Mr. Tonno Vahk reports

ATON REPORTS NEW RESULTS FROM METALLURGICAL TESTING ON RODRUIN AND HAMAMA WEST SULPHIDE MINERALISATION

Aton Resources Inc. has provided an update on the results of further preliminary metallurgical test work from its Rodruin and Hamama West projects. Rodruin and Hamama West are both located within the company's 100-per-cent-owned Abu Marawat concession in the Eastern Desert of Egypt.

Highlights:

• Two composite samples representing the main sulphide mineralization types at Rodruin underwent preliminary metallurgical test work investigating the potential to produce saleable copper and zinc concentrates. The composite samples were prepared from selected diamond drill half-core intervals.
• Results from a locked-cycle flotation test carried out on sample ROMS-007 produced a copper concentrate of 28.1 per cent copper at a recovery of 69.2 per cent and a zinc concentrate of 61.6 per cent zinc at a recovery of 79.6 per cent.
• Sequential flotation tests carried out on the Rodruin sulphide mineralization types indicate that potentially saleable copper and zinc concentrates can be achieved at reasonable metal recoveries and grades. Both the copper and zinc concentrates contain reasonable gold and silver credits.
• A single bulk composite sample representative of the sulphide mineralization at Hamama West underwent metallurgical test work, including cyanidation leach testing and flotation test work, to assess its amenability to cyanide leaching and the potential to produce a saleable gold-bearing or gold-silver-bearing concentrate. The composite sample was prepared from selected diamond drill half-core intervals and RC (reverse circulation) percussion drill chips.
• Whole-ore cyanide leach test work showed that 49.8 per cent of the gold was recoverable by cyanide leaching. Metal recoveries of 47.1 per cent and 26.1 per cent were also obtained for silver and copper, respectively.
• Rougher flotation optimization found that 81.2 per cent and 75.7 per cent of gold and silver were recoverable to a concentrate, at grades of 3.41 grams per tonne gold and 84.8 grams per tonne silver, and at a high mass pull of 25.5 per cent by weight.
• A bulk sulphide float recovered 85 per cent of the gold and 83 per cent of the silver to a rougher concentrate assaying 2.98 grams per tonne gold and 94.9 grams per tonne silver, respectively.
• Bulk concentrate cyanide leach test work showed that a gold recovery of 54.8 per cent was achievable at a particle size of 80 per cent passing 10 micrometres. Silver and copper recoveries of 60.3 per cent and 47.0 per cent were achieved, respectively.
• The Hamama West sulphide mineralization was not amenable to conventional CIL (carbon in leach) nor flotation followed by ultrafine grinding/CIL processing routes. A bulk sulphide float produces a potential precious metal concentrate containing gold and silver credits.

"These preliminary metallurgical test work results from the Rodruin gold-polymetallic sulphide mineralization 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 chief executive officer. "The results from testing of the Hamama West sulphide mineralization were less positive and indicate that the sulphide mineralization 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 test work, 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."

Metallurgical test work program -- Rodruin

Two composite samples were prepared from the Rodruin mineral deposit for metallurgical testing, which were representative of the two main sulphide mineralization types, hosted in intensely phyllic-altered and carbonate rock types. This preliminary test work program was designed to follow on from testing of the oxide mineralization types carried out in early 2023, which indicated that the Rodruin oxide mineralization is amenable to processing using heap leach and conventional CIL technology (see news release dated March 9, 2023). The program was specifically focused on the sulphide mineralization at Rodruin to evaluate the potential of processing both the main sulphide mineralization 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 and 45 kilograms. Two samples were composited from the two main sulphide mineralization types, specifically phyllic-hosted and carbonate-hosted mineralization. Details of the samples are provided in an attached table.

The diamond drill half-core samples were dispatched from Egypt to Wardell Armstrong International Ltd. (WAI) in December, 2022, for metallurgical testing at its laboratory located in Cornwall, United Kingdom, with test work commencing in January, 2023. The half-core intervals were combined to prepare two composite samples, which underwent a process evaluation test work program consisting of head assays, XRD (X-ray diffraction) analysis, and rougher, cleaner and locked-cycle flotation testing.

