Aton Reports up to 97.9% Gold Recovery From Initial Scoping Level Metallurgical Testwork at the Semna Prospect

VANCOUVER, BC / ACCESSWIRE / January 4, 2024 / Aton Resources Inc. (TSXV:AAN) ("Aton" or the "Company") is pleased to update investors on the results of initial scoping level metallurgical testwork from its recent Semna drill discovery. Semna is located within the Company's 100% owned Abu Marawat Concession ("Abu Marawat" or the "Concession"), in the Eastern Desert of Egypt, see Figure 1.

Highlights:

• 2 composite metallurgical samples (SMMET-01 and SMMET-02), representative of mineralisation from the Main Vein zone at Semna, underwent scoping testwork. The 2 samples were selected and composited by Aton geologists from reverse circulation percussion ("RC") drill hole samples, and dispatched to Wardell Armstrong International Ltd ("WAI") in the UK for testing;
• The 2 composite samples were subjected to whole ore cyanide leach tests at a grind size of 80% passing 75µm. The leach test results showed final gold recoveries of 97.4% (SMMET-01) and 97.9% (SMMET-02), after 48 hours of leaching. Silver recoveries were 85.2% (SMMET-01) and 87.9% (SMMET-02);
• The 2 composite samples were also subjected to two-stage bulk gravity separation tests at grind sizes of 80% passing 212µm and 75µm. Gold and silver recoveries to the gravity concentrates were 56.4% and 38.0% respectively from sample SMMET-01, and 62.2% and 39.0% respectively from SMMET-02;
• Intensive cyanide leaching of the SMMET-01 gravity concentrate achieved gold and silver recoveries of 98.3% and 96.5% respectively, after 48 hours. Leaching of the SMMET-02 gravity concentrate achieved gold and silver recoveries of 98.6% and 97.3% respectively, after 48 hours;
• Separate cyanide leaching of the gravity tailings achieved gold and silver recoveries of 93.0% and 78.1% from the SMMET-01 sample after 48 hours, whilst gold and silver recoveries from the SMMET-02 sample were 93.6% and 87.5% after 48 hours;
• The combined gravity concentration + leach test results showed final gold recoveries of 96.0% (SMMET-01) and 96.7% (SMMET-02), after 48 hours of leaching. Silver recoveries were 85.1% (SMMET-01) and 91.3% (SMMET-02);
• Initial scoping tests indicates that the Semna Main Vein zone mineralisation is amenable to treatment by both conventional CIL, and gravity concentration-leach processing options.

"These initial scoping level metallurgical testwork results from Semna are exceedingly encouraging. The very high recoveries of both gold and silver indicate that the mineralisation that we have drilled to date in the Main Vein zone at Semna is readily amenable to treatment using both conventional CIL and gravity-leach process routes" said Tonno Vahk, Interim CEO. "This is very positive for us to be able to report these excellent metallurgical testwork results at such an early stage, and the new Semna discovery continues to look highly promising. Preparations for the phase 2 diamond drilling programme at Semna continue to advance rapidly, and we remain on track to start drilling later this month. We envisage the next phase of metallurgical testwork will be undertaken once we have drill core available for testing. We are also very close now to finalising the mining licence at Abu Marawat with the Egyptian Mineral Resources Authority and the Ministry of Petroleum and Mineral Resources, and we look forwards to being able to provide further updates on this very soon."

2 samples were prepared from RC drill samples for metallurgical testing, and were composited to represent the Main Vein zone ("MVZ") mineralisation at the Semna mineral deposit, as drilled to date. Samples were collected onsite from the bagged reject portion of the 1m sample splits from the phase 1 Semna RC drilling programme (see news release dated December 18, 2023). Both composite metallurgical samples weighed slightly less than 40kg. Details of the 2 composite samples are provided in Table 1, and the sampled drill hole collar locations are shown in Figure 2. The 2 composite samples were dispatched from Egypt to WAI's Truro laboratory in the United Kingdom, for a scoping level metallurgical testwork programme consisting of head assays, whole ore cyanide leach testing, gravity separation tests and cyanidation leaching of the gravity products.

The 2 metallurgical samples were composited from bulk reject material from the 1m sub-sample splits from the RC drilling programme, which were retained onsite at the Rodruin sample preparation facility (see news release dated December 18, 2023).

The SMMET-01 sample was composited from 26 separate 1m intervals from 7 different holes which intersected the western portion of the MVZ (see Figure 2), each weighing approximately 1.5kg. The individual grades of the 1m sub-samples varied between 0.40 g/t Au and 94.8 g/t Au, with the weighted average estimated grade of the composite sample being 9.75 g/t Au and 5.5 g/t Ag (Table 1). The individual 1m samples were taken from downhole depths of between 50-189m, and were composed of fresh sulphide mineralisation, displaying only occasional minor localised oxidation.

The SMMET-02 sample was composited from 39 separate 1m intervals from 5 different holes which intersected the eastern portion or extension of the MVZ (see Figure 2), each weighing approximately 1kg. The individual grades of the 1m sub-samples varied between 0.34 g/t Au and 51.8 g/t Au, with the weighted average estimated grade of the composite sample being 8.81 g/t Au and 3.8 g/t Ag (Table 1). The individual 1m samples were taken from downhole depths of between 56-141m, and were composed of fresh sulphide mineralisation, displaying only minor localised oxidation.

Table 1: Details of the composite metallurgical samples

Head assays for gold, silver, copper, lead, zinc, arsenic, sulphur (total and sulphide) and carbon (total) were undertaken in-house by WAI using an aqua regia digest with an atomic absorption spectroscopy ("AAS") finish.

Separate sub-samples of the SMMET-01 and SMMET-02 composite samples were sent by WAI for additional head assay analyses by ALS Minerals. Gold and silver were analysed by metallic screen fire assay (ALS analytical code ME-SCR21). The samples were also analysed for a full multi-element suite of elements, and mercury, using a four acid digest followed by an ICP mass spectrometry finish (ALS analytical codes ME-MS61 and Hg-MS42), see Appendix A.

The results of the head assays are provided in Table 2. The screen fire assay analyses showed the SMMET-01 composite to grade 9.64 g/t Au and 8 g/t Ag, whilst the SMMET-02 composite was shown to grade 8.51 g/t Au and 6 g/t Ag.

Table 2: Head assay results

The screen fire gold assay results show good correlation with the original RC drill results (see Tables 1 and 2), and indicate that the c. 40kg bulk samples submitted for metallurgical testwork are representative of mineralised intervals sampled in the RC drill holes.

Separate to the assay results, the screen fire assay data also indicated that less than 10% of the gold and silver in both samples was distributed within the coarse (+100μm) fraction.

Base metal analyses showed both samples to be low in copper with 0.20% in the SMMET-01 composite and 0.086% in the SMMET-02 composite, whilst zinc grades were 0.007% and 0.006% respectively. Lead and arsenic were below the detection limit of 0.001% (Table 2). The multi-element ICP mass spectrometry analyses also indicated that the levels of deleterious elements including bismuth, cadmium, mercury and antimony were all very low, to a maximum of 2.54 ppm Bi in sample SMMET-02 (Appendix A).

Sulphur levels within the samples were 2.46% S_(TOT) for the SMMET-01 composite and 1.50% S_(TOT) for the SMMET-02 composite (Table 2), with the data showing that 96-97% of the sulphur was present in the sulphide phase. This data confirms the relatively low concentrations of sulphide minerals present in the MVZ mineralisation at Semna, and that the mineralisation is predominantly fresh, with only minor oxidation of the drilled mineralisation, as evidenced by the limited amount of iron and copper oxide minerals logged during the drilling.

A single whole ore cyanidation leach test was conducted on each of the composite samples at a grind size of 80% passing 75µm. The purpose of these tests was to investigate the amount of gold and silver that can be recovered from each sample by means of cyanide leaching.

Results are summarised in Table 3 below.

Table 3: Whole ore cyanide leach test results

The test results showed that 93.5% of the gold in the SMMET-01 composite was recovered after 24 hours of leaching, increasing to 97.4% when the leach residence time was increased to 48 hours. Gold recovery from the SMMET-02 composite was 100.0% after 24 hours, reducing slightly to 97.9% after 48 hours.

75.2% of the silver in the SMMET-01 composite was recovered after 24 hours of leaching, increasing to 85.2% when the leach residence time was increased to 48 hours. Silver recovery from the SMMET-02 composite was 85.9% after 24 hours, increasing slightly to 87.9% after 48 hours.

Bulk gravity tests

Each composite was subjected to a programme of bulk gravity separation followed by cyanide leaching of the gravity products.

A 20kg sample of each composite was subjected to two stages of gravity processing using a Knelson KC-MD3 centrifugal gravity concentrator, with the first stage being conducted at a target grind size of 80% passing 212µm, and the second stage being conducted at a target grind size of 80% passing 75µm.

Results of the bulk gravity separation tests are shown in Table 4 below:

Table 4: Bulk gravity separation test results

The results showed that, after two stages of gravity separation, 56.4% of the gold and 38.0% of the silver had been recovered to the gravity concentrate for the SMMET-01 composite.

Gold and silver recoveries to the gravity concentrate for the SMMET-02 composite were 62.2% and 39.0% respectively.

In both cases approximately 1% of the total mass of the tested sample was recovered to the respective gravity concentrates.

Cyanide leaching of gravity concentrates

The gravity concentrates generated during the gravity separation stage were subjected to leach testing to evaluate the amount of gold and silver that could be recovered via intensive cyanidation leaching.

The intensive cyanidation leach tests were carried out for 48 hours with 20g/L sodium cyanide and 5g/L LeachWell™ GC.

Results of the gravity concentrate intensive cyanidation leach tests are shown in Table 5 below: