Bluebird First-pass Metallurgical Test-work Delivers 23% Copper and 1.5 g/t Gold in Concentrate

-          Initial results of early test-work show that up to 97% of the copper in a drill-core composite from the Bluebird project can be extracted via conventional flotation, delivering a copper concentrate grading 23% copper (Cu) and 1.5 g/t gold (Au) (see grade recovery curves, Figure 1).

-          The flotation upgrade represents a 10-fold increase in copper and a 4-fold increase in gold concentration from the diamond drillhole intersection in BBDD0045 of 61.8m @ 2.3% Cu, 0.4 g/t Au including 13.2m at 9.6% Cu, 1.51 g/t Au1.

-          The metallurgical test-work was undertaken to determine overall copper and gold recovery parameters for typical mineralisation seen in shallow and deeper copper-gold bearing intersections, enabling the Company to determine the optimal extraction process for the Bluebird mineralisation.

-          Four flotation tests on a drill-core composite sample from BBDD0045 achieved over 91% Cu, and up to 97% Cu recovery to concentrate, at a range of grind sizes from 53 µm to 75µm (refer Table 1).  Gold recovery to the flotation concentrate was significant at 66%.

-          Separate gravity (Falcon) concentration test-work (see Figure 2), conducted on the master composite sample (BB_45_1), upgraded the sample from 0.23 g/t Au to 0.67 g/t Au – a 3-fold increase. The gravity concentrate contained 32.6% of the gold and 15.7% of the copper (refer Table 2).  Intense cyanidation leaching of the gravity concentrate was able to extract 90.2% of the contained gold recovered in the gravity circuit.  Further work will explore further gravity concentration and leaching stages, in conjunction with flotation, to potentially increase gold recovery.

-          The initial report from the metallurgical consultant, Strategic Metallurgy, shows that these positive results achieved from the initial (rougher) flotation tests, and the gravity and cyanidation leach test work on the Bluebird core samples, are very likely to be further improved in the ‘cleaner’ stage of flotation.

-          A new drilling program to commence following the Northern Territory wet season will aim to define and extend the Bluebird discovery zone (see longitudinal projection, Figure 3) and enable a maiden copper-gold Mineral Resource to be estimated, with potential to support a stand-alone mining and processing development at the Company’s Barkly Project.

Tennant Minerals CEO Vincent Algar commented:

“The significant initial copper flotation results with 23% copper and 1.5 g/t gold in concentrate, and the high copper recoveries of up to 97%, are extremely encouraging and indicate potential for positive outcomes from future economic studies into mining and extraction to produce a saleable copper and gold concentrate.

“Copper with gold concentrates of this grade are potentially economic at current copper and gold prices, and provide the Company with a strong incentive to continue drilling, advance metallurgical test-work and define a maiden Mineral Resource.

“We look forward to launching our next drilling program to define and extend the enlarged mineralised footprint as we progress plans to establish a stand-alone mining and processing operation to capitalise on the resurgent global demand for copper and gold.

“Multiple drilling intersections at Bluebird have already confirmed the discovery of high-grade copper with gold mineralisation over a 500m strike-length and to over 300m depth, with further expansion potential shown to over 400m depth and along more than 800m of strike.”

March 26th, 2024 – Tennant Minerals Ltd (“the Company”) is pleased to provide an update on metallurgical test-work of diamond drill core samples from the high-grade Bluebird copper-gold discovery in the Northern Territory.

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 20052 (see location, Figure 4).

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.

METALLURGICAL FLOTATION RESULTS – ROUGHER TESTS 

Four rougher flotation tests were conducted on the master composite sample from BBDD0045 (BB_45_1), and promising results were obtained from these tests.  In the initial tests, copper recovery was over 90%. By modifying the reagent scheme and reducing reagent consumption, copper recovery improved to over 93%, peaking at 97% (for a concentrate grade of 21% to 23% copper).

The flotation copper grade and recovery graphs for these tests are provided in Figure 1 and the concentrate grade and recovery results are summarized in Table 1, below.

