Midnight Sun Continues Rapid Strike Expansion at Dumbwa; Now 6.7 Kilometres of Near-Surface Copper Mineralization

12:30 Uhr  |  GlobeNewswire

VANCOUVER, June 29, 2026 - Midnight Sun Mining Corp. (TSXV: MMA / OTCQX: MDNGF) ("Midnight Sun" or the "Company") is pleased to report additional results from 77 holes on its wholly owned Dumbwa copper deposit, located in Solwezi, Zambia. Drilling has now surpassed 260 holes and 56,855 metres ("m"), confirming continuous near-surface sulphide copper mineralization over 6.7 kilometres ("km") of strike at Dumbwa. Five drill rigs continue to expand the deposit northward along strike and laterally to the east and west of known mineralization.

Highlights of Drilling include:

• DBW-26-200 intercepted 0.42% Cu over 21.6m.
• DBW-26-165 intercepted 0.51% Cu over 13.7m.
• DBW-26-150 intercepted 0.38% Cu over 25.0m.
  

Midnight Sun's President and CEO, Al Fabbro, states, "To date, we have demonstrated that Dumbwa is, at a minimum, a 6,700 metre long and 600 metre to 1,000 metre wide, north-south, strain-controlled copper system. It is typically near, or at, surface, and extends to greater than 200 metres depth. It features a high-grade, central corridor ranging in width from 100 to 600 metres within a broader mineralized shell which can exceed 1,000 metres in width.

Our initial, discovery drilling is broadly spaced with holes positioned 50 to 100 metres apart on each of the east-west lines, with the lines spaced 100 to 200 metres apart north to south. As a result, on any individual line/section, it is expected that only 2 or 3 holes are positioned within the highest-grade corridor, while a higher percentage of holes are positioned in the lower-grade shells. It is evident from our work to date; the higher-grade core shows strong grades and continuity within individual segments of the deposit.

As our drilling has progressed north of the disruption zone we just passed through, we are again seeing good development of visually strong copper mineralization and the northernmost holes we have reported today demonstrate the return of thick, higher-grade mineralization within the central corridor of the deposit."

The Company will host a technical webinar with Midnight Sun's COO, Dr. Kevin Bonel, to discuss the results announced in this news release on Tuesday, June 30^th, 2026, at 10am PST. You can access the webinar via the link provided here: Webinar Link

Drilling Highlights Table:

• Assay results based on four-acid digest, ICP-OES finish. Intervals listed are based on drilling intervals and therefore are considered relative rather than true widths.
• The full table of assays including locations is available on the Company's website and can be accessed through this link: Dumbwa Drill Hole Location and Assay Table.

Phase One Drilling Progress

Drilling has now intersected continuous near-surface sulphide copper mineralization over 6.7km of strike at Dumbwa (see Figures 1, 2, 3 and 4 below). Assays have been received for the first ~5.2km of the drilled trend, and five drill rigs are continuing northward along strike and laterally to the east and west of known mineralization.

Recent drilling has focused on the continued expansion of the Dumbwa Deposit northward, while also refining the lateral boundaries of mineralization, which has resulted in an additional 1.4km of strike extension to the north. This drilling intersects the same geology that characterizes Dumbwa, comprising flat - to gently east-dipping biotite and muscovite-biotite schists hosting sulphide copper mineralization. Importantly, the higher-grade core of the north-south-trending Dumbwa shear zone has re-emerged beyond the northwest-southeast structural corridor, where weaker schist development and associated grade attenuation had previously been encountered. Mineralization remains open along the full extent of the copper-in-soil anomaly, in select areas to the east and west, and at depth.

Approximately 12,500m of Phase One drilling remains to complete the planned testing of the initial 11.5km strike extent, with the program expected to conclude in Q3 2026.

The Strategy Behind Every Drill Hole

The objective has been to define the Dumbwa deposit quickly, methodically, and completely. From the outset, the drill program has been designed to test the full mineralized envelope, which includes the higher-grade core as well as the surrounding lower-grade mineralization, in order to define the overall dimensions and continuity of the system.

To achieve this, drill fences are spaced approximately every 100 to 200m along the 20km strike of the target area, with drill holes positioned every 50 metres across each east-west fence. Beginning at the southern property boundary, drilling has progressively advanced northward, systematically building the deposit one fence at a time.

This approach has now defined a mineralized system extending approximately 6.7km in strike length. The central higher-grade zone is typically between 200 and 600m wide with the total mineralized envelope commonly extending from 1.0 to 1.5km across (see Figures 3 and 4 below).

As a result, each drill fence typically contains only two to three holes within the higher-grade core, while many holes test the surrounding lower-grade mineralization. This is intentional. Demonstrating the full width and continuity of the mineralized system requires drilling to its margins rather than focusing exclusively on the higher-grade centre.

Concentration only on the higher-grade core would result in the deposit remaining open to the east and west, leaving its true dimensions undefined. By systematically drilling the entire mineralized corridor, we are establishing both the geometry of the higher-grade core and the full extent of the broader mineralized system.

This context is critical when interpreting individual assay results. Viewed as a table of drill intersections, many holes appear to return lower grades. Viewed in their geological context, however, those same holes are defining the boundaries of a large, continuous mineralized system while progressively delineating the significant higher-grade core within it.

Figure 1: Dumbwa drilling to date, plotted on 11.5km Phase One copper-in-soil anomaly, target area.

Figure 2: Dumbwa drilling to date, magnified to show current 5.3km drilled strike extent, plotted on Phase One copper-in-soil anomaly, target area.

Figure 3: Assay grade shells superimposed on the Dumba soil anomaly showing the correlation between high soil anomalies and medium to high grade mineralised intercepts at Dumbwa. Drilling continues to follow the soil anomaly north.

Figure 4: 11.5 kilometre Phase One Target area - Assay grade shells superimposed on the Dumba soil anomaly showing the correlation between high soil anomalies and medium to high grade mineralised intercepts at Dumbwa. Drilling continues to follow the soil anomaly north.

Quality Control/Quality Assurance

Drilling was conducted using a conventional diamond drilling rig and drill core was captured for the entirety of each hole and placed into plastic core trays. All drill holes were cored in PQ until stable ground was achieved and then reduced to HQ size for the remainder of each hole. Sampling was based on visible copper mineralisation, and sample intervals honoured any important lithological boundaries. Core was then cut in house using a diamond saw and the right half of core was placed into a 200-micron plastic bag, assigned a unique sample number, and recorded into GeoSpark logging system. Samples always remained under the supervision of Midnight Sun staff to maintain chain of custody. Since March 2026, a total of 14,730 samples were then delivered to SGS Labs located in Kalulushi, Zambia, a fully accredited laboratory. Once received, the samples were sorted, dried, crushed, and pulverized (SGS code PRP90) followed by four-acid digest with ICP-OES finish (SGS Code ICP42S). Copper range of detection is 0.01-10%. Additionally, since April 2026 a total of 6,589 samples have been submitted to Intertek laboratory in Kitwe for sample preparation. Sample pulps were then shipped to Intertek Perth, Western Australia for analysis by four-acid digest with ICP-OES finish. Midnight Sun follows an in-house QA/QC program that consists of a random insertion every 10th sample of either a coarse blank, fine blank, coarse duplicate, fine duplicate, or Certified Reference Material (standards).

Qualified Person: Darin Labrenz, P.Geo., a consulting geologist for the Company and Qualified Person under NI 43-101, has reviewed and approved the technical data and contents of this release.

About Midnight Sun

Midnight Sun is rapidly advancing the Solwezi Copper Project, with a focus on our flagship Dumbwa copper deposit. The Project is located near the town of Solwezi in the heart of the Zambia-Congo Copperbelt, the world's second-largest copper-producing region. This prolific mining district is renowned for hosting multiple major copper deposits, and benefits from excellent infrastructure, an established mining workforce, and a long history of successful production.

The Solwezi Copper Project is surrounded by producing copper mines, including the geologically similar Lumwana mine just west of our project and First Quantum's Kansanshi mine - Africa's largest integrated metallurgical processing facility, approximately 6 kilometres east of the company's recently announced Kazhiba Oxide Resource. This highly favourable location highlights the district-scale potential of Midnight Sun's land package.

The Dumbwa copper deposit underlays a robust 20-kilometre copper-in-soil anomaly, and ongoing drilling has demonstrated strong geological similarities to the nearby Lumwana mine, underscoring the potential scale of this new copper system.

Led by an experienced geological team with a proven track record of major discoveries in the Zambia-Congo Copperbelt and globally, Midnight Sun's goal is to delineate Zambia's next generational copper deposit.

ON BEHALF OF THE BOARD OF MIDNIGHT SUN MINING CORP.
Al Fabbro
President & CEO

For Further Information Contact:
Adrian O'Brien
VP Business Development and Communications
Tel: +1 604 809 6890
Em: adrian@midnightsunmining.com

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This news release contains "forward-looking statements" within the meaning of the applicable Canadian securities legislation that are based on expectations, estimates, assumptions, geological theories, and projections as at the date of this news release. The information in this news release about any information herein that is not a historical fact may be "forward looking statements." Any statement that involves discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (which may, but not always, include phrases such as "anticipates", "expects", "plans", "scheduled", "believed" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking statements and are intended to identify forward-looking statements.

Although the forward-looking statements contained in this news release are based upon what management believes, or believed at the time, to be reasonable assumptions, the Company cannot assure readers that actual results will be consistent with such forward-looking statements, as there may be other factors that cause results not to be as anticipated, estimated or intended. Such factors include, among others, risks relating to the timing and ability of the Company to obtain and the timing of the approval of relevant regulatory bodies, if at all; risks relating to property interests; risks related to access to the project; risks inherent in mineral exploration, including the fact that any particular phase of exploration may be unsuccessful; the availability of contractors; geo-political risks; the global economic climate; metal prices; environmental risks; political risks; and community and non-governmental actions. Further to this, geological similarities or characteristics are not guarantees or certainties of successful exploration. Neither the Company nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking statements. The Company does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

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