Latest test-work results come as the Company prepares to launch a new drilling program at Bluebird aimed at defining a maiden Mineral Resource and testing new target zones

 

Figure 1: Cleaner Flotation Concentration of Chalcopyrite from BBDD0045, Bluebird Copper-Gold Discovery

 

-            Results from latest flotation test-work (Figures 1 to 3) on bulk-samples from Bluebird1 diamond core holes BBDD0045 and BBDD0046 (Figure 4), have confirmed excellent flotation recoveries and high-concentrate grades of copper (Cu) and gold (Au) exceeding commercial benchmarks2. Test-work outcomes include:

Cleaner flotation results from a BBDD0045 chalcopyrite (copper-sulphide) rich sample, grading 2.7% Cu and 0.47 g/t Au, produced an exceptional concentrate grade of 29.6 % Cu and 3.96 g/t Au, while recovering 94.4% of Cu and 75.8% of Au. A high-grade copper and gold sub-sample from BBDD0045, grading 9.7% Cu and 1.55 g/t Au, yielded a concentrate grade of 26.5% Cu and 2.36 g/t Au, with significant recoveries of 98% of Cu and 57% of Au. A sample from BBDD0046 (1.14% Cu and 0.08 g/t Au) that contained higher-tenor copper sulphide minerals bornite and chalcocite as well as chalcopyrite, returned a 25.4% Cu and 1.84 g/t Au concentrate grade, while recovering 91.3% of Cu and 79.3% of Au in cleaner flotation.

-            The metallurgical analysis to determine optimum copper flotation conditions and to identify an extraction pathway for unrecovered gold (~30% of Au) using gravity and leaching methods is ongoing, with further updates to follow.

-            The excellent flotation test-work results come as the Company prepares to launch a new drilling program to define and extend the Bluebird discovery zone (see longitudinal projection, Figure 5), as well as test other key targets, with the aim of delivering a maiden copper-gold Mineral Resource with the potential to support a stand-alone mining and processing operation at Bluebird (see Figure 6 for location). Drilling will commence as soon as road conditions allow after the recent wet season.  

 

Tennant Minerals CEO Vincent Algar commented:

 

“Building on our  significant initial copper flotation test-work results1, the latest  more detailed cleaner-flotation tests, conducted over a wider range of material types, demonstrates the Bluebird copper and gold mineralisation can consistently deliver high-grade and potentially commercial copper concentrates of 24%-29% copper with gold content of up to 4 g/t. High copper recoveries which are consistently over 90%, and up to 98%, also underline the potential for positive outcomes from future economic studies into mining and extraction to produce a saleable copper and gold concentrate.

 

“Furthermore, comparisons with reported copper-with-gold traded concentrates2, and from other successful mines in the Tennant Creek area3, support the view that Bluebird concentrates have the potential to be highly valuable at current copper and gold prices - which are continuing to rise.

 

“These excellent results give us further encouragement as we prepare for our next drilling phase at Bluebird to continue expanding this exciting high-grade copper-gold discovery. Our overall goal is to establish a substantial resource base within our 100%-owned Barkly Project, which will support a stand-alone mining and processing operation at a time of increasing global demand for both copper and gold.”

 

Tennant Minerals Ltd (ASX: TMS) (“the Company”) is pleased to announce exceptional results from metallurgical test-work of diamond drill core samples from the high-grade Bluebird copper-gold discovery in the Northern Territory (see location, Figure 6).

 

Bluebird is one of multiple copper-gold targets within a 5km geophysical footprint at the Company’s 100% owned Barkly Project, located on the eastern edge of the richly-endowed Tennant Creek Mineral Field (TCMF), which produced 5.5Moz of gold and 700kt of copper from 1934 to 20054 (see location, Figure 6).

 

Drilling to date at Bluebird has identified significant, high-grade copper-gold mineralisation over an 800m strike length and to a depth of more than 400m5,6. The mineralisation is associated with intense hematite alteration and brecciation with malachite, native copper and visible gold in the upper parts of the zone, which transitions to primary sulphide mineralisation including chalcocite, bornite and chalcopyrite.

