill) TYPE SIZE

(Ill)

f'L \l1l,:rlTY- 'iO-l'iO o. (,-I. 'i ~:.'O 0. 11% lU.+2 Several shafts 20 000'1' Four quartz As fQ.r EgansI'LL\I"IEIL'-; : Sn (veins) veins grading Prospec t.

O.It:'Sn; gradeof fracturestockworksunknown.

\lclJO'''ELLS: 70,0 ? ? ? '11.8.+2 Minor trenching ? Possible ezten- As for Eganssion to Flaherty Prospect.and PlWlllllersprospects.

S mltEYSelll :1':10: (S.S. ) 1:.'01l ~O ~tl ? 9 Early sl-uicing 500 000 'lua ternary age, Grid & topographic

near ~lbo~t Creek m3 Limited data; survey. Drill ing(West of potential appears LSA.Burns limi ted eas t ofMarsh Ilurns MarshFaul t). fault.

l.1,,'::!t mOl x • ? ? '/ ? ? Tertiary aDd Stream samplillglul ::W"YLI'~ {- ilr ... a ~> 'lua ternary age; and assay.Itl 11jU: l': '100 ()(Ilhll.~ no other data.

.J'o.

--------------------6.

J

PIW"';PIXT "nllKe: IV lDTIl m~1' I'll GIL \IlE MIN'.' WORK CO~U'Lr;TED APrllOx. COlliIEN'I'S lU::CUMlII';NDATIONSLI':~(i nc (m) (m) '1'Y1'~; SI:lE

(ml

E(;.\SS rntU: area ? ? 9 Early sluicing ? Tertiary age Grid & topo/olr"phicAl.l.lIVI \1. - 17'5 OO()m~ - Limi ted records survey_ Uri 11 ing.

!.SA, Costeaning!.SA.

,.j;;o,

(X;

~"o~."

.';>I III "I

--------------------f.\IILE 4

",HE.lL LVTIVYCHE P'IY. Lill.A~O~L\LY TARUL\TlON

A!'1l1\LlLY V \ LVI'; LuC.\l'IuN /lEI. \ fEll IfOllK COMPLE'I,};/) COMMENTS RECOMA~1)ATIONS

MINII- GEOPHYSICAL -

GIILF COUll"!': -I .1. mg'll. 1100m east of ? LA. Ilegional gravi ty Residual Bouguer Grid &: topogra phi c survey;WE:' I' Storey" Creek survey_ anomaly indica tes IDapping;

Mine. (V.E. Leaman, major apophysi 8 coateaning; _1974). similtlr in gross drilling.

form to Aberfoyle& Storeys Creekcupolas.

,HH:' WO Yl.E ~rr:ST -0.6 mf.(a I. I~OOIU :-Ill' of ? I. ,.\. As above. This is the SW As above.(EIi\'iS) .\he r f oy 1e mine . and of a major NE

trending granitehigh. Interpret-ation complicatedby post Permianfaulting & gravitystation spacing.

S ISm:T C' tJ:EI\ -o.H mg-al. GOOm SlY of ? (,+8D As above Although. located As above,Storeys Creek in granite "shelf"Mine - an aplite body

is recorded here.

- ~- L- L....:- L..-:- L...i- &.-J- a........J-2.

L...i- L-.J- L-J- L.-I- l..--J- L...J- L...J- -

ANO\lILY VALUE LUc.ll'luN ItELIl'ElJ 1V0lU\ CUMPLEl'J::j) COMMENTS JU:COMto!EN lJA I'IUNSMIN~

- G!':OCJ!1:;),IICIL -s,; ~'1 I )Oppm, Sn 700m NE of ? l.A. Stream 8ediment Anomalou8 value8 for Additional stream sediment

'.')ppm. IV AlJerfoyle sllmplinjl;. both Sn and W; 8Ilmpling; mapping;)Iine. ( UIl- (Ros8llrden Mine8 pos8ibly related to cos teaning.na.med trilJ, Ltd. 1982) Kookaburra S.E..\lJerfoyleitivulet. )

SS ~L 16opplll. 5n lklll Se of ? 1 As above. Very anomalou8 values As above.{JOppm. IV ,Iberfoyl e for both Sn and Wmay

~l i ne. (uu- be due to ei ther 8trikenamed trill. extension of LutwycheIlJerfoyle SE, or to contaminatiODRivulet). from Aberfoyle tailings

ss )7 ")It ppm. SII I:!OOm NE of ? Stream sediment Anomalous value for W Additional stream sedimentttO ppm. IV Storeys Creek sttmpl ing. only. Sample located sampling, mapping,

Mine. (Upper ftos8arden Mines on structural "high" costeaning.ol.lJe rfoy 1e Ltd. 1')82. and along strike fromltivuletl Golf Course West,

Lutwyche etc.

SS 'I? »)Ollp!'''. Sn lkm WSW of ? In, +2 A8 above Very anomalous value A1I above (see a180 programl'ippm. W. AlJerfoyle for Sn only. P08sibly for Brock8 Pr08pect).

Mine. (Junc- related to Brocks .,j;;o,

tion Tiller II< Pr08pect etc. 00StoreY8 eks.) e..~

0

-

The Blue Tier Batholith. Geol. Surv. Bull. 55.

Storeys Creek Mine. Tas. Dept. Mines Unpub. Rep.

489035

Tas. Dept Mines. Unpub Rep.

Wolframite Veins of Aberfoyle and8th Comm. Min. and Metall. Congo

Cassiterite andStoreys Creek.1. p. 506-511.

Notes on the Royal George Tin Mine. Tas. Dept.Mines. Tech. Rep. 11 p. 57 -65.

Eastern Hill. Storeys Creek. Tas. Dept. MinesUnpub. Rep.

Mammoth Tin Areas. Storeys Creek. Tas Dept. MinesUnpub. Rep.

Brocks Prospect. Rossarden. Tas. Dept. Mines Unpub.Rep.

The Aberfoyle Vein System, Rossarden. Tas. Proc.Aus. IMM 181 p. 75-91.

Plummers workings. Rossarden. Tas. Dept. MinesUnpub. Rep.

The Avoca Mineral District. Geol. Surv. Tas.Bull 40.

REFERENCES

The Emplacement and Geometry of the MineralizedQuartz Veins at Rossarden-Storeys Creek. Unpub.B. Sc. (Hons.) Thesis, Monash Univ.

Greisenization and mineralization at AnchorTin Mine, NE TaslDlania Trans. lnst. Min. Metal!.82 B p. 135-146:

The geology of the Tin-Tungsten deposits. AberfoylcTas. Dept. Mines Unpub. Rep.