Head assays

Subsamples of the two composite metallurgical samples were sent by WAI for head assay analysis at ALS Minerals' geochemical laboratory at Loughrea, Ireland and were analyzed for gold (by screen fire assay), silver, copper, lead, zinc, arsenic, iron and selenium. Additional analysis for deleterious elements was not undertaken, but this additional analytical work is planned. The results of the head assays are provided in an attached table.

The gold head assays measured by screen fire assay show good correlation with the estimated grade of the composited drill core samples. Silver, copper, lead and zinc 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 test work 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.

Flotation test work -- Rodruin

Rougher optimization tests

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

The flotation route tested involved sequential copper and zinc flotation. A primary grind size of 80 per cent passing 75 micrometres was utilized for rougher flotation optimization, except for ROMS-006 FT3, where a grind size of 80 per cent passing 53 micrometres was used. Results are summarized in an attached table.

Rougher optimization test work showed optimum copper and zinc recoveries to concentrates from the ROMS-006 sample were 87.9 per cent at a grade of 2.32 per cent copper and 62.6 per cent at a grade of 16.0 per cent zinc, respectively. For the ROMS-007 sample, optimum flotation performance achieved recoveries of 87.4 per cent at a grade of 3.54 per cent copper and 91.5 per cent at grade of 9.95 per cent 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 an attached table.

Three-stage open-circuit cleaner optimization test work demonstrated that, for sample ROMS-006, final concentrate grades of 32.3 per cent copper at a recovery of 54.0 per cent, and 52.2 per cent zinc at recovery of 63.9 per cent could be achieved, respectively. Furthermore, gold and silver were recovered to the final copper concentrate at grades of 103 grams per tonne gold and 1,512 grams per tonne silver, respectively.

The same three-stage cleaning conditions were utilized for sample ROM-007, from which final concentrate grades of 34.9 per cent copper at a recovery of 42.4 per cent and 50.3 per cent zinc at a recovery of 67.3 per cent were achieved, respectively. Gold and silver were recovered to the final copper concentrate at grades of 32.4 grams per tonne gold and 1,012 grams per tonne silver, 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 mineralization 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 an attached table.

Results from the locked-cycle flotation test carried out on ROMS-007 showed that a copper concentrate grading 28.1 per cent copper at a recovery of 69.2 per cent and a zinc concentrate grading 61.6 per cent zinc at a recovery of 79.6 per cent could be produced. Gold and silver were recovered to the final copper concentrate at grades of 30.9 grams per tonne gold and 659 grams per tonne silver, 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 (scanning electron microscopy) and XRD) analysis confirms geological interpretation that the samples can be subdivided into two broad categories of mineralization, as follows:

• Sample ROMS-006 represents phyllic-hosted mineralization and is mainly composed of quartz, phyllosilicate minerals (chlorite, illite and mica) and pyrite. This sample is representative of the higher-grade gold-polymetallic mineralization intersected in holes ROD-071 (see news release dated May 10, 2022), ROD-075 (see news release dated June 1, 2022) and also the lower zone of mineralization in hole ROD-117 (see news release dated Dec. 20, 2022).
• Sample ROMS-007 represents carbonate-hosted mineralization and is predominantly composed of dolomite, talc, quartz and pyrite. This sample is representative of the carbonate-hosted mineralization intersected in holes ROP-050 (see news release dated Jan. 29, 2019) and the upper zone of mineralization in hole ROD-117 (see news release dated Dec. 20, 2022).

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 that would be acceptable saleable concentrates, as shown an attached table, could be considered.

Metallurgical test work program -- Hamama West

A single composite sample representative of the sulphide mineralization at the Hamama West mineral deposit was prepared for metallurgical testing. This preliminary test work program was designed to follow up on testing of the oxide mineralization types carried out in 2017 to 2018 (see news release dated Feb. 22, 2018), which indicated that the Hamama West oxide mineralization is amenable to processing using heap leach and conventional CIL technology. The new phase of test work was focused on the sulphide mineralization 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 metal concentrate.

