Mineralization Remains Open Along Strike and at Depth Beyond Resource Pit

Prime Mining Corp. (TSX: PRYM) (OTCQX: PRMNF) (Frankfurt: 04V3) is reporting expansion drilling results from the Company’s Los Reyes Project, located in Sinaloa State, Mexico. These results are from 2024 drilling at the Z-T Trend and are not included in the Company’s May 2, 2023 Mineral Resource Estimate.

Expansion Drilling Highlights in the Z-T Trend

The Company is reporting 15 core holes at Tahonitas with the following highlights:

• 6.93 grams per tonne gold-equivalent (6.64 gpt Au and 22.4 gpt Ag) over 2.0 metres estimated true width in hole 24TA-117, including:
  • 19.71 gpt AuEq (18.90 gpt Au and 62.8 gpt Ag) over 1.0 m etw;
• 1.51 gpt AuEq (1.0 gpt Au and 39.6 gpt Ag) over 14.2 m etw in hole 24TA-119, including:
  • 4.34 gpt AuEq (2.60 gpt Au and 134.5 gpt Ag) over 2.4 m etw.
• 1.47 gpt AuEq (1.21 gpt Au and 19.9 gpt Ag) over 10.7 m etw in hole 24TA-131, including
  • 7.28 gpt AuEq (6.80 gpt Au and 37.4 gpt Ag) over 0.8 m etw.

Prime Mining Corp. Chief Executive Officer Scott Hicks commented, “Following up on our April news release, in which we shared the discovery of a new shoot at the south-east end of Z-T, the drill results we are reporting today again reflect the high-grade nature of the Z-T Trend and its continuity at depth and along strike. We are continuing our drilling program at the south-east end of Z-T while our generative drilling program at the north-west end of Z-T is testing the Mariposa underground target. To-date, we have drill-tested a linear strike length of approximately three kilometres at Z-T.”

Scott Smith, Executive Vice President of Exploration, added, “These holes continue to prove out the extent of mineralization at Z-T, where we are drilling out vertical gaps to support future resource updates. In addition, with new access in place, we are now drilling significant step outs further along strike to the southeast. We have an additional kilometre of new access along strike to test where detailed mapping has confirmed the structure continues. This is in addition to the three kilometre strike length that has been drill-tested”

Figure 1: Expansion drilling update

Tahonitas Drill Hole Highlights¹

^{1)   A complete table of assay results from all deposits and all secondary zones intersected utilizing a 0.20 gpt Au cut-off is on the Company’s website.
2)   Estimated True Widths (ETW) are estimated based on drill hole geology or comparisons with other on-section drill holes.
3)   Au Equivalent (AuEq) is calculated as Au gpt + (Ag gpt x ($22/$1700)) where $22 and $1700 are the price of one ounce of Ag and Au respectively (in US dollars).
4)   Composite assay grades presented in summary tables are calculated using a Au grade minimum average of 0.20 gpt or 1.0 gpt as indicated in “Au Cut-off” column of Summary Tables. Maximum internal waste included in any reported composite interval is 3.00 m. The 1.00 gpt Au cut-off is used to define higher-grade “cores” within the lower-grade halo.}

INTERPRETATION

24TA-117 displays high grade gold and silver mineralization and remains open to the south-east, while both 24TA-119 and -117 indicates mineralization remains open down-dip. Hole 24TA-119 intercepted gold and silver-bearing mineralization at an elevation of 270m above sea level and approximately 425m down-dip (as measured along the structure) from the current pit bottom.

Holes 24TA-130 and -131 successfully indicated continuity of high-grade mineralization immediately beneath the MRE pit, in an area which was previously drilled at a sub-optimal orientation to mineralization due to access constraints. 24TA-131 is particularly impactful because it connects two previously separate shoots of high-grade mineralization, returning higher grades than estimated in the May 2023 MRE.

24TA-127 intersected high gold-equivalent grades approximately 275m along strike and 350m down-dip from the MRE pit bottom. These results, along with 24TA-117 and -119, continue to grow the newly discovered lobe of high-grade mineralization outlined in our April 2024 release. This high-grade lobe remains open down-dip and along strike to the southeast.

The next steps for expansion drilling at the Z-T Trend are focused on the newly discovered high-grade shoot at Tahonitas defined by 24TA-110, -112, -116, -117, and -119, and to follow-up on open mineralization along strike at the far southeast end of the ZT trend.

The ongoing discovery of mineralization hosted at relatively shallow depths continues to suggest the following:

1. Shallow early-stage intersections that may support pit expansion to the southeast near surface.
2. Demonstrates that the Tahonitas structure continues to be mineralized for 350m along strike from the south-east pit crest.
3. The potential to discover more high-grade plunging shoots with continued drilling at depth within the new southeast strike extension and potentially high-margin underground feed.
4. Continuity of grades at depth; grades that are high enough to potentially support underground resource estimation below the current resource pit bottom.

As noted in earlier Z-T Trend releases focused on Tahonitas, the high-grade plunging shoots are still open at depth and along strike in multiple areas along the Trend.

Figure 2: Z-T Area drilling update

Figure 3: Z-T Area long section with drill holes highlighted (A-A’)

 Figure 4: Z-T Area (Tahonitas) cross section B-B’

2024 Outlook

Prime has completed approximately 28,000 metres of its targeted 40,000-metre 2024 drill program to-date (within budget) and will continue to evaluate drilling plans using its success-based approach. This evaluation will also include prioritization of targets based on probability of resource development and generative area discovery potential.

Four drill rigs are currently active on site at Los Reyes, with 2024 exploration focused on:

• Extending the high-grade Z-T Trend shoots that remain open at depth, as well as along strike, both north and south.
• Expanding the known high-grade mineralization at Guadalupe East.
• Increasing the Central Trend resource through additions at Noche Buena and its connection to San Miguel East.
• Generative target drilling of high-grade intercepts at Las Primas, Mariposa, Fresnillo, Mina and others to further develop the resource potential at Los Reyes.

Links to Figures:

• Figure 1 – Expansion drilling update
• Figure 2 – Z-T Area drilling update
• Figure 3 – Z-T Area long section with drill holes highlighted (A-A’)
• Figure 4 – Z-T Area (Tahonitas) cross section B-B’

Links to Tables:

• Table 1 – Drill Intercepts in this Release
• Table 2 – Drill Intercepts to Date

About the Los Reyes Gold and Silver Project

Los Reyes is a rapidly evolving high-grade, low sulphidation epithermal gold-silver project located in Sinaloa State, Mexico. Since acquiring Los Reyes in 2019, Prime has spent approximately CAD$52 million on direct exploration activities and has completed over 185,000 metres of drilling (to March 31, 2024). On May 2, 2023, Prime announced an updated multi-million-ounce high-grade open pit constrained resource (see the May 2, 2023 press release for more details).

May 2, 2023 Resource Statement

Drilling is on-going and suggests that the three known main deposit areas (Guadalupe, Central and Z-T) are larger than previously reported. Potential also exists for new discoveries where mineralized trends have been identified outside of the currently defined resource areas.

Historic operating results indicate that an estimated 1 million ounces of gold and 60 million ounces of silver were recovered from five separate operations at Los Reyes between 1770 and 1990. Prior to Prime’s acquisition, recent operators of Los Reyes had spent approximately US$20 million on exploration, engineering, and prefeasibility studies.

QA/QC Protocols and Sampling Procedures

Drill core at the Los Reyes project is drilled in predominately HQ size (63.5 millimetre “mm”), reducing to NQ (47.6 mm) when required. Drill core samples are generally 1.50 m long along the core axis with allowance for shorter or longer intervals if required to suit geological constraints. After logging intervals are identified to be sampled, the core is cut and one half is submitted for assay. RC drilling returns rock chips and fines from a 133.35 mm diameter tricone bit. The returns are homogenized and split into 2 halves, with one half submitted for analysis and the other half stored.

Sample QA/QC measures include unmarked certified reference materials, blanks, and field duplicates as well as preparation duplicates are inserted into the sample sequence and make up approximately 8% of the samples submitted to the laboratory for each drill hole.

Samples are picked up from the Project by the laboratory personnel and transported to their facilities in Durango or Hermosillo Mexico, for sample preparation. Sample analysis is carried out by Bureau Veritas and ALS Labs, with fire assay, including over limits fire assay re-analysis, completed at their respective Hermosillo, Mexico laboratories and multi-element analysis completed in North Vancouver, Canada. Drill core sample preparation includes fine crushing of the sample to at least 70% passing less than 2 mm, sample splitting using a riffle splitter, and pulverizing a 250-gram split to at least 85% passing 75 microns.

Gold in diamond drill core is analyzed by fire assay and atomic absorption spectroscopy of a 30 g sample (code FA430 or Au-AA23). Multi-element chemistry is analyzed by 4-Acid digestion of a 0.25-gram sample split (code MA300 or ME-ICP61) with detection by inductively coupled plasma emission spectrometer for a full suite of elements.

Gold assay techniques FA430 and Au-AA23 have an upper detection limit of 10 ppm. Any sample that produces an over-limit gold value via the initial assay technique is sent for gravimetric finish via method FA-530 or Au-GRA21. Silver analyses by MA300 and ME-ICP61 have an upper limit of 200 ppm and 100 ppm, respectively. Samples with over-limit silver values are re-analyzed by fire assay with gravimetric finish FA530 or Au-GRA21.

Both Bureau Veritas and ALS Labs are ISO/IEC accredited assay laboratories.

Additional Notes

Metres is represented by “m”; “etw” is Estimated True Width and is based on drill hole geometry or comparisons with other on-section drill holes; “Au” refers to gold, and “Ag” refers to silver; “gpt” is grams per metric tonne; some figures may not sum due to rounding; Composite assay grades presented in summary tables are calculated using a Au grade minimum average of 0.20 gpt or 1.0 gpt as indicated in “Au Cut-off” column of Summary Tables. Maximum internal waste included in any reported composite interval is 3.00 m. The 1.00 gpt Au cut-off is used to define higher-grade “cores” within the lower-grade halo.

Gold equivalent grades are calculated based on an assumed gold price of US$1,700 per ounce and silver price of $22 per ounce, based on the formula AuEq grade (gpt) = Au grade + (Ag grade x ($22 / $1,700)). Metallurgical recoveries are not considered in the in-situ grade estimate but are estimated to be 93% and 83% for gold and silver, respectively, when processed in a mill, and 72% and 25% respectively when heap-leached. See the June 12, 2023 Los Reyes Technical Report for additional details.

Qualified Person

Scott Smith, P.Geo., Executive Vice President of Exploration, is a qualified person for the purposes of National Instrument 43-101 and has reviewed and approved the technical content in this news release.

About Prime Mining

Prime is managed by an ideal mix of successful mining executives, strong capital markets personnel and experienced local operators all focused on unlocking the full potential of the Los Reyes Project. The Company has a well-planned capital structure with a strong management team and insider ownership. Prime is targeting a material resource expansion at Los Reyes through a combination of new generative area discoveries and growth, while also building on technical de-risking activities to support eventual project development.