The. Mt. Rex Mine..

Mineralization at Aberfoyle Tin Mine Rossarden, Tasmania. Proc. Aus. IMM 181 p. 93-145

The Geology of the Rossarden-Storeys CreekDist~ict. Geol. Surv. Tas. Bull. 46.

The zoned mineral deposits of the ScamanderSt. Helens District. GeoL Surv. Tas. Bull. 53.

The Petrology and Geochemistry of the BenLomond Granite and Associated Tin-TungstenMin. Unpub. B. Sc. (Hons.) Thesis, Univ.Tas.

URQUHART. G. 1966

SCOTT. J. B. 1929

REID. A.M. & HENDERSON Q.J. 1929

SCOTT. J.B. 1934

NYE, P.B. 1941

KINGSBURY. C.J.R. 1965

HENDERSON, Q.J. 1935

EDWARDS. A.B. & LYON R.J.P. 1957

BLISSETT. A.H. 1959

HELLSTEN, K.J. 1979

HENDERSON. Q.J. 1936

HENDERSON, Q.J. 1946

KEID. H.G.W. 1954

LYON R.J.P. 1957

GROVES. D.l. 1977;

GROVES. D.l. & TAYLOR. R.G. 1973

GROVES. D.l. 1972

CLAYTON. W.F. 1981'

-J4

URQUHART. G. 1967 The Rex Hill Mine. Geol. Surv. Tas. Rep. No.9.

,

I

489036

MINES

Action Officer J Initials ,

I~O .

File Ref'.:';.E~.L~~~

17 MAY 1?~----IDoc. Ref.

1__-----1=----=1Resubmit to. 1 Date I

Fll~..... ;", It

MAY 1988

EL59/83

WHEAL LUTWYCHE PTY. LTD.

RELINQUISHMENT REPORT

..........~..... ,IIIIIIIIIIIIIIIIIIII

•

IIIIIIIIIIIIIIIIIIIII

Ll8°0':>,/... ~f "J.

THIS PAPER OUTLINES THE TIN-TUNGSTEN MINERALIZATIONOF THE EXPLORATION LICENSE.

IT APPLIES TO THE AREA TO BE RELINQUISHED AS WELLAS THE RETAINED AREA.

RESEARCH WORK ON THE AREA SHOWED IT TO BE LESSPROSPECTIVE THAN THE AREA RETAINED THEREFORE NOFIELD WORK WAS CARRIED OUT.


•

489038

TIN - TUNGSTEN - .BASE METAL MINERALIZATION

ASSOCIATED WITH

THE BEN LOMOND GRANITE BATHOLITH

ABERFOYLE DISTRICT

:-;ORIHEAST TAS:-l.I..'O IA.

r. G. SL"}~!O~S.

Sl"}!':-{O:;S GF.OSERV((£S pry. LtIJ.


•

TABLE OF CO~n:~TS

SU;l:-L\RY

GEOLOGY OF THE BE~ LOMOND BATHOLITH

A. LitHOLOGIES

B. GEOCH~IICAL CHARACTERIStiCS

C. CmIPARISO~ WITH THE BLUE TIER BATHOLitH

D. CO~CLUSIO~

~1I~ERALIZATiO~

A. MI~E~\LIZArIO~ ASSOCIATED WITH THE BLUE TIER BATHOLITH

B. MI~E~~LIZATIO~ ASSOCIATED WITH THE BE~ LOMO~D BATHOLITH

C. GREISEN POTE~TIAL I~ THE BEN LOMOND BATHOLITH

D. TU~GSTEN-TI~-COPPER-SILVER/LEAD/ZI~C

ZO:H~G POTENTIAL ASSOCIAfED WITH THE BE~ LlJMO~D BATHOLITH.

EXi'I.')~H IO~ RATIll:;ALE

A. RA~K OF UEPOS IrS

B. STRLCn:~~L Cll~S IDERATiO~S

I. JtJI:;TS. FALLTS A.'I;D VEI~ ORI£~TATI0:;S

2. SUB SLRFACE GR.\~ ITE ~IORPHllLOGY

3. UISCCSSIO~

t'RtJSPEC rs ,\>;0 A:;tJ:L\UES

PAGE ~O.

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I '; •

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17.

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2l.

SL'l1liARY

(04890[10

The potential for zoned W-Sn-Cu-Ag/Pb/Zn mineralization is indeterminate on

present knowledge, and several possibly relevant features in the area require

evaluation.

in or related to the Ben

(iii)

(iv)

(v)

The Ben Lomond Granite Batholith shows a strong mineralogical and geochemical

affinity with the fractionated granitoids of the Blue Tier Batholith, and has

itself been fractionated from a calc-alkali granite (biotite granite) to an

alkali granite (inferred biotite/muscovite granite).

Structural cvnsiJerations involvins r.1dpp~d d~fects. anJ ~r.lvlty b~lS~d sub

surface granite morpholo;;y impl\' t:l<ljor :-'"W Clnd pwbably :it:) tr"nding tt"".lrs

inflUenced b,.'th th~,~r,lllite/.\pti.tl! intrll-iC)\li. md the-iuh~eqllt.'nt prtm.:.lry

rn i:1~r,l t i 4:.1 t L~'n.

The potential occurrence of large greisen sheets (eg. Anchor deposit) is con

sidered to be minor, and the potential for ::lassive "greisens" (Ardlethan type)

even more remote.

The inferred biotite/muscovite granite shows a strong geochemical correlation

with several muscovite/biotite" granites ("tin granites") in the Blue Tier

Batholith.

Five primary associations of mineralization occur

Lomond Batholith, namely:

(i) Exogranitic quartz vein systems (strike extent>" 500m);

(ii) Exogranitic quartz vein systems (strike extent /( 100m) and

fracture stockworks;

Endogranitic quartz veins and greisen veins;

En~Jgranitic fracture stockworks and greisen pipes;

Aplite and greisenized aplite bodies.

IIIIIIIIIIIIIIIIIIII"~I

II

(ii) 489041

II

Several major residual Bouguer gravity anomalies exist in the area, and

appear similar in status to the Aberfoyle and Storeys Creek aplite bodies.

The primary mineral deposits in the Rossarden area have been ranked according

II to inherent tin metal content, probability of occurence, assumed metallur

gical character. and the suitability for various mining methods.

