Aton Reports New Results from Metallurgical Testing on Rodruin and Hamama West Sulphide Mineralisation

VANCOUVER, BC / ACCESSWIRE / July 28, 2023 / Aton Resources Inc. (TSXV:AAN, Financial) ("Aton" or the "Company") is pleased to update investors on the results of further preliminary metallurgical testwork from its Rodruin and Hamama West projects. Rodruin and Hamama West are both located within the Company's 100% owned Abu Marawat Concession ("Abu Marawat" or the "Concession"), in the Eastern Desert of Egypt.

Highlights:

"These preliminary metallurgical testwork results from the Rodruin gold-polymetallic sulphide mineralisation are most encouraging, and indicate that saleable copper and zinc concentrates can be produced, containing very respectable gold and silver metal credits. The copper concentrate in particular recovers high grades of gold and silver, and could potentially be sold as a precious metals concentrate" said Tonno Vahk, Interim CEO. "The results from testing of the Hamama West sulphide mineralisation were less positive and indicate that the sulphide mineralisation is refractory, and is not amenable to CIL processing. However high recoveries of gold and silver to a bulk concentrate indicate that a precious metals concentrate could potentially be produced from Hamama West, and this could provide Aton with some synergies when processing sulphide material from both the Hamama West and Rodruin deposits, as well as the higher grade Abu Marawat deposit, which contains significantly higher copper grades than either Rodruin or Hamama West. In the light of the results from this phase of metallurgical testwork Aton has decided to defer the immediate work on the revised mineral resource estimate for the Abu Marawat Concession, as it evaluates a net smelter return approach to the resource estimation, in order to fully assess the potential of the Hamama West, Rodruin and Abu Marawat gold-silver-copper-zinc sulphide deposits. The Company is continuing to push ahead towards its immediate primary goal, which is the completion of its application for the exploitation licence at the Abu Marawat Concession, and plans to submit this application to the Egyptian Mineral Resources Authority within the coming two months. The application for the exploitation licence will be based on a ‘commercial discovery' comprising open pit mine and heap leach projects on the oxide gold caps of both the Hamama West and Rodruin deposits, which will represent the first two mining projects in the planned phased development of the Abu Marawat Concession."

Figure 1: Geological plan of the Rodruin area, showing the main mineralised zones and the collars of the drill holes sampled in samples ROMS-006 and ROMS-007

Metallurgical testwork programme - Rodruin

Two composite samples were prepared from the Rodruin mineral deposit for metallurgical testing, which were representative of the two main sulphide mineralisation types, hosted in intensely phyllic altered ("phyllic") and carbonate rock types. This preliminary testwork programme was designed to follow on from testing of the oxide mineralisation types carried out in early 2023, which indicated that the Rodruin oxide mineralisation is amenable to processing using heap leach and conventional CIL technology (see news release dated March 9, 2023). The programme was specifically focused on the sulphide mineralisation at Rodruin to evaluate the potential of processing both the main sulphide mineralisation types by flotation, with the goal of producing saleable copper and zinc concentrates.

Samples were selected from diamond drill half core intervals (HQ and PQ size), to produce total sample weights between 40-45kg. 2 samples were composited from the 2 main sulphide mineralisation types, specifically phyllic and carbonate hosted mineralisation (see Figure 1). Details of the samples are provided in Table 1.

Metallurgical sample ID

Drill hole ID's

Mineralisation type

Sample weight

Estimated grades ¹

Au (g/t)

Ag (g/t)

Cu (%)

Pb (%)

Zn (%)

ROMS-006

ROD-071, ROD-080, ROD-112

Phyllic hosted

40.7 kg

2.33

21.6

0.25

0.03

2.94

ROMS-007

ROD-048, ROD-091

Carbonate hosted

44.4 kg

0.58

10.3

0.23

0.02

3.26

Notes:

Table 1:

The diamond drill half core samples were dispatched from Egypt to Wardell Armstrong International Ltd ("WAI") in December 2022, for metallurgical testing at their laboratory located in Cornwall, UK, with testwork commencing in January 2023. The half core intervals were combined to prepare 2 composite samples, which underwent a process evaluation testwork programme consisting of head assays, XRD analysis, rougher, cleaner and locked cycle flotation testing.

