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COMPLETES RECONNAISSANCE EXPLORATION PROGRAM AND DEFINES DRILL TARGETS AT THE JEMI HEAVY RARE EARTH ELEMENT PROJECT, MEXICO Results Include 0.43% Total Rare Earth Oxide And 0.17% Heavy Rare Earth Oxide, with several sample results pending

Drill Results Exploration Programs

MONUMENTAL MINERALS CORP.

COMPLETES RECONNAISSANCE EXPLORATION PROGRAM AND DEFINES

DRILL TARGETS AT THE JEMI HEAVY RARE EARTH ELEMENT PROJECT,

MEXICO

Results Include 0.43% Total Rare Earth Oxide And 0.17% Heavy Rare Earth Oxide, with

several sample results pending

News Release - Vancouver, British Columbia – December 14, 2022: Monumental Minerals Corp.

(“Monumental” or the “ Company”) (TSX -V: MNRL; FSE: BE5; OTCQB: MNMRF) is pleased to

provide an update on exploration at the Jemi rare earth element (REE) project (the “Project”) located in

Coahuila, Mexico, about 40 km south of the Texas, USA border . Recent work has included mapping,

lithogoechemistry, rock and stream sediment sampling.

A four-month exploration program was completed at Jemi from August 2022, with the objective to reduce

the search space from approximately 800 hectares, as defined by an airborne radiometric and magnetic

survey (see press release dated May 3, 2022), to the delineation of discreet drill targets. The program, which

focused on the Jemi Dykes and Veladora North areas known to host peralkaline intrusion related REE

mineralization, consisted of detailed geological mapping, regional stream sediment sampling, ground

radiometric geophysical surveys, and lithogeochemical sampling.

To date, 37 whole-rock analytical results from rocks collected at the Jemi Dykes area have been received

while results for 269 samples from Jemi Dykes and Veladora North areas are pending. Of the 37 samples,

11 (eleven) returned values greater than 0.15% total rare earth oxide (TREO 1), including 6 samples that

returned values greater than 0.23% TREO1 and up to 0.43% TREO1 (22KRP004) (Table 1).

Heavy rare earth oxide (HREO2) values (include dysprosium (Dy) and terbium (Tb)), ranged between 1614

parts per million (ppm) and 39 ppm in peralkaline pegmatites, averaging 447 ppm. Six samples exceeded

680 ppm, including three that exceeded 830 ppm (Table 1).

Light rare earth oxides (LREO3) values including neodymium (Nd) and praseodymium (Pr), returned values

up to 0.26% and 0.23%, with values in trend with HREO2 concentrations suggesting similar REE-hosting

phases in the peralkaline rock samples.

Dr. Jamil Sader, CEO and Director comments:

“Our exploration at the Jemi Dykes area of the Jemi Project has defined where Monumental will

drill to delineate the rare earth, tantalum, and niobium bearing pegmatites. This program has de-

risked the geological complexity and provides us with the confidence needed before moving to the

next stage, which is drilling. We anticipate the pending results of analytical work will define

further drill targets at the Veladora North area.”

1 Total Rare Earth Oxides (TREO) includes: La2O3, Ce2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3,

Tm2O3, Yb2O3, Lu2O3, Y2O3.

2 Heavy Rare Earth Oxides (HREO) includes: Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3, Y2O3,

3Light Rare Earth Oxides (LREO) includes La2O3, Ce2O3, Pr2O3, Nd2O3, Sm2O3.

Table 1. Rare earth element and other critical metal assay result s from select samples from the Jemi Dykes area of

the Jemi Project.

Rock samples with the highest REE content are those that are classified as peralkaline (sodium plus

potassium concentrations are greater than aluminum concentrations). In most hard rock HREE ore deposit

mineral systems, rocks must be peralkaline in order for the crystallization of HREE bearing silicate minerals

such as eudialyte to occur. Eudialyte is a highly complex Na, Ca, Fe/Mn, Zr silicate mineral that can contain

up to 10% RE 2O3 (enriched in HREEs), and 12% ZrO 2. Geological mapping has confirmed that samples

with the highest TREO and HREO values are from pegmatitic bodies. Three-dimensional airborne

magnetics modeling show that surface pegmatite bodies are spatially associated wi th a numerous larger

magnetic anomalies at depth that may represent potential source intrusions (Figure 1 ). Specific drill

locations will target these pegmatites.

In addition to being REE -mineralized, samples are also mineralized with respect to tantalum (Ta) and

niobium (Nb). Laboratory determination of these critical elements in all samples from the Jemi project

return values to 534 ppm Ta 2O5 and greater than (>) 3576 ppm Nb 2O5. Within the Jemi Dykes area

specifically, laboratory determinations return v alues in 4 pegmatite samples that are greater than 68 ppm

Ta2O5 and 919 ppm Nb2O5, and one sample that returned values of 170 ppm Ta 2O5 and 2560 ppm Nb2O5.

Concentrations of these elements meet the threshold to be considered potentially economically significant.

Rare Earth Element Applications

Because of their unusual physical and chemical properties, the REEs have diverse defense, energy,

industrial, and military technology applications. Demand for REEs is expected to outstrip supply until at

least 2030 dominantly due the increase in demand for neomagnets for EVs and other electric motors (e.g.,

wind turbines, water pumps). The four key REEs that represent 94% of the REE market by value are Nd,

Pr, Dy, and Tb, all of which are enriched at Jemi. Neodymium-iron-boron magnets, which are the strongest

known type of magnets, are used when space and weight are restrictions are present. The addition of HREEs

terbium or dysprosium to magnets can double their optimal operating temperature from 80°C to 160°C. In

addition, dysprosium with praseodymium increases a magnet’s coercivity (the resistance of a magnetic

material to change in magnetisation).