II

II

II

II

II

II

II

IIII

III

II

II

II

•

The three highest ranking categories of mineralization are exogranitic quartz

•vein systems, aplite/greisenize~aplitebodies, and exogranitic veins in

association with fracture stockworks.

III A. LITHOLOGIES

3/.

GEOLOGY OF THE BE~ LOMO~D BATHOLITH

489042

II

Following some detailed investigations in recent years (Hellsten 1919. and

Clayton 1981). data on the Ben Lomond Granite has increased considerably.,

Ithe main granitoid types in the Rossarden area are:

1. Coarse grained. variably porphyritic biotite granite;

4. Microgranite;

5. Aplite;

6. Pegmatite;

1. Quartz-feldspar porphyries.

3. Fine/medium grained quartz-muscovite-tourmaline rock(QMT);

2. Fine grained porphyritic biotite granite;I

II

III The course grained (cg.) biotite granite occupies the largest volume,with

the fine grained (fg) porphyrite granite variably present within or surrounding

I the former.

II The tourmaline leucogranite [Q~l) outcrops mainly between Tasmania and

III

~isbet Creeks northwest of Aberfolye. ~linor intrusive phases are represented

by microgranite.aplite.peg~atite,and porphyry dykes; the aplite also occurs as

sto~ks of cupolas emanating from the main granite body, and the latter variably

enveloped by a carapace of microgranite.

IB. GEOCHEMICAL CHARACTERISTICS

II

rypLcal elements llseJ as indicators of increasin~ fr31:tiundtLon in ~ranLtlc

rocks are ~tg, Ca, Sr, Ba, Li, ~a, K, Rb, Sn and ·w. [he depletion "f ~a(t-K)

and the alkaline e,uth elements is accompanied by increases in L1. Rb, Su. ',; an.

F. The. cunv~ntL.Jtl,ll metlhhi L,f pr~:->t.~ntin~ fr.h.:ti,)l1.1tiL' 11 tr~nJ..:; l!1 ~r,lllitil:

I rockg is to ~r,lr)h thlt'.~ (.lt1\) .It ~t~/l.i vcC..:oll:-i t~~ r,lt id K/Rh. :->Ih.:ll t~l.lt

•

rock.

Anchor mine).

elements with common fractionation trends in the following rating:

substitution of these elements seemed likely), it was decided to combine all

489043

indicate a trend toward the alkali

porphyritic granite, microgranite (dyke),

- decreasing values of this ratio c0nfir~_l'il the K/Rh trend, but

greisenized .lplite, and tl:~ ~r:t[lites.

also emph.:lsi::3ed a r.l.:ljor gap he tween the group tlf ')-~-T r,--:k., .lplite and

K + ~a

Li+Rb1.

the aplite, whereas the trends of decreasing K and ~a imply the opposite. Con-

to the high values in the greisenized aplite (? similar to the greisen at the

Excluding the microgranite data, the trends of increasing Li and decreasing Ba

progressively lower values for both ratios

biotite granite to microgranite to Q-M-T rock to aplite to greisenized aplite.

4/.

l~

The trend of increasing Rb suggests that the Q-M-T rock is a differentiate of

quartz-muscovite-tourmaline rock, aplite, and greisenized aplite (11 Level

sequently, (because of the anomalous Mg and Ca values, and because isomorphous

granites.

rock, meant that the MgfLiratio in particular was not a useful discriminant

aTy tourmaline, while the low Ca reflects the absence of fluorite in the Q-M-T

Aberfoyle).

anomalously low Ca, and erratic Li values from the microgranite and the Q-M-T

However, the limited analytical data, combined with some anomalously high Mg,

and Na also follows the K/Rb trend, but the trend of Sr is erratic, due partly

of fractionation. The high Mg values probably reflect the formation of second-

The K/Rb ratio showed a distinct trend from f.g. porphyritic granite to e.g.

namely eg. biotite granite, Lg.

The chemistry of six granitic rocks from the Ben Lomond Granite were stodied,

I, ~

IIIIIIIIIIIIIIIIIII

•

II 2. Mg+Ca+Sr+Ba

LHRb

5/.

- progressively declining values of this ratio also

IIII

confirmed the K/Rb trend and also indicated three groups of similar

values, ie: f.g. porphyritic granite (13), e.g. biotitegranite (l3),

microgranite (7), aplite (4.6), greisenized aplite (4.l) and Q-M-T rock

(3.5).


.,Blue Tier Batholith, from which the following salient features are taken:IGroves (1977) gave a succinct description of the geology etc. of the

I 1. The Blue Tier Batholith consists of a suite of calcalkaline granitic rocks

which show a normal fractionation trend characterised by increasing Si, AI, K,

I Li, Rb, F and Sn, and decreasing Fe, Mg, Ca, Sr and Ba. The geochemical

II

evidence suggests a single magmatic fractionation series, from granodiorite

to adamellite to calc-alkali granite to alkali granite.

2. The adamellite and clac-alkali granite interval of this series is

represented by biotite granites/adamellites which are typically coarse

I grained or porphyritic. They form large homogenous steep sided plutons,

IIIIIIIII

and collectively account for> SO vol% of the Blue Tier Batholith.

3. The alkali granites are represented by muscovite-biotite granite,

typically fine ~edium grained, with a general sh~et like form; they are

strongly fractionated with low K/Rb. Mg/Li, Sr and Ba, but high Sn, Wand F.

~lain examples are the Mt. Paris. ~lt. Willi-1m, ~lt. Cameron and Lottah sheets;

related but slightly different sheets of biotite-muscovite granite occur at

Sheoak Hill, Little Mt. Horror and Constable Creek. These latter sheets of

granite are Ch<..lLlcteri.seJ by the presence of tourmaline, lack of fluurite

and biotite in excess of muscovite.

I 6/.

IIIIIIIIII

with granitoids from the Blue Tier area. based on petrological and geochemical

characteristics (particularly Mg/Li. K/Rb. Sn, Li. Sr, Ba).)

, ,(i) ,The Ben Lomond c. g. biotite granite,very similar to the Boobyalla and

Poimeoa (adjacent to the Anchor mine) granite plutons;

(ii) The tourmaline leucogranite (Q-M-T rock) is very similar to the Mt.

Paris muscovite-biotite granite sheet, but also has affinity with the Sheoak

Hill. Little Mt. Horror and Constables Creek biotite-muscovite granite

The poimena biotite granite forms part of the fractionated series of granitic

rocks mentioned previously. and is intruded by the muscovite-biotite granite2

(alkali or "tin granite") of the Lottah sheets.

