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Erdene Reports Bayan Khundii GOLD Project Exploration Results from Dark Horse Prospect

Exploration Programs

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www.erdene.com 1 [email protected]

ERDENE REPORTS BAYAN KHUNDII GOLD PROJECT EXPLORATION

RESULTS FROM DARK HORSE PROSPECT

Press Release

Halifax, Nova Scotia

2023.07.31

Erdene Resource Development Corporation (TSX: ERD | MSE: ERDN) (“Erdene” or the

“Company”) is pleased to announce results of recent exploration at the Dark Horse Gold

prospect, part of the greater Bayan Khundii Gold Project. The Dark Horse Gold prospect

is located approximately two kilometers north of the planned Bayan Khundii (BK) open-

pit in the Khundii Minerals District (the “District”), in southwest Mongolia.

Quotes from the Company

“Since discovery in early 2021, Erdene has defined a 1.5-kilometre mineralized trend at

the Dark Horse Mane, including the very high-grade Dark Horse Mane South Deposit at

the Bayan Khundii Gold Project ,” said Peter Akerley, Erdene’s President and CEO .

“Results from the most recent exploration work open up several new targets for follow up

in the 20 square kilometer greater Dark Horse prospect area that show potential to host

high-grade gold mineralization.”

“Located just two kilometres north of the initial Bayan Khundii open-pit, ore from Dark

Horse Mane will be incorporated into the feasibility study update, expected to be

announced in the coming weeks ,” continued Mr. Akerley. “ Growing resources at Dark

Horse will strengthen the already strong economics of the Bayan Khundii Gold Project.”

Exploration Program Results

Erdene recently completed a shallow drilling and geophysical exploration program across

the greater Dark Horse prospect at the Bayan Khundii Gold Project (Figures 1 and 3) .

The program included an 18 -hole scout exploration drilling campaign, totaling 1,040

metres, and a gradient array induced polarization (IP) geophysical survey covering nine-

square kilometres over the core of the greater Dark Horse prospect. The program was

primarily designed to test for near-surface oxide related gold mineralization, similar to the

Dark Horse Mane deposit, and to identify targets for follow-up deeper drilling.

The program identified multiple areas of near-surface, gold and indicator element

anomalism, with 12 holes intersecting anomalous gold (greater than 0.1 g/t and up to 5.8

g/t Au) and 16 holes returning indicator element mineralization locally over wide intervals

up to 55 metres . Gold, together with antimony, arsenic and molybdenum , geochemical

anomalies are characteristic of the Dark Horse deposit and were instrumental, in the initial

discovery of high-grade, near-surface gold mineralization at the Dark Horse Mane. These

results suggest gold mineralized hydrothermal flu ids, carrying gold and other related

elements, affect a wide zone within the greater Dark Horse area.

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Highlight gold intersections from the program are provided in Table 1.

Table 1: Dark Horse Q3 2023 Drilling Highlights

(Intervals averaging over 0.30 g/t gold)

Hole From To Interval (1) g/t Au

AAD-222 2 8 6 1.44

And 17 18 1 0.41

And 24 25 1 0.71

AAD-226 22 30 8 1.03

Incl 24 25 1 5.17

AAD-235 40 50(2) 10 0.96

Incl 42 43 1 5.81

1. Reported intervals in this release are downhole appare nt widths. Continued exploration is required to confirm anisotropy of

mineralization and true thicknesses

2. End of hole

Hole AAD-222 was a step-out from previous north-south trending trenches and drill holes

that returned up to 70.2 g/t gold over 2 metres (AAD-12). The intersection of

mineralization in AAD-222 extends the area of known gold mineralization approximately

135 metres along trend to the southwest, increasing the gold mineralization strike length

to 250 metres. Mineralization in this zone remains open along trend for hundreds of

meters. Additionally, mineralization remains open at depth, with exploration to date testing

to a maximum depth of 110 metres.

Hole AAD-226 was a near surface follow -up hole to AAD-110 that re turned 7 metres of

1.46 g/t gold in the area of East Mane. Hole AAD-226 intersected near surface oxide gold

mineralization above the previously intersected mineralization in AAD-110. The newly

acquired gradient array IP data sh ows that t he East Mane prospect is located along a

strong north-south lineation, parallel to the Dark Horse Mane trend, that extends over 3

kilometres (the N-S width of the IP survey area). This lineation may represent a previously

unidentified N-S structure. Wide spaced drilling along this lineation, as well as rock and

soil geochemical surveys, have returned gold and thick intersections of indicator element

anomalism. Follow-up exploration will be undertaken later in the year.

Hole AAD -235 was drilled in the Altan Arrow area, where earlier drilling and trenching

returned strong gold, silver and base metal mineralization along a 1.2-kilometre long NE

trend. In addition to the gold mineralization, AAD -235 returned two metres averaging 65

g/t silve r, 0.34 % lead and 0.06% molybdenum (from 42 to 44 metre s downhole). This

combination of elements is more typical of dee per epithermal mineralization, closer to a

possible porphyry center at depth in the untested northeast portion of the Khundii mining

license. Anomalous molybdenum mineralization in soil sampling extends along trend two

kilometres to the northeast, an area that has not been drilled tested to date.

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Gradient Array Survey

A detailed gradient array IP survey, focusing on defining near surface (up to 100 metres

depth) chargeability and resistivity targets, was completed over a nine square kilometre

area, centered on Dark Horse Mane.

The gradient array survey show s the major NE trend of structures, as well as a strong

north-south trends, supporting the structural interpretation of extension zones opening

along a set of NE trending major strike-slip faults, hosting north-south trends of

mineralization identified at Dark Horse Mane . A number of parallel zones with similar

geophysical signatures to known mineralization at Dark Horse Mane have been identified.

These areas are under tested or untested by drilling , including the strong north-south

lineation through East Mane, intersected by AAD-226.

Also of note are t wo north-south, elongated gradient array chargeability/resistivity

anomalies, 400 and 700 metres , respectively, west of Dark Horse Ma ne South. These

zones have the same gradient array IP signature as Dark Horse Mane South and similarly

lie just north of a major NE trending structure interpreted to be a deep-seated structure

and likely conduit for mineralizing fluids. These new geophysical anomalies represent

strong new exploration targets. Together with other geological and geochemical data, all

zones of gradient array IP anomalism wi ll be assessed and prioritized for future drilling.

(See Figure 4)

Gold Mineralization at Bayan Khundii

The area of known g old mineralization within the Bayan Khundii Project a rea extends

from Ulaan in the southwest, through the Bayan Khundii Gold Deposit and north

throughout the greater Dark Horse prospect, covering an area of over 40 square

kilometres. Gold mineralization is focused along northeast-southwest and related north -

south structures, that acted as conduits for minera lized fluids from deep magmatic

sources, potentially related to porphyry centers at depth (Figures 2 and 5).

The variety of minerals associated with the gold mineralization , and the large area of

mineralization, suggests either multiple magmatic /porphyry sources , varying depths of

mineralization (with subsequent varying levels of uplift and erosion to expose different

depths of mineralization at the current surface) or both.

The greater Dark Horse pros pect (approximately 20 square kilometres) is located in the

northern portion of the Khundii mining and Ulaan exploration licenses and is characterized

by elevated gold in soil anomalism with multiple surface rock -chip, trench and drill core

samples assayin g greater than 1 g/t gold. Trace element anomalism, geophysical

anomalies related to alteration and mineralizati on, structures interpreted to represent

conduits for mineralizing fluids, and alteration signatures supporting an epithermal

mineralization model characterize the greater Dark Horse prospect area.

The Dark Horse Mane prospect is associated with a north-south trending, linear structural

corridor which intersects deep seated northeast trending transform faults, believed to be

a conduit for primary m ineralizing fluids. The N -S structure has been traced over five

kilometres, from the southern portion of the Bay an Khundii deposit to the northern

extension of Dark Horse Mane. Gold mineralization is hosted within strongly altered

tuffaceous and volcanocla stic rocks, crosscut by quartz and quartz -hematite veins and

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stockwork zones. The Dark Horse Mane shallow oxide zone begins at surface, hosting

supergene enriched gold zones with values up to 195 g/t over 1 metre and ranging in

thickness from 20 to 60 metres vertical depth with locally deeper oxidation along fractures.

The high -grade oxide body exhibits strong conti nuity along a north -south strike.

Mineralization remains open along strike and at depth.

