Bunker Hill Mining Corp. is now fully permitted to proceed with mining operations at the Bunker Hill mine. All of the mine’s land package lies on patented ground, which allows for underground mining activity, provided emissions permitting is obtained. An earlier announced agreement with the U.S. Environmental Protection Agency (EPA) provides the company with the only emissions permit required — a water discharge permit that allows for the EPA to continue managing the processing of the mine effluent from the Bunker Hill mine, for at least five years, with an opportunity to continue this arrangement thereafter.
Bunker Hill has initiated a NI 43-101 technical report on the property, and this report is expected to be released in the third quarter of 2018. Bunker Hill hopes to use this report to apply for a listing on the TSX. Data from approximately 1,000 historic diamond drill holes will be input into a wire frame software package, which will generate suitably constrained solids that may demonstrate 3-D continuity and economically interesting grades. This information may be included in the report. These holes are part of more than 3,400 holes historically drilled on the property, for which the company has the drill logs. Many high-grade intