Data release [made at SA Director of Mines' discretion] : Eucla Basin Project tenement Group 1. Joint annual reports, for the period 1/1/2016 to 31/12/2018. Plus EL 6369 surrender.
Published: 28 Feb 1919 Created: 12 Nov 2024 Revised: 12 Nov 2024

27 contiguous licence areas within the eastern Eucla Basin, that span a combined 21,772 square km of ground between points as far as 90 km north of the Trans Australian Railway, 50 km east of Nullarbor and extending right down to the coastline,...

27 contiguous licence areas within the eastern Eucla Basin, that span a combined 21,772 square km of ground between points as far as 90 km north of the Trans Australian Railway, 50 km east of Nullarbor and extending right down to the coastline, and continuing further south-eastwards to as close as 20 km north of Ceduna, have been given joint reporting status in conjunction with meeting amalgamated expenditure and relinquishment requirements. 17 of the licences are subject to a farm-in agreement that Iluka signed with Doray Minerals Ltd in November 2014 to allow the latter to undertake gold exploration plus searching for hard rock metalliferous mineralisation. During the first, 2016 joint reporting year, Iluka's New Commodities team conducted ground geophysical surveys, aircore drilling, and passive seismic studies. Over the period March to June 2016, 63.15 line km of ground-based moving loop transient EM (MLTEM) surveying were performed for Iluka along 65 traverses over two potential magmatic copper-nickel prospects located within the Fowler Domain, with readings taken at 696 stations. A further 3.2 line km of fixed loop (FL)TEM survey were read at one of these prospects along four traverses (66 stations). In March-April 2016, 77 vertical aircore holes for a total of 3551.5 m were drilled within the northern part of the Fowler Domain on ELs 5417, 5564 and 5878 to identify and test the mineral potential of inferred mafic and ultramafic basement igneous intrusive rocks at six copper-nickel targets. Interpreted geological maps for the drilled prospects are presented, in addition to the basic data collected. Doray Minerals separately undertook a campaign of bedrock aircore drilling during April to June 2016 (143 vertical holes for a total penetration of 12,564.5 m) to investigate Target C, a previously discovered regolith surface gold anomaly spanning parts of ELs 5539 and 5685, and later on, for the entire set of holes, they laboratory assayed 8500 x 1-metre hole depth interval composited downhole samples. The aim was to define any regolith unit - dependent chemostratigraphy that might improve the understanding of complex regolith geochemical behaviour, particularly gold pathfinder trace element mobility and dispersion properties in places with known deformation of the underlying bedrock (i.e. the Oolabinna Shear Zone, which has a similar timing to the gold-mineralised Yarlbrinda Shear Zone). Most of the drilling took place on a 2 km x 400 m hole spacing, forming a grid within the bounds of a buried granite intrusion that is deformed by later faulting going through it. For meeting a further aim of gathering contrasting geochemical data from other, as yet unexplored areas, a connected single 23 km long regional drill traverse was made with holes 400 m apart to test the regolith environment above three major basement geological domains, the Fowler, Wilgena and Nuyts, as well as above the deformed traces of three intervening shear zones, the Oolabinnia, Coorabie and Yerba Shear Zones. On behalf of Iluka, a duplicate set of drill cuttings samples was also collected from within the transported sands section in holes WGAC0104 through WGAC168, for the purpose of mineral sands exploration. No reliable method for empirically determining the dispersive behaviour through regolith of gold and its pathfinders has emerged from the company performing a detailed multivariate analysis of the drillhole geochemical data, which were treated as logical groupings defined by their spatial association with seven typical different weathering intensity sections of the regolith sequence. But from doing this work, it seems clear that the ancient groundwater pH and salinity variations and changing flow patterns existing through time within the regolith would have exerted a powerful control on individual element mobility, once a particular element left the fresh basement rock. So understanding the influence of past groundwater regimes appears to be key to unravelling gold and pathfinder dispersion history. This conclusion notwithstanding, a close comparison that was made of the stacked distributions of the dominant dispersing elements, having identities arrived at through principal component analysis and factor analysis done on each regolith section, indicated to Doray Minerals that there could be potential to have gold mineralisation occurring in the deformed geological domain contact belts surrounding the Coorabie Shear Zone, as well as adjacent to interpreted fault zones within the granite intrusion. It is expected that splays off the shear zone are most likely to be the mineralised parts within the deformation belts. However, preferential pointers to the type of mineralisation that could occur were not readily obvious in the pathfinder element data. Doray has chosen to present herein its analysis and interpretation of most of the accepted geochemical pathfinders that are identified with orogenic gold deposits, and to discuss the possible scenarios for the dispersive evolution of these elements in the regolith. During the second licence year, Doray Mineral Ltd withdrew from the joint venture with Iluka. Work completed by Iluka during the period included a desktop review, Amalgamated Expenditure Agreement planning, survey preparation and rehabilitation. During Year 3 of the Eucla Basin Project, Iluka undertook 3 drilling projects on Nundroo, Gobi and JA West prospects. A total of 172 RC Aircore holes for 8221 m were drilled. Heritage surveys were also completed for the drilling project areas. The Nundroo program targets included a Pleistocene marine incursion which has deposited sands in an embayment into the Paleogene Eucla Basin; and possible HM accumulations at an interpreted T-Max position (sea cliff confinement). Drilling at the Gobi Project consisted of 3 traverses orientated to maximise the likelihood of intersecting a postulated mineralised horizon. The JA West exploration rationale postulated that HM deposits are formed in a Jacinth-Ambrosia HM resource setting westward of the Jacinth-Ambrosia HM district, at times of lower sea-level in a location; and the HM accumulations were buried beneath younger cover that includes substantial thicknesses of indurated limestone. The Nundroo drilling determined that there was no prospectivity for HM within these tenements. The Gobi drilling intersected significant mineralisation along the northern-most traverse and confirmed potential continuation of shoreline between Kalahari and Gobi over a possible strike length of 20 km. The JA West drilling intersected mineralisation in a low-grade band on-lapping a gentle basement rise approximately 1,200 m wide. In July 2018, Iluka Resources entered into a Farm-in and Joint Venture Agreement with Western Areas Limited to explore for precious metals in the area comprised of ELs 5452, 5675, 5878, 5879 and 6251, collectively known as the WSA FiJVA Tenements. Work undertaken by Western Areas during the reporting period includes multi-element assaying of basement samples (58) collected by Iluka during previous drilling. Western Areas have completed XRF analysis and multi-element assaying of basement samples and are preparing for upcoming field programs for 2019.