The Mt. Paris muscovite-biotite granite sheet intrudes both Mathinna Beds,

and the western edge of the Poimena granite,and both the Lottah and Mt. Paris

sheets host important primary tin deposits.

D. CO:-lCLUS IO:-lS.

to represent the calc alkali to alkali granite end of a normal granitic frac-

I. The sequence of crystallization of the Ben Lomond granitic rocks appearsII tionation series. as follows:

IIIIIIII

(i) f.g. porphyritic granite [chilled margin of (ii)]

(ii) e.g. biotite granite (major phase of Ben Lomond Batholith)

(iii) ~licrogranite

(iv) E/m.g. biotite/muscovite granire (inferred, and now altered to quartz-

muscovite-tourmaline rock).

(v) Aplite (and probably pegmatite. quartz-feldspar porphyry)

(~) Greisenization of the biotite/muscovite granite + aplites.

2. A major geochemical hiatus occurs ;;eneatly ab0ut the S,l",e time ,lei the

intrusion of the microgranite dykes.

3(i) A stron~ mineral"gic,tl and ge"chemical affinity l'"ists hetween t'l" B"n

Lom"nd C.»t. biotite gr,1nlt" ,lnd the P"ben,l bi"tit" ,rmit,,;

IIIIIIIIIIIIIIII

IIIII

•

7/.

3(ii) A strong geochemical affinity exists between the Ben Lomond (inferred)

bioV~u3 grani~e and the Mt. Paris muscovite-biotite granite;. )

3(iii) A less significant mineralogical and geochemical affinity exists between

the Ben Lomond (inferred) biotite/muscovite granite and the Constables Creek

biotite-muscovite granite.

4. The sequence of crystallization (points 1,2 above) and the correlations

made (in point 3 above) with the Blue Tier Batholith, suggest the Ben Lomond

(inferred) biotite/muscovite granite is a younger intrusive body, enplaced

near the top of the older Ben Lomond biotite granite.~

5. In common with the primary tin mineralization in the Blue Tier Batholith,

the Ben Lomond (inferred) biotite/muscovite granite and the aplite (cupolas etc)

appear to be the penultimate crystallized portions of the residual magmatic

fluids that were eventually to greisenise both rock types, and to precipitate

the Sn-W-Sulphide minerals present in the Aberfoyle etc. quartz veins.

II

8/.

MINERALIZATION

48904'7

II

III'IIIIIIIIIIII

•

It is considered appropriate. in view of the mineralogical and geochemical

affinity of the Ben Lomond Batholith with portions of the Blue Tier Batholith,

to review the primary mineralization in the latter. in order to fully assess

the mineral potential of the Ben Lomond Batholith.


Primary mineralization occur~ in three groups. Sn + W. Cu + Ag-Pb-Zn. and

Au. Au-Ag deposits.

I. Tin - Tungsten

This mineralization (cassiterite and wolframite) shows a close spatial rela-

tionship with the muscovite-biotite granites. although small lodes occur in

the Constables Creek sheet (biotite') muscovite granite) and in the Poimena

pluton (biotite granite).

The main modes of mineralization are exogranitic quartz-wolframite-cassiterite

veins, and cassiterite in fractures, and endo granitic ~reisen veins. pipes

and sheets, and quartz-wolframite (~ molybdenite ~ bismuthinite) veins.

2. Copper and Silver-lead-Zinc

This mineraliz~tion is exemplified in the Scamander area wh~re it is part of

a lonal sequence 3ssociated with the Constables Creek biotite-nuscovite granit~.

[he zonation appe.lrs to follow the classic hydrothermal sequence, na""ely frow

the contact aureole outward the zones are H(!Mo '1li), Sn, (Cu(-As-Zn-Pb), and

,\g-Pb-Zn (-As-Cu]). [he ~enetic association of the latter zone with the Con-

stables Creek granite is conjectural. and it may be related to a granodiorite

J. G.J Id and GO ld-S tl ver

This type of mIneralization "..:..:ur. to the west of the zonal ,equen..:e described

,tbuve. and i'i prtJb~lbly aSSnCl.lteJ with the Pyen~,ln,l ~r..lthh1i0ri.tc.

IIIII

9/.

489048B. MINERALIZATION ASSOCIATED WITH THE BEN LOMO~ BATHOLITH

Actual and potential primary mineralization associated with the Ben Lomond

Batholith is detailed in Table I.

Although 13 categories are shown in this table, there is considerable over-

lap between the groups, such that 5 main primary associations can be recog-

nized:

IA exogranitic quartz vein systems (strike extent ~ SOOm);

Categories Sand 7 are considered either too small, or to have insufficient

grades to be of economic interest. It is apprent that the modes of primary

II

I

IB+2

J+8A

4+8B

6+80

exogranitic quartz vein systems (strike generally ~lOOm),

and fracture stockworks;

endogranitic quartz veins, and greisen veins;

endogranitic fracture stockworks(minor) and greisen pipes;

aplite and greisenized aplite bodies.

IIIIIIIII

•

W-Sn-base metal sulphide mineralization are virtually identical between the

Blue Tier and Ben Lomond batholiths, the main difference being the apparent

absence of greisen sheets (8C) and disseminated cassiterite in granite (5).

C. GREISEN POTENTIAL IN THE BEN LOMOND BATHOLITH

The formation of greisen sheets requires a mini~um of roof rock fracturing

and Groves (1977) suggested that provided the roof rocks were not fractured,

greisen veins were associated with thick muscovite-biotite granites (eg. Mt.

Paris) I ,lnd that ~reisen sheets were associated with thin lI t in grani.tes"

[ego Lottah sheets, Anchor deposit etc. J).

[he v~ll idity of the:ie ,t?;reisen r!HJd021s (thick ,lnJ thin "tin ~r'lnLt ...,~'). C..lonot

f~rred Ben Lomo:--:J "tin ~r.uli.t~!l1l by ,.111 Iln~y with th~ ~tt. Plri'i "tin ~Llnlte".

• '....~.,

'~.'1\>-':- - - - - - ~ - ... - - - - - ... - - -

1'\1I/J:

.IC I'U \1, 1'\ II 1'11'1'1-:'\ 1'1\1, \11 "1:11.\1.1 Z \ l'lIlN .\SSllC IHm 1'1 nil 'fUI-: IJK.. LtlMliNIl Il.l'rlluL I 'rII

-\11 "EiL\LI I. U'III!'i TYPE (litE IIINl:IL\lli li\NGU~: MI"l.:u.\J.~ liIW>E Sl~ (TONNES) IDWU'LES

~:X"';ILI';J I'leLA. 4uurt.z V~lIlM Cs Wf (Cp Sp Gil) 1I tz Apy Py J.2~CI.l 2.1xlg0 (UG) Aberfoyle (actull1 prouue tion)

V';UOID "tnhe) 'to • 1-0.5~CW 10dO (01') Aberfoylel~I1.Judrlz V~inH Cs (Wf Mol Qtz 0.4-0.9:'Sn r.:-50 000 (UG) Brocks, FlabertysPlummera

(.lUU.. )(!1I tz ~ 3.5x106(OP):!. }o',l'dcture Stuchworkg Cs (Cp Sp) Py) 0.25~Sn (Great Pyramid), IJrocka

Storeys Creek

,~

1\''1';11\'\11'1.

1. \.IuHrlz Vt'iUM I'll' (Mo C" III Cp) ~tz TID Mu"c Py Apy 0.7~Sn 5-50 000 ~UG) I.llUlllllO th , Ben LOlDond Tung"ten4. "nt(, lUC1.4 S tucJ... wurks Ca :t~luse, Kaol) 0.25-1. !J:'Sn ~ 150 000 UG) Rex llill (see i.!lI)'i. tirtull tt- Cs lItz Feld I.lusc Iliot ? ? (Lottah Sheet)L. .\1'1 i t .. Wf (;s (Sp ~to) lItz Krell! Ab ~ 0.20-0. 5!J:'CW 10xlO° (01') Aberfoyle7. Pt:'~uus t 1 tt' Cs Qtz Feld 'fin ~h,se Top ·10.05~n 'I Ivanhoe (Itansome)". lirt' i St"U

A. V.·l.n~ Cs (Iif ) 1I tz ~Iusc 'I'm ~' I I'y O.O~n 75 000 (UG) I.lWIIIDO tilKaol

Sp Cp c" (lill) 1I tz Musc Py Apy t'l O.lt~Sn 500 000 (UG) lLoyal GeorgeI'm I\nol

C" Qtz ~Iu"e 'I'm n Py 5%SIl ....<10 000 ~Uli) lien LOlllOnd TinH. j) J pt~ C" 'ltz (Musc) Jo'l 'fID Kuo I 'J. 'l.'S1l $" 15 000 UG) Great Uepublic

Sp.Gn Cp CS I'/f Qtz (Muse) Apy FI U.25-I.~Sn ~150 000 (UG) Rex Hill (Carpa thia)Chi Py

2x106 (01')C. She-tot Cs Cp Mo(Wr Seh lin) lItz Musc FI 0.2~Sn (Anchor)IJ. Cupulu IH Cs Sp M" Qtz Musc Chi Kuol ~ o. :W-O • 5:'<:W IOxl06 (01') Aberfoyle1:. 1"* lil"> 1v .... cs(lir Mo Hi CI' sp) lltz Muse ChI 'fin Kuo I O.5-().7~Sn 0.5-2xl06 (01') (Aruweat, South Wild Cherry)

AI.IINL\1.'I. Str.."", l'lde,or Cs N..\ ? ? Storey. Creek

I

489049

- - - - - - - - - - - - - - - • iii - - - -'rAIlU: I

(1)( il)(,ll )(,v)(v)(vI)

LEGE\IJ

All 8 ize c.Ja ta rt>J'ers to i.n 8 i tu tonnea~e8.

UG - in situ tonnl"H~e amenable for underg:rouruJ. extraction.~lP - i.n situ tonneag,c ilJuenuble for open pit extruction.fonneage aud ~ratle ltutu in Cute~ory 2 mineru'lization referE~uml.dt"~ Hhowu iu hrucket.l:J 'tire not u.tIsociated with the UeneM - Sn + WIl3~'

to the Greut I'yr8J11id.LOlllond Grani te but buve .. "imilar byurotherl1l1l1 origin.

IIIU;Ih:Cp:eH:Gn:llu:Set!:~p:

111' :

'I I "Ell\l.SlJi~lDuthiniteChl\lcopyri teClassi teri teoutllena~Iu Iy~uen i teScllet-l i te~phaleri tpliul Craw, te

'.

I;.L\GLJ:; .\lr\'·:lllLS.\IJ: AI~ite

Apy: ArsenupyriteIllot: llioti teChi: ChloriteF.. \ d: ~'e lusparK!-'elu: I'utl\..~ium I"t'\d~pnr

haul: Knulln.\lUl:Jc: ~lu~covi te

l'y: Pyri telJt~: ~ullru

Top: 'J'UpllZTw: fourmnlllle

However. kaolin is nl't unC~~i.'_-h)n in both the Blue Tier and Bt:n L·-..mc'nd hath()lit~ .

in the western and southern areas.

to have a similar probability of occurence to that of the greisen veins and

hydro-

48905112/.

pipes, (see Table 2).

1. The present western and southern margins are characterised by primary

thermal alteration and may not be a true greisen.

Accordingly the potential occurence of gr~isen sheets in the north east portionI'

have been more deeply eroded that the north east area.

the effects of mineralizing fluids traversing the older granite en route to a

incipient (IB+2) and extensive (IA) fracturing occurred in the Mathinna Beds.

3. The northeast area, on present knowledge, appears to be characterised by

mineralization in the form of greisen veins (3+8A) and greisen pipes (4+8B),

the Ben Lomond Batholith, namely the western and southern sides of the granite

2. There is an apparent absence of muscovite-biotite granite ("tin granite")

to a quartz-muscovite-tourmaline rock.

of the Ben Lomond Batholith can not be precluded, and statistically would appear

high level (and now totally eroded) "tin granite".

The Ardlethan type mineralization (8E) has also been included in the greisen

category in Table I, although it is characterised by low te::lperature

The following features of the Ben Lomond Batholith appear relevant in the

assessment of greisen sheet potential;

exogranitic quartz veins, and fracture stockworks; this implies that both

formed by the alteration of e.g. biotite granite and f.g. porphyritic granite,

These features are interpreted to indicate different degress of unroofing of

The greisen veins and pipes typical of the western side are thought to represent"

4. The inferred "tin granite" in the north east area has been gfoeisenized

(presumably both are equivalent to the older granite in the Rossarden area).

I IIIIIIIIII

,'I'II,IIIIIilIII

•

2J.

occur in association with categories SA, B (and ? C) requires further evaluation.

At present, because of the speculative staus of this type of mineralization

(in liE Tasmania), its probability of occurence must be low ('''<0·01), (see Table

48905213/ .

