Southwest Critical Materials presents Pumpkin Hollow special-use permit and technical plans to Yerington council

Southwest Critical Materials LLC (SCM) filed a Special Use Permit application and comprehensive project plan for the Pumpkin Hollow underground mine restart and possible Southwest open-pit development. The city packet—presented to the Yerington City Council March 9—includes technical studies, permit lists, a water-management strategy and a three-year reclamation cost update.

The application, which the Yerington Planning Commission recommended conditionally on Feb. 25, 2026, describes a phased underground restart with initial processing capacity of 5,000 short tons per day (tpd), a potential expansion to 6,500 tpd, and an underground production shaft used to hoist ore to surface. The plan states processing would use SAG and ball mills with three-stage flotation; dewatered tailings would be handled by high-pressure filtration and placed in a dry stack tailings (DST) facility, with paste backfill used underground.

City staff packaged a set of conditions the Planning Commission recommended for council consideration, including: quarterly coordination between SCM, the City of Yerington and Mason Valley Fire Protection District; annual status reports to the Planning Commission and City Council; a traffic plan with approved access routes for employees, deliveries and suppliers; a road maintenance and mitigation agreement tied to traffic impacts; and annual updates to the submitted emergency response plan. The staff recommendations also require SCM to maintain all applicable federal, state and local permits and to present annual reviews of the SUP.

The application materials include engineering and environmental analyses. SCM reports the DST will be constructed on private lands controlled by the company, that geochemical testing shows tailings and most mine rock are non-acid generating (Non-PAG), and that DST design and monitoring were developed with a third-party engineer of record. Water-management descriptions state the site operates a dewatering system (capacity ~1,800 gallons per minute), recharges much of the clarified water to rapid infiltration basins (RIBs), and reuses some pumped groundwater in processing; a revised hydrology model and updated Water Pollution Control Permit applications are expected to follow completion of further studies.

Reclamation and bonding are prominent in the packet. SCM filed a three-year reclamation cost update showing a posted reclamation bond of $8,153,748 and a proposed total estimated reclamation cost of $11,784,580; the plan details shaft-closure methods, plans to revegetate and recontour disturbed areas, and monitoring and post-closure inspection schedules.

Council did not record a final SUP vote in the meeting minutes. The council packet and staff recommendations now serve as the formal record for next steps: the Planning Commission's conditional recommendation and the city's staff conditions are in place should the council consider formal action at a later meeting. The packet also includes ancillary materials (technical appendices, monitoring well plans, and a detailed disturbance table) that city staff and regulators will use in future permit evaluations.