Altamira Gold Reports 92% Gold Recovery from Metallurgical Tests Using the Alternative Clean Mining Thiosulphate Leach Technique on Drill Samples from the Maria Bonita Target, Cajueiro Project, Brazil

Altamira Gold Corp. (TSXV: ALTA) (FSE: T6UP) (OTC Pink: EQTRF), ('Altamira' or the 'Company') is pleased to announce that it has received the results of an initial metallurgical leach characterisation test on a drill core composite sample of primary mineralization from the recent Maria Bonita discovery within the Cajueiro project in Para state, Brazil.

This test complements those test results released on March 1, 2023, using the conventional cyanide leach technology. The current test was conducted at SGS Australia and CSIRO laboratories in Western Australia using a proprietary thiosulphate leach technique developed by Clean Mining, a subsidiary of Clean Earth Technologies (CET), based in Singapore. CET is commercialising a non-cyanide approach to leaching of gold ores that was originally developed in Australia by CSIRO. Cyanide leaching is the traditional method to extract low grade gold. Thiosulphate leaching offers a more environmentally benign route to gold extraction.

Highlights

A 24-hour agitated leach test using the thiosulphate leach agent, at a grind size of 80% passing 75-microm, recovered 92% of total gold content.

The head grade of the sample treated compares well with the original assays of the diamond drill composites making up the sample (50g fire assays). The original assays from the drill samples gave 1.07g/t gold. The Clean Mining laboratory head grade (500g sample) gave 1.04g/t gold. The Clean Mining leach test resulted in a back-calculated head grade of the sample (after leaching) of 1.10g/t gold (1000g of leach test sample). These results underline the consistency of the mineralization.

A cyanide leach test was also conducted in parallel using the same grind and leach time and yielded a gold recovery of 91%. These results correlate very well with recently announced cyanide leach tests carried out in the Testwork laboratory in Brazil, which also returned an average cyanide leach gold recovery of 91% for primary mineralized material from Maria Bonita.

Final drill results from a series of reconnaissance drill holes completed during 2022 at the Santa Helena project returned several notable intercepts including 0.8m @ 44.8 g/t gold and 0.9m @ 10.4 g/t gold.

Altamira Gold President and CEO, Michael Bennett, commented; 'We are pleased to receive this very positive result, which underlines the potential for a non-cyanide process route to be technically highly competitive with conventional cyanide leaching at our Cajueiro project. Our previous work with Clean Mining on oxide material from the existing Cajueiro resources, gave similar highly encouraging results, and we have now achieved high recoveries with primary material from the new Maria Bonita discovery. This initial test creates a strong option to now evaluate the application of both the Clean Mining and conventional cyanide leach technologies to a start-up heap leach project.'

Consulting metallurgist Ian Gordon Hall Dun BSc (Eng), MSc., who has 45 years of experience as a metallurgist in Brazil, observed, 'This leach test supports the concept of Altamira utilising a non-cyanide route to gold recovery for the Maria Bonita project. At this initial stage, the results provide higher gold recoveries than conventional cyanide leach at low reagent consumption rates which is a very positive initial result. We will further develop this option through testing both the Clean Mining and conventional cyanide leach routes for heap leaching conditions'.

CAJUEIRO PROJECT

The Cajueiro project is located approximately 75km NW of the town of Alta Floresta in the state of Mato Grosso in central western Brazil and is easily accessible by road and has grid power. Cajueiro forms one of three key projects that Altamira controls in the region, the other two being Apiacas and Santa Helena.

Maria Bonita Metallurgical results

Following completion of holes MBA001-MBA004, a representative composite sample of fresh rock mineralization was prepared from assay sample coarse rejects, returned from the analytical laboratory. The sample weighed 5kg and was comprised of 15 subsamples of individual core intervals, each of which measured 0.77-1.5m.

The samples were submitted to Clean Mining and the testwork was conducted at SGS Australia and CSIRO laboratories in Western Australia from January to February 2023.

Clean Earth Technologies (CET) is a Singapore-based EnviroTech company that focuses on the identification, development, and commercialization of research for non-toxic, environmentally friendly industry processes and remediation. CET has two patented technologies, a nontoxic leach reagent and a resin-based collector.

The testwork programme involved crushing and grinding the sample to 80% passing 75 microns. Standard bottle roll leach tests were conducted using 1000 g of sample repulped to 40% solids, with pH adjusted to 5-7 for Clean Mining's reagent and 10.8 for a comparable cyanide leach test.

For the Clean Mining leach test, 31.2 grams of clean leach reagent (CLR), equivalent to 20 grams of reagent per litre of liquor) and 5.6 grams of clean leach enhancer (CLE) equivalent to 3.7 grams of reagent per litre of liquor were added. The concentration of reagents and the pH were monitored for the duration of the test. After 48 hours of leaching, the pulp was filtered and washed with three displacements of water.

The results indicate a consumption of 3.59 kg/t of CLR and 0.36 kg/t of CLE and an average gold recovery of 92.1% within 24 hours. As concluded by Clean Mining, 'The ore has shown low reagent consumption, high gold recovery and fast leaching kinetics'.

About Altamira Gold Corp.

The Company is focused on the exploration and development of gold projects within western central Brazil. The Company holds 8 projects comprising approximately 190,000 hectares, within the prolific Juruena gold belt which historically produced an estimated 7 to 10Moz of placer gold. The Company's advanced Cajueiro project has NI 43-101 resources of 5.66Mt @ 1.02 g/t gold for a total of 185,000 oz in the Indicated Resource category and 12.66Mt @ 1.26 g/t gold for a total of 515,000oz in the Inferred Resource category.

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