Head assays

Sub-samples of the 2 composite metallurgical samples were sent by WAI for head assay analysis at ALS Minerals' geochemical laboratory at Loughrea, Ireland, and were analysed for Au (by screen fire assay), Ag, Cu, Pb, Zn, As, Fe and S. Additional analysis for deleterious elements was not undertaken, but this additional analytical work is planned. The results of the head assays are provided below in Table 2:

Head assay results

Estimated Au grade (g/t) ²

Metallurgical sample ID

Assay (g/t)

Assay (%)

Au ¹

Ag

Cu

Pb

Zn

As

Fe

S

ROMO-006

2.31

24.5

0.22

0.02

2.52

0.04

4.8

12.2

2.33

ROMO-007

0.55

10.5

0.25

0.02

3.33

0.01

9.3

>10.0

0.58

Notes:

Table 2:

The Au head assays measured by screen fire assay show good correlation with the estimated grade of the composited drill core samples (Table 2). Ag, Cu, Pb and Zn head assays also showed good correlation with the estimated grades of the composite samples.

The good correlation in assay results indicates that the composited samples prepared for metallurgical testwork are representative of the drill core intervals sampled.

Mineralogical analysis

The XRD results showed the samples as being gangue dominated. The phyllic hosted ROMS-006 composite sample is predominantly composed of quartz, phyllosilicate minerals (chlorite, illite, mica) and pyrite. The carbonate hosted ROMS-007 composite sample contained a mixture of dolomite, talc, quartz and pyrite. Sphalerite occurs as a minor but significant constituent of both samples.

The results of the XRD analysis are shown in Figure 2:

Figure 2: Results of XRD analysis

Flotation testwork - Rodruin

Rougher optimisation tests

The two sulphide samples were subjected to flotation testing to investigate the potential to recover base metal concentrates from the sulphide mineralisation.

The flotation route tested involved sequential copper and zinc flotation. A primary grind size of 80% passing 75μm was utilised for rougher flotation optimisation, except for ROMS-006 FT3 where a grind size of 80% passing 53µm was used. Results are summarised in Table 3.

Sample

ID

Test

Product

Mass

pull

(%)

Grade

Recovery (%)

Cu

(%)

Zn

(%)

Au

(g/t)

Ag

(g/t)

S_TOT

(%)

Cu

Zn

Au

Ag

S_TOT

ROMS-006

FT1

Cu Ro conc.

8.87

2.32

10.3

17.8

37.7

23.5

87.9

35.1

66.7

74.2

56.2

Zn Ro conc.

10.1

0.16

16.0

3.78

32.7

22.0

6.86

62.6

16.1

15.6

37.5

ROMS-007

FT3

Cu Ro conc.

6.04

3.54

2.23

5.04

89.8

36.5

87.4

3.95

53.9

55.0

19.3

Zn Ro conc.

31.4

0.07

9.95

0.59

9.98

29.2

9.61

91.5

32.6

31.8

80.3

Table 3:

Rougher optimisation testwork showed optimum copper and zinc recoveries to concentrates from the ROMS-006 sample were 87.9% at a grade of 2.32% copper, and 62.6% at a grade of 16.0% zinc, respectively. For the ROMS-007 sample optimum flotation performance achieved recoveries of 87.4% at a grade of 3.54% copper, and 91.5% at grade of 9.95% zinc, respectively.

Open cycle cleaner tests

A series of open circuit cleaner flotation tests were subsequently conducted based upon the optimum rougher flotation conditions. A summary of the optimum open circuit results is provided in Table 4.

Sample ID

Test

Product

Mass pull

(%)

Grade

Recovery (%)

Cu

(%)

Zn

(%)

Au

(g/t)

Ag

(g/t)

S_TOT

(%)

Cu

Zn

Au

Ag

S_TOT

ROMS-006

FCT9

Cu Cl 3 conc.

0.50

32.3

9.17

103

1,512

32.9

54.0

1.65

19.5

28.5

2.45

Zn Cl 3 conc.

3.30

0.36

52.2

3.29

52.5

34.7

4.07

63.9

4.23

6.70

17.5

ROMS-007

FCT5

Cu Cl 3 conc.

0.31

34.9

3.24

32.4

1,012

33.3

42.4

0.30

17.7

31.1

0.92

Zn Cl 3 conc.

