Data release - as updated : Mount Lyndhurst and Mount Lyndhurst South. Annual reports and joint annual reports to licences' joint expiry/full surrender, for the period 23/2/2006 to 18/10/2015.
Published: 20 Oct 1915 Created: 12 Nov 2024 Revised: 12 Nov 2024

A large area covered by two adjoining tenements that together are centred ~ 50 km north-east of Leigh Creek has been explored for possible buried economic copper oxide and sulphide mineralisation that may be associated with diapirs of the Adelaide...

A large area covered by two adjoining tenements that together are centred ~ 50 km north-east of Leigh Creek has been explored for possible buried economic copper oxide and sulphide mineralisation that may be associated with diapirs of the Adelaide Geosyncline, particularly along their unmapped edges. During the first year of tenure, the grant licensee Copper Strike Ltd performed a literature review of information about known mineral occurrences in the Mount Lyndhurst region, studying the recorded data from abandoned mines and previous drillholes. Limited field work was undertaken to assess some of the larger prospects. Some exploratory drilling was planned, but it could not be done because of the company's inability to secure a suitable drilling rig. A Work Area Clearance Agreement was signed with the Adnyamathanha people. During the second year of the project, work undertaken by incoming licensee Syrah Resources Ltd consisted of the evaluation of two historic copper prospects via detailed, 1:2500 and 1:500 scale geological mapping and rock chip sampling, and later exploratory RC percussion drilling of the White Lead prospect with 7 inclined holes having a total penetration of 582 m. The Stones Claim prospect could not be tested because the Adnyamathanha People would not allow earthmoving and drilling to occur there; Syrah Resources requested further arbitration with respect to its proposed drilling at this prospect. At White Lead, mapping confirmed that prospective shales and siltstones of the Tapley Hill Formation dip 60 - 70 degrees to the south along a strike of approximately 280 degrees. The unit that hosts the main copper-bearing lode is a white-grey shale/siltstone horizon, commonly with a tillite component (glacial pebbles/ dropstones). The majority of the old copper workings (pits and trenches), with visible malachite and chalcocite mineralisation, occur in this shale/ siltstone unit. Up section to the south, the shale/ siltstone unit is overlain by siltstone/ fine-grained sandstone, while down section to the north, footwall sediments consist of a coarse-grained, gritty sandstone which is underlain by structurally chaotic rocks of the Lyndhurst Diapir comprising a mixture of siltstone, sandstone, limestone, dolomite and diorite. Syrah decided to test the White Lead copper mineralisation by drilling relatively close-spaced percussion holes near the main lode, in an area where Adelaide and Wallaroo Fertilisers has earlier recorded the best mineralisation. Five holes were put in at 50 m spacing to test mineralisation along the strike of the lode, and two step-back holes were sited to test for possible mineralisation at depth. The best results were recorded in the central part of the target area, including : WLDH002: 26 m @ 0.87% Cu, including 8 m @ 1.69% Cu WLDH003: 18 m @ 0.91% Cu, including 10 m @ 1.29% Cu WLDH006: 30 m @ 0.80% Cu, including 12 m @ 1.61% Cu. The drill results showed that high grade copper is not restricted to the shale/siltstone horizon that hosts the White Lead main lode, since significant mineralisation is also present in the overlying siltstone unit, which recorded the highest copper grades in drill holes WLDH003 and WLDH006. The copper occurs as the secondary minerals malachite and chalcocite formed in quartz veins, joints and fractures, and appears to be typical of near-surface supergene enrichment. It lies within 40 m of the surface, and is open along strike and, in places, to the south. The two deeper drilholes failed to find significant copper within rocks of the Lyndhurst Diapir, which is located to the north of the lode. However, wide-spaced historic drilling to the west of this area had reported anomalous copper in the diapir rocks, close to the contact with the lode. Because the prospective White Lead mineralised strata have a large number of historical workings and geochemically anomalous copper spread along a strike length of several kilometres, Syrah thought that there is significant scope for identifying extensions to the mineralisation. Therefore, during the third year of the project, it performed further detailed geological mapping of these rocks in July 2008 and undertook a campaign of RAB drilling during August-September 2008 with 60 inclined holes for a total of 2237 m. The RAB holes were positioned on grid lines spaced 100 m apart along the east-west trend of the host strata, and tested an overall strike length of ~3 km to the east and west of the main White Lead workings. It had been intended to drill all these holes down to at least 40 m, but ten of the holes did not reach this depth due to rig equipment problems. However, the aim of the drilling was not compromised, as the total depths of these ten holes were sufficient to provide a satisfactory test of potential copper mineralisation. Based on the results of the RC and RAB drilling, six areas of significant copper mineralisation (named Areas 1 to 6 going from west to east) were defined, and possible non - JORC compliant resources for