Southwest Critical Materials proposes Pumpkin Hollow restart: plans for 5,000–6,500 tpd, a larger workforce and updated reclamation costs

Southwest Critical Materials LLC (SCM) filed a three-year update to its Pumpkin Hollow Project plan and Special Use Permit application that details a staged restart of underground copper operations, new operational controls and an updated reclamation cost estimate.

The plan, dated January 2026 and provided to local permitting authorities, says SCM completed construction of the underground mine before 2019 and operated from 2019 until 2024, when the previous owner entered Chapter 11 and the assets were purchased by SCM in October 2024. SCM proposes to restart underground development in the third quarter of 2026, stockpile ore on surface, and begin processing operations in early 2027. The restart plan is designed around a 5,000‑ton‑per‑day (tpd) nameplate capacity with staged optimizations to increase throughput to 6,500 tpd after steady-state operations.

SCM told regulators the site had about 75 people on site at the end of 2025 and that workforce levels would rise to about 375 staff over the next 16 months as construction and operations scale up. The company said the operation would run two 12‑hour shifts per day, year‑round, and that peak construction staffing could reach about 150 workers.

The application describes processing by three‑stage flotation with high‑pressure filtration of tailings and placement into a Dry Stack Tailings (DST) facility. SCM emphasizes a zero‑discharge approach: process fluids are engineered to be contained, reclaimed, and reused; secondary containment is sized to hold at least 110 percent of the largest process component; and tailings will be filtered to a target moisture content of roughly 15–17% before stacking.

SCM reports supporting studies including a hydrogeologic model, geochemical characterization, DST engineering, and a Surface Water Management Plan. The hydrogeologic modeling, the company said, indicates drawdown local to the mine but concluded that drawdown would not extend into the Mason Valley alluvial aquifer even 1,000 years after mining ends. The plan also notes that geochemical tests indicate most mine rock and tailings are non‑acid generating (Non‑PAG).

The project plan summarizes permits it holds or will seek, including Water Pollution Control Permits NEV2008103 (sitewide) and NEV2008109 (dewatering), a Class II Air Quality Operating Permit, potable water and wastewater approvals, and reclamation/permitting administered by the Nevada Division of Environmental Protection (NDEP) Bureau of Mining Regulation and Reclamation (BMRR). SCM said all current and proposed surface facilities are on private lands it controls and that no Bureau of Land Management Plan of Operations is required.

In its three‑year reclamation update, SCM used Nevada’s Standardized Reclamation Cost Estimator and reported a total estimated reclamation cost of $11,784,580 while the current posted bond is $8,153,748. The update lists authorized disturbance of 445 acres, with about 302.48 acres already constructed and the rest planned. The reclamation plan includes designs and closure methods for the production shaft and two vent shafts, the DST cells, a Mine Rock Storage Facility, rapid infiltration basins for dewatering recharge, and a detailed seed mix and revegetation plan.

SCM said the DST will be constructed in lined cells on private land west of the plant and that to be conservative it assumes four lined cells and a test cell will be built and bonded. The plan says one DST cell and related infrastructure have been used since 2019 and that third‑party monitoring has not identified material issues to date. SCM also described water management: pumped groundwater will be routed to Rapid Infiltration Basins (RIBs) for recharge, with additional RIB locations under evaluation; a revised hydrology study and updated WPCP application are expected after the hydrology work is complete, anticipated in May 2026.

Regulatory discussions and supporting technical reports will guide the final permit conditions. The plan documents a comprehensive monitoring, spill response, and emergency response program; it also describes closure plugs and multi‑layer grout/bentonite shaft seals designed to prevent connection of the shaft to regional aquifers.

The update will proceed through normal NDEP and local review processes; the Planning Commission and City Council may be involved for certain local land‑use approvals tied to the Special Use Permit process. The company’s stated restart schedule, existing permits, bond status, and the difference between the estimated closure cost and the posted bond will be central topics in permitting and public review.