Erdene Resource Development Corporation announced commencement of exploration at the Dark Horse Gold prospect, located approximately two kilometers north of its Bayan Khundii Gold Project in the Khundii Minerals District (the District) in southwest Mongolia. Program Overview The second quarter 2023 greater Dark Horse exploration program includes 18 shallow holes totaling approximately 1,000 metres to test for near-surface oxide related gold mineralization similar to the Dark Horse Mane deposit. In conjunction with the diamond drill program, the Company is also completing a gradient array IP geophysical survey covering a 9 square kilometre area, over the core of the greater Dark Horse prospect.

The target area (see Dark Horse Prospects Plan Map attached in release) exhibits extensive gold and indicator element mineralization over several kilometres along NE trending structures and their intersections with N-S faults, parallel to the Dark Horse Mane structure. Results from this program will establish priority targets for a larger program, scheduled to start in third quarter, following the receipt and interpretation of results from the current drilling and geophysical programs. Dark Horse Prospect Overview The greater Dark Horse prospect (approximately 20 square kilometres) is located in the northern portion of the Khundii mining and Ulaan exploration licenses and is characterized by promoted gold in soil anomalism with multiple surface rock-chip, trench and drill core samples assaying greater than 1 g/t gold. Trace element anomalism, geophysical anomalies related to alteration and mineralization, structures interpreted to represent conduits for mineralizing fluids, and alteration signatures supporting an epithermal mineralization model characterize the greater Dark Horse prospect area.

To date, the Company has completed 24,092 metres of drilling in 218 holes ranging in vertical depths from 8 to 318 metres within the greater Dark Horse prospect portion of the Khundii mining license, including 28 holes totaling 2,355 metres in 2022. Most of the drilling to date has been focused on the Dark Horse Mane discovered in early 2021. Erdene discovered Dark Horse Mane, 2 kilometres north of the Bayan Khundii deposit, when initial drilling returned 6.0 g/t gold over 45 metres, beginning 10 metres downhole, including 8 metres of 27.1 g/t gold (AAD-58).

Drilling over the past year has defined a 1.5-kilometre trend of alteration and gold mineralization within the Dark Horse Mane prospect that remains open along strike to the north and south, and at depth. Highlight interceptions at Dark Horse Mane since the initial discovery include: AAD-126: 30 metres of 5.6 g/t gold, beginning 10 metres downhole, including 24.1 g/t over six metres, starting 26 metres downhole AAD-137: 24.5 metres of 9.4 g/t gold beginning 1.5 metres downhole, including 13.5 metres of 16.1 g/t gold AAD-138: 25 metres of 6.1 g/t gold beginning 18 metres downhole, including 8 metres of 17.1 g/t gold AAD-177: 23 metres of 11.4 g/t gold beginning 1 metre downhole, including 4 metres of 59.8 g/t gold within 8 metres of 32.2 g/t gold AAD-178: 15 metres of 42.8 g/t gold beginning 11 metres downhole, including 3 metres of 160.4 g/t gold within 5 metres of 123.5 g/t gold AAD-218: 12 metres of 20.2 g/t gold beginning at surface, including 6 metres 39.6 g/t gold 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 mineralizing fluids. The N-S structure has been traced over five kilometres, from the southern portion of the Bayan Khundii deposit to the northern extension of Dark Horse Mane.

Gold mineralization is hosted within strongly altered tuffaceous and volcanoclastic rocks, crosscut by quartz and quartz-hematite veins and 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 continuity along a north-south strike.

Mineralization remains open along strike and at depth. The near surface oxide gold zones discovered at Dark Horse 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 alteration 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 feeder 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 trending 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 quartz lithocaps and hosted within tuffaceous to porphyritic volcanoclastic units. RC drilling in second quarter 2022 identified several prospects within the greater Dark Horse area. Multiple RC holes at East Mane, an 8-hectare area, 500 metres east of Dark Horse Mane, returned anomalous gold (up to 0.22 g/t gold over 3 metres) and pathfinder elements (antimony and arsenic).

The East Mane area also exhibits structural and geological similarities to high-grade Dark Horse Mane South mineralization.