The near surface oxide gold zones discovered at Dark H orse Mane are the result of

oxidation of sulfide bearing epithermal veins and hydrothermal breccias within white mica

altered host lithologies. Limited deeper drilling has intersected gold bearing epithermal

veins and associated white mica and sulfide alte ration zones to a depth of up to 230

metres vertically, that remains open at depth. The gold mineralization near surface at

Dark Horse Mane is related to broader areas of structurally controlled alteration and

mineralization believed to be connected to fee der structures, distributing gold bearing

fluids over a wide area as these fluids approached the paleo surface. Evidence for these

feeder structures includes a series of exposed residual quartz lithocaps, associated

locally with increasing copper anomalism at depth, interpreted to predate the gold

mineralization. These lithocaps are distributed along dominant NE tre nding structures

believed to represent transform faults and potentially feeder conduits from a magmatic

porphyry source at depth. The highest -grade gold bearing oxide zones at the southern

end of the Dark Horse Mane are located proximal to the residual qua rtz lithocaps and

hosted within tuffaceous to porphyritic volcanoclastic units.

Continued success in identifying gold mineralization in the greater Dark Horse area, and

beyond, together with increased understanding of the controls on mineralization, suggest

high potential for the discovery of additional gold mineralization both near surface and at

depth across the Bayan Khundii Project area. It is anticipated that by incorporating the

new exploration data into our geolog ical model, additional high priority target s will be

identified. A return to drilling at the Bayan Khundii Project, including at Dark Horse, is

expected later in the year.

About Erdene

Erdene Resource Development Corp. is a Canada-based resource company focused on

the acquisition, exploration, and development of precious and base metals in

underexplored and highly prospective Mongolia. The Company has interests in three

mining lice nses a nd an exploration license in Southwest Mongolia, where exploration

success has led to the discovery and definition of the Khundii Minerals District. Erdene

Resource Development Corp. is listed on the Toronto and the Mongolian stock exchanges.

Further information is available at www.erdene.com. Important information may be

disseminated exclusively via the website; investors should consult the site to access this

information.

Qualified Person and Sample Protocol

Peter Dalton, P.Geo. (Nova Scotia), Senior Geologist for Erdene, is the Qualified Person

as that term is defined in National Instrument 43-101 and has reviewed and approved the

technical information contained in this news release. All samples have been ass ayed at

SGS Laboratory in Ulaanbaatar, Mongolia. In addition to internal checks by SGS

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Laboratory, the Company incorporates a QA/QC sample protocol utilizing prepared

standards and blanks. All samples undergo standard fire assay analysis for gold and ICP-

OES (Inductively Coupled Plasma Optical Emission Spectroscopy) analysis for 33

additional elements. For samples that initially return a grade greater than 5 g/t gold,

additional screen-metallic gold analysis is carried out which provides a weighted average

gold grade from fire assay analysis of the entire +75 micron fraction and three 30 -gram

samples of the -75 micron fraction from a 500 gram sample.

Erdene’s drill core sampling protocol consisted of collection of samples over 1 or 2 metre

intervals (depending on the lithology and style of mineralization) over the entire length of

the drill hole, excluding minor post -mineral lithologies and un -mineralized granitoids.

Sample intervals were based on meterage, not geological controls, or mineralization. All

drill core was cut in half with a diamond saw, with half of the core placed in sample bags

and the remaining half securely retained in core boxes at Erdene’s Bayan Khundii

exploration camp. All samples were organized into batches of 30 including a commercially

prepared standard, blank and either a field duplicate, consisting of two quarter -core

intervals, or a laboratory duplicate. Sample batches were periodically shipped directly to

SGS in Ulaanbaatar via Erdene’s logistical contractor, Monrud Co. Ltd.

Reported intervals are apparent thicknesses, i.e., downhole widths. The current Bayan

Khundii drill holes (reported in this release) are all dipping from 45 to 60 degrees and

oriented to intersect SW dipping WNW trending gold bearing veins. Additional study is

required to confirm true widths. Reported grades for intervals are weighted averages

based on length of sampling intervals. No top cut has been applied; however, all intervals

greater than 10 g/t gold and 100 g/t gold are reported individually for clarity.

