Thursday’s Gossan Resource
Thursday’s Gossan Resource
Thursday’s Gossan Chalcocite Blanket has an estimated (using a 0.2% Cu grade lower cut-off) – 28Mt at 0.4% copper for a contained 110kt of contained copper 1. The resource is a near surface secondary chalcocite enriched blanket over a porphyry copper deposit. Thursday’s Gossan copper mineralisation was discovered in the 1970s with a small gossan at surface located just north of a railway cutting.
In August 2015 the annual review of the Thursday’s Gossan Mineral Resources was undertaken. While drilling was conducted during the 2015 financial year in the area, targeting well-developed primary porphyry copper-gold mineralisation at depth, no drilling was completed in the area of the existing secondary-enriched copper mineralisation. Consequently, the Mineral Resources at Thursday’s Gossan were reviewed in the context of the assumptions underpinning the 2013 Mineral Resources estimate. This review concluded that: “The Thursday Gossan Chalcocite Copper Inferred Resource Estimate, August 2015, remains unchanged from the Thursday Gossan Chalcocite Copper Inferred Resource Estimate, August 2013. There has been no additional data collected from the deposit and although economic circumstances affecting the mining industry have changed since 2013 the assumptions utilised in 2013 remain valid, if not for the current situation but for future situations.“
The Thursday’s Gossan Chalcocite deposit (TGC) is more appropriately a supergene enrichment of primary porphyry-style copper mineralisation. Mineralisation is characterised by chalcopyrite, covellite and chalcocite copper sulphide mineralisation within a sericite, illite and kaolin clay alteration assemblage. Copper mineralisation is within a flat lying enriched ‘blanket’ of overall dimensions of 4 kilometres north-south by up to 1.5 kilometres east-west by up to 60 metres thick with an average thickness of approximately 20 metres commencing at an average depth below surface of approximately 30 metres. The majority (circa 60%) of the Mineral Resources reside within a higher grade zone of approximate dimensions of 1 kilometre x 300 metres by 35 metres thick.
Reporting of Thursday’s Gossan Chalcocite Copper Resource against criteria in Table 1 JORC Code 2012
The Thursday Gossan Chalcocite Copper Inferred Resource Estimate, August 2015, remains unchanged from the Thursday Gossan Chalcocite Copper Inferred Resource Estimate, August 2013. There has been no additional data collected from the deposit and although economic circumstances affecting the mining industry have changed since 2013 the assumptions utilised in 2013 remain valid, if not for the current situation but for future situations. Stavely Minerals have advised that tenure over the Thursday Gossan Chalcocite deposit is in good standing and that there are no impediments to undertaking further evaluation of the deposit.
Details of the 2013 resource estimate have been reported in “Thursday Gossan Copper, Victoria, Australia, 2013 Resource Estimate Report” prepared for Northern Platinum Pty Ltd, a forerunner for Stavely Minerals Limited who now hold tenure over the project area. The following summary of the 2013 Inferred Resource Estimate applies to the 2015 resources publically stated by Stavely and is repeated here unchanged to support their statement. The reader can substitute 2015 for 2013 and Stavely Minerals for Northern Platinum in the text on the following pages.
The Thursday’s Gossan Chalcocite Copper August 2013 Inferred Resource Estimate is an inverse distance squared Cu estimate of the tabular sub-horizontal supergene style mineralisation of the deposit and is tabulated below. The estimate was undertaken, classified and reported according to the guidelines set out in The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserve (the JORC Code, 2012 Edition).
The Thursday’s Gossan Chalcocite Copper August 2013 Inferred Resource Estimate:
Table shows rounded estimates. This rounding may cause apparent computational discrepancies. Significant figures do not imply precision. Nominal copper grade reporting cuts applied. Three mineralised thicknesses reported as varied economic factors are likely to be applicable to each.
- Is based on historic drilling data of unknown reliability and quality however there are no obvious reasons to question that the holes were drilled to test a flat lying supergene copper deposit.
- Extends intermittently for a strike length of 4000m (NS) a breadth of 1500m and vertically up to 60m thick. The model includes prospects known as Thursday Gossan Chalcocite Copper, Junction and Drysdale.
- Is underpinned by 2355 Cu assays from 225 holes (1493 nominal 3m composites). Cu grades were interpolated without any cuts or restrictions. A tonnage factor of 2.10g/cc was applied to all mineralised blocks.
- Reconciles well both statistically and spatially with the source assay data.
- Was undertaken by Duncan Hackman who is a member of the Australian Institute of Geoscientists and has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity undertaken to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (The JORC Code, 2012 Edition).
Click to view the Thursday’s Gossan JORC 2012 Table 1, Sections 1, 2 and 3 criteria.