Monty is an exciting new Copper deposit, located at the Springfield Project in the Bryah Basin, 10km from DeGrussa.
Monty is a recent VMS discovery, where the maiden Mineral Resource estimate of 1.05Mt @ 9.4% Cu & 1.6g/t Au1 for 99,000t of contained copper and 55,000oz of contained gold has been declared.
The Monty deposit is the first discovery of high-grade massive sulphides outside the known DeGrussa deposits, with the potential for more VMS discoveries across Springfield.
Mineral resource estimate
The JORC Indicated and Inferred Mineral Resource is 1.05 million tonnes grading 9.4% copper and 1.6g/t gold1 and includes a high-grade massive sulphide component of 763,000t grading 12.1% Cu and 2.1g/t Au for 92,000t of contained copper and 52,000 oz of contained gold1. The Mineral Resource is reported by Sandfire as part of the Springfield Joint Venture.
The maiden Monty Mineral Resource is an exceptionally high-grade resource which was delineated within 11 months of its discovery. It is the first deposit to be discovered outside of the DeGrussa VMS complex and, importantly, provides proof-of-concept for the potential of the region to host multiple centres of VMS copper-gold mineralisation.
The geological model and Mineral Resource estimate were based on the data from 82 diamond drill holes completed by contractor DDH1 Drilling. The drilling was completed on a nominal 30m by 40m spacing, which provided sufficient confidence in the model for Sandfire to classify 99% of the calculated resources into the JORC Indicated category, which is available for conversion to Ore Reserve following the completion of appropriate studies.
The maiden Monty Mineral Resource estimate reported by Sandfire is set out below.
Table 1: Monty Mineral Resource – 31 March 2016.
Copper and gold mineralisation at the Monty Deposit is hosted in a sequence of sediments (siltstone, sandstones and conglomerates) and basaltic rocks. Mineralisation occurs in a series of massive sulphide lenses that are interpreted to have been deposited at different stratigraphic levels within the sedimentary package.
The modelled mineralisation at Monty is contained within seven stacked lenses of massive sulphide (see Figure 1) and a Halo mineralisation envelope that encapsulates the massive sulphide mineralisation. Over 87% of the contained metal is within two main lenses.
Sandfire have modelled halo mineralisation, both internal to the main massive sulphide lenses and as an external skin that sits directly adjacent to the high-grade massive sulphides. Based on the available drilling, the highly altered sulphidic halo mineralisation has been interpreted by Sandfire to extend below the limits of the modelled massive sulphide lenses (see Figure 1).
Talisman also notes that two separate zones of high-grade bornite mineralisation have been modelled by Sandfire within the two main massive sulphide lenses. With only four holes intersecting these lenses of high tenor mineralisation, Sandfire have been careful to limit the interpreted extent of this material.
Mineralisation in these bornite-containing zones is of significantly higher tenor than that in the normal (i.e. non-bornite containing) massive sulphide zones.
Further work is required to further understand the potential extent of the bornite mineralisation and determine if there is an opportunity to mine direct shipping ore (DSO).
Figure 1: Monty resource showing all modelled mineralisation.
Monty was first identified by Talisman in June 2011 when the Company intersected a narrow zone of potentially remobilised copper in hole SPD020, which returned 0.3m grading 7.6% copper from 502m. Follow-up drill hole SPD021 also intersected a zone of potentially remobilised copper with 0.5m grading 1.3% copper and 1.0g/t gold from 347.5m.
Following the signing of the farm-in joint venture with Sandfire Resources NL in December 2013 (please refer to the Springfield Joint Venture for more details), Sandfire undertook an extensive data review of the entire Springfield Project, which led to an extensive fixed-loop EM (FLEM) survey and diamond drilling campaign over key targets.
In May 2015, Sandfire completed diamond drill hole TLDD0002A at Monty to test a subtle, late-time EM anomaly at a depth of ~400m. This hole intersected a stratigraphic horizon similar to the exhalative environment seen adjacent to massive sulphides at DeGrussa, as well as trace disseminated chalcopyrite. A strong down-hole EM (DHEM) conductor was identified 15m off-hole at TLDD0002A and follow-up drilling was recommended.
On 25 June 2015, follow-up drill hole TLDD0004A returned assay results of 16.5m grading 18.9% copper and 2.1g/t gold from 409.5m down-hole.
Follow-up drilling along 80 metres along strike from TLDD0004A subsequently encountered additional massive sulphides, with hole TLDD0005 returning a high-grade massive sulphide intersection of 9.2m grading 11.8% Cu and 2.9g/t Au from 417.0m down-hole within a broader mineralised zone of 13.1 metres grading 8.4% Cu and 2.1g/t Au from 416.7m down-hole.
Feasability & Development
TLRC0004 intersected 18m of massive sulphides at a down-hole depth of 108m a further 135m along strike from TLDD0005 on 20 July 2015. The drilling program at Monty expanded and continued, culminating in the maiden Mineral Resource estimate being released on 13 April 2016.
1Information that relates to the Monty JORC 2012 compliant Mineral Resource estimate is information previously published by Sandfire Resources NL (“Sandfire”) and is available on the Sandfire and ASX websites (see announcement “Maiden High-Grade Mineral Resource for Monty VMS Deposit: 99,000t of Copper and 55,000oz of Gold”, dated 13 April 2016 (Sandfire Announcement)). For full details of the Monty Resource estimate, including the Competent Person’s Statement related to the estimation of the Monty Mineral Resource, please refer to the Sandfire Announcement.
Talisman confirms that it is not aware of any new information or data that materially affects the information included in the Sandfire Announcement, and that all material assumptions and technical parameters underpinning the estimates in the Sandfire Announcement continue to apply and have not materially changed and confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original Sandfire Announcement.