Tennant Identifies Stand-Out Geophysical Targets to Replicate the High-Grade Bluebird Copper-Gold Discovery
Priority targets with even stronger geophysical signatures than Bluebird, including Perseverance with previous shallow drilling results of up to 50 g/t gold2
- Imaging and modelling of the detailed drone magnetics data recently-flown over the Barkly (Bluebird) Project at Tennant Creek has been combined with detailed gravity modelling to define 12 stand-out copper-gold targets in the 2km priority Bluebird-Perseverance Target Zone, within the greater 5km strike-length Bluebird Corridor.
- Several of the new coincident magnetic-gravity targets have even stronger geophysical signatures than the Bluebird discovery, which has produced spectacular copper-gold drilling results including:
63.0m @ 2.1 % Cu and 4.6 g/t Au from 153.0m (down hole) in BBDD00121- including 27.55m @ 3.6 % Cu and 10.0 g/t Au from 160.45m
- including 7.0m @ 1.4 % Cu and 38.5 g/t Au from 181.0m.
- Significantly, the largest coincident magnetic-gravity feature is centred on the shallow Perseverance gold workings, 1.5km along strike from Bluebird, where previous bonanza drill-intersections of 3m @ 50.0 g/t Au2 and 3m @ 43.2 g/t Au2 are interpreted to sit above the modelled magnetic/gravity high. This may represent a major copper-gold system at depth.
- Tennant will immediately follow-up the latest results with an induced polarisation (IP) survey over Bluebird to detect and explain the signature of the copper-gold sulphide mineralisation. This will assist IP-testing of the other targets to prioritise for RC/diamond drill-testing.
Tennant Minerals Chairman Matthew Driscoll commented: “The stand-out targets generated from the new magnetics and gravity modelling have further increased our confidence that Bluebird will prove to be the first of a series of high-grade copper-gold discoveries along the 5km Bluebird Corridor.
“We are particularly excited that the largest coincident magnetic-gravity feature was identified beneath the shallow gold workings at Perseverance, which produced bonanza gold grades of up to 50g/t from previous drilling. Indeed, Perseverance is one of several targets with substantially stronger geophysical signatures than Bluebird, which recently produced a stellar drill hit of 63 metres grading 2.1% copper and 4.6 g/t gold.
“The next step is to complete our IP survey to help prioritise the new targets, after which we’ll crank up the drill-rigs again and test our belief that Bluebird is just part of a major new high-grade copper-gold system at Tennant Creek.”
Northern Territory focused copper-gold explorer, Tennant Minerals Limited (ASX:TMS), is pleased to announce that the Company has completed imaging and inversion modelling of its new drone magnetics.
When combined with detailed gravity models, interpretation of the new magnetics has identified 12 coincident magnetic-gravity copper-gold targets within a 2km “Bluebird-Perseverance Target Zone” extending west of the high-grade Bluebird copper-gold discovery1. This major target zone includes an exceptionally strong magnetic-gravity feature centred below the Perseverance gold workings where previous shallow drilling produced bonanza gold grades of up to 50 g/t Au2 (see drone magnetics imagery, Figure 1 and gravity imagery, Figure 2 below - with interpreted structures and targets. Figure 3 shows the combined drone magnetics and gravity inversion models).
Figure 1: Bluebird-Perseverance magnetic intensity (reversed) image, with structures & magnetic-gravity targets
Figure 2: Bluebird-Perseverance bouger gravity image, with interpreted structures & magnetic-gravity targets
Bluebird sits within Tennant Mineral’s Barkly Project in the Tennant Creek Mineral Field (TCMF). The TCMF produced more than 5Moz of gold and 500kt of copper between 1934 to 20053 (see location, Figure 4).
Then Bluebird discovery recently produced spectacular high-grade copper-gold intersections including 63m @ 2.1 % Cu and 4.6 g/t Au from 153.0m including 27.55m @ 3.6 % Cu and 10.0 g/t Au in BBDD00121 (see longitudinal projection, Figure 5 and cross sections, Figure 6 and Figure 7).
The intersection of high-grade copper and gold at Bluebird highlights the Project’s potential to host deposits similar to other previously mined ore-bodies in the Tennant Creek Mineral Field such as the Peko deposit, which produced 3.7Mt @ 4% Cu and 3.5 g/t Au from 1934 and 19813, and Nobles Nob, which produced 2Mt @ 17.3 g/t Au from 1947 to 19863. Peko and Nobles Nob are both located within 20km of Bluebird in identical geological settings (Figure 4).
Modelling of detailed gravity survey data indicates Bluebird is associated with a gravity high, that is part of a 5km strike-length gravity anomaly (“Bluebird Corridor”1). The gravity high indicates widespread iron enrichment, which is associated with the major copper-gold deposits in the Tennant Creek Mineral Field (Figure 4).
Within the Bluebird Corridor a deep-seated, west-southwest trending gravity high has been modelled, extending for 2km and linking the Bluebird deposit with a large gravity feature identified below the historic Perseverance gold workings (Figure 2).
Previous ground magnetics indicated that Bluebird is associated with a discrete, reverse-polarised magnetic anomaly. The relatively poor-quality ground magnetics data was not obtained over the Perseverance area.
