Regulus Reports Attractive Copper Extraction Rates Using Nuton Bio-Leaching and Provides Update on Integrated Sulphide Project Resource Estimate

/EIN News/ -- VANCOUVER, British Columbia, May 20, 2025 (GLOBE NEWSWIRE) -- Regulus Resources Inc. ("Regulus" or the "Company", TSX-V: REG, OTCQX: RGLSF) is pleased to provide an update on the Phase Two metallurgical test program with Nuton LLC (“Nuton”), a Rio Tinto venture. As well, the Company is pleased to provide an update on the integrated resource estimate currently being completed with Compañía Minera Coimolache S.A. (“Coimolache”, collectively with Regulus, the “Parties”), to evaluate the integrated Coimolache Sulphide/AntaKori copper-gold project (“Integrated Sulphide Project”).

Nuton Phase Two Program

The Company continues to work with Nuton to evaluate Nuton’s proprietary sulphide bio-leaching technologies at the AntaKori project. The Phase One program identified that material from AntaKori was amenable to Nuton’s proprietary sulphide bio-leaching technology (see July 6, 2023 press release). In the Phase Two program, a variety of conditions are being evaluated, with each test column using different sets of conditions to evaluate the optimal setup for leaching AntaKori mineralization (particularly enargite-rich high-sulphidation mineralization which makes up the bulk of mineralization at the AntaKori project).

The Company is reporting on the progress of four columns today. Three of the four columns were focused on testing different conditions for enargite-rich high-sulphidation mineralization, while the other column was utilized to test chalcopyrite-dominant porphyry mineralization. The results thus far from the Phase Two program are very encouraging, as Nuton was able to achieve attractive copper extractions utilizing its Nuton bio-leaching technology on both styles of mineralization. As well, this test work has refined the understanding of which set of conditions produces attractive copper extractions for enargite-rich high-sulphidation mineralization. To date, the highest copper extraction for enargite-rich high-sulphidation mineralization is 88.3% (see Figures 1 and 2). To date, the highest copper extraction for porphyry-hosted chalcopyrite mineralization is 87.9% (see Figures 1 and 2). As mentioned previously, this phase of test work is designed to evaluate various conditions to establish the optimum additives for bio-leaching enargite-rich high-sulphidation mineralization. As such, two of the columns identified conditions that produced slower extraction rates and hence less favourable conditions than the column conditions that produced the 88.3% extraction. However, copper extractions in both of these columns continue to trend upwards. Four additional columns have since been started to further refine the optimal conditions achieved and reported here for leaching AntaKori’s enargite-rich high-sulphidation mineralization with Nuton’s bio-leaching technology. The Company will report on these additional columns when they are at or nearing completion.

Integrated Sulphide Project

Regulus and Coimolache, owner of the Tantahuatay oxide gold mine adjacent to the AntaKori project, continue to advance the Integrated Sulphide Project resource estimate. The Parties have worked collaboratively over the past several months to develop an integrated geological model effectively blending views on geology, structure and mineralization styles, which was a critical step before moving towards an integrated resource estimate. The Parties have hired SRK Peru to develop the resource estimate on the Integrated Sulphide Project and it is anticipated that the study will be completed mid-year. As per the agreement between the Parties, the results of this study can only be publicly reported or shared with third parties upon mutual agreement of the Parties.

John Black, Chief Executive Officer of Regulus, commented: “We are very encouraged by the results of the Phase Two program with Nuton. Conditions have been established under which attractive copper extraction is achieved from both high-sulphidation and porphyry mineralization utilizing Nuton’s bio-leaching technology. With several other columns underway, we continue to view Nuton’s bio-leaching technology as one of several potential processing options for mineralization at AntaKori. As well, we have made considerable progress on the integrated resource estimate with Coimolache, with the creation of an integrated geological model. SRK Peru now has all the information they need to complete the resource estimate on the Integrated Sulphide Project and we look forward to receiving the final results soon.”

Qualified Person

The scientific and technical data contained in this news release pertaining to the AntaKori project has been reviewed and approved by Dr. Kevin B. Heather, Chief Geological Officer, FAusIMM, who serves as the qualified person (QP) under the definition of National Instrument 43-101.