-III

D. TUllGSTEll-TIN-COPPER-SILVER/LEAD/ZIliC ZONING POTENTIAL ASSOCIATED WITH THE

BEll LOMOND BATHOLITH

,I11Iii

The mineralogical and geoch~ical affinity of the Ben Lomond (inferred) biotite/

muscovite granite with the Constables Creek biotite-muscovite granites has

been mentioned in the preceding sections; this latter granite is associated

with a W-Sn-Cu-Ag/Pb/Zn zoned sequence of mineralization in the Scamander area.

t) 1

,Ii,I;1\II1\

Minor, localized zoning occurs in the greisenized muscovite-biotite granite of

the Lottah sheet (Anchor deposit), and consists of successive partly overlapping

Mo, Sn and Cu rich intervals.

The potential for a zonal sequence of mineralization to be associated with the

Ben Lomond Granite is difficult to assess, mainly because of the lack oE

exploration east of the Lutwyche deposit. The available data for the Rossarden

area is as follows:

I1\II

1. ~Iineralogical zoning in the Aberfoyle deposit (and to a lesser extent in

the Storeys Creek deposit) is well documented, with Sn increasing dnd Wdecreasinl!;

with distance from the granite/aplite.

2. The composition of wolframite in the Aberfoyle and Storeys Creek deposits

shows a depletion in ~m with distance from the granite/aplite. ~olframite from

the ~.J zone in the SC~lm.:lnder area show a similar trend with Jist~l:l~e from the

Consubl~s Creek Gr,wite.

3. L.lte st.lgesulphides (typically Zn rich) u..:cur within a 5011\ r,ldlus of the

and chlorite.

4. There is a crude mineral zonation in the Rossarden area from the greisenized

(inferred) "tin granite" in the vicinity of the Mammoth deposit hosting W (tMo

tSntBi) mineralization outward to the Aberfoy1e-Storeys Creek line of deposits

hosting Sn-W (tCutZntPb) mineralization.

S. Soil geochemical work by Aberfoyle Ltd. in the Rifle Range area (lSOOm NE

of Aberfoyle and approK 2000m from the nearest granite), located coincident Cu

-As-Zn anomalies; this area is also noted for the lack of Sn-W mineralization.

However. the Lutwyche vein syste~ (Sn-W) is located only SOOm SW of Rifle Range.

IIII

IIIII'IIIIIIIIIIIII'.

l4/. 488053

The categories of mineralization shown in Table I were combined in to the five

main associations, and then initially ranked according to the contained (in

situ) tin metal as shown in Table 2. Grades used in this calculation were as

shown in Table 2, except for the following: IA (0.20% Sn), IB (0.50%Sn), 4 +

8B (0.50% Sn), 6 + 80 (0.20% Sn) and 8E (0.50% Sn).

IIIflIiI

I(I \Ii

A. RANK OF DEPOSITS

151.


489054

IIIIiIl(II

IIIIIIIII

Additional factors considered relevant in the ranking of these associations

for exploration priority include the probability of occurrence. the metallurgical

character and mining methods (cut off grades etc).

The probability of occurrence of a given category of mineralization can only

be estimated from the 21 recorded deposits associated with the Ben Lomond

Batholith, whilst the metallurgical characteristics are largely assumed, and

based on limited data from Aberfoyle Ltd. Pre-concentration factors are a

measure of the quartz vein contalt of the deposit.

In addition, the gross dimensions of the deposit were considered in terms of

suitability for open pit extraction using an arbitary scale of probabilities

ranging from low (10% chance) to medium (50% chance) to high (100% chance).

"Application of the foregoing parameters is shown in Table 2,

The resultant rank values correlate with the tonneage (contained So) ranking

for the three most prospective targets, namely exogranitic quartz veins,

followed by aplite/greisenized aplite stocks, followed by exogranitic quartz

veins and fracture stockworks.

The intermediate rankings are represented by gr~i~c~ sh~ets. ~rei~~n veins

ilnd massive greisen, and th-.: lnwcst r3nk by ~r(>i.sen pir't-'s.

-_._----'r.\.Hl.1·; ~

._------- ,- - --=I'll hLUtY III SLit lU/_lnuN CUIJ!:; CUI' l'AI~!:;j} PltUll.1.H 1LI 'l'Y w.;'fALLU1UilCAL PRulWllLlTY RANK kANK

'riN U~· ."". ·,.,'r.,.., Uf' IJl:lJl)JlIo 5:1(,(TllN:\~) uCCUII.IU::NCI:; (I' ) 1'1u::..cUN" I~UVI::IU' (" > IWt:N 1'IT

~'ACTuR i'Ul'EN'flAL (~)I 2 J 10 5 6 7

t:.lugnuH LtC 'ludr t..:l. V~ lU~ 1,\ ~lJ ('lUU ~~ ) 7U 100 11 7LU 11 7t>u

ApI t t~/gn·J.:;c!ul£t'(l .up! J. te t> .. tW ~U UUU 20 I ~50 100 2 OUO 2 UUOcupola

~~'&:-':"ilYc ~n' i ~t!1L HI~ lu uuu 11 ?l '170 100 70 7u

'j.t~~ut-!.r('1I1l1C tiuurt.z Vt'lll::;i III + 2 lJ lHJO 1~ " I 'I{JO 75 ')100 lou')i:uuJ frae lure ~ tuckworks

t;I't·I~l.·n sJit'l't be " UOU 'IH 1 ~}U 100 It>U lbu

twJu;!rdlH LJ C IluuS-LZ vt"ins j + bA .. ')UU 23 1.2 h5 10 I0Io9 105alllJ f,rt:' i ~t~U Vt'lHM

l·~JUlll": '"au" tiC fracture I. + bl! I UOl) H 1 1(,5 10 j:.! ')

:"! t~H.:kwurk~ tt g,Ct" 1 St"ll !' Ipe

•I B. STRUCTURAL CONSIDERATIONS

17/.489056

I l. JOINTS, FAULTS A.."<n VEIN ORIENTATIONS

••••I

'.'.III

"

II

•II

•I

•

The country rock Mathinna Beds have been folded along generally NW trending

folds, which are tight, symmetrical and similar in style. Slaty and fracture

cleavages are axial plane to the major folds, which plunge gently to the SE;

axial planes dip steeply to the SW.

(a) Joints

Joints in the Ben Lomond Granite trend NNW, NE and ENE, and are regarded as

pre-Permian in age. Joints in the Mathinna Beds trend WNW, NNW and NE are

best developed in quartzite rich units, and are considered to be fold related

(ie. pre-granite).

(b) Faults

Faults in the Ben Lomond Granite are sinuous and generally trend ~~ to N~~

(Castle Carey Fault) and NNE to NE (Burns Marsh, Aberfoyle 1, 2 and 3 Faults);

they were considered by Blissett(1959) to have both pre and post Permian move

ment, with most of the displacement occuring in several post-Permian episodes (ie.

Jurassic and Tertiary).

The faults are normal resulting in horst and graben structures, and in the

Rossarden area the ~~ set appear to pre date the NE set.

Faults in the ~Uthinna Beds (Rossarden area) essentially match those in the

granite, as follows:

(i) ~~ set - bedding faults, dipping 60-80° SW (eg Kookaburra F,lult)

(ii) N-~~E set - dipping 40-70 0 W (eg Aberfoyle faults)

(iii) NE set - vertically dipping '.5° NI, and 90°

(~) Vein Orientations

Mineralized quartz veins occtlr in three groups:

(i) .:\bcrfoyl~ tyre - :-itri.ke ~;-S~~E. Jippin~ »)_;~l3,..J

(it) Lutwyche t''"pe - strike \:.;. ,1ippin~ .;-?O":';:'Ii'

(iil) Bdttcr~~ t\';'c - ... tri.k\.~ \E. Ji.I'Pil\~ {\!'t'r,l:<~ '·h).}.

II

•'I11

•1I

'.I .

489057Aplite dykes have generally similar orientations to the quartz veins,

while some microgranite dykes trend ENE •

2. SliB-SURFACE GRAN lIE MORPHOLOGY

The gravity survey of part of the Rossarden area by Leaman (1974) indicated

that this was the most useful method of geophysical exploration, following the

failure of seismic and electrical methods. Interpretation of ~lathinna Beds

isopachs allowed the construction of sub-surface contours on top of the granite,

with the following results:

(a) Faults - orientations ranging from NNE-NE to NW and thus confirming the

NNE-NE trending Burns ~Iarsh and Aberfoyle faults. However. a previously un-

recognised ~~ trending fault, (termed the Eastern Hill Fault), was located,

and is a major feature.

(b) Regions of steep gradients on the granite surface, .which trend ~~, NE

and ENE, and defining the following:

'I (i) A NW trending "plateau" containing the Storeys Creek deposit, in

II

•I1I'III•

"hich the aplite cup<lla is similarly orientated;

(ii) A NE trending 'peninsul~'containing the Aberfoyle deposit, but in which

the aplite cupola is apparently orientated NE;

(iii) A NE trending "peninsula" (?horst) originating near the junction of the

Eastern Hill and Burns ~arsh faults. The Aberfoyle West gravity 8naomaly,

(Tat Ie 3) is located at the SW end of this feature, termed Egans Peninsula;<0

(iv) A very prominent rectangular "peak" (1 aplite stock) offset from the

NE extremity of Egans Peninsula. It is termed the Golf Course West gravity

anomaly, (Table 3).

(v) An ENE trending "plateau" containing Brocks Prospect at its northern

~argin. This feature is termed Brocks Plateau, and is bounded to the west by

the Burns ~larsh Fault, and the east by the Aberfoyle No.3 fault. The n"rthern

:-;.lr.~in of this pl.1teau trends similarly to i..Jne of th(' -inints in the ~rilnitc.

II' 3. DISCUSSION

19/.489058

II1IIIIIIIIIIIIIII

(a) The gravity defined faults and regions of steep gradient in the granite

surface (See Plan) have trends which can be entirely correlated with the

known regional defects (joints, faults) in both the Ben Lomond Granite and the

Mathinna Beds.

(b) The Ben Lomond Batholith is elongate in the direction of the regional

trend of the Mathinna Beds (NW-SE), and it is likely that~ of the aplite

bodies are controlled by this orientation. Additional controls on aplite

.,orientation are likely to be those exerted by the original granite morphology,

and which can be inferred from the trend of defects in both the Ben Lomond

Batholith and Mathinna Beds, (eg. the NE trend).

(c) Reconstruction of the granite topography in the Aberfoyle Graben (during

pre-Permian time), by extending the Eastern Hill Fault to the SE shows that the

Storeys Creek and Aberfoyle aplite cupolas, plus the inferred Egans cupola

(Aberfoyle West gravity anomaly), are all loc~ted immediately east of this

fault (See Plan).

(d) The Golf Course West gravIty anomaly occurs within a ~v trending horst

bounded by the Rifle Range and, extrapolated) Kookaburra faults on the east

and west sides respectively. The Lutwyche vein system is also located within

this horst, including the SE extension, and the location of anomalous strean

sediment samples (5537, 5526) either in ,or dr.,inin~ from,this horst (or its

extension) imply that it has a potential strike ,'f )' ,:':::1.

(e) The broad syrmnetry of the Eastern Hill fault (with associ3ced aplite

cupolas), ar,d the similarly trer...lin~ Kookaburra fault (With inferred aplite hodi"

at Lutwyche and GalE Course Hesd, suggests that these ~V trending faults are

major features; and are probably syn-tectonic with granite emplacement.

(0 HeIbel''' (1979) showed that "brupt ch:mges i" ,~r,mite m"r?holo~y (lnclud

in.~ apLi.te protru:iions). could ,let as zun~s LIt str~::iS Cl)ncentclth'o due tu the

co~binatt~n of 0v~rbllrJ~n strei~ mllJified by ~rilnit~/'lpllte ~h!p~..I~J the

hl~h fluid pre~-;qre within the <ir-mite!.lpl ite.

20/.IIIIIII'••IIIIIIIIIII

•

489059maximized alon~ the upper edge of these obtuse angled features, resulting

in a concentration of hydraulic fractures.

(g) Zones of mineralization will follow those hydraulic fractures, and may

be broadly distributed about the primary granite/aplite obtuse angled features.

(i) abrupt change in granite shape _ maximum hydraulic fracturing 'll

6 (+80), IA.

(ii) granite shelf, marginal to fault~ moderate hydraulic fracturing~

18+2.

(iii) granite shelf _ minimum hydraulic fracturing _ 3+8A/4+8B ---....

Se. .,

. - - -- - - - - -_./.••••.... -_...'. jJ ..... -~.

