Western Australia, WA, Australia
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The Mt Cattlin spodumene (lithium)-tantalum mine is located 2 km north of the town of Ravensthorpe, 400 km SE of Perth and 180 km WNW of Esperance in SW Western Australia (#Location: 33° 33' 47"S, 120° 2' 7"E).
Regional Setting and Deposit Geology
The Mt Cattlin deposit is a spodumene-rich, tantalum-bearing, pegmatite within the Ravensthorpe Greenstone Belt. The latter is localised along the boundary between the Youanmi and Southwest terranes of the Archaean Yilgarn Craton, immediately to the north of their common intersection with the east-west Mesoproterozoic Albany-Fraser Orogen along the Southern Ocean coastline.
The Ravensthorpe Greenstone Belt is restricted to the north-closing, south-plunging Beulah Synform. This structure has two limbs, the Carlingup and Cocanarup domains to the east and west respectively, each composed of meta-sedimentary quartzofeldspathic gneiss, schist, iron formations, and ~2.96 Ga felsic and ultramafic volcanic rocks. The core of the synform is occupied by the ~25 km diameter Ravensthorpe Terrane, an oval shaped, low-K, calc-alkaline intrusive/extrusive complex of comparable age to the greenstone limbs. This complex is composed of a coarse, outward fining, intrusive core, the Manyutup Tonalite, flanked on its margins by basaltic, andesitic and dacitic volcaniclastic rocks with minor lavas of the Annabelle Volcanics. To the south, this complex and the two greenstone belt limbs, are overlain by an allochthonous sheet of multiply deformed Mesoproterozoic metasedimentary rocks, the Mount Barren Group, thrust northwards from the Albany-Fraser Orogen. The Annabelle Volcanics are best preserved in the western half of the complex, with only fault-bounded slivers on the eastern limb. The outer contacts of the Annabelle Volcanics appear to be everywhere defined by inwardly dipping thrusts, part of a 2 to 3 km wide, semicircular complex of thrust faults in the outer margin of the Ravensthorpe Terrane. Thrusting has subsequently transported both the Cocanarup Domain and the Manyutup Tonalite/Annabelle Volcanics complex to the NE above the Carlingup domain.
Mineralisation at Mt Cattlin occurs as a 1 to 20 m thick, shallow-dipping to flat-lying tabular pegmatite dyke. This dyke is covers an area of ~1 x 1.5 km, near the axis of the Beulah Synform. It occurs within the complexly thrusted northeastern margin of the Ravensthorpe Terrane, and appears to be controlled by thrust planes. It has a slightly undulose upper surface, which locally subcrops, although the depth to the upper surface is generally 24 to 60 m, deepening to the NE on the margin of the drilled deposit. Locally it splits into two parallel dykes. Swarms of stacked thinner, similarly flat Li-Ta pegmatite dykes have also been encountered in drilling over widths of up to 50 m at depth below the main pegmatite. All of these dykes are hosted within intermediate to mafic volcanic facies of the Annabelle Volcanics, both pyroclastics and lavas, but also passing into the Manyutup Tonalite. The pegmatite dykes and host sequence are cut by ENE and north-south striking, 70 to 100 m thick dolerite and gabbro dykes interpreted to be of Proterozoic age. A subvertical, NNW trending, west block down fault with sinistral displacement, offsets both the pegmatite and dolerite/gabbro dykes, producing gaps in the deposit’s continuity. The weathering profile is shallow, with fresh rock generally being encountered at depths of <20 m.
The pegmatite composition varies vertically and laterally, with three end members being recognised, specifically simple pegmatite, and complex lepidolite and albite-spodumene varieties. The bulk of the deposit is a simple pegmatite. It has a diverse mineralogy, with component minerals that include cleavandite (albite), microcline, perthite, spodumene, muscovite and Iepidolite, with minor tourmaline (schorlite and elbaite), beryl, microlite, columbite-tantalite, sphalerite, amblygonite-montebrasite, triphylite, apatite, spessartine and fluorite. Where the full pegmatite is developed, it may comprise an upper, marginal, muscovite rich pegmatite with low tantalite and high tin values. This gives way to spodumene bearing zones, up to 12 m thick, and locally a central core composed of spodumene, Iepidolite, pink tourmaline, microlite and tantalite. The lower margin is usually thinner than the upper fringe, and comprises spodumene, feldspar and muscovite. Elevated tantalum grades are generally confined to the centre of the pegmatite. The lithium bearing minerals include spodumene [LiAlSi2O6 containing ~8% Li2O], Iepidolite [K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2], amblygonite [LiAl(PO4)F], montebrasite [LiAl(PO4)(OH)] and triphylite [LiFe2+PO4]. Tantalum minerals include columbite-tantalite [Fe2+Nb2O6 - (Fe, Mn)Ta2O6] and microlite [(Na,Ca)2Ta2O6(O,OH,F)].
Reserves and Resources
Published JORC compliant ore reserves and mineral resources are as follows, as at December, 2009 (Grobler et al., 2010):
Proved reserve - 2.683 Mt @ 1.08% LiO2, 135 ppm Ta2O5
Probable reserve - 8.684 Mt @ 1.04% LiO2, 151 ppm Ta2O5
TOTAL reserve - 11.367 Mt @ 1.05% LiO2, 147 ppm Ta2O5
Measured resource - 2.672 Mt @ 1.17% LiO2, 150 ppm Ta2O5
Indicated resource - 9.629 Mt @ 1.09% LiO2, 171 ppm Ta2O5
Inferred resource - 3.575 Mt @ 1.00% LiO2, 145 ppm Ta2O5
TOTAL resource - 15.875 Mt @ 1.08% LiO2, 161 ppm Ta2O5
Mining commenced at Mt Cattlin in March, 2016.
The most recent JORC compliant Mineral Resources released by Galaxy Resources in December, 2016 were:
Measured resource - 2.540 Mt @ 1.20% Li2O, 152 ppm Ta2O5
Indicated resource - 9.534 Mt @ 1.06% Li2O, 170 ppm Ta2O5
Inferred - 4.343 Mt @ 1.07% Li2O, 132 ppm Ta2O5
TOTAL Resource - 16.416 Mt @ 1.08% Li2O, 157 ppm Ta2O5
This description is largely drawn from "Grobler, F., Lorenzen, L, White, D., Blair, A., Lowe, K., Jones, I. and Bradley, T., 2010 - Independent technical review of the assets of Galaxy Resources; Prepared by Snowden Mining Industry Consultants Pty Ltd for Galaxy Resources Limited, 95p."
The most recent source geological information used to prepare this summary was dated: 2010.
Record last updated: 1/8/2017
This description is a summary from published sources, the chief of which are listed below.
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