The new, high-resolution, drone magnetics survey data that has now been (reverse) imaged and modelled has highlighted a west-southwest trending magnetic high (see Figure 1) interpreted to represent a mineralised fault zone associated with the high-grade copper-gold mineralisation intersected at Bluebird1,4.
Multiple other magnetised fault structures continue west-southwest to intersect the Perseverance target, 2km west of Bluebird, where the largest coincident magnetic-gravity feature occurs. The strong reverse-polarised magnetic anomaly at Perseverance is coincident with the deep-seated gravity high that links with Bluebird, defining the 2km strike-length Bluebird-Perseverance Target Zone (see combined magnetics-gravity inversion models, Figure 3 below).
Figure 3: Combined drone magnetics and gravity inversion models showing Bluebird-Perseverance Target Zone
Previous RC drilling under the Perseverance workings produced shallow high-grade gold intersections such as 3m @ 50.0 g/t Au from 42m in PERC0152 and 3m @ 43.2 g/t Au from 72m in PERC0012. These results may represent the upper-part of a major copper-gold system which is indicated by the large and deep-seated gravity anomaly (ironstone) and the coincident, reversely-polarised magnetic anomaly (magnetite associated with copper-gold mineralisation) which is analogous to the Bluebird geophysical signature.
All up, the Company has identified 12 coincident magnetic-gravity targets within the 2km Bluebird-Perseverance Target Zone (see Figures 1, 2 and 3). Previous shallow RAB drilling failed to penetrate the leached-weathered zone in these target areas and, apart from at Bluebird, has not tested the underlying magnetic-gravity features.
The geophysical evidence suggests that Bluebird is just one of a number of even stronger coincident magnetic-gravity highs with the same signature as the Bluebird copper-gold deposit.
The Company will immediately carry out an IP dipole-dipole survey over the Bluebird deposit to detect the sulphides associated with the copper-gold mineralisation. This will allow the Company to rank and prioritise the magnetic-magnetic targets identified within the 2km strike-length Bluebird-Perseverance Target Zone for drill testing.
Further RC and diamond drilling follow-up programs will then be fast-tracked following completion of the IP surveys and modelling of the key priority targets.
THE BLUEBIRD DRILLING PROGRAM
Recent drilling at the Company’s Barkly copper-gold project, 45km east of Tennant Creek (see location Figure 4, below), has focussed on follow-up drill testing the Bluebird copper-gold discovery to the west and at depth below previous drilling4 to scope the extent of the high-grade copper and gold mineralisation.
The first stage of this follow-up drilling program included 6 holes for 1,700m1 that tested the westerly plunging copper-gold shoot and produced the thick, high-grade copper and gold intersections in the initial hole, BBDD00121 (63m @ 2.1 % Cu and 4.6 g/t Au from 153.0m including 27.55m @ 3.6 % Cu and 10.0 g/t Au).
Figure 4: Location of the Barkly-Babbler Project and major historical mines in the Tennant Creek Mineral Field
All 6 diamond drillholes intersected extensive hematite-magnetite alteration and visible copper mineralisation1. This drilling has extended the zone to the west over a strike length of >150m and to a depth of more than 200m below surface, where it remains completely open (see longitudinal-projection, Figure 5 and cross sections, Figure 6 and Figure 7).
Core samples from a further three mineralised intersections (BBDD0013, 14, 15)1 are currently being assayed and the final two holes of the program (BBDD0016, 17)1 will be submitted to the lab shortly.
Following receipt and interpretation/modelling of results from this program and completion of down hole electromagnetics (DHEM) from the two western-most holes, BBDD0016 and BBDD0017, a second stage of drilling will be carried out to expand the footprint of the high-grade copper-gold mineralisation at Bluebird.
Figure 5: Bluebird longitudinal projection with significant intersections and new holes with results to come
Fig. 6: Cross-section 448,380mE & BBDD00094
Fig. 7: Cross-section 448,360mE & BBDD00105 & 121
REFERENCES
1 17 August 2022. Tennant Minerals (ASX:TMS): “63m @ 2.1% Copper and 4.6 g/t Gold Intersected at Bluebird”.
2 Feb 1995, Posgold. Final Report for Exploration Licence 7693, 2/6/92 to 25/11/94. NTGS Report CR19950192.
3 Portergeo.com.au/database/mineinfo. Tennant Creek - Gecko, Warrego, White Devil, Nobles Nob, Juno, Peko, Argo.
4 08 March 2022. Tennant Minerals (ASX:TMS): “Spectacular 50m @ 2.70% copper intersection at Bluebird”.
5 15 March 2022. Tennant Minerals (ASX:TMS): “More Exceptional Copper Intersections from Bluebird”.
6 29 July 2022. Tennant Minerals (ASX:TMS): “Quarterly Activities Report to 30 June 2022”.
***ENDS***
This release was authorised by the Board of Tennant Minerals Ltd.
For enquiries please contact:
Matthew Driscoll
Non-Executive Chairman
M: +61 417 041 725
Stuart Usher
Company Secretary
M: +61 499 900 044
Media and Broker enquiries:
Andrew Rowell
White Noise Communications
M: +61 400 466 226