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Endeavor, Elura |
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New South Wales, NSW, Australia |
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Zn Pb Ag
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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 Endeavor, previously Elura, zinc-lead-silver deposit is located 46 km north of Cobar and 700 km west of Sydney in central New South Wales, Australia (#Location: 31° 9' 42"S, 145° 39' 25"E).
For details of the regional geological and tectonic setting, see the Geological Setting section of the Cobar Mineral Field record.
The ore deposit is hosted by the early Devonian CSA Siltstone of the Amphitheatre Group, towards the northern margin of the Cobar Basin, which is in turn part of the Lachlan Fold Belt in central New South Wales. The Amphitheatre Group is a thick, monotonous sequence of turbiditic mudstone and siltstone, with minor fine grained sandstone beds. The host CSA Siltstone contains local thin tuffaceous beds and overlies crinoidal limestone of the Kopje Formation. The sequence is characterised by a lack of intrusive bodies.
At Elura, the CSA Siltstone is a very dark grey to black, fine grained, finely bedded to laminated siltstone to shale with pale grey siltstone beds and occasional sandy bands. In the mine area the rocks have only undergone mild lower greenschist facies metamorphism.
The host strata are strongly folded and faulted near the orebody. The faults are characterised by quartz breccia zones up to several metres in width with some sulphides and chlorite alteration. Other faults with NNW and NNE trends truncate and intersect the sulphide deposit and define a NNW oriented transpressional high strain corridor characterised by vertical and overall dextral strike-slip movement (Brown et al., 2017).
Unlike the Cu and Cu-Au deposits at Cobar, Elura is not associated with the intensely faulted basin margins. The ore deposit includes one major pipe-like body of mainly massive sulphides that is 100 to 200 m in diameter, with a vertical extent of >800 m. This pipe occurs on the southern extremity of the deposit. It is progressively accompanied to the NNW by five interconnected steeply dipping sulphide lenses and a number of smaller pods offset from the sulphide lenses to the NW of its northern limit. Overall the orebody has a vertical dip and NNW strike over a 700 m horizontal interval. The main sulphide bodies are elliptical in plan, and crosscuts the deformed CSA Siltstone sedimentary sequence at a high angle. The orebodies are terminated at ~1000 m below surface, ~200 m above the contact between the CSA Siltstone and the underlying Kopje Formation. However, that limestone hosts minor, discontinuous 10 to 30 cm thick lenses of zinc-rich mineralisation at or near its upper contact with the CSA Siltstone (Brown et al., 2017).
Adjacent pipe/lenses are linked by massive, vein and stringer mineralisation. At depth the massive sulphides are enshrouded by a sub-vertical envelope of sulphide veining. Each of the pipes has a core of massive, banded, pyrrhotitic sphalerite ore, surrounded by siliceous pyrrhotitic and/or pyritic mineralisation which comprises a dense stockwork of pyrrhotite dominated sulphide veins at the contact between the massive ore and wallrocks.
The original pre-mining 'Identified Mineral Resource' was (Brown et al., 2017) - 45.6 Mt @ 8.4% Zn, 5.5% Pb, 102 g/t Ag; of which 13.5 Mt had been mined by 1996.
The combined proved + probable reserve in 1997 were 20.8 Mt @ 8.3% Zn, 5.2% Pb, 64 g/t Ag.
At June 30, 2007, the resource and reserve figures quoted by CBH Resources were:
Measured + indicated + inferred resources - 27.4 Mt @ 6.5% Zn. 3.7% Pb, 68 g/t Ag, 0.2% Cu,
Proved + probable reserves (included in resources) - 17.9 Mt @ 5.5% Zn. 3.2% Pb, 51 g/t Ag, 0.2% Cu.
The remaining resource at the end of 2016 (Brown et al., 2017) was: 13.4 Mt @ 8.2% Zn, 5.2% Pb, 4 g/t Ag.
The deposit was originally discovered in 1973 by Electrolytic Zinc Ltd and subsequently developed by the same company. Mining commenced in 1983. Through mergers and reorganisation it was owned by North Limited and then Pasminco Limited, before passing to CBH Resources Ltd in 2003. The operation was placed into Care and Maintenance in December 2019 as a result of the depletion of the current known reserve and the time and cost required to obtain access to deeper known resources (CBH Resources ASX Release 13 December, 2019).
The most recent source geological information used to prepare this decription was dated: 2017.
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.
Endeavor
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Brown, R.E., Coffey, J., Hosken, J., Johnston, C. and Lenard, M., 2017 - Cobar district mineral field: in Phillips, G.N., (Ed.), 2017 Australian Ore Deposits, The AusIMM, Melbourne Mono 32, pp. 739-746.
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de Roo J A 1989 - The Elura Ag-Pb-Zn mine, Australia - ore genesis in a slate belt by syndeformational metasomatism along hydrothermal fluid conduits: in Econ. Geol. v84 pp 256-278
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Schmidt B L 1990 - Elura zinc-lead-silver deposit, Cobar: in Hughes FE (Ed.), 1990 Geology of the Mineral Deposits of Australia & Papua New Guinea The AusIMM, Melbourne Mono 14, v2 pp 1329-1336
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Webster A E, Lutherborrow C 1998 - Elura zinc-lead-silver deposit, Cobar: in Berkman D A, Mackenzie D H (Eds), Geology of Australian and Papua New Guinean Mineral Deposits The AusIMM, Melbourne pp 587-592
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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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