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About this record

Record No mesac29768
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Mineral Company Report - Mineral Exploration
Contributor Gap Geophysics Australia Pty Ltd;Southern Geoscience Consultants Pty Ltd
Sponsor Iluka Resources Limited
Tenement
Tenement Holder Iluka (Eucla Basin) Pty Ltd;Doray Minerals Ltd
Operator Iluka Resources Limited;Doray Minerals Ltd
Geological Province
Mine Name Woodford prospect;Firefly prospect
Stratigraphy
Commodity
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 DMITRE in accord with the provisions of Section 15AL of the South Australia Mining Act 1971,...

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 DMITRE in accord with the provisions of Section 15AL of the South Australia Mining Act 1971, and Regulation 17 of the South Australia Mining Regulations 2020. Includes: Klein, R. February 2017. Annual technical report Eucla Basin/Maralinga Project Iluka Farm-In Agreement. Doray Minerals Ltd. Appx. 3 to annual technical report to 31st December 2016. Pg. 230-274. Geographic Locality: Ooldea Range;Barton Range;Yumbarra Conservation Park;2016 Fowler Project MLEM/FLEM Surveys Doc No: Env 12983 Drillhole: FOW0237AC - FOW0313AC;(335891 - 335903);(375227 - 375290);WGAC0104 - WGAC0246;(293720 - 293862)

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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/mesac29768
Citation Lockheed, A.;Lowndes, R.;Parker, C.;Mortimer, R.;Klein, R.;Reynolds, T.;Maycock, S.;Taylor, M. 1919. Data release [made at SA Director of Mines' discretion] : Eucla Basin Project tenement Group 1. Joint annual reports, for the period 1/1/2016 to 31/12/2018. Plus EL 6369 surrender. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac29768

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[132,-32],[133.5,-32],[133.5,-30.5],[132,-30.5],[132,-32]]]}
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