Take on a podcast episode from The Carbon Curve, originally published Wed, 21 Oc. Listen: https://carboncurve.substack.com/p/canadas-next-industrial-play-the

TL;DR

  • Canada Nickel’s Crawford project claims up to 1.5 Mt CO2/yr storage via in-process tailings carbonation — reaction time cut from ~a decade to 3–6 hours. Big if real.
  • Key nuance the hosts skip: in-process carbonation is a sink; it’s removal only if the CO2 is atmospheric. Third-party CO2 storage there is CCS, not CDR.
  • Arca’s measurement, reporting, and verification (MRV) stack: dynamic closed chambers + eddy covariance, cross-checked against solid-phase mineral mass over 4 months. Useful, concrete description.
  • Dipple on price mismatch: miners think $20–30/t; mineralization needs $50–200/t. Explains why majors walked away in the early days.
  • Policy watch: push to get mineral carbonation recognized under Canada’s CCUS Investment Tax Credit.

Na’im Merchant (Carbon Removal Canada) hosts the third instalment of his “Canada’s Next Industrial Play” miniseries on The Carbon Curve, with Mark Selby and Scott MacDougall of Canada Nickel and Greg Dipple, co-founder of Arca. The episode covers how carbon storage got engineered into the Crawford nickel project near Timmins, Ontario, and how Arca measures mineralization at working mine sites.

The Crawford story is the headline. Selby describes the July 2022 origin: a 10 kg bucket of ultramafic tailings, a lab CO2 cylinder, and a weekend — matching what BHP’s passive tailings in Western Australia achieved over years. That mine booked roughly 30,000 t/yr of credits before closing; Crawford’s in-process version bubbles and stirs CO2 through fine slurry to a target pH, now a fully engineered step in the feasibility study. Scott MacDougall adds that an Australian startup, NetZero, could lift tailings capacity 10–15x, and an ARPA-E-funded University of Texas team tested injecting carbonated water into boreholes on site. What the conversation glosses over: injecting CO2 into tailings makes the mine a storage asset, but it’s only durable CDR if the CO2 comes from air or biogenic sources. Scott’s mention of regional partners stacking Clean Fuel Regulation credits by storing their CO2 at Crawford is a CCS play. Still valuable, still a different ledger.

Dipple’s section is the practitioner’s meat. Arca’s “three dials” (water content, surface area, pore-water chemistry) yield ~10x faster uptake by tilling tailings 6–12 inches deep; microwave activation of hydrous minerals — “microwave popcorn,” releasing bound water to break the structure — reportedly delivers hundreds-fold reactivity and goes to field deployment next year. On MRV, Arca measures a ~100 ppm CO2 drop in a watermelon-sized chamber over 2–3 minutes, validates against eddy covariance across a quarter- to half-hectare footprint, then confirms with solid samples that mineral CO2 gain equals atmospheric loss. He’s candid on reversal: products are hydrous magnesium carbonates with 10,000-year natural analogues, but strong acid or >300°C re-releases CO2, so reprocessing tailings for metal is the leakage scenario requiring covenants and buffer pools. Mount Keith (now closed) taught them that process water at twice seawater salinity changes the chemistry — something no lab run anticipated.

For context: Arca’s 10-year Microsoft deal for nearly 300,000 t is the reference offtake here; Canada Nickel’s path runs through the CCUS Investment Tax Credit, the Clean Technology Manufacturing credit, Ontario’s emissions performance standards, and the EU’s Carbon Border Adjustment Mechanism — a credit stack worth watching as a template. The Quebec Surficial Mineralization Hub in Thetford Mines, launched with Frontier, is the test bed for legacy tailings. The first episode of this series covered Undo’s enhanced rock weathering on farms — same chemistry, different feedstock logistics.

Useful for anyone pricing mineralization credits, building MRV for solid-phase storage, or trying to read where the CCS/CDR boundary falls in Canadian tax policy.