these areas were calculated using the drillhole data ( as modified by a number of assumptions herein explained at length ). The tonnages were calculated using a cut-off grade of 0.3% Cu, a minimum width of 2.0 m and an SG of 2.2 g/cubic cm (not supported by test work). A potential combined copper resource of ~710,000 tonnes @ 0.75% Cu was calculated ( but it was recognised that the exploration target figure could be considerably higher, given that there is a 100 m spacing between RAB lines, a mineralisation depth of only 20 m had been adopted, and there is scope for additional copper to exist both to the north and south of the areas so far tested ). During the fourth year of the project, with exploration now under the management of Hong Kong - based joint venture earn-in partner Zurich Resources, work undertaken included: - identification of significant copper occurrences from open source literature - purchase and processing of ASTER hyperspectral data - reprocessing of CRAE airborne magnetic and radiometric survey data acquired in the early 1990s - field inspection of known copper occurrences, ASTER and magnetic data features - limited orientation handheld XRF spectrometric stream sediment and soil geochemical sampling and assaying. The remote sensing and geophysical image processing work was done to try to identify hydrothermal alteration zones and bedrock structures or intrusive bodies which could have controlled the loci of mineralisation. The pXRF results suggested that above-background copper concentrations might be reliably detected in the silt to fine sand fraction of detritus recently deposited in active drainage channels. During the fifth year of the project, work undertaken by Zurich Resources included: - trial ground magnetic surveying (basic coverage, no data submitted) - systematic grid-based soil geochemical sampling for - prospect geological mapping at 1:5000 scale - acquisition of induced polarisation and resistivity surveys - 3D inversion and interpretation of IP and ground magnetic data - analysis of orientation alteration mapping ground-truthing spectrometric data obtained by handheld ASD FieldSpec scans of surface samples. The Aster alteration mapping data clearly identified the White Lead and Lynda intrusive complexes in EL 3522 and the Federal – Paulls Consolidated trend in EL 3550 as priority follow-up targets, given the known copper shows in each area and the proximity of both copper and ASTER features to intrusive bodies. After Zurich had conducted limited pXRF spectrochemical sampling of soil, outcrop and stream sediments on these prospects, it decided to prioritise them for defining drill targets in the order 1. White Lead prospect, 2. Lynda- Lorna Doone prospect and 3. Mount Bourne prospect (Federal mine area). A number of substantiated oxide and sulphide targets were identified at the former two prospects by the application of several exploration methods including taking 380 line km of ground magnetic readings at 100 m station spacings, interpreting bedrock geochemistry gained by drilling 351 auger holes at 50 m spacings, collecting 1203 pXRF spectrochemical analyses on 300 m x 100 m prospect grids, and taking dipole-dipole IP readings over 1.7 square km and 6.6 square km grids using 100 m or 120 m station intervals. During the sixth year of the project, to further inform its intrusion-related hydrothermal genetic model for copper sulphide mineralisation in the project area, Zurich Resources acquired separate ground gravity surveys on both of renewed ELs 4790 and 4791 during November and December 2012. 693 stations were read at 250 m x 250 m grid spacing on the Lorna Doone prospect, and 374 stations were read at 500 m x 500 m spacing, closing in to 250 m x 250 m grid spacing, on the Mount Bourne prospect. Very similar gravity lows elongated east-west were outlined at both prospects, probably reflecting bulk densities of the intrusive rocks. No work was done on the project licences during Year 7 because of a reduction in the copper price and through adverse sentiment caused by news received that Phoenix Copper had downgraded the prospectivity of its nearby Leigh Creek copper oxide resource. During the eighth year of the project, having revised its mineral search objectives towards locating more remunerative copper-gold deposits due to a downturn in the exploration industry and attendant difficulties with raising risk funds, Zurich Resources undertook more ground geophysical surveys. A gradient array IP/resistivity survey based on six arrays covering 6.25 square km was acquired during November-December 2013 at the Mount Bourne prospect, and a detailed ground gravity survey of 1500 stations covering a 3.5 km x 4.0 km area there was read at 500 m x 500 m station spacing, infilled to 100 m x 100 m station spacing, also during November-December 2013. The gravity results appeared to clearly define sedimentary units and faulting within them, but the progress of the survey was cancelled halfway, due to lack of funds, before its coverage could extend further eastwards and cross over inferred intrusion - related targets. During Year 9, Zurich Resources informed Syrah Resources (Syrah) of its intention to withdraw from the joint venture, several months before the tenements were due to expire. A review conducted by Syrah of all the data collected by Zurich and of compiled historic exploration results then led to Syrah deciding to fully surrender both licences because of a perceived lack of shallow, viable drilling targets.