 

Following earlier success using rougher flotation tests on the master composite sample from BBDD0045 (BB_45_1)1, promising results have been obtained from further work on higher-grade composite samples in BBDD0045, as well as a bulk-composite from BBDD0046. The drilling intersections from these holes are shown on cross section, Figure 4, and summarised below:

 

-        61.8m at 2.3% Cu, 0.4g/t Au from 149.2m in BBDD00465, and,

-        36.7m @ 1.14% Cu, 0.08 g/t Au from 129.3m in BBDD00456

 

A single set of optimal conditions has been determined for the treatment of fresh, transitional and very high-grade materials with no degradation in flotation performance. This enables the Company to develop an extraction process for the Bluebird copper and gold mineralisation, and other critical elements such as bismuth and cobalt, while also providing a solid foundation for an economic model for the project.

 

After the recent cleaner stage flotation testing of mineralised samples, the Company’s metallurgical consultant, Strategic Metallurgy, has indicated a potentially commercial process plant using Bluebird materials could produce a copper concentrate of 24-29% Cu with a copper recovery of over 90% from all materials, using similar conditions. Gold reports with the copper concentrate at average grades between 1.5 g/t Au and 4 g/t Au, recovering between 58% and 79% Au.  The balance of the gold is reporting to flotation tails, which are the subject of on-going gravity and cyanidation test-work.   

 

Previous mining and processing operations within the TCMF, such as at the Peko mine3, treated flotation tailings, with gravity and cyanidation leaching, to extract remnant gold after copper extraction. The presence of gold in the tails at Peko (up to ~30%3) is consistent with the results to date from Bluebird, and the Company is doing further work to develop this part of the processing circuit to substantially increase gold recovery.

 

METALLURGICAL FLOTATION RESULTS – CLEANER AND VARIABILITY TESTS

 

The Bluebird test-work program has proceeded to cleaner flotation tests and variability testing (see flow-sheet for cleaner flotation shown in the Figure 2), which involves regrinding the flotation product from the rougher cells and re-floating them. This is an industry standard process and it is commonly used in the processing of copper-rich sulphide ores.

 

Overall, four representative diamond core samples have now been tested, each with slightly different characteristics, allowing the Company to assess the behaviour of different ore types and groupings. Table 1 below gives a description of the samples tested to date. The combined recovery curves for each of the optimised tests and results are shown in Figure 3 and Table 2 respectively. These recovery curves and high copper grades indicate the presence of significant amounts of higher-tenor copper minerals, bornite and chalcocite in addition to the primary ore mineral - chalcopyrite.

 

The cleaner test-work results have clearly demonstrated flexibility in producing various concentrate grades, with the possibility of producing copper concentrate with grades ranging from 24% to 29% and very high recoveries of over 90%, and up to 98%, from all composites.

 

Composite sample BB_45_AD, representing a complete intersection of typical mineralisation at Bluebird (grading 2.7% Cu, and 0.47g/t Au), yielded an impressive cleaner concentrate result of 29.6% Cu and 3.96g/t Au, recovering 94.4% of Cu and 75.8% of Au.  

 

The shorter, very high-grade copper interval tested in BB_45_AD_H (see Table 1), contained high copper and increased gold (9.7% Cu and 1.55 g/t Au) compared to the wider intersections. The cleaner concentrate produced graded 26.5% Cu and 2.36 g/t Au, with an impressive 98.2% of Cu and 56.9% of gold recovered.

 

The sample tested from drillhole BBDD0046, which is vertically above BBDD0045 (see cross section, Figure 4), and intersected mineralisation at a shallower depth, contained more transitional copper minerals such as bornite and chalcocite and returned an impressive 25.4% Cu, 1.84 g/t Au concentrate grade, recovering 91.3% of Cu and 79.3% of Au in cleaner flotation.

 

The concentrates produced are comparable to commercial copper concentrates grading 26% Cu, 1.1g/t Au (Copper Concentrate TC index MB-CU-0287 by FastMarkets)2, as well as historical concentrates produced previously in the TCMF grading 24.7% Cu from the Peko Mine and 26.5% Cu from the Warrego Mine3. This gives confidence to the Company when considering future economic studies on Bluebird Mineral Resources.

 

Table 1 Variability sample descriptions for Bluebird Flotation test work.

Drillhole/ sample name

Interval

Description

Composite Grade (assayed)

BBDD0045/BB_45_1

154m – 200.7m (46.7m)

Brecciated ironstone, hematitic siltstone with zones of intense copper mineralisation including massive chalcopyrite and veinlets of bornite and chalcocite.

3.4% Cu, 0.17g/t Au, 19% Fe

BBDD0045/BB_45_AD

149.2m – 200.7m (51.5m)

As above

2.7% Cu, 0.47 g/t Au, 20% Fe

BBDD0045/BB_45_AD_H

149.2m – 161.9m (12.7m)

Brecciated ironstones with zones of intense copper mineralisation including massive chalcopyrite and veinlets or bornite and chalcocite.  