Figure 1 – Grade and recovery curves for BB_45_1

Table 1 – Summary of the flotation concentrate grade and recovery results of BB_45_1

GRAVITY TEST-WORK RESULTS 

Three kilograms of the BB_45_1 composite, ground to 80% passing (P80) 75-micron (µm) grind size, were subjected to a three-passes Falcon concentration test (to improve recovery).  The objective of this test is to recover free gold into a gravity concentrate. The arrangement of the Falcon gravity separation process is shown in Figure 2, below.

A total of 252 grams (g) of concentrate was collected and this concentrate was subjected to intensive leach conditions (after taking sub-samples) for 24 hours in a 20% solids pulp (5.0% sodium cyanide (NaCN) [weight/volume – w/v], 0.08 grams per gram of sample (g/g) Leachwell at pH 12 for 24 hours). A summary of the gravity and cyanidation results is provided in table 2 below (Sample JR-009).

The gravity separation results in Table 2 show that 8.6% of the feed, which contains 32.6% gold and 15.7% copper, reported to the Falcon concentrate. After Falcon concentrate leaching, 90.23% of the gold in this concentrate (29.4% of the gold in the feed) was recovered in the cyanide leach liquor. However, 12.4% of the copper was also reported to this leach liquor. Further test work will aim to reduce the copper content and optimize free-gold recovery.

Figure 2 – Falcon gravity process to produce free gold concentrate.

Table 2 – Falcon concentrator gravity and cyanidation results (JR009 - P80 75 µm*).

      * Sample passing 80% 75 µm.

ONGOING AND FUTURE METALLURGICAL WORK

Ongoing metallurgical test-work includes the flotation and gravity concentration on the composite samples from a higher-grade composite including an additional high-grade gold zone in BBDD0045, and a composite from drillhole BDD0046 (36.7m @ 1.14% Cu, 0.08 g/t Au3 - BBDD0045 is directly above BBDD0046, see Figure 3 below). Results for this test work are expected in the coming weeks.

The ultimate purpose of this initial phase of metallurgical test work on the Bluebird bulk samples is to understand the extractive behavior of the gold and copper in the mineralisation. The combined flotation and gravity concentration results from drillholes BBDD0045 and BBDD0046 will be used to define a preliminary processing circuit design for the known mineralisation. This will be of great assistance in designing the further metallurgical work needed for scoping and feasibility studies, to be conducted by the Company in the future.

NEXT STAGE OF DRILLING PLANNED TO DEFINE AND EXPAND BLUEBIRD FOOTPRINT

The Company is preparing to commence further drilling at Bluebird (see Figure 3) and along the highly prospective 2.5km Bluebird-Perseverance Corridor3 in the coming weeks, at the onset of the dry season in the Northern Territory.

Several drilling companies have indicated their availability to provide both reverse circulation (RC) and RC-Diamond drilling services, which will be required to test several priority targets. 

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

a)      To further define the high grade-copper-gold mineralisation at Bluebird aiming at defining a maiden Mineral Resource for the project, and,

b)      to drill test a number of Bluebird “look-alike” targets along strike and at depth.

The significant combined gravity-magnetic target at Perseverance, where previous high-grade drilling results of up to 3m @ 50 g/t Au4 have been identified, represents a high priority drilling target for the Company, as it aims to greatly expand the scale of the Bluebird – Perseverance mineralised footprint.

Figure 3: Bluebird longitudinal projection highlighting the outstanding high-grade intersections at Bluebird and planned drilling to expand the footprint.

ABOUT THE BARKLY PROJECT AND THE BLUEBIRD COPPER-GOLD DISCOVERY

The Bluebird 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 20052 (see Figure 4 below).

Drilling to date at Bluebird has identified copper-gold mineralisation over an 800m strike length and now to over 400m depth. 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 4: Location of the Barkly Project and major historical mines in the Tennant Creek Mineral Field.

REFERENCES

1 12/02/2024. Tennant Minerals (ASX.TMS): “Exceptional 61.8m 2.3% Copper Intersection at Bluebird”.

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

3 22/01/2024. Tennant Minerals (ASX.TMS): “New Copper Intersection Extends Bluebird Over 400m Depth”.

4 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 Officer

P: +61 (08) 94817833

Stuart Usher

Company Secretary

M: +61 (0) 499 900 044