Regulus Reports Attractive Copper Extraction Rates Using Nuton Bio-Leaching and Provides Update on Integrated Sulphide Project Resource Estimate
NEWS RELEASE
Regulus Reports Attractive Copper Extraction Rates Using Nuton Bio-Leaching and
Provides Update on Integrated Sulphide Project Resource Estimate
May 20, 2025 (Vancouver, BC) - 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: [email protected]
For further information, please contact:
Regulus Resources Inc.
Ben Cherrington
Tel: +1 347 394 2728
Email: [email protected]
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).
0
10
20
30
40
50
60
70
80
90
100
VO-B VO-C PO-F
Copper Deportment
Other
Cu Clays
Tet-Ten
Tetrahedrite
Cu Oxides
Covellite
Chalcocite/Digenite
Enargite
Enargite - Zn
Bornite
Chalcopyrite