Bunker Hill rebuild: silver-focused restart and haulage constraints for mine planners
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Bunker Hill Mining has begun feeding ore through its rebuilt Idaho mill, drawing down a 20,000-ton stockpile as it ramps towards 1,800 tons per day and about nine concentrate truckloads daily to Teck’s Trail smelter 210 km away. CEO Sam Ash is positioning the historic zinc-lead operation as a future primary silver mine, targeting the Cate-8 zone, estimated conceptually at 50,000–168,000 tons grading 5.75–9.32 oz silver-equivalent per ton, with drilling such as 28.6 ft at 3.02 oz/t Ag, 7.44% Pb and 0.85% Zn. The main constraint is underground haulage, with a proposed “Bunker Hill 2.0” expansion adding a new portal and 10,000-ft decline, backed by a US EXIM Bank letter of intent for up to $150 million.
Technical Brief
- 2022 prefeasibility study set initial restart capex at US$55 million including contingency, now exceeded.
- Capital development for the first 3–5 years of the mine plan is already in place underground.
- Liquidity comprises just under US$30 million cash (31 March) plus a US$10 million undrawn Teck facility.
- Multi‑metal streaming was removed via refinancing with Sprott’s royalty/streaming arm; only a royalty and silver‑backed debt remain.
- Cate‑8 conceptual target: 50,000–168,000 short tons at 5.75–9.32 oz/ton AgEq (~1 Moz), 40–91.5 m from workings.
- Key intercept BHE26‑02: 8.71 m at 103 g/t Ag, 7.44% Pb, 0.85% Zn from 138 m downhole.
- Second notable hole BHE26‑03: 4.72 m at 6.4 oz/ton Ag, 20.4% Pb, 0.5% Zn, ~94 m from development.
- Desktop estimate for the proposed 10,000‑ft haulage decline is ~US$60 million within a US EXIM LOI of up to US$150 million.
- Workforce has passed 100 employees, expected to peak near 200 as ramp‑up and new development advance.
- Additional near‑mine exploration is planned at Motor vein, Ranger‑Page corridor and Government Gulch geophysical anomaly to 300 m depth.
Our Take
With initial restart capital in the 2022 PFS at US$55 million and a desktop decline estimate of US$60 million, the mine plan’s three- to five-year capital development window suggests Bunker Hill will likely need to stage further financing or hedge silver/lead exposure once ramp-up is demonstrated, a pattern seen across several of the 331 copper/silver keyword-matched pieces in our database.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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