4.45

0.17

50.3

0.60

23.3

33.6

3.08

67.3

4.76

10.4

13.5

Table 4:

Three-stage open circuit cleaner optimisation testwork demonstrated that for sample ROMS-006, final concentrate grades of 32.3% copper at a recovery of 54.0%, and 52.2% zinc at recovery of 63.9% could be achieved, respectively. Furthermore, gold and silver were recovered to the final copper concentrate at grades of 103 g/t Au and 1,512 g/t Ag, respectively.

The same three-stage cleaning conditions were utilised for sample ROM-007, from which final concentrate grades of 34.9% Cu at a recovery of 42.4%, and 50.3% Zn at a recovery of 67.3% were achieved, respectively. Gold and silver were recovered to the final copper concentrate at grades of 32.4 g/t Au and 1,012 g/t Ag, respectively.

Locked cycle tests

A single locked cycle test was carried out on the ROMS-007 sample, as the predominant lithology of the two sulphide mineralisation samples, based on the test conditions used in the FCT5 open cycle cleaner test. A summary of the flotation performance as an average of the final three cycles is shown in Table 5.

Product

cycle

Cycle

Mass pull (%)

Assay

Distribution (%)

Cu

(%)

Zn

(%)

Au

(g/t)

Ag

(g/t)

S_TOT

(%)

Cu

Zn

Au

Ag

S_TOT

Cu Cl concentrate

4-6

0.6

28.1

4.20

30.9

659

32.5

69.2

0.73

31.5

38.3

1.68

Zn Cl concentrate

4-6

4.4

0.25

61.6

0.97

28.2

32.8

4.52

79.6

7.33

12.2

12.6

Final tailings

4-6

95.0

0.07

0.71

0.38

5.32

10.4

26.3

19.6

61.2

49.5

85.7

Feed

4-6

100.0

0.24

3.41

0.58

10.2

11.5

100

100

100

100

100

Table 5:

Results from the locked cycle flotation test carried out on ROMS-007 showed that a copper concentrate grading 28.1% Cu at a recovery of 69.2%, and a zinc concentrate grading 61.6% Zn at a recovery of 79.6% could be produced. Gold and silver were recovered to the final copper concentrate at grades of 30.9 g/t Au and 659 g/t Ag, respectively. Both the copper and zinc concentrates contain reasonable levels of gold and silver credits.

Discussion of results

The gold head assays reported by ALS correlate well with the estimated composite sample grades, calculated from the weighted diamond drill hole assays, and indicate that the composite metallurgical samples are representative of the sampled intervals.

The mineralogical (SEM, XRD) analysis confirms geological interpretation that the samples can be sub-divided into two broad categories of mineralisation, as follows:

Results of the locked cycle test indicate that saleable copper and zinc concentrates can potentially be produced with reasonable gold and silver credits.

Based on the open cycle cleaner test results, other final copper and zinc cleaner products which would be acceptable saleable concentrates, as shown in Table 6, could be considered.

Sample ID

Test

Product

Mass

pull

(%)

Grade

Recovery (%)

Cu

(%)

Zn

(%)

Au

(g/t)

Ag

(g/t)

S_TOT

(%)

Cu

Zn

Au

Ag

S_TOT

ROMS-006

FCT9

Cu Cl 2 conc.

0.8

24.0

11.7

93.7

1,283

33.9

65.7

3.5

29.0

39.5

4.1

Zn Cl 2 conc.

3.9

0.4

49.3

4.2

61.6

35.4

5.4

72.3

6.4

9.4

21.4

ROMS-007

FCT5

Cu Cl 1 conc.

0.8

22.9

4.6

25.0

577

30.6

71.8

1.1

35.1

45.7

2.2

Zn Cl 3 conc.

4.45

0.17

50.3

0.60

23.3

33.6

3.08

67.3

4.76

10.4

13.5

Table 6:

Metallurgical testwork programme - Hamama West

A single composite sample representative of the sulphide mineralisation at the Hamama West mineral deposit was prepared for metallurgical testing. This preliminary testwork programme was designed to follow up on testing of the oxide mineralisation types carried out in 2017-18 (see news release dated February 22, 2018), which indicated that the Hamama West oxide mineralisation is amenable to processing using heap leach and conventional CIL technology. The new phase of testwork was focused on the sulphide mineralisation at Hamama West to evaluate its potential amenability to cyanide leaching, and the potential of flotation methods to produce a saleable gold-bearing, or a gold and silver-bearing precious metals concentrate.

