RB 2010/00001 Investigation of partial leach soil surveys at the Tunkillia gold prospect, South Australia.
Published: 01 Nov 2009 Created: 25 Nov 2024 Revised: 27 Nov 2024

Geochemical soil samples were taken along two traverses over shear-hosted gold mineralisation in Area '223' at the Tunkillia gold prospect, located 550 km north-west of Adelaide. The objective was to assess the effectiveness of near-surface soil...

Geochemical soil samples were taken along two traverses over shear-hosted gold mineralisation in Area '223' at the Tunkillia gold prospect, located 550 km north-west of Adelaide. The objective was to assess the effectiveness of near-surface soil sampling for locating mineralisation in areas where the bedrock is deeply weathered and is covered by an aeolian dune field. One sampling traverse lay along the crest of a longitudinal dune that cross-cuts the mineralised zone, while the other lay along the adjacent swale. Samples were collected from 5-25 cm depth, sieved to <200 microns, and gold and other trace element concentrations were determined on partial extracts obtained by leaching using sodium pyrophosphate with cyanide. The partial leach soil analytical preparatory process was chosen so as to increase the proportion of loosely bound ions detectable in the sample that can potentially reflect the presence of underlying mineralisation, as compared to using a process that digests the entire mineral grain, thus acting to dilute the effect of such ions present in the sample. The specific leach chemistry was chosen based on previous work done at this location (Fabris et al., 2009). The cyanide is an effective extractant for gold and silver, and sodium pyrophosphate is regarded as effective at liberating metal ions from organic matter, plus any associated with aluminium oxides and some clays. A hand-held X-ray fluorescence analyser was used to determine iron, calcium and its proxy strontium. Gold assay results for both of the traverses had their highest values over the mineralised zone. Samples from the dune traverse, however, yielded significantly reduced levels of extractable gold, and this produced an Au anomaly-to-background ratio that was much less than for the samples collected along the swale traverse. It is concluded that near-surface soil sampling and partial leach analysis could potentially be a viable and cost-effective geochemical exploration strategy to utilise in the region, provided that regolith, landform and vegetation factors are taken into consideration in determining what are the appropriate background values against which individual sample data will be evaluated.

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About this record

Record No d20010208
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Departmental Publication - Geological Survey Geoscience Publication
Contributor PIRSA Minerals and Energy Resources Div., Geological Survey Branch
Sponsor
Tenement
Tenement Holder
Operator
Geological Province
Mine Name Tunkillia gold deposit;Area 223 orebody
Stratigraphy Tunkillia Suite
Commodity
Notes
Notes: See also related subject matter mentioned in RB 2009/3.
Geographic Locality: Western Gawler Ranges;Tunkillia Rockhole;Yarlbrinda Shear Zone
Doc No: RB 2010/00001

Notes: See also related subject matter mentioned in RB 2009/3. Geographic Locality: Western Gawler Ranges;Tunkillia Rockhole;Yarlbrinda Shear Zone Doc No: RB 2010/00001

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/d20010208
Citation Fabris, A.J. 2009. RB 2010/00001 Investigation of partial leach soil surveys at the Tunkillia gold prospect, South Australia. Departmental Publication - Geological Survey Geoscience Publication. Government of South Australia.
https://pid.sarig.sa.gov.au/document/d20010208

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[134.5,-31.5],[135,-31.5],[135,-31],[134.5,-31],[134.5,-31.5]]]}
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