More +

About this record

Record No mesac26017
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Mineral Company Report - Mineral Exploration
Contributor Khumsup Pty Ltd
Sponsor Zurich Resources Pty Ltd
Tenement
Tenement Holder Copper Strike Ltd;Syrah Resources Limited
Operator Copper Strike Ltd;Syrah Resources Limited;Zurich Resources Pty Ltd
Geological Province Adelaide Geosyncline
Mine Name Liberation mine;Federal mine;Paulls Consolidated mines;Stones claim;Mount Burr mine;Mallee mine;Fielders claim;Red Oxide prospect;Mount Ogilvie prospect;White Lead prospect;Lorna Doone prospect;Mount Bourne prospect
Stratigraphy
Commodity copper
Notes
Notes: This release to the public of the subject mineral exploration data, namely, company data which was acquired more than 5 years ago, is being done by DSD in accord with the provisions of Section 77D of the Mining Act 1971 and Regulation 88 of...

Notes: This release to the public of the subject mineral exploration data, namely, company data which was acquired more than 5 years ago, is being done by DSD in accord with the provisions of Section 77D of the Mining Act 1971 and Regulation 88 of the Mining Regulations 2011. During September 2007, full ownership of the two subject tenements was transferred from Copper Strike Ltd to Syrah Resources Ltd, with the formal transfer of licence interests, rights and obligations being finalised on 6/2/2008. Farminee Zurich Resources Pty Ltd signed a Joint Venture Agreement (JVA) with Syrah Resources Ltd (Syrah) on 21/12/2009, that allows it to earn up to an 80% interest in EL 3522. Another JVA it made with Syrah on 2/2/2010 allows it also to earn up to an 80% interest in EL 3550. Geographic Locality: Northern Flinders Ranges;Mount Lyndhurst Station;Mount Lyndhurst Diapir;Mount Burr Diapir;Mundy Fault;2012 Lorna Doone Gravity Survey;2012 Mount Bourne Gravity Survey;2013 Lyndhurst Project Gradient Array IP / Resistivity Survey;2013 Lyndhurst Project Gravity Survey Doc No: Env 11549 Drillhole: WLDH001 - WLDH007;(291558 - 291564);RB001 - RB060;(291498 - 291557) Drillhole Unit No: 6637 00321

More +

Language English
Metadata Standard ISO 19115-3

Citations

Use constraints License
License Creative Commons Attribution 4.0
Persistent identifier https://pid.sarig.sa.gov.au/document/mesac26017
Citation Lees, T.;Eadie, E.M.;McLellan, A.C.;Louwrens, D.J.;Cameron, I.;Dagang, J.C.T. 1915. Data release - as updated : Mount Lyndhurst and Mount Lyndhurst South. Annual reports and joint annual reports to licences' joint expiry/full surrender, for the period 23/2/2006 to 18/10/2015. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac26017

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[138.5,-30.5],[139,-30.5],[139,-30],[138.5,-30],[138.5,-30.5]]]}
Purpose

                    
                    

                    
                  
Lineage