9.7% Cu, 1.55g/t Au, 27% Fe

BBDD0046/BB_46_1

129.3m – 166m (36.7m)

Brecciated ironstones, hematitic siltstones with intense copper mineralisation including stringer chalcopyrite and traces of bornite and chalcocite.

1.14% Cu, 0.08g/t Au, 22% Fe

 

Figure 2: Cleaner flotation circuit flowsheet

 

Figure 3: Copper Concentrate Recovery Curve –Cleaner Flotation Concentrates Bluebird

 

Table 2: Table of Flotation cleaner concentrate, feed and recovery, Cu-Au, Bluebird

Met sample /Job Number

Calculated Feed

 

Concentrate Grade and Recovery

Cu

Au

Weight % of Feed

Cu

Recovery

Au

Recovery

(%)

(g/t)

 

(%)

(%)

(g/t)

(%)

BB_45_1/ JR0037

2.16

0.22

8.68

24.2

97.3

1.5

58.2

BB_45_AD/ JR032

2.18

0.36

6.97

29.6

94.4

3.96

75.8

BB_45_AD_H/ JR044

8.75

1.35

32.5

26.5

98.2

2.36

56.9

BB_46_1 / JR040

1.29

0.11

4.65

25.4

91.3

1.84

79.3

 

ONGOING AND FUTURE METALLURGICAL WORK

 

The excellent results achieved from test-work to date are highly encouraging for the development of a simple and straightforward processing pathway to deliver economic copper and gold concentrates from any future operation at Bluebird. The ultimate purpose of this initial phase of metallurgical test-work on the Bluebird bulk samples is to understand the extractive behavior of the copper and gold in the mineralisation, and use this information to develop a preliminary processing circuit design for the identified mineralisation.

 

More work is being carried out in the following areas to improve our understanding of the metallurgical behaviour of the Bluebird mineralisation;

 

-          Refining optimal conditions for all material types to simplify the processing circuit design and maximise the economic outcome.

-          Gold recoveries in copper flotation concentrates in results to date range from 58-70% of Au. Further investigation into this variability of gold recovery, and refinement of the method for recovery of the remaining gold in copper concentrate tailings, is being investigated. Further work will also optimize recovery of gold in gravity concentrates as previously reported to the ASX1.  Given current high gold prices, this work is very important for the project.

-          Test-work to date has been completed on fresh and partly oxidised copper sulphides. Identification of other mineralisation types requires further test-work on different sample materials to ensure all materials, that may report to a future plant are understood and accounted for in testing.

 

NEXT STAGE OF DRILLING PLANNED TO DEFINE AND EXPAND BLUEBIRD FOOTPRINT

 

The Company is finalising a new drilling program at Bluebird (see proposed new drillholes on longitudinal projection, Figure 5) and along the highly prospective 2.5km Bluebird-Perseverance Corridor. This drilling program will commence once roads damaged by heavy rain in the Tennant Creek area are repaired, enabling a drilling crew to be mobilised to the site.

 

Drilling is expected to include both reverse circulation (RC) and diamond drilling to test priority targets.

 

The dual objectives of drilling within the Bluebird-Perseverance Corridor during 2024 are:

 

a)              Further test and extend the high-grade copper-gold mineralised zone at Bluebird to define a maiden Mineral Resource for the project, and,

b)             to drill test multiple Bluebird ‘look-alike’ targets along strike and at depth (see Figure 5).

 

The significant combined gravity-magnetic target at the Perseverance prospect, where previous high-grade drilling results of up to 3m @ 50 g/t Au7 have been identified, represents one such high-priority drilling target which could expand the scale of the Bluebird-Perseverance mineralised footprint.

 

Figure 4: Bluebird cross section 448,300mE showing high-grade copper intersections in BBDD0045 and BBDD0046. Metallurgical Samples described in Table 1 are extracted from these drillhole intervals.

 

Figure 5: Bluebird longitudinal projection showing key copper-gold intersections, the mineralised zone, new targets and planned drilling.

 

ABOUT THE BARKLY PROJECT AND THE BLUEBIRD COPPER-GOLD DISCOVERY

 

The high-grade Bluebird copper-gold discovery is part of the Company’s 100% owned Barkly Project which comprises two exploration licences located 40km east of Tennant Creek in the Northern Territory. The mineralisation intersected at Bluebird is typical of the high-grade copper-gold orebodies previously mined in the Tennant Creek Mineral Field, which produced over 5.5Moz of gold and over 700kt of copper from 1934 to 20054 (see Figure 6 below).