SAMPLE_ID TREO HREO LREO Dy2O3 Tb2O3 Nd2O3 Pr2O3 Ho2O3 Lu2O3 Y2O3 Nb2O5 Ta2O5 ZrO2 Rock Type

(%) (ppm) (%) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (%)

22KRP004 0.424 1614.406 0.263 155 23 491 145 34 12 1060 2561 170 >1.35 Peralkaline

22062 0.324 968.868 0.228 96 15 377 107 22 10 599 1117 79 0.81 Peralkaline

22KRP002 0.292 829.630 0.209 83 12 341 104 19 10 504 920 69 0.95 Peralkaline

22079 0.263 769.898 0.186 74 12 359 100 15 7 489 448 43 0.86 Peralkaline

22071 0.263 395.326 0.223 37 5 316 103 8 6 235 429 25 0.81 Peralkaline

22074 0.231 677.481 0.164 64 9 244 73 13 5 442 1029 51 1.28 Metaluminous

22KRP001 0.193 299.969 0.163 30 5 260 81 6 5 177 508 26 0.47 Peralkaline

22KRP007A 0.181 138.922 0.167 12 2 165 61 3 2 86 306 18 >1.35 Peralkaline

22076 0.176 420.150 0.134 41 7 236 71 8 3 267 559 32 1.24 Peralkaline

22KRP006 0.175 769.989 0.098 72 11 160 43 16 7 504 740 49 >1.35 Peralkaline

22-JSP-03 0.164 465.992 0.118 43 7 218 65 9 4 300 2038 140 >1.35 Metaluminous

Figure 1. Map of 3D airborne geophysical anomaly interpreted to r epresent the magmatic intrusion, which is the

source of pegmatite dykes that have been mapped at surface. Dysprosium oxide values are highly anomalous (to 155

ppm) in these pegmatites.

Methodology and QQA/QC

The analytical work reported on herein was performed by ALS Canada Ltd. (ALS) at Hermosillo, Mexico

(sample preparation) and Vancouver, B.C. (ICP -MS fusion). ALS is an ISO -IEC 17025:2017 and ISO

9001:2015 accredited geoanalytical laboratory and is independ ent of Monumental Minerals and the QP.

Rock samples were subject to crushing at a minimum of 70% passing 2 mm, followed by pulverizing of a

250-gram split to 85% passing 75 microns. A 0.1-gram sample pulp was then subject to multi-element ICP-

MS analysis v ia 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, P.Geo. (BC) Principal and Consultant of APEX Geoscience Ltd. of Edmonton, AB,

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 Corp. 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, USA border which the

Company has an option to acquire 100% of the 3,650-hectare project. The Company has an option to acquire

a 75% interest and title to the Laguna cesium-lithium brine project located in Chile and a 50.01% interest

in the Salar De Turi lithium project in Chile.

On behalf of the Board of Directors,

/s/ “Jamil Sader”

Jamil Sader, Chief Executive Officer and Director

Contact Information:

Email: [email protected]

Or

Max Sali, VP Corporate Development and Director

Email: [email protected]

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the

policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news

release.

Forward Looking Information

This news release contains “forward‐looking information or statements” within the meaning of applicable securities

laws, which may i nclude, without limitation, the potential plans for the Company’s projects , receipt of additional

results from Jemi, the expected timing and completion of potential drilling at Jemi, other statements relating to the

technical, financial and business prospects of the Company, its projects and other matters. All statements in this news

release, other than statements of historical facts, that address events or developments that the Compan y expects to

occur, are forward-looking statements. Although the Company believes the expectations expressed in such forward -

looking statements are based on reasonable assumptions, such statements are not guarantees of future performance

and actual results may differ materially from those in the forward-looking statements. Such statements are based on

numerous assumptions regarding present and future business strategies and the environment in which the Company

will operate in the future, including the price of metals, the ability to achieve its goals, that general business and

economic conditions will not change in a material adverse manner and that financing will be available if and when

needed and on reasonable terms. Such forward -looking information refle cts the Company’s views with respect to

future events and is subject to risks, uncertainties and assumptions, including the risks and uncertainties relating to the

interpretation of exploration results, risks related to the inherent uncertainty of exploration and cost estimates and the

potential for unexpected costs and expenses and those other risks filed under the Company’s profile on SEDAR at

www.sedar.com. While such estimates and assumptions are considered reasonable by the management of the

Company, they are inherently subject to significant business, economic, competitive and regulatory uncertainties and

risks. Factors that could cause actual results to differ materially from those in forward looking statements include, but

are not limited to, continued availability of capital and financing and general economic, market or business conditions,

failure to secure personnel and equipment for work programs , adverse weather and climate conditions, risks relating

to unanticipated o perational difficulties (including failure of equipment or processes to operate in accordance with

specifications or expectations, cost escalation, unavailability of materials and equipment, government action or delays

in the receipt of government approvals, industrial disturbances or other job action, and unanticipated events related to

health, safety and environmental matters), risks relating to inaccurate geological assumptions, failure to maintain all

necessary government permits, approvals and authorizations, failure to obtain surface access agreements or

understandings from local communities, land owners or Indigenous groups, fluctuation in exchange rates, the impact

of Covid-19 or other viruses and diseases on the Company’s ability to operate, an inability to predict and counteract

the effects of COVID-19 on the business of the Company, including but not limited to, the effects of COVID -19 on

the price of commodities, capital market conditions, restriction on labour and international travel and supply chains,

decrease in the price of rare earth elements, lithium, cesium and other metals, loss of key employees, consultants, or

directors, failure to maintain community acceptance (including from the Indigenous communities), increase in costs,

litigation, and failure of counterparties to perform their contractual obligations . The Company does not undertake to

update forward‐looking statements or forward‐looking information, except as required by law.