AIG WA Branch BASE METALS not precious but vital. Overview of Dugald River geology Monday 20 th June 2011

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1 AIG WA Branch BASE METALS not precious but vital Overview of Dugald River geology Monday 20 th June 2011

2 REGIONAL GEOLOGICAL SETTING WONGA BELT MARY KATHLEEN ZONE Dugald River Withnall 2008

3 REGIONAL GEOLOGICAL SETTING TIME-SPACE DIAGRAM Current position of the Dugald River sequence Historic position of the Dugald River sequence Withnall 2008

4 LOCAL GEOLOGY Coocerina Fm Knapdale Quartzite Dugald River Slate Sequence

5 LOCAL GEOLOGY IDEALISED CROSS SECTION Coocerina Fm Knapdale Quartzite Dugald River Slate Sequence Mt Rosebee fault Sequence youngs west Sequence overturned youngs east Lady Clayre Dolomite Cu mineralisation Carbonate-banded slate Zn-Pb-Ag mineralisation Massive black slate Silica-flooded structures Porphyroblastic muscovite schist Mafic porphyry Biotite-epidote schists Knapdale feldsarenite

LOCAL GEOLOGY DUGALD RIVER STRATIGRAPHY Lithology Mafic Porphyry

5mm Description Coarse grained, dark grey-green to blackish-green

Massive, dark grey, sulphidic, carbonaceous impure limestone (dolomite).

5mm Finely laminated, generally fine grained dark to mid grey,

5mm Massive, fine to medium grained dark grey carbonaceous, carbonate

5mm Medium grained, rather strongly foliated and crenulated

5mm Fine grained, weakly laminated dark grey graphitic/carbonaceous

Ca-Banded Biotite Schist 250µm Massive to weakly foliated and layered,

ragged pale pink garnet schist. Slate 0.

psammopelite/metasiltstone, representing a former slightly carbonaceous

6 LOCAL GEOLOGY DUGALD RIVER STRATIGRAPHY Lithology Mafic Porphyry Dolomite Hand Sample Thin Section 0.5mm Description Coarse grained, dark grey-green to blackish-green hornblende gabbro. Williams-Naraku Intrusive. Massive, dark grey, sulphidic, carbonaceous impure limestone (dolomite). Lady Clayre Dolomite. Grey-Banded Slate 0.5mm Finely laminated, generally fine grained dark to mid grey, carbonaceous slate. Upper Ca- Banded Slate 0.5mm Massive, fine to medium grained dark grey carbonaceous, carbonate banded dolomitic slate. Mica Schist 0.5mm Medium grained, rather strongly foliated and crenulated quartzmuscovite-biotite-garnet schist. Lower Ca- Banded Slate 0.5mm Fine grained, weakly laminated dark grey graphitic/carbonaceous sulphide bearing dolomitic slate. Ca-Banded Biotite Schist 250µm Massive to weakly foliated and layered, fine to medium grained, granular texture, grey biotite and scattered ragged pale pink garnet schist. Slate 0.5mm Dark grey, fine grained, weakly to moderately foliated psammopelite/metasiltstone, representing a former slightly carbonaceous and sulphidic siltstone. Biotite Schist 125µm Massive to weakly foliated and layered, fine to medium grained, granular texture, grey biotite and scattered ragged pale pink garnet schist. Quartzite 0.5mm Fine to medium grained, pale grey-pink, massive to faintly laminated, thoroughly recrystallised carbonate (dolomite) bearing feldsarenite. 0.5mm

LOCAL GEOLOGY PASSIVE MARGIN? Halite Pseudomorphs (scapolite) Playa lake sabkha setting KN01 523.

