The desk read is simple this morning: with three-month LME copper sitting around $13,735/t on June 17 — within a whisker of the $14,527.50 all-time high struck January 29 — the cheapest way to be long the metal is to own a mid-cap that is already converting the price into cash and has a sanctioned growth project still to land. That's Capstone Copper (TSX:CS / ASX:CSC).

The fact pattern: Capstone's Q1 2026 was its sixth consecutive quarter of record adjusted EBITDA — $329.1 million on $652.5 million of revenue, with adjusted net income of $94.8 million ($0.12/share) and EBITDA margins around 50%. The balance sheet is doing the work the bulls wanted: net debt fell $42 million to $738 million, dropping net debt/EBITDA to 0.7x. That's deleveraging out of free cash flow at the top of the price cycle — exactly the script.

The growth that re-rates this stock isn't in the numbers yet. That's the whole trade.

Here's the cost-curve discipline. Capstone's 2026 guidance is 200,000–230,000 tonnes of copper at C1 cash costs of $2.45–$2.75/lb — costs guided higher than 2025 on inflation and lower grades at Mantos Blancos and Pinto Valley. So this is not a low-cost story today; it's a margin story riding a $6+/lb price. The re-rate lever is the Mantoverde Optimized (MV-O) brownfield expansion: capital cost of $176 million, unchanged, lifting the sulphide concentrator to roughly 45,000 tpd, with the ramp slated for Q4 2026 and sustained throughput in early 2027. Company slides map a path from ~225kt today to 265kt with MV-O and ~375kt with Santo Domingo, whose sanction decision is expected in H2 2026.

The risk is honest and worth flagging: Q1 sulphide production of 40,875t was 11% below the prior-year quarter, and Capstone has been navigating Mantoverde labour negotiations. In our view a strike at the wrong moment is the one thing that dents this thesis — watch it.

Who else is levered to the same move. Ero Copper (TSX/NYSE: ERO) is the purer "new-mine-ramping" trade: its Tucumã operation in Pará, Brazil hit commercial production in Q3 2025 and is guided to 32,500–37,500t in 2026 within consolidated guidance of 67,500–77,500t — up to 20% growth — at consolidated C1 of $2.15–$2.35/lb. Fitch upgraded Ero to 'B+' on the ramp, citing a shift to positive free cash flow and EBITDA stepping up toward ~$550 million in 2026 from ~$360 million in 2025. If you want the smaller, higher-beta version of the Capstone setup, it's Ero.

For scale and contrast: Ivanhoe Mines ($IVN) is the cautionary counterweight — Kamoa-Kakula ($IVN) in the DRC cut 2026 guidance to 290,000–330,000t on March 31 after underground recovery work, having produced 71,417t in Q1. Ramps don't always go up in a straight line, and the market is paying for reliability right now. And Antofagasta ($ANTO) ($ANTO) is the large-cap Chilean pure-play that moves on the same copper tape without the single-asset ramp risk.

The Take (conviction 4/5): at $13,700 copper, Capstone is a cash machine whose biggest catalysts — MV-O late this year, a Santo Domingo sanction after — are still ahead of the print. We're constructive, with two eyes on Mantoverde labour and the Q4 ramp curve. Ero is the higher-octane sibling; Ivanhoe is the reminder that the ramp, not the price deck, is the variable that bites.