 

Drilling to date at Bluebird has identified copper-gold mineralisation over an 800m strike length and to a depth of more than 400m. The mineralisation is associated with intense hematite alteration and brecciation with malachite, native copper and visible gold in the upper parts of the zone, which transitions to primary sulphide mineralisation including chalcocite, bornite and chalcopyrite.

 

The Company has adopted a dual strategic approach of defining the Mineral Resource potential of Bluebird whilst also testing other key targets in the expanded 2.5km Bluebird-Perseverance corridor.

 

Figure 6: Location of the Barkly Project and major historical mines in the Tennant Creek Mineral Field.

 

REFERENCES

 

1 26/03/2024. Tennant Minerals (ASX.TMS): “Bluebird Metallurgy Delivers 23% Cu, 1.5g/t Au Concentrate”.

2 https://www.fastmarkets.com/methodology/metals/copper-concentrates-index/

3 Kyte, W, J, 1969, AusImm Bulletin, Ore Treatment by Peko Mines NL

4 Portergeo.com.au/database/mineinfo. Tennant Creek: Gecko, Warrego, White Devil, Nobles Nob, Juno, Peko, Argo.

5 12/02/2024. Tennant Minerals (ASX.TMS): “Exceptional 61.8m 2.3% Copper Intersection at Bluebird”.

6 22/01/2024. Tennant Minerals (ASX.TMS): “New Copper Intersection Extends Bluebird Over 400m Depth”.

7 11/03/2024. Tennant Minerals (ASX.TMS): “New Drilling to Test Expanded 2.5km Footprint at Bluebird”.

 

Authorised for release by the board of directors.

 

***ENDS***

 

For enquiries please contact:

 

Vincent Algar

Chief Executive Office  

P: +61 (08) 9481 7833

 

Stuart Usher

Company Secretary

M: +61 (0) 499 900 044

 

CAUTIONARY STATEMENT REGARDING FORWARD LOOKING INFORMATION

 

This release contains forward-looking statements concerning Tennant Minerals Ltd. Forward-looking statements are not statements of historical fact and actual events and results may differ materially from those described in the forward-looking statements as a result of a variety of risks, uncertainties, and other factors. Forward-looking statements are inherently subject to business, economic, competitive, political and social uncertainties and contingencies. Many factors could cause the Company’s actual results to differ materially from those expressed or implied in any forward-looking information provided by the Company, or on behalf of, the Company. Such factors include, among other things, risks relating to additional funding requirements, metal prices, exploration, development and operating risks, competition, production risks, regulatory restrictions, including environmental regulation and liability and potential title disputes.

 

Forward looking statements in this release are based on the company’s beliefs, opinions and estimates of Tennant Minerals Ltd as of the dates the forward-looking statements are made, and no obligation is assumed to update forward looking statements if these beliefs, opinions and estimates should change or to reflect other future developments.

 

COMPETENT PERSON DECLARATIONS

 

The information in this release that relates to Metallurgical Results and Interpretations is based on information compiled by Nick Vines, Executive Director at Strategic Metallurgy Pty Ltd. Mr Vines is a Member of the Australasian Institute of Mining and Metallurgy (AusIMM) and has sufficient experience which is relevant to the metallurgical test work on the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking 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’. Mr Vines consents to the inclusion in the release of the matters based on this information in the form and context in which it appears.

 

The information in this report that relates to exploration results is based on information compiled and/or reviewed by Mr Chris Ramsay. Mr Ramsay is the General Manager of Geology at Tennant Minerals Ltd and a Member of the Australian Institute of Mining and Metallurgy (‘MAusIMM’). Mr Ramsay has sufficient experience, including over 25 years’ experience in exploration, resource evaluation, mine geology, and development studies, relevant to the style of mineralisation and type of deposits under consideration to qualify as a Competent Person as defined in the 2012 Edition of the Joint Ore Reserves Committee (‘JORC’) Australasian Code for Reporting of Exploration Results, Minerals Resources and Ore Reserves. Mr Ramsay consents to the inclusion in this report of the matters based on this information in the form and context in which it appears.

 

ASX LISTING RULES COMPLIANCE

 

In preparing this announcement the Company has relied on the announcements previously made by the Company as listed under “References”. The Company confirms that it is not aware of any new information or data that materially affects those announcements previously made, or that would materially affect the Company from relying on those announcements for the purpose of this announcement.