7 LOCAL GEOLOGY PASSIVE MARGIN? Halite Pseudomorphs (scapolite) Playa lake sabkha setting KN m NQ3 Clastic marginal facies Fluvial braided streams and alluvial fans at basin edge with sandy aprons. Planar, cross-strat and wavy laminated sands with carbonate cement Knapdale feldsarenite Emergent mud flat facies Transitional wet mudflats, with disrupted laminated horizons Lower biotite schist Flooding deposits mud units. Bacterial reduction of sulphate = H 2 S + iron sulphides Slate The ponded brines precipitate halite Carbonate-banded biotite-scapolite schist Basin inundated with large volumes of clastic material during prolonged wet seasons Mica schist Carbonate layers from emergent mudflats, precipitation from lake water, evaporation, algal mats Carbonate-banded dolomitic slate Submergent lake facies Pyritic limestone represents the byproduct of subaqueous sulphate reduction in the deepest part of the basin Lady Clayre Dolomite Lack of volcanic units within the sequence suggests rifting did not proceed all the way to sea floor spreading passive margin

8 DUGALD RIVER ZN OUTCROP Dugald gossan depleted in Zn, enriched in lead and silver. Cerussite, Plumbojarosite, Smithsonite, Mn-oxides, Goethite Outcrop looking north Geobotanical Anomaly 2.96% Zn, 4.69% Pb, Ag from 0m Massive sulphide Gossan Plumbojarosite + Goethite Gossan Outcrop Zinc Weed - Polyarpia spp.

75% Zn, 11% Pb, 410ppm Ag from 246m #81001 1m @ 18.

95% Zn, 10.65% Pb, 435ppm Ag from 248m #81003 1m @ 16.

55% Pb, 484ppm Ag from 249m #81004 1m @ 18% Zn, 11.

9 DRILL CORE # % Zn, 5.98% Pb, 257ppm Ag from 245m # % Zn, 11% Pb, 410ppm Ag from 246m # % Zn, 11.7% Pb, 450ppm Ag from 247m # % Zn, 10.65% Pb, 435ppm Ag from 248m # % Zn, 10.55% Pb, 484ppm Ag from 249m # % Zn, 11.25% Pb, 462ppm Ag from 250m # % Zn, 1.27% Pb, 103ppm Ag from 251m DR % Zn, 4.72 Pb, ppm Ag from 200m

MINERALISATION Host N-NW striking, sinistral oblique-slip shear zone within subparallel Dugald slate sequence. Mineralisation contemporaneous with the Mt Roseby Schist.

Mineralisation Style Dominated by sphalerite, galena with gangue of graphitic slate, pyrrhotite and pyrite.

10 MINERALISATION Host N-NW striking, sinistral oblique-slip shear zone within subparallel Dugald slate sequence. Mineralisation contemporaneous with the Mt Roseby Schist. Syn-tectonic upgraded and remobilised clastic-dominated or sedimentary-hosted lead-zinc deposit (CD Pb-Zn Leach et al 2010). Mineralisation Style Dominated by sphalerite, galena with gangue of graphitic slate, pyrrhotite and pyrite. Texture dependent on deformation and po-py content; Sulphide dominated sulphide-matrix breccia Slate dominated sulphide-matrix breccia Banded Sulphide Mineralisation confined to the main lode and lesser western lenses Alteration Carbonate depleted, silica-sericite altered, dolomitic slates with peripheral carbonate and pyrrhotite-pyrite veining/halo. Footwall garnet alteration. Manganese Deleterious Manganese occurs within sphalerite lattice, alabandite, and to a lesser extent garnet.

re-crystallised to High-Fe Disseminated Low-Fe Sphalerite

11 MINERALISATION Re-crystallised banded syngenetic mineralisation DR m Downhole Disseminated Low-Fe re-crystallised to High-Fe Disseminated Low-Fe Sphalerite and Pyrite DR m Downhole Crustiform Low-Fe Sphalerite and Pyrite

CROSS SECTION Thick HW shear zone & FW silicification at structural inflections with pinched-out lode Strong Ba anomaly between lenses Pyrrhotite rich dropper or Trouser leg concordant with massive

12 CROSS SECTION Thick HW shear zone & FW silicification at structural inflections with pinched-out lode Strong Ba anomaly between lenses Pyrrhotite rich dropper or Trouser leg concordant with massive dolomite horizon Upper section of lode highly sheared & deformed with streaky sphalerite in cleavage Zn:Mn is > 10:1 Ag:Sb is > 3:1 < 1% Mn < 1% Pb Lower section of lode relatively undeformed massive breccia with remobilised sulphides Zn:Mn is < 10:1 Ag:Sb is < 3:1 > 1% Mn > 1% Pb

MINERALISATION STYLES DLMB Massive Breccia DLMS Massive Sphalerite

Pyrrhotite Slatey Breccia Mixed sphalerite-pyrrhotite matrix supported

quartz clasts Sphalerite-rich matrix supported milled breccia, massive

Pyrrhotite-rich matrix supported milled breccia, massive fine grained

undifferentiated, clast to matrix supported breccia with angular slate

13 MINERALISATION STYLES DLMB Massive Breccia DLMS Massive Sphalerite Breccia DLMP Massive Pyrrhotite Breccia DLSB Slatey Breccia DLPB Pyrrhotite Slatey Breccia Mixed sphalerite-pyrrhotite matrix supported milled breccia, massive fine grained sulphide matrix, rounded slate and quartz clasts Sphalerite-rich matrix supported milled breccia, massive fine grained sulphide matrix, Sp>Po, rounded slate and quartz clasts Pyrrhotite-rich matrix supported milled breccia, massive fine grained sulphide matrix, Po>Sp, rounded slate and quartz clasts Slatey breccia, undifferentiated, clast to matrix supported breccia with angular slate clasts in sulphide matrix Pyrrhotite-rich slatey breccia Slate clasts in sulphide matrix

MINERALISATION STYLES DLBD Banded Banded Ore.

bands, rare fine pyritic slate lenses DLSS Sulphide

sulphide bands and cross cutting sulphide stringers

alteration zones and mineralized quartz veins DLCB

14 MINERALISATION STYLES DLBD Banded Banded Ore. Slate with sphalerite pyrrhotite, galena and pyrite bands, rare fine pyritic slate lenses DLSS Sulphide Stringer Sulphide stringers, Black slate with sulphide bands and cross cutting sulphide stringers DLQZ Siliceous Mineralisation Siliceous mineralized alteration zones and mineralized quartz veins DLCB Carbonate Mineralisation Carbonate replaced mineralized zones

RESOURCE June 2010 Resource at a 6% Zinc Cut-off Classification Mt Zn Pb Ag Fe Mn (%) (%) (g/t) (%) (%) Measured 20.6 13.

15 RESOURCE June 2010 Resource at a 6% Zinc Cut-off Classification Mt Zn Pb Ag Fe Mn (%) (%) (g/t) (%) (%) Measured Indicated Inferred Total

16 CAMP

17 CAMP

MINING BASICS Mining 2Mt per year for 23yr mine life 39Mt Reserve, 43Mt Mining inventory First zinc concentrate production in 2014 Twin declines South Mine (1.

18 MINING BASICS Mining 2Mt per year for 23yr mine life 39Mt Reserve, 43Mt Mining inventory First zinc concentrate production in 2014 Twin declines South Mine (1.6Mtpa production) predominantly long hole open stoping with footwall drive to access draw points North Mine (0.6Mtpa production) using bench stoping Levels spaced at 25m Rock fill, Paste fill and open stoping will be used Metallurgy Coarse primary grind of 60µm followed by a carbon pre float Lead flotation with rougher/scavenger regrind and zinc flotation with a scavenger regrind (12 µm) Zinc recovery of 86%, Lead 68% and Silver 70%

mapping along Dugald River fault zone 1:2,000 Infill resource definition 25m x 25m

19 CURRENT WORK Grouting program of historic drill holes Continued exploration and resource extension Regional RAB program Regional mapping 1:5,000 Detailed mapping along Dugald River fault zone 1:2,000 Infill resource definition 25m x 25m surface and underground Exploration decline and ore drives Honours research projects

20 DUGALD RIVER THANKS

it AUSIMM COBAR MINING SEMINAR

Straits Resources Limited it AUSIMM COBAR MINING SEMINAR Brownfields Exploration at Girilambone: Understanding the Mineralised Systems August 2010 Phil Shields / Phil Jones LOCATION TRITTON OPERATIONS