Hycroft Hits 82.7 Metres at 87.52 g/t Silver, Feeder Still Unproven

• Hycroft reported 82.7 metres (m) at 87.52 grams per tonne (g/t) silver and 0.77 g/t gold from the shallower part of the Brimstone system.
• Two holes at Brimstone were mineralized from surface to depths of 153.0 m and 142.2 m.
• Drilling below the known system returned an 18-metre zone of stockwork veining, including 1.5 m at 120.00 g/t silver from a depth of 645.9 m.
• The deeper holes remain high in the system and continue toward the feeder target.
• Vortex was extended approximately 150 m to the west, returning 12.5 m at 375.41 g/t silver.

What Has Happened

Hycroft Mining Holding Corporation (Nasdaq: HYMC) reported further results on August 18, 2026, from the 2025 to 2026 exploration drill program at the Hycroft Mine in northern Nevada. At Brimstone, one of 2 high-grade silver systems on the property, drilling extended mineralization closer to surface and returned 82.7 metres (m) at 87.52 grams per tonne (g/t) silver and 0.77 g/t gold from 122.2 m depth. Two further holes, drilled beneath the known Brimstone mineralization to test a potential feeder system, returned alteration and stockwork veining, but not a comparable grade intercept. At Vortex, the second system, high-grade silver extended approximately 150 m to the west, with 12.5 m at 375.41 g/t silver. Approximately 15,585 m of an approximately 26,000-metre core program had been completed by August 18, 2026, since the program began in August 2025.

Closer to Surface at Brimstone

Five holes extended the shallower part of the Brimstone system, the portion lying nearest the surface. One of them confirmed continuity of the high-grade system through its widest section, returning 82.7 m at 87.52 g/t silver and 0.77 g/t gold from 122.2 m depth. Within that interval, 19.4 m graded 108.19 g/t silver and 2.10 g/t gold, and a 0.7-metre interval graded 14.35 g/t gold.

Two of the 5 holes carried mineralization from surface, over 153.0 m at 9.87 g/t silver and 0.44 g/t gold, and over 142.2 m at 17.66 g/t silver and 0.37 g/t gold. A third returned 149.4 m at 33.32 g/t silver and 0.42 g/t gold, including 8.5 m at 148.12 g/t silver and 1.37 g/t gold. A fourth returned 147.8 m at 32.34 g/t silver and 0.44 g/t gold, including 4.4 m at 546.83 g/t silver. Grades of this nature can potentially be supportive of both an open-pit and an underground context, which leaves the choice of mining method open instead of settling it.

Brimstone now measures approximately 300 m wide from north to south and approximately 500 m long from east to west, measured down the dip of the system. The system remains open in all directions and at depth, so those dimensions describe it only as drilled to date. The shallower drilling has therefore added width and continuity to a body whose outer limits are still undefined.

Drilling Below the Known System

The same program is testing something the shallower holes cannot reach. A geophysical anomaly identified in 2025 indicated a potential feeder system below the known mineralization, and 2 holes were stepped out approximately 90 m down dip from the initial holes drilled in late 2025. Both returned alteration and geochemistry, the mineral and chemical changes fluids leave in rock, consistent with the Brimstone fluid pathway.

One of the two intersected an 18-metre zone of stockwork veining, meaning many small veins cutting the rock in several directions, and the only grade reported inside that zone is 1.5 m at 120.00 g/t silver from 645.9 m depth. The same hole returned 2.7 m at 44.63 g/t silver and 0.10 g/t gold from 664.8 m depth. On the section drawing published with the results, both deep holes plot below and outside the shaded body that maps mineralization above 68.5 g/t silver, in a stockwork vein zone annotated as open at depth. The alteration, geochemistry and veining are consistent with the interpretation of a feeder system at depth, but drilling remains high in the system and will continue to advance toward the target.

Vice President, Exploration of Hycroft Mining Holding Corporation, Alex Davidson, separates the deeper drilling from the high-grade already well defined nearer the surface:

"Now the next phase is what's deeper. And that's a critical point for us."

The difference between the two depths lies in the kind of evidence available. Nearer the surface, the system is being measured in metres and grams per tonne; at depth, it is being tracked by the changes fluids left in the rock as they passed through it.

Alteration, Veining & Structural Control

The indicators the exploration team works from at depth are the ones it uses to decide whether a hole has entered the system at all. Management says Hycroft was historically developed as a leach project drilled with reverse-circulation (RC) rigs, so there is extensive shallow RC drilling on the property, and the current work looks below much of what earlier drilling defined. What the team looks for in each hole is the right kind of alteration, the density of veins, added silica, and evidence that something has broken the rock up.

Work on the structural model established an east-west control at Brimstone that the team drills across to understand how fluid moved through the rock, since fluid movement is governed by that structure. Holes are stepped one at a time rather than batched. Where a hole looks promising, the rig offsets it; where it does not, the rig moves to another area of the veins and returns once that hole has been fitted into the model.

Exploration Manager of Hycroft Mining Holding Corporation, Justin Davenport, describes how a single hole is angled to cut those controls:

"This hole is targeting kind of the northern side of our higher-grade Brimstone mineralization. We do know that there's east-west controls, and so this hole's actually oriented more back to the south as we cross those east-west controls and try and understand some of the extensive mineralization at depth."

Each hole has to confirm where the controlling structure lies before the next can be positioned against it, which sets the pace of the deeper program.

Broader Context

The high-grade silver at Brimstone and Vortex is included in a much larger low-grade resource. The 2026 mineral resource estimate, at US$3,100 per ounce for gold and US$36 per ounce for silver, holds combined measured and indicated resources of 16,414 thousand ounces of gold and 562,575 thousand ounces of silver across heap leach and mill material, contained within a computer-generated optimized pit holding 4.92 billion tonnes of total material. That estimate has an effective date of January 21, 2026, so it predates every hole reported in August. It is a resource and not a reserve, and no modifying factors for mine and process design have been applied to it.

Within that resource, the high-grade silver domains are defined at a silver cutoff of 68.57 g/t. Brimstone accounts for 3,198 thousand tonnes measured and indicated at 0.368 g/t gold and 269.54 g/t silver, holding 27,711 thousand ounces of silver. Vortex accounts for 14,940 thousand tonnes at 0.543 g/t gold and 130.14 g/t silver, holding 62,507 thousand ounces of silver.

Davidson puts a scale on the work still ahead for both systems:

"It's going to take a heap of drilling. It's going to take a bit of time to get all that understanding, but there's really interesting things coming out of Vortex."

Three mining options remain open: a large open-pit, a high-grade underground operation, or a hybrid in which high-grade underground complements the pit. Engineering analysis for a decline is well underway. The technical report behind the current plan gives an after-tax net present value at a 5% discount rate (NPV5%) of US$4.3 billion and an internal rate of return (IRR) of 16.9% over a 51-year mine life, on a base case of US$3,600 per ounce for gold and US$48.00 per ounce for silver, and it does not support a development decision.

What to Watch Next

The remainder of the drill program is already allocated between the two systems. Approximately 7,200 m of core will be drilled at Brimstone, and approximately 3,000 m at Vortex, where drilling expands across the breadth of the deposit, targeting the northern, southern, and eastern extensions in addition to the western zone. The program initially uses 2 core rigs and 1 RC rig, with 2 more core rigs added in the second half of 2026, for a total of 5. Management says drilling runs 24 hours a day, year-round.

An assessment of restarting the heap leach operation is scheduled for the same period.

What has not been made public is how the Brimstone metres divide between the deeper feeder test and the shallower step-outs, and no target depth or date has been given for reaching the feeder itself. Nor has the company described what would settle the question, as distinct from advancing it. No hole below the known system has yet returned grade over width, so the deeper half of the Brimstone story remains an interpretation supported by alteration, geochemistry, and veining.

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