Forward-Looking Statements

Certain information regarding Erdene contained herein may constitute forward -looking

statements within the meaning of applicable securities laws. Forward-looking statements

may include estimates, plans, expectations, opinions, forecasts, projections, guidance, or

other statements that are not statements of fact. Although Erdene believes that the

expectations reflected in such forward-looking statements are reasonable, it can give no

assurance that such expectations will prove to have been correct. Erdene cautio ns that

actual performance will be affected by a number of factors, most of which are beyond its

control, and that future events and results may vary substantially from what Erdene

currently foresees. Factors that could cau se actual results to differ mater ially from those

in forward-looking statements include the ability to obtain required third party approvals,

market prices, exploitation, and exploration results, continued availability of capital and

financing and general economic, market or business cond itions. The forward -looking

statements are expressly qualified in their entirety by this cautionary statement. The

information contained herein is stated as of the current date and is subject to change after

that date. The Company does not assume the oblig ation to revise or update these

forward-looking statements, except as may be required under applicable securities laws.

NO REGULATORY AUTHORITY HAS APPROVED OR DISAPPROVED THE

CONTENTS OF THIS RELEASE

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Erdene Contact Information

Peter C. Akerley, President and CEO, or

Robert Jenkins, CFO

Phone: (902) 423-6419

Email: [email protected]

Twitter: https://twitter.com/ErdeneRes

Facebook: https://www.facebook.com/ErdeneResource

LinkedIn: https://www.linkedin.com/company/erdene-resource-development-corp-/

20 km

Landsat 8 True Colour

Shallow, High-Grade, Gold and Polymetallic Deposits and Prospects

Exploration License

Mining License

Prospect

Deposit

Au

Cu

Mo

BK Gold Deposit

Discovered: 2015

Shovel Ready High-grade, Open-Pit gold

Project; >600koz >2g/t Au Resource

Ulaan SE Gold Discovery

Discovered: 2021

Blind-top Discovery

Dark Horse Gold Discovery

Discovered: 2021

High-grade, near-surface Discovery

Discovered: 2012

Gold Polymetallic Deposit

>500koz Au Resource ~ 2g/t

Altan Nar Gold Deposit

Zuun Mod Moly & Copper Deposit

Largest advanced, undeveloped Molybdenum-

copper project in Asia; >400Mlbs Molybdenum

Khundii Gold Project production and economics based on July 2020 Bankable Feasibility Study

N

THE KHUNDII MINERALS DISTRICT – MULTI-MILLION OUNCE POTENTIAL

Four Gold Discoveries, Molybdenum-Copper Deposit and Multiple High-Priority Targets

The Bayan Khundii Gold Deposit – Project Area

N

GREATER DARK HORSE

2000 m

DARK HORSE DEPOSIT (2021-22)

Drill Hole From To M Au g/t G*M

UDH-10 99 139 40 3.77 151

UDH-14 192 226 34 5.43 185

UDH 22 85 150 65 3.11 202

UDH-21 115 192 77 3.19 246

UDH-35 187 228 41 8.10 332

Drill Hole From To M Au g/t G*M

BKD-292 0.9 23 22.1 20 442

BKD-98 39 170.5 131.5 3.86 508

BKD-261 13 125 112 5.9 661

BKD-288 11.5 17 5.5 125.9 692

BKD-231 193 207 14 158.3 2216

Drill Hole From To M Au g/t G*M

AAD-58 10 55 45 5.96 268

AAD-137 1.5 26 24.5 9.37 230

AAD-146 15 32 17 16.65 283

AAD-177 1 24 23 11.37 262

AAD-178 11 26 15 42.84 643

Gold ≥ 0.1 g/t*

Primary Target Structure

Anomalous Indicator*

(±Sb, As, Qtz Veining, Alteration)

Secondary Structure or Splay

*Based on drill result interpolation only

BAYAN KHUNDIIPROJECT AREA – LARGE, HIGH-GRADE, EPITHERMAL GOLD SYSTEM

Multiple High-Grade Gold Targets: Over 10km of Mineralized Structures – Exploration Largely Limited to Upper 150 Metres

BK DEPOSIT (2018-22)

ULAAN DEPOSIT (2021-22)

District Section

HISTORIC GOLD

INTERSECTION HIGHLIGHTS

G*M=GRAM X METRES