Short version: The mine you’re thinking of is almost certainly Mountain Pass, California—the U.S.’s large rare-earths operation. It was idled in 2015 and then revived under MP Materials beginning in 2017; today it’s producing separated oxides (including NdPr) and building out downstream magnet capacity. So “reopening” (or re-reopening) a large U.S. rare-earths mine involves much more than turning the trucks back on—it’s a full supply-chain reboot.Here’s what’s typically involved, using Mountain Pass as the model:
- Secure the asset and validate the resource
- Acquire the mine/plant and update reserve & metallurgical models; Mountain Pass was idled in 2015 and taken over in 2017 by MP Materials to restart operations. mpmaterials.com
- Environmental reviews, permits, and social licence
- Restarting mining and (especially) chemical separation means federal NEPA review plus state permitting (e.g., California). Projects can opt into FAST-41 to coordinate/track multi-agency timelines on the federal dashboard. Community engagement, water use, tailings, and legacy cleanup are central. www.permitting.gov
- Rehabilitate or build processing/separation
- Mining alone isn’t enough; you need flotation, roasting/leaching, and solvent-extraction circuits to separate oxides (Nd, Pr, Dy, Tb, etc.). MP Materials restarted separation and shipped first NdPr oxide in 2023, scaling through 2024–25. mpmaterials.com
- Add downstream refining & magnets (to avoid export bottlenecks)
- U.S. strategy now pushes for on-shore metal and magnet production. MP built a Fort Worth facility and began metal trials, with further magnet capacity planned; DoD has made large strategic investments to anchor domestic demand and pricing. mpmaterials.com
- Line up financing and incentives
- Expect a mix of equity, offtakes, and public support: DoD contracts/grants/loans (e.g., support for heavy REE separation and major magnet capacity), DOE programs, and the §45X advanced manufacturing/critical minerals tax credits that improve project economics. www.businessdefense.gov
- Rebuild operating systems, workforce, and supply chains
- Hire/retain specialty operators and chemists; secure reagents (extractants/solvents), power, water, and transport; update automation and environmental monitoring; and set up product quality pathways for oxides/metals.
- Secure offtakes and market access
- Long-term contracts with automakers/tech/defense reduce price risk and fund capex. Recent U.S. deals include government price floors/offtakes and commercial agreements to anchor magnet output. www.ft.com
- Commissioning, ramp, and de-risking
- Plan for staged commissioning: concentrate → separated oxides → metals → magnets. MP’s path: restart mining (2017–18), start separation & sell NdPr (2023), set records in 2024 production, and expand magnet capacity toward 2028. Policy and trade shifts (e.g., tariffs) can force pivots in sales routes and timelines. www.gisreportsonline.com What this means in practice
- Timeline: often multi-year from restart decision to steady-state separation/magnet output, even at an existing site. FAST-41 can help coordinate federal reviews; state processes still apply. www.permitting.gov
- Capital: high, because separation/magnet facilities are the cost drivers; recent U.S. build-outs rely heavily on DoD/DOE support and §45X credits. www.ft.com
- Strategic context: the government is actively backstopping domestic rare-earth supply chains (heavy-REE separation, magnet plants, price floors) to reduce dependence on China. www.businessdefense.gov If you want, I can sketch a phased plan (with a strawman timeline, permit map, and capex buckets) tailored to Mountain Pass or to a hypothetical U.S. restart—just say which path you prefer.