Dr. Jamil Sader reports

MONUMENTAL MINERALS ANNOUNCES MAIDEN DRILLING PROGRAM AT THE JEMI HEAVY RARE EARTH ELEMENT PROJECT, MEXICO

Monumental Minerals Corp. has planned a maiden drilling program project at the Jemi rare earth element (REE) project in Coahuila, Mexico, approximately 40 kilometres south of the Texas, United States, border. Rock sampling across a broad area discovered high grades of heavy rare earth elements (HREEs) dysprosium (Dy) and terbium (Tb), and light rare earth elements (LREEs) neodymium (Nd) and praseodymium (Pr), all critical to permanent magnets for EVs (electric vehicles). Additionally, samples contain high concentrations of niobium (Nb) and tantalum (Ta). The exploration work resulted in the definition of six high-priority drill targets.

An extensive surficial exploration program was completed at Jemi, with the aim of defining discreet drill targets. Exploration focused on the Jemi dikes and Veladora North prospect areas within Monumental's claims, which host peralkaline intrusion-related REE mineralization. The work consisted of detailed geological mapping, regional stream sediment sampling, ground radiometric geophysical surveys and lithogeochemical sampling (see the company's news release dated April 4, 2023). Based on that exploration work, Monumental has planned an initial drill program consisting of 1,800 metres over six drill holes, targeting high-priority targets. All permits, land access agreements and drilling contracts have been obtained, and the drilling program will commence the first week of July, 2023. It is expected to take approximately 60 to 90 days to complete, and assay results are expected within six weeks of sample submission to a commercial laboratory.

Dr. Jamil Sader, chief executive officer and director, comments: "We are excited to initiate our maiden drill program at our Jemi project. We have derisked this project from both ESG [environmental, social and governance] and technical aspects, and our next step is to confirm our geological models through drilling. The six high-value targets selected have minerals and geochemistry with similar characteristics to other well-defined hard rock peralkaline REE systems globally, and we are optimistic that drilling will further define an REE mineralized system below the surface at Jemi. With two recent strategic financings, we are fully funded to complete this program."

The goal of the drill program is to define and delineate the source of REE-mineralized (eudialyte-plus/minus-aegirine-rich) intrusive dikes and sills. Dysprosium oxide (Dy2O3) and terbium oxide (Tb2O3) in surface samples within the priority areas that are classified as peralkaline (92 samples) range between 959 parts per million (ppm) and four ppm, and 147 ppm and 0.7 ppm, respectively. The average concentration for Dy2O3 is 110 ppm and the average for Tb2O3 is 17 ppm. The magnetic light rare earth oxides (LREOs), namely neodymium oxide (Nd2O3) and praseodymium oxide (Pr2O3), ranged between 3,173 ppm and 30 ppm, and 824 ppm and eight ppm, respectively. The average concentration for Nd2O3 is 467 ppm and for Pr2O3 it is 132 ppm. These values are in trend with HREO (heavy rare earth oxide) concentrations and the ratio of HREO to LREO is consistently, on average, 1:2, suggesting similar REE-hosting phases across the project.

In addition to being REE-mineralized, the surface samples are also enriched with respect to tantalum (Ta) and niobium (Nb). Assays for these critical elements in all samples from the Jemi project returned values to 976 ppm Ta2O5 and greater than 3,576 ppm Nb2O5, with an average concentration of Ta2O5 of 114 ppm and Nb2O5 of 1,114 ppm.

Upcoming conferences

Monumental Minerals will be attending the Lithium Supply and Raw Battery Materials conference in Las Vegas from June 19 to June 22, 2023, and the Lithium Latin America conference in Buenos Aires on July 5 to July 6, 2023. The company will be meeting with a number of direct lithium extraction (DLE) technology companies, as well as producers, investment funds and suppliers in order to bring more awareness and potential future partnerships to its projects.

Rare earth element value and the global energy transition

Because of their unusual physical and chemical properties, REEs have diverse energy, industrial and military technology applications. It is projected that rare earth magnets will maintain dominant market share, powering EVs as well as other types of electric motors (for example, wind turbines and water pumps) this decade, as there is minimal to no substitution risk. Significant demand growth is therefore expected, and the already tight market and elevated price levels for key magnet rare earths (Nd, Pr, Dy and Tb) is likely to continue. The strongest magnets are neodymium-iron-boron (NdFeB), and are used when space and weight are restrictions are present. The addition of terbium and dysprosium to NdFeB magnets can double their optimal operating temperature from 80 degrees to 160 degrees. In addition, dysprosium with praseodymium increases a magnet's coercivity (the resistance of a magnetic material to change in magnetization).

The four key REEs (Nd, Pr, Dy and Tb) represent 94 per cent of the REE market by value, all of which are enriched at Jemi. Concentrations of Nb and Ta are also enriched and could potentially be economically significant.

Qualified person

The scientific and technical information contained in this news release has been reviewed and approved by Kristopher J. Raffle, PGeo (British Columbia), principal and consultant of APEX Geoscience Ltd. of Edmonton, Alta., a director of the company and a qualified person as defined in National Instrument 43-101 -- Standards of Disclosure for Mineral Projects. Mr. Raffle verified the data disclosed, which includes a review of the sampling, analytical and test data underlying the information and opinions contained therein.

About Monumental Minerals Corp.

Monumental Minerals is a mineral exploration company focused on the acquisition, exploration and development of mineral resource properties in the critical and electric metals sector. The company's flagship asset is the Jemi HREE project located in Coahuila, Mexico, near the Texas, United States, border, which the company has an option to acquire 100 per cent of the 3,650-hectare project. The company has an option to acquire a 75-per-cent interest and title to the Laguna cesium-lithium brine project located in Chile and a 50.01-per-cent interest in the Salar De Turi lithium project in Chile.

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