---
schema_version: "secwatch.filing_event.v1"
accession: "0001493152-21-023603"
form_type: "8-K"
ticker: "BHLL"
cik: "0001407583"
company_name: "Bunker Hill Mining Corp."
filed_at: "2021-09-24T23:59:59+00:00"
generated_at: "2026-06-29T01:30:05.866451+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Bunker Hill PEA shows 42% NPV increase to $143M; AISC down 29% to $0.47/lb

## Summary
- After-tax NPV (5%) of $143M vs. $101M in June PEA; IRR 35.2% with 2.6-year payback.
- All-in sustaining cost (AISC) falls 29% to $0.47 per payable lb of zinc; cash costs down 33%.
- Average annual free cash flow of $25.2M over extended 11-year mine life; 41% increase in total FCF.
- Initial capital cost of $44M (incl. 20% contingency) for 18-month restart; total production of 990M zinc-equivalent lbs.
- Metal price assumptions unchanged from April PEA ($1.15/lb Zn, $0.90/lb Pb, $20/oz Ag).

## SEC filing metadata
- accession: 0001493152-21-023603
- form_type: 8-K
- ticker: BHLL
- cik: 0001407583
- company_name: Bunker Hill Mining Corp.
- filed_at: 2021-09-24T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1407583/000149315221023603/0001493152-21-023603-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1407583/000149315221023603/form8-k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001493152-21-023603
- JSON: https://secwatch.observer/filing/0001493152-21-023603.json
- Plain text: https://secwatch.observer/filing/0001493152-21-023603.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.