Copper Restart Drilling Runs Ahead of the Studies That Value It

• A preliminary economic assessment (PEA) is computed against a resource estimate frozen at an effective date, not against later drilling.
• The estimate behind the coming study at Minto is effective June 10, 2026.
• Minto's Phase 2 program began on May 1, 2026, and had drilled 45,299 meters (m) by August 18, 2026.
• Of the 187 Phase 2 holes drilled, the 34 at Ridgetop had no reported assays, with laboratory turnaround of six to eight weeks.
• A second estimate is targeting the first part of 2027, so today's drilling reaches a mine plan one study later.

Introduction

A restart project, where a plant and a set of permits already exist, requires no mill to be designed from scratch and no new authorizations, only amendments to those already in place. It reaches a production date through drilling and study at the same time. A preliminary economic assessment (PEA) is computed against a resource estimate, and every resource estimate is frozen at an effective date. Metal intersected after that date has nowhere to go in that study.

The gap between the two used to be narrow, because a developer who had finished drilling had nothing new to add. It is wider now. The same market conditions that make a restart worth attempting also reward drilling hard while the engineering is underway, so the drill data and the model advance on separate schedules and meet again only at the next estimate.

The distance is measurable. A drill program can be 90% complete while the study written alongside it draws on a model closed months earlier, and the metal in between waits for the following cycle. That metal may improve the economics or complicate them. Either way, its absence from the first study is decided by a date rather than by judgment. 

Industry Context

The concentrate market has tightened to the point where the fee structure has inverted. Treatment and refining charges, the fees smelters charge miners to process concentrate, have turned negative, which Selkirk Copper describes as a first for the industry and a measure of how little concentrate is reaching smelters. Two dated observations frame the metal side: US$3.75 per pound for copper on January 1, 2023, and US$6.61 per pound for copper on August 13, 2026. Gold and silver moved along the same axis, from US$1,846 per ounce for gold and US$24.23 per ounce for silver on the first date to US$4,387 per ounce for gold and US$64.99 per ounce for silver on the second.

Input costs have not moved in step. Labor, fuel, and consumables have all risen, though not to the same extent as the metals. A move of that size changes what a metric ton of ore is worth, and with it, how a company approaches exploration, resource modeling, mine planning, and mineral processing.

The study sequence a restart developer commits to is fixed in advance. An economic assessment comes first, followed by a feasibility study, then an investment decision, and finally a roughly 12-month execution program before commissioning. Each step is scheduled by date, not triggered by the arrival of data, and each is computed against the resource estimate that was current when the work began. 

Emerging Practices & Industry Progress

Developers have compressed that calendar by running exploration and study work concurrently. A drill program of tens of thousands of meters (m) can be underway while engineers are costing a mill rebuild, and the two produce output on schedules that do not meet. Drilling yields assays continuously. A study needs one frozen model to compute against.  

An effective date is not a publication date. The estimate is announced only after the modeling and reporting work is finished, so publication day is later than the date the estimate speaks to. Any study built on that estimate inherits the same cut-off, whatever the drills have returned since.

The remedy is repetition, not speed. A second estimate prepared at the feasibility stage accounts for the drilling that the first one missed; the mine plan is rebuilt against it, and the cycle repeats in the study that follows. A first economic assessment is therefore an early pass at a number that is still moving.

Remaining Challenges

Three filters stand between the metal intersected in the core and the metal carried in an economic study, and the first is the laboratory. One current Yukon copper restart reports assay turnaround of six to eight weeks, with core prepared at a facility in Whitehorse and analyzed in Vancouver. Results released in August on that program came from holes drilled in May. A program that finishes drilling in late September will still be releasing assays through the fall. 

The second filter is the mine plan. Not every metric ton in a resource estimate can be scheduled, sequenced, and mined at a profit, and the share that survives is decided by grade, by proximity to existing underground workings, and by the order in which lenses can be extracted. Planning across multiple lenses is worked sequentially, which is why a larger resource does not translate into a larger plan on the same timetable. 

The third filter is the price at which the resource was constrained. The Yukon estimate confines material inside pit and underground shapes computed at US$4.60 per pound for copper, US$3,300 per ounce for gold, and US$40 per ounce for silver, with open-pit material taken above a C$30 net smelter return cut-off and underground material above C$80. Those are the prices the estimate was built at, not the prices copper was trading at when it was published. Whatever the drilling adds, the plan drawn inside those shapes inherits the same assumptions until the next estimate replaces them.

Company or Project Examples 

Selkirk Copper Mines (TSXV: SCMI | OTCQX: SKRKF | FRA: IO20) is advancing the former Minto copper-gold-silver mine in central Yukon, 250 kilometers north of Whitehorse, toward a restart decision. Its Phase 2 drill program began on May 1, 2026, and targets 50,000 m of expansion, exploration, and infill drilling, together with geotechnical data collection. By August 18, 2026, it had reached 45,299 m in 187 holes, representing 90% of the planned meterage. Of those 187 holes, the 34 drilled at Ridgetop, covering 3,402 m, had no reported assays. Drilling continues until approximately late September, with assays arriving through the fall.

The estimate the coming study is computed against is effective June 10, 2026, and was announced on July 30, 2026. It reports 47.8 million metric tons of measured and indicated material at 0.89% copper, 0.34 grams per metric ton (g/t) gold, and 3.2 g/t silver, containing 940 million pounds of copper, alongside 16.9 million metric tons of inferred material at 0.76% copper. Selkirk Copper has committed to completing the PEA in the third quarter of 2026, with the larger estimate folded into mine development plans, waste storage facility designs, and capital, sustaining, and operating cost estimates.

President and Chief Executive Officer of Selkirk Copper Mines, M. Colin Joudrie, draws the line between what the current model absorbed and what it left for the next one:

"It does not yet include the next phase of drilling that's only going to come in the feasibility, so there will be sort of a rinse and repeat process that happens here." 

Joudrie puts a number on how much of the indicated tonnage survives into a schedulable plan:

"Right now we're sort of in the 40 to 45% range of that indicated getting into the mine plan. I would like to see it a little bit higher."

Results released on August 20, 2026, pushed the model in both directions. Infill drilling at Minto North returned 6.01% copper, 8.77 g/t gold, and 36.6 g/t silver over 1.93 m, within a broader interval of 1.49% copper equivalent over 33 m, and a 50-m step-out at Area 118 returned 3.39% copper, 0.61 g/t gold, and 16.5 g/t silver over 6.0 m. At Copper Keel, seven of eight reported holes intersected mineralization, but grades were variable and somewhat lower than expected, and the results indicate limited potential for additional resource expansion in that area. The feasibility study is targeting a start around the end of September 2026, a second estimate in the first part of 2027, an investment decision by the middle of that year, and wet commissioning of the mill in the early part of the second quarter of 2028. Everything found since June 10, 2026, will be reported, modeled, and scheduled, and the estimate the third-quarter assessment is computed against closed before any of it existed.

Regional or Jurisdictional Perspective

The regulatory clock at a restart is set by a filing calendar rather than by the geology. Selkirk Copper is pursuing an amendment route through a district-office-level review, covering the quartz mining license, the exploration license, and the water licenses. The most recent operator of the same mine assumed authorizations it turned out not to hold, and the amendment work is built to avoid repeating that. The territorial water board and the environmental and socio-economic assessment board have both been brought to the site to see the plan in place.

Land tenure sets a second schedule. The Selkirk First Nation is a self-governing First Nation centered in Pelly Crossing, 280 kilometers north of Whitehorse, which signed its Final and Self-Government Agreements in 1997 and owns 4,740 square kilometers of settlement land, including 2,408 square kilometers where it owns both surface and subsurface. It acquired 100% of the Minto Project and vended it into Selkirk Copper through a reverse takeover, and it is indirectly the largest equity holder in the company, at 18.2%. Its Category A settlement lands surround and underlie the mine site. 

Neither of those schedules waits for an assay. The permit filing is targeting October 2026, and the economic assessment is in the third quarter of the same year; nothing in the company's disclosure links the two. Management has argued that the site needs planning on a multi-year cycle instead of annual ones, that water stored underground by the territorial government during closure still has to be removed as both a physical and a permitting problem, and that contract mining in the territory is more expensive than the company would like. Those items move on their own calendars while the drill data accumulates.

Industry Outlook

Where the new copper supply will come from over the next three years is partly a question about the mines already operating. Selkirk Copper's management points to a producing base whose production plans are being missed, whose grades are falling, and whose equipment is aging. Two of the world's largest mines, one in Indonesia and one in Chile, have not recovered production after failures. 

Joudrie widens the frame to that producing base: 

"Many of the big companies and the big mines around the world were built in the 70s, 80s, and early 90s, almost all of them. And now they're going through the second, third, and sometimes fourth mine life extension."

That places restart assets at the front of the near-term queue, and it also means the studies describing them are read as supply forecasts. A study computed against an estimate closed months before publication reports less metal than the drills have already outlined. The size of any revision is separate from its direction, and the direction is not automatically upward: infill drilling confirms a model in some zones and returns grades below it in others.

What improves with each cycle is the precision of the answer, not the guarantee of a better one. At a property where only 3 kilometers of a 7-kilometer mineralized trend inside the licensed mine area has been explored, that precision is several estimates away. Anyone reading a restart pipeline off first-pass economics is reading it one estimate behind the rigs. 

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