ON BEHALF OF THE REGULUS BOARD
(signed) "John Black"
John Black
CEO and Director
Tel: +1 (604) 685-6800
Email: info@regulusresources.com

For further information, please contact:

Regulus Resources Inc.
Ben Cherrington
Tel: +1 347 394 2728
Email: ben.cherrington@regulusresources.com

About Regulus Resources Inc. and the AntaKori Project

Regulus is an international mineral exploration company run by an experienced technical and management team. The principal project held by Regulus is the AntaKori copper-gold-silver project in northern Peru. The AntaKori project currently hosts a resource with indicated mineral resources of 250 million tonnes with a grade of 0.48 % Cu, 0.29 g/t Au and 7.5 g/t Ag and inferred mineral resources of 267 million tonnes with a grade of 0.41 % Cu, 0.26 g/t Au, and 7.8 g/t Ag (independent technical report prepared by AMEC Foster Wheeler (Peru) S.A., a Wood company, titled AntaKori Project, Cajamarca Province, Peru, NI 43-101 Technical Report, dated February 22, 2019 - see news release dated March 1, 2019). Mineralization remains open in most directions.

For further information on Regulus Resources Inc., please consult our website at www.regulusresources.com.

About Nuton

Nuton is an innovative venture that aims to help grow Rio Tinto’s copper business. At the core of Nuton is a portfolio of proprietary copper leaching technologies and capability. Nuton has the potential to economically unlock copper from hard-to-leach ores, including primary sulfides and, in doing so, increase domestic production of critical minerals to support the energy transition. Nuton technologies can achieve market-leading recovery rates and boost copper production in new, ongoing and historical operations, increasing resource utilization and maximizing their value. With significantly lower energy and water needs than conventional concentrating and smelting, and the ability to produce copper cathode at the mine site, Nuton offers a reliable source of domestically produced copper, with a short mine-to-metal supply chain and the ambition to set industry-leading ESG credentials. One of the key differentiators of Nuton is the ambition to produce the world’s lowest footprint copper while having at least one Positive Impact at each of its deployment sites, across its five pillars: water, energy, land, materials and society.

For more information please visit https://nuton.tech/.

Forward Looking Information

Certain statements regarding Regulus, including management's assessment of future plans and operations, may constitute forward-looking statements under applicable securities laws and necessarily involve known and unknown risks and uncertainties, most of which are beyond Regulus' control. Often, but not always, forward-looking statements or information can be identified by the use of words such as "plans", "expects" or "does not expect", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates" or "does not anticipate" or "believes" or variations of such words and phrases or statements that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved.

Specifically, and without limitation, all statements included in this press release that address activities, events or developments that Regulus expects or anticipates will or may occur in the future, including the development of the AntaKori project described herein, and management's assessment of future plans and operations and statements with respect to the completion of the anticipated exploration and development programs, may constitute forward-looking statements under applicable securities laws and necessarily involve known and unknown risks and uncertainties, most of which are beyond Regulus' control. These risks may cause actual financial and operating results, performance, levels of activity and achievements to differ materially from those expressed in, or implied by, such forward-looking statements. Although Regulus believes that the expectations represented in such forward-looking statements are reasonable, there can be no assurance that such expectations will prove to be correct. The forward-looking statements contained in this press release are made as of the date hereof and Aldebaran does not undertake any obligation to publicly update or revise any forward-looking statements or information, whether as a result of new information, future events or otherwise, unless so required by applicable securities law.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Figure 1 – Copper deportment by mineral

Figure 2 – Copper extractions (VO stands for volcanic-hosted, high-sulphidation, enargite-rich mineralization, PO stands for porphyry-hosted, chalcopyrite-rich mineralization).

Photos accompanying this announcement are available at

https://www.globenewswire.com/NewsRoom/AttachmentNg/1ed00b4f-7f26-42b9-806a-f25de6d372be

https://www.globenewswire.com/NewsRoom/AttachmentNg/509bd861-f204-4c64-933d-71575f33afcf