A bulk composite sample, HAMS-01, was collected from a combination of diamond drill half core intervals (HQ and PQ size, 10 holes), and RC percussion drill chips (5 holes) to produce a total sample weight of 88.6 kg (see Table 7). The holes sampled were spread out along the strike length and the entire vertical extent of the sulphide mineralisation at Hamama West (Figure 3).

Metallurgical sample ID

Drill hole ID's

Zone

Mineralisation type

Estimated grades¹

Au (g/t)

Ag (g/t)

HAMS-01

AHA-024, AHA-026, AHA-044, AHA-058, AHA-061, AHA-067, HAD-002, HAD-004, HAD-005, HAD-010, HAP-147, HAP-157, HAP-193, HAP-195, HAP-199

Hamama West (Main Zone)

Sulphide

0.82

28.62

Notes:

Table 7:

The HAMS-01 diamond half core and RC percussion chip samples were also dispatched from Egypt to WAI in December 2022, for metallurgical testing at their laboratory located in Cornwall, UK, with testwork commencing in January 2023. The half core intervals and RC percussion chips were composited in order to prepare 2 composite sub-samples, which underwent a process evaluation testwork programme consisting of head assays, diagnostic leach test, rougher and cleaner flotation testing, and bulk sulphide flotation, followed by ultra-fine grinding and bottle roll cyanide leach testing.

Head assays

A sub-sample of the HAMS-01 metallurgical composite sample was sent by WAI for head assay analysis at ALS Minerals' geochemical laboratory at Loughrea, Ireland, and was analysed for Au (by screen fire assay), Ag, Cu and S. Additional analysis for deleterious elements was not undertaken, but this additional analytical work is planned. The results of the head assays are provided below in Table 8:

Metallurgical sample ID

Assay (ppm)

Assay (%)

Estimated grades ²

Au ¹

Ag

Cu

S

Au (g/t)

Ag (g/t)

HAMS-01

0.94

29.26

0.021

3.01

0.82

28.62

Notes:

Table 8:

The Au and Ag head assays show good correlation with the estimated Au and Ag grades of the composited drill core and RC samples (Table 2 above).

The correlation in assay results indicates that the HAMS-01 bulk composite sample prepared for metallurgical testwork is representative of the drill core and RC percussion chip intervals sampled.

Flotation testwork - Hamama West

Rougher optimisation tests

A series of rougher flotation tests were conducted on the HAMS-01 sample to optimise suitable conditions for gold and silver recovery by means of sulphide flotation. Results of the rougher optimisation tests are shown in Table 9.

Product

Mass pull (%)

Residence time (mins)

Assay

Recovery

Assay

Recovery

Au (g/t)

Au (%)

Ag (g/t)

Ag (%)

FT1 final Ro conc.

25.5

15

3.41

81.2

84.8

75.7

FT2 final Ro conc.

16.5

15

2.80

53.5

80.3

50.1

FT3 final Ro conc.

21.3

15

2.66

70.2

92.4

69.9

Table 9:

Gold grades in the rougher optimisation concentrates ranged from 2.66 g/t to 3.41 g/t gold, for tests FT3 and FT1, respectively. Silver grades ranged from 80.3 g/t to 92.4 g/t, for tests FT2 and FT3, respectively.

Open cycle cleaner tests

A single cleaner test was carried out to determine the sample's amenability to increasing the flotation concentrate gold and silver grades. Results of the open cycle cleaner test results are shown in Table 10.

Product

Mass pull

(%)

Assay

Recovery

Assay

Recovery

Au (g/t)

Au (%)

Ag (g/t)

Ag (%)

FCT1 Ro conc.

25.1

2.75

82.2

94.4

81.0

FCT1 Cl conc. 1

20.9

2.95

73.6

101.1

72.4

FCT1 Cl conc. 2

19.3

3.08

71.0

105.7

69.8

Table 10:

Final open circuit cleaner concentrate gold and silver assays indicate minimal upgrading of the material from 2.75 g/t to 3.08 g/t gold, and 94.4 g/t to 105.7 g/t silver, respectively. Based on results of the open cycle cleaner test exploring the production of a saleable gold concentrate was abandoned.

Bulk sulphide float test

A bulk sulphide flotation test was carried out to produce bulk rougher concentrate for cyanidation leach testwork. Results of the bulk sulphide float test are summarised in Table 11.

Product

Mass pull (%)

Assay

Distribution (%)

Au

(ppm)

Ag

(ppm)

Cu

(%)

S_TOT

(%)

Au

Ag

Cu