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

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 its laboratory located in Cornwall, United Kingdom, with test work commencing in January, 2023. The half-core intervals and RC percussion chips were composited in order to prepare two composite subsamples, which underwent a process evaluation test work program consisting of head assays, diagnostic leach test, rougher and cleaner flotation testing, and bulk sulphide flotation, followed by ultrafine grinding and bottle-roll cyanide leach testing.

Head assays

A subsample 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 analyzed for gold (by screen fire assay), silver, copper and sulphur. Additional analysis for deleterious elements was not undertaken, but this additional analytical work is planned. The results of the head assays are provided in an attached table.

The gold and silver head assays show good correlation with the estimated gold and silver grades of the composited drill core and RC samples.

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

Flotation test work -- Hamama West

Rougher optimization tests

A series of rougher flotation tests were conducted on the HAMS-01 sample to optimize suitable conditions for gold and silver recovery by means of sulphide flotation. Results of the rougher optimization tests are shown in an attached table.

Gold grades in the rougher optimization concentrates ranged from 2.66 grams per tonne to 3.41 grams per tonne gold for tests FT3 and FT1, respectively. Silver grades ranged from 80.3 grams per tonne to 92.4 grams per tonne 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 an attached table.

Final open-circuit cleaner concentrate gold and silver assays indicate minimal upgrading of the material from 2.75 grams per tonne to 3.08 grams per tonne gold and 94.4 grams per tonne to 105.7 grams per tonne 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 test work. Results of the bulk sulphide float test are summarized in an attached table.

The results shown in an attached table indicate that 85.0 per cent and 83.1 per cent of the gold and silver were recovered to the bulk sulphide concentrate, assaying 2.98 grams per tonne gold and 94.9 grams per tonne silver, respectively.

The bulk flotation concentrate produced in this phase of test work was used as the feed material for the cyanidation leach test work.

Cyanidation leach test work -- Hamama West

Bulk concentrate samples were leached under various conditions to evaluate gold and silver extraction kinetically by stirred beaker cyanidation.

Whole-ore cyanidation leach test results

Whole-ore cyanide leach test work was conducted on the bulk flotation concentrate sample. Following this, leaching test work was also conducted on the bulk flotation concentrate at various regrind particle sizes to enhance gold and silver liberation. Solid sample streams were subjected to gold and silver assay by aqua regia digestion with ICP-OES finish. A summary of the whole-ore cyanidation leach test results is provided in an attached table.

Gold recovery was limited to 49.8 per cent after 48 hours of leach time, with 90.5 per cent of the relative gold recovery occurring during the first hour of leaching. Final silver and copper recoveries were 47.1 per cent and 26.1 per cent, respectively, with the silver and copper having slower cyanide leach kinetics relative to gold.

Low overall gold recovery is mainly attributed to the high deportment of gold within sulphide minerals, which are inert to the cyanidation process. Additionally, copper dissolution into the leach liquor contributed to the high cyanide consumption level.

Concentrate cyanidation leach test results

Following the first phase of whole ore cyanidation, a second phase of leaching test work was also conducted on the bulk flotation concentrate at various regrind particle sizes in order to enhance liberation of gold and silver. A summary of the concentrate cyanidation leach test results is shown in an attached table.

A maximum gold recovery of 55.6 per cent was obtained after eight hours of cyanide leaching at a grind size of 80 per cent passing 10 micrometres, and a maximum silver recovery of 60.3 per cent was obtained after 48 hours of cyanide leaching at a grind size of 80 per cent passing 10 micrometres.

Diagnostic leach tests

Diagnostic leaching was undertaken to evaluate the gold and silver deportment across the bulk flotation concentrate and demonstrated significant gold deportment in sulphide species, which hosted 32.4 per cent of the total gold from the flotation concentrate. A summary of the diagnostic leach test is shown in an attached table.

Gold deportment in the flotation concentrate shows that 47.9 per cent of the gold is recoverable by cyanide leaching, which is comparable with the results obtained from the cyanidation leach test work on unground flotation concentrate, where a gold recovery of 48.9 per cent was achieved after 48 hours of leaching. Of the total gold, 32.4 per cent, 8.1 per cent and 11.5 per cent are encapsulated within sulphide, carbonaceous or carbonate, and other species, respectively.

Sulphide mineralization was still found to be present in the leach residue after nitric acid treatment, indicating that gold is present in sulphide mineralization refractory to nitric acid attack, interpreted as being primarily pyrite, and accounted for in the subsequent phases of diagnostic treatment.

Silver deportment in the flotation concentrate shows 43.4 per cent of the silver is cyanide recoverable, similar to the results from whole ore cyanide leaching (47.1 per cent recovery after 48 hours leaching), and unground bulk flotation concentrate cyanide leaching (43.4 per cent after 48 hours). Of the silver, 20.9 per cent, 6.55 per cent and 29.2 per cent are deported in sulphide, carbonaceous or carbonate, and other species, respectively.

Copper deportment in the flotation concentrate shows 27.1 per cent of the copper is cyanide recoverable, which was also similar to the results from the whole-ore cyanide leaching and the unground bulk concentrate cyanide leaching. Of the copper, 52.4 per cent, 9.4 per cent and 11.2 per cent are deported in sulphide, carbonaceous or carbonate, and other species, respectively.

Discussion of results

Interpretation of the diagnostic leach test work indicates that a significant component of the gold is associated with sulphide minerals, interpreted as being predominantly pyrite. A smaller component is associated with carbonate gangue minerals and other species, which make up a significant portion of the Hamama West mineralization. Silver is interpreted as being deported partially as electrum, where it is recovered under similar conditions to that as the gold. A further significant component of the silver is deported in sulphosalt minerals (other species). Investigation of the Hamama West mineralization by ore microscopy techniques has indicated gold to be deported as fine particles, frequently less than 10 micrometres in diameter, some of which are seen to be encapsulated within pyrite and other sulphide and sulphosalt species.

The Hamama West sulphide mineralization was not shown to be able to produce a gold-bearing sulphide concentrate (requiring a minimum grade of approximately 20 to 25 grams per tonne gold). This is due to the close association of a significant proportion of the fine-grained gold with pyrite and other carbonate, sulphide and sulphosalt mineral species.

The cyanidation leach test work indicated that the sulphide mineralization is not treatable adopting conventional CIL nor by flotation/UFG/CIL process routes due to the refractory nature of the sulphide mineralization.

The sulphide mineralization is amenable to processing by flotation. High gold and silver values were recovered to a bulk sulphide flotation concentrate, which has the potential to be sold as a precious metal concentrate due to the combined gold and silver grades.

About Aton Resources Inc.

Aton Resources is focused on its 100-per-cent-owned Abu Marawat concession, located in Egypt's Arabian-Nubian Shield, approximately 200 kilometres north of Centamin's world-class Sukari gold mine. Aton has identified numerous gold and base metal exploration targets at Abu Marawat, including the Hamama deposit in the west, the Abu Marawat deposit in the northeast and the advanced Rodruin exploration prospect in the south of the concession. Two historic British gold mines are also located on the concession at Sir Bakis and Semna. Aton has identified several distinct geological trends within Abu Marawat, which display potential for the development of a variety of styles of precious and base metal mineralization. Abu Marawat is 447.7 square kilometres in size and is located in an area of excellent infrastructure; a four-lane highway, a 220-kilovolt power line and a water pipeline are in close proximity, as are the international airports at Hurghada and Luxor.

Qualified person

The technical information contained in this news release was prepared by Gary Patrick, BSc, MAusIMM, CP (metallurgy), principal consultant of Metallurg Pty. Ltd. Mr. Patrick is a qualified person under National Instrument 43-101, Standards of Disclosure for Mineral Projects.

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