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Wiluna Uranium - Centipede, Lake Maitland, Lake Way, Dawson-Hinkler, Millipede, Nowthanna |
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Western Australia, WA, Australia |
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U
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Wiluna Uranium Project includes the Centipede, Lake Way, Lake Maitland, Dawson-Hinkler, Millipede and Nowthanna deposits. The centres of the largest of these, Lake Way and Centipede are ~15 km SE and ~30 km SSE of the town of Wiluna in Central Western Australia, and 65 km NE of the Yeeliree deposit (#Location: 26° 42' 30"N, 120° 20'E and 26° 51'N, 120° 21'E respectively). Dawson-Hinkler and Lake Maitland are is 40 km SSW and 110 km SE of Wiluna respectively.
The regional geology of the Wiluna area comprises Archaean crystalline bedrock, dominated by granite, cut by the eastern margin of the Archaean Norseman-Wiluna greenstone belt, which is characterised by sedimentary and basic volcanic rocks. Granite and gneiss are found to the east. Mineralisation occurs as a series of shallow calcrete-hosted uranium deposits, the largest of which are Centipede and Lake Way. These are associated with the broad palaeochannel deltas that empty into the Lake Way hyper-saline playa, which itself represents the remnants of a major primary palaeo-drainage system of predominantly Tertiary age. Centipede is on the southwestern margin of the NW-SE elongated, 30 x 10 km, Lake Way, while the Lake Way deposit is on the Lake's northern margin (Toro Energy, 2010).
The carnotite mineralisation sits within a wide, shallow, flat lying and relatively continuous horizon that is 2 to 4 m (maximum ~6.5 m) thick, located below alluvial overburden at a depth between 1 and 12 m below the surface, associated with, but not limited to, a thicker zone of calcareous concretions. Uranium mineralisation is associated with calcrete/dolomite, carbonated silty clay and carbonated sand. These occur within a typical fluviatile/deltaic sequence composed of shallow surficial sediments ranging from narrow clay layers to areas of coarse sand and grit with minimal clay that may be up to 40 m thick. These sediments were laid down within the palaeochannel drainage system and follow the ancient channel structures. The present day drainage has eroded the existing channels resulting in a complex, discontinuous ore body. The mineralisation generally occurs at, or in close proximity to the current water table, typically 1 to 2 m below ground level. Mineralisation formed through hydro-geological processes, associated with groundwater interaction in drainage channels and deltas that flow into present day salt lakes (Toro Energy, 2010).
The mineralisation at both Centipede and Lake Way is dominated by carnotite (K2(UO)2(VO4)2.3H2O), a potassium-uranium vanadate mineral, which has been precipitated out of solution and preserved within the lower reaches of tributary palaeochannels following subtle changes in groundwater chemistry and evaporation. It occurs as micro- to crypto-crystalline coatings on bedding and slippage planes, small concentrations within silty clay and clay sequences, and within interstices between sand and silt grains, in fissures and voids within calcrete, dolomitic calcrete, siliceous calcrete and silcrete, and appears to have been precipitated onto any available surface (Toro Energy, 2010).
The Lake Way deposit has irregular outlines within a 4 km diameter area, while Centipede has a horseshoe shape over a similar area.
Published resource estimates (Toro Energy, 2019) at a 200 ppm U3O8 cut-off are:
Centipede and Millipede:
Measured + Indicated + Inferred resource - 19.7 Mt @ 0.553 kg/t U3O8 = 10 886 tonnes of U3O8;
Lake Maitland:
Indicated resource - 22.0 Mt @ 0.545 kg/t U3O8 = 11 975 tonnes of U3O8;
Lake Way:
Indicated resource - 10.3 Mt @ 0.545 kg/t U3O8 = 5580 tonnes of U3O8;
Dawson-Hinkler:
Indicated + Inferred resource - 13.6 Mt @ 0.315 kg/t U3O8 = 4264 tonnes of U3O8;
Nowthanna:
Inferred resource - 13.5 Mt @ 0.399 kg/t U3O8 = 5398 tonnes of U3O8;
TOTAL Resource @ 200 ppm cut-off:
Measured + Indicated + Inferred resource - 79.0 Mt @ 0.482 kg/t U3O8 = 38 102 tonnes of U3O8;
TOTAL Resource @ 500 ppm cut-off:
Measured + Indicated + Inferred resource - 23.0 Mt @ 0.916 kg/t U3O8 = 21 050 tonnes of U3O8;
The most recent source geological information used to prepare this decription was dated: 2012.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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