28 April 2023

NOTICE OF AGM AND DESIGNATED FOREIGN ISSUER STATUS

Horizonte Minerals Plc (AIM/TSX: HZM) ("Horizonte" or the "Company") announces that its annual report and accounts for the year ended 31 December 2022, together with Management's Discussion and Analysis as at 31 December 2022, and Notice of Meeting and Management Information Circular have been posted to shareholders and are available to download on the Company's website at www.horizonteminerals.com and on the System for Electronic Document Analysis and Retrieval (SEDAR) at www.sedar.com.

The Company's Annual General Meeting ("AGM") will be held at 12:30pm on 24 May 2023 at Horizonte's offices located at Rex House, 4-12 Regent Street, London, SW1Y 4RG.

Designated Foreign Issuer status in Canada

The Company has determined that, as at and from the beginning of the current financial year on 1 January 2023, it is a "designated foreign issuer" as defined in National Instrument 71-102 - Continuous Disclosure and Other Exemptions Relating to Foreign Issuers ("NI 71-102") and subject to the regulatory requirements of AIM, a market operated by the London Stock Exchange. Accordingly, the Company is able to rely on certain exemptions from the continuous disclosure obligations imposed under Canadian securities legislation as permitted under NI 71-102.

A key implication is that the Company will no longer be required to report quarterly financial information, and will instead now report financial results on a semi-annual basis, in line with market practice in the UK, and as required by the AIM Rules for Companies with quarterly operation updates.

The next financial information to be reported will be the Company's half yearly report, in respect of the six months to 30 June 2023, which will be published no later than 30 September 2023. This will be followed by the Company's audited financial statements for the year ending 31 December 2023, published no later than 30 June 2024; in each case, in accordance with the AIM Rules for Companies.

For further information, visit www.horizonteminerals.com or contact:

ABOUT HORIZONTE MINERALS

Horizonte Minerals plc (AIM & TSX: HZM) is developing two 100%-owned, Tier 1 projects in Pará state, Brazil, the Araguaia Nickel Project and the Vermelho Nickel-Cobalt Project. Both projects are large scale, high-grade, low-cost, low-carbon and scalable. Araguaia is under construction with first metal scheduled for early 2024, when fully ramped up with Line 1 and Line 2, is forecast to produce 29,000 tonnes of nickel per year. Vermelho is at feasibility study stage and is expected to produce 24,000 tonnes of nickel and 1,250 tonnes of cobalt to supply the EV battery market. Horizonte's combined production profile of over 60,000 tonnes of nickel per year positions the Company as a globally significant nickel producer. Horizonte's top three shareholders are La Mancha Investments S.à r.l., Glencore plc and Orion Resource Partners LLP.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

Except for statements of historical fact relating to the Company, certain information contained in this press release constitutes "forward-looking information" under Canadian securities legislation. Forward-looking information includes, but is not limited to, information relating to: the holding of the Company's AGM; the applicable reporting requirements in respect of the Company's financial information and results; and the anticipated timing for reporting and publishing the Company's financial information and results. Generally, forward-looking information can be identified by the use of forward-looking terminology 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". Forward-looking information is based on the reasonable assumptions, estimates, analysis and opinions of management made in light of its experience and its perception of trends, current conditions and expected developments, as well as other factors that management believes to be relevant and reasonable in the circumstances at the date that such statements are made, and are inherently subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of the Company to be materially different from those expressed or implied by such forward-looking information, including but not limited to various risks associated with the legal and regulatory framework within which the Company operates, together with the risks identified and disclosed in the Company's disclosure record available on the Company's profile on SEDAR at www.sedar.com, including without limitation, the annual information form of the Company for the year ended December 31, 2022. Although management of the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements.