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Erdene Continues to Expand New Ulaan GOLD Discovery 77 Metres of 3.2 G/T GOLD, Including 27 Metres of 8.7 G/T GOLD and 152 Metres of 1.7 G/T, Including 65 Metres of 3.1 G/T GOLD

Drill Results

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ERDENE CONTINUES TO EXPAND NEW ULAAN GOLD DISCOVERY

77 METRES OF 3.2 G/T GOLD, INCLUDING 27 METRES OF 8.7 G/T GOLD AND

152 METRES OF 1.7 G/T, INCLUDING 65 METRES OF 3.1 G/T GOLD

Press Release

Halifax, Nova Scotia

2021.10.20

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

“Company”) is pleased to announce assay results from four (4) holes in the South Ulaan

gold discovery expansion drill program. Today’s results confirm thick sequences of high-

grade gold mineralization continue west of the initial discovery.

Highlights

• Drilling expands mineralization at South Ulaan to the west, with multiple thick gold

mineralized zones with high-grade intersections:

o UDH-21: 77 metres of 3.2 g/t gold and 71 metres of 0.8 g/t gold

§ Includes 27 metres of 8.7 g/t gold , including one metre of 156.5 g/t

gold

o UDH-22: 65 metres of 3.1 g/t gold within 152 metres of 1.7 g/t gold

§ Includes 7 metres of 18.5 g/t gold, including one metre of 119.8 g/t

gold

o UDH-19: 190 metres of 0.7 g/t gold

§ Includes 5 metres of 12.5 g/t gold , including one metre of 60.6 g/t

gold

• Together with the Bayan Khundii deposit, Dark Horse and Altan Arrow Prospects,

these results demonstrate the potential scale of mineralization within the Khundii-

Ulaan Hydrothermal system

o Results from drilling at the Dark Horse Zone, consisting of 36 holes totaling

2,286 metres, will be reported by mid-Q4

o Developing exploration plans to test high -priority geochemical and

geophysical targets throughout the large Khundii-Ulaan system

Quotes from the Company:

“Today’s results confirm the significance of the Ulaan gold discovery and are a testament

to the potential for discovery across the wider area,” said Peter Akerley, Erdene’s

President and CEO . “This new discovery is producing the thickest intervals of gold

mineralization intercepted in the District to date, including exceptionally high-grade zones,

and remains open at depth and to the west.”

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“Ulaan is part of a very large gold-bearing hydrothermal alteration system underlying our

Khundii and Ulaan licenses that shows the potential to host a multimillion-ounce gold

deposit,” continued Mr. Akerley. “Exploration continues across this system with results

from additional drilling at our Dark Horse prospect anticipated by mid-Q4.”

Summary of Drill Results

The recently completed Ulaan drill program was designed to test the extent of

mineralization around the discovery drill holes reported on August 11, 2021 ( see press

release). The program consisted of nine (9) holes totaling 3,204 metres. Drill ho les were

spaced 25 to 50 metres apart and to a maximum depth of 461 metres, testing targets over

an area of approximately 1.2 square kilometres.

Assay results from five (5) drill holes (UDH -14 to UDH-18) were reported on September

23, 2021 (see press release ). Results for the final four (4) holes (UDH-19 to UDH -22),

with an aggregate meterage of 1,401.1 metres, are reported herein. Highlights are

provided below in Table 1 , and a drill hole plan map and section are attached to this

release.

Table 1: Ulaan Q4 2021 Drilling Highlights (Intervals averaging over 0.30 g/t gold)

Hole From To Interval (1) g/t Au

UDH-19 82 272 190 0.73

Incl 87 92 5 12.52

Incl 87 88 1 60.55

UDH-20 98 100 2 1.10

And 288 298 10 0.59

UDH-21 115 192 77 3.19

Incl 131 158 27 8.74

Incl 139 140 1 156.54

Incl 155 156 1 20.98

And 209 280 71 0.81

Incl 222 230 8 1.92

Incl 257 271 14 2.79

And 304 318 14 0.34

And 346 350.3(2) 4.3 0.38

UDH-22 85 236.7 151.7 1.71

Incl 85 150 65 3.11

Incl 87 94 7 18.50

Incl 93 94 1 119.80

And 332 338 6 0.33

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

mineralization and true thicknesses

2. End of hole

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Gold mineralization intersected at South Ulaan begins approximately 80 metres from

surface and is hosted within the same white mica altered lapilli tuff sequence which hosts

Erdene’s Bayan Khundii epithermal gold deposit, located just east on the Khundii mining

license. Gold grades up to 156.5 g/t are related to intense quar tz ± hematite veins and

stockwork zones potentially related to a bounding structure and/or feeder conduit. Gold

mineralization at South Ulaan also appears to be partially controlled by lithology with low

permeability silicified ash tuffs focusing fluid flow and coarser lapilli tu ffs a cting as a

preferred host to mineralization relative to the finer grained lithologies.

In general, the highest -grade gold mineralization occurs within intervals of pervasive

silicification combined with adularia and whi te mica alteration cut by epithermal style,

irregular quartz -hematite, quartz -adularia, quartz -white mica veins and quartz -chlorite-

magnetite veins. In many instances visible gold has been observed finely disseminated

within these veins.

Khundii-Ulaan Mineralized System

The Ulaan exploration license and adjoining Khundii mining license cover nearly 4,000

hectares of the Khundii-Ulaan hydrothermal alteration zone , which extends from Ulaa n

over 10 kilometres to the northeast. This alteration trend has a central zone of intense

secondary silica with a peripheral halo of sericite alteration, and an outer zone of white

mica and sericite, which hosts the Bayan Khundii gold deposit. This northeast trending

alteration area, which incorporates the Ulaan, Bayan Khundii , Dark Horse and other

mineralized targets in the area, is associated with a regional structural dilational jog and

associated major volcano-plutonic centre, along a northeast trending transform fault. The

various styles of alteration and mineralization within the Khundii-Ulaan target area are

consistent with a fertile magmatic island arc, with evidence for possible arc migration, and

overlapping or telescoped mineralization along major structures.

Exploration results to date suggest the greater Khundii-Ulaan alteration zone and known

gold occurrences are part of the same , large, gold-bearing hydrothermal system which

remains largely under-explored. Gold mineralization identified to date is hosted within an

expansive, white mica and silica altered tuffaceous sequence exposed around the

periphery of the Khundii-Ulaan hydrothermal alteration system. Quartz vein textures and

clay alteration compositions indicate a large-scale epithermal type gold mineralizing

environment existed within the Khundii-Ulaan system with the tuffaceous lithologies

acting as preferred hosts for gold mineralization . Exploration planning is currently

underway to test multiple high-priority geological, geochemical and geophysical targets

across the Khundii-Ulaan target area.

Khundii Gold District

Erdene’s deposits are in the Edren Terrane, within the Central Asian Orogenic Belt, host

to some of the world’s largest gold and copper-gold deposits. The Company has been the

leader in exploration in southwest Mongolia over the past decade and is responsible for

the discovery of the Khundii Gold District comprised of multiple high -grade gold and

gold/base metal prospects, one of which is currently being developed, the 100%-owned

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Bayan Khundii Gold Project, and another which is being considered for development, the

100%-owned Alta n Nar Project. Together, these deposits comprise the Khundii Gold

Project.

The Bayan Khundii Gold Resource1 includes 585,100 ounces of 2.19 g/t gold Measured

and Indicated (“M&I ”)2 and 35,900 ounces of Inferred resources at 2.18 g/t gold. Within

the M&I resource, a Proven and Probable open-pit reserve totals 409,000 ounces at 3.7

g/t gold3 (press release here), providing significant potential for reserves growth with the

development of the remaining M&I and Inferred resources1.

In July 2020, Erdene announced the results of an independent Feasibility Study for the

Bayan Khundii Gold Project (press release here). The Feasibility Study results include an

after-tax Net Present Value at a 5% discoun t rate and a US$1,400/oz gold price of

US$100 million and Internal Rate of Return (“IRR”) of 42%. The Feasibility Study

envisions an open -pit mine at Bayan Khundii, producing an average of 63,500 oz gold

per year, for seven years, at a head grade of 3.71 g/t gold, utilizing a conventional carbon

in pulp processing plant. Production is expected to commence in 202 3 based on the

current project schedule.

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

the acquisition, explorat ion, and development of precious and base metals in

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

mining licenses and two exploration licenses in Southwest Mongolia, where exploration

success has led to the discovery and definition of the Khundii Gold 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 assayed at

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

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 eleme nts. 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

1 For details of the Mineral Resources see Erdene’s Q2/2021 results press release, dated August 16, 2021, and the

Company’s Q2 2021 MD&A, available on the Company’s website or SEDAR.

2 M&I: 232,700 ounces of 2.39 g/t gold Measured and 352,400 ounces of 2.08 g/t gold Indicated

3 P&P: 165,000 ounces of 4.4 g/t gold Proven and 256,000 ounces of 3.4 g/t gold Probable; For details of the Mineral

Reserves see Khundii Gold Project NI 43 -101 Technical Report, Tetra Tech December 4, 2019 available on the

Company’s website or SEDAR

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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, ex cluding 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 th e 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 Ulaan drill

holes are all dipping at 85 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 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 pro ve to have been correct. Erdene cautions 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 cause actual results to differ materially 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 gen eral economic, market or business conditions. 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 obligation 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

Erdene Contact Information

Peter C. Akerley, President and CEO, or

Robert Jenkins, CFO

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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-/

© 2021 Erdene Resource Development Corp.

All rights reserved

BAYAN KHUNDII

GOLD DEPOSIT

DARK HORSE

GOLD PROSPECT

Altan

Arrow

Gold Prospect

West Gate

Gold Anomaly

Tourmaline

Breccia

Gold Zone

Khundii

North

Gold Prospect

THE BAYAN KHUNDII (“RICH VALLEY”) DISCOVERY

Khundii – Ulaan Tenements, BK Deposit and Prospects Location Map

Ulaan

Exploration License

Erdene

100% Ownership

Khundii

Mining License

Erdene

100% Ownership

Intense White Mica

Sericitic

Core

Khundii – Ulaan Hydrothermal Alteration Footprint

Intense white mica and Phyllic Zone

Pervasive white mica Argillic zone

Intense Silicification

1 km 1 km

Khundii – Ulaan Active Discoveries and Prospects

Pervasive Alteration Footprint

South

Ulaan

Plan Map

ULAAN

GOLD DISCOVERY

© 2021 Erdene Resource Development Corp.

All rights reserved

ULAAN GOLD DISCOVERY – 300 METRES WEST OF BAYAN KHUNDII DEPOSIT

Bayan Khundii Gold Trend Continuation and Ulaan Gold Discovery

Ulaan

Exploration License

100%

Erdene

Khuren

Tsav

Exploration

License 100%

Erdenes

Alt

Khundii

Mining License

100%

Erdene

Bayan Khundii

Proposed Pit

Dark Horse

2.4 Kilometres

500 m

Gold in Soil +

Rock Chip Anomaly

Tenement Boundary

Projected Trend

Gold Mineralization

N

Bayan Khundii Gold Deposit

and Mineralized Trend

3

SE ULAAN

PROJECT AREA

INSET MAP