1'111' -;1'EC'f S I'HIKE 1,lll'l'l! DEI' I'll GIUlll:: ~IJN'} "UIII\ CUW'LE 1't.:1J .U'l'llUX. COw.u:N'I'S IlliCO.u.u..:.... UA l'IuNSl.I:~\a; I'I! (w) (01) 'rnE SIZE

(01)

II\ICoJU I'll .Sur"iIC~: I.OU HxlI. 1 1IJ ().7"5n 3 ) 101ac t mupping, 75 OOOT ) Type SA No further work

1,UO Hx I .1) 111 o .1):"",Su HA ) cOHtt.~uuinK, LS,\. ) winer.. l iaa tion required.O. llt;;'Sn ) Mev.. rts 1 old pi te ) ..c tual1y greieen

) lIud trenches. ) envelopee 1m) ) thick encloeing) ) quartz veille.) ) Uneconomic grade) '. ) ill ~rani teo) ) Qu..rtz veins) ) volume ..nd grade

L. t;. : <- !,UO HxO.1II ~7() $' (). 7~' 3. ) 50 000'1' ) not eufficientV~· i Wi ~u ) ) for ..pen pi t.

1.1; ~\~; 'I St> Vt' rH 1 '/ 'I '/I,A. uld COM t~uns ? Win..ral i"a tion IIrid e.. topogrul'hicVI'lUS po... ibly aseoc- su.rvey; COd tt!unil{)~:.! iated with LS,\' Percu8Miou•

inferred aplite dri II ing L::;.A.

CUpull"

hltut'h~: 5so '/ '( 'ill ll. I):' 1 .U+2. :lever.. l trenchee ? . N.. rrow qUl&Tta Grid & topographic

Sn unu shufts; 20 vein. with eurveYi Coeteuningshallow ,!iamond irregular but . UiA. Percuseiontwlt'!8. rich Sn dnlling, L::;.A.

mineralization.Sn .. leo inf ra.e tures.

-._---- --------------2.

A.'1Ut.l.lLY VILLE UK., l'IuN ItEUn:O IVUltK <:mU'u; I'Jill CU~1EN1'S IlliCO.\lllU::N IJA l'1lINSMIN~

- G~;\lCllt:\lIC lL -~s :.'') J10ppm. So 700m Nt: of ? l.A. Stream seuilllent AnolWlJous values for Additional s trell/a sediment

1.'5ppm. IV Aherfoyle sUlUp1inf.!:. both Sn and W; Bampling; ....Plling;,line. (llll- (lloss.. r,len MineB possibly related to COB teaning.n"lu~d tl'lh. Ltd. 1982) Kookaburra S.B..\he r f "y I e,tivulet. )

SS :!(.. J l>Uppm. Sa lkru Se of ? 1 As tilJove. Very anomslous values AB above.ulJppm. W .lherfoyl e for Ao th sJi' und W may

Mine, (un- be due to ei ther strikelluw(Hl trih. extension of Lutwyche\hert'oyle SE. or to contaminationtti vulet). frolll Aberfoyle tailings

l;S 17 )1'1'1'01. Su l:!OOm NE of ? StreuUJ aedi'JJent Ano.... louB value fot W Additional ~treWD 8ediw~utl,l)ppm. IV Storeys C"~t.·k sumplillg, only. SamJ.le loca ted s_pling .....pping.

,line. (U ppe r It"8Bllrden MineB on Btruetural "high" cOBteaning..\.hed'nyle I. ttl. 1')tl~ .. -and along Btrike fromllivulet) Golf Coursll WeBt,

Lutwyche etc.

SS " 'j 110Ilpp",. :-in \1",. WSW of ?1l1.+2 As ahove Very anomalouB value AB above (Bee also rrograml)ppm. w. Aherl'oyl .. for Sn only. I'onibly for llroeks ProBpect •

~1 i ne. (June- related to Brockstiol1 Ti~~r & ProBpect etc.Storeys Ck •• )

The Blue Tier Batholith. Geol. Surv. Bull. 55.

The zoned mineral deposits of the ScamanderSt. Helens District. GeoL Surv. Tas. Bull. 53.

Eastern Hill. Storeys Creek. Tas. Dept. MinesUnpub. Rep.

The Aberfoyle Vein System, Rossarden, Tas. Proc.Aus. I~lM 181 p. 75-91.

4890~2I,)

!~

II

Tas. Dept Mines. Unpub Rep.

Wolframite Veins of Aberfoyle and8th Comm. Min. and Metall. Congo

REFERENCES

Brocks Prospect. Rossarden. Tas. Dept. Mines Unpub.Rep.

Mineralization at Aberfoyle Tin Mine Rossarden. Tasmania. Proc. Aus. IMM 181 p. 93-145

Cassiterite andStoreys Creek.1, p. 506-511.

The Emplacement and Geometry of the MineralizedQuartz Veins at Rossarden-Storeys Creek. Unpub.B. Sc. (Hons.) Thesis. Monash Univ.

The geology of the Tin-Tungsten deposits. AberfoyleTas. Dept. Mines Unpub. Rep.

The Geology of the Rossarden-Storeys CreekDist~ict. Geol. Surv. Tas. Bull. 46.

The Petrology and Geochemistry of the BenLomond Granite and Associated Tin-TungstenMin. Unpub. B. Sc. (Hons.) Thesis. Univ.Tas.

The. Mt. Rex Mine.•

grelsenization and mineralization at AnchorTin Mine. NE TaslDlania Trans. Inst. Min. Metall.82 B p. 135-146:

EDWARDS. A.B. & LYON R.J.P. 1957

BLISSETT. A.H. 1959

KEID. a.G.w. 1954

HELLSTEN. K.J. 1979

CLAYTON. W.F. 1981'

GROVES. 0.1. & TAYLOR. R.G. 1973


KINGSBURY. C.J.R. 1965


GROVES. 0.1. 1972


LYON R.J.P. 1957

GROVES. 0.1. 1977;

IIIIIIIIIIIIIIII:1II~I

•

NYE. P.B. 1941

REID. A.M. & HENDERSON Q.J. 1929

SCOTT, J.B. 1929

SCOTT. J.B. 1934

URQUHART. G. 1966

URQUHART. G. 1967

Plummers workings, Rossarden. Tas, Dept. MinesUnpub. Rep.

The Avoca Mineral District. Geol. Surv. Tas.Bull 40.

Mammoth Tin Areas, Storeys Creek. Tas Dept. MinesUnpub. Rep.

Storeys Creek Mine. Tas. Dept. Mines Unpub. Rep.

Notes on the Royal George Tin Mine. Tas. Dept.Mines. Tech. Rep. 11 p. 57 -65.

The Rex Hill Mine. Geol. Surv. Tas. Rep. No.9.

._--_._----~~.,_.-

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