Dr. Jamil Sader reports

MONUMENTAL MINERALS FINALIZES DRILL TARGETS AND PLANS DRILLING PROGRAM AT THE JEMI HEAVY RARE EARTH ELEMENT PROJECT, MEXICO

Monumental Minerals Corp. has released all assay results and proposed drill targets from the Jemi rare earth element (REE) project in Coahuila, Mexico, about 40 kilometres south of the Texas, United States, border. Rock sampling across a broad area discovered high grades of the critical magnet metals dysprosium (Dy) and terbium (Tb), resulting in the definition of six high-priority drill targets.

Four months of exploration has been completed at Jemi, with the aim of defining discreet drill targets. This work consisted of detailed geological mapping, regional stream sediment sampling, ground radiometric geophysical surveys and lithogeochemical sampling. Exploration focused on the Jemi dikes and Veladora North prospect areas, which host peralkaline intrusion-related REE mineralization.

A total of 296 assays have been received for surface rock chip samples from Jemi dikes and Veladora North. Samples that are both peralkaline and anomalous in REEs, tantalum and niobium (116 samples) define four discreet priority areas within Monumental's mineral concessions. The priority areas each exhibit high densities of mineralized (eudialyte plus/minus aegirine rich) intrusive dikes, which have intruded into limestone or marble and range in thickness from two metres to 0.1 metre (average of 0.7 m thickness). Three-dimensional modelling of airborne magnetic data (see company's news release dated May 3, 2022) indicates that a larger intrusive body and potential source for the mineralized dikes may lie at a shallow depth (less than 300 m) beneath the dikes. Based on these results, six preliminary drill targets have been chosen and a drilling program is anticipated to commence in June, 2023.

Dr. Jamil Sader, chief executive officer and director, comments: "Our technical team has succeeded in defining six highly prospective drill targets based on mapping, rock chip sampling and geophysics. These targets have similar characteristics to other well-defined hard-rock peralkaline REE systems globally and we are optimistic that drilling will further define a REE mineralized system below the surface at Jemi. We are planning towards a drilling program at both Jemi dikes and Veladora North to commence in Q2 2023."

Of the 116 samples within the priority areas, 74 samples returned values greater than 0.15 per cent total rare earth oxide (TREO), including six samples that returned values greater than 1 per cent TREO to a maximum value of 2.4 per cent TREO. The average TREO samples within the AOIs is 0.24 per cent, and a minimum value of 12 parts per million (ppm).

Dysprosium oxide (Dy2O3) and terbium oxide (Tb2O3) in samples within the priority areas and classified as peralkaline (92 samples) range between 959 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, 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 in the peralkaline rock samples.

In addition to being REE mineralized, 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 (tantalum pentoxide) and greater than 3,576 ppm Nb2O5 (niobium pentoxide), with an average concentration of Ta2O5 of 114 ppm and Nb2O5 of 1,114 ppm.

Rock grab samples are selective samples by nature and as such are not necessarily representative of the mineralization hosted across the Jemi project.

Rare earth element value and the global energy transition

Because of their unusual physical and chemical properties, the REEs have diverse defence, energy, industrial and military technology applications. It is projected that rare earth magnets will maintain dominant market share, powering electric vehicles as well as other types of electric motors (such as wind turbines, 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 C to 160 degrees C. In addition, dysprosium with praseodymium increases a magnet's coercivity (the resistance of a magnetic material to change in magnetization).

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

Methodology and quality assurance/quality control

The analytical work reported on herein was performed by ALS Canada Ltd. at Hermosillo, Mexico (sample preparation), and Vancouver, B.C. (inductively coupled plasma mass spectrometry fusion). ALS is an ISO-IEC 17025:2017 and ISO 9001:2015 accredited geoanalytical laboratory and is independent of Monumental Minerals and the qualified person. Rock samples were subject to crushing at a minimum of 70 per cent passing two millimetres, followed by pulverizing of a 250-gram split to 85 per cent passing 75 microns. A 0.1-gram sample pulp was then subject to multielement ICP-MS analysis via lithium-borate fusion to determine individual REE content (ME-MS81). Monumental Minerals' quality assurance/quality control (QA/QC) program for field rock samples includes the insertion of certified reference standards into the sample sequence to confirm the accuracy of the reported results. Monumental Minerals detected no significant QA/QC issues during review of the data, and is not aware of any sampling or other factors that could materially affect the accuracy of the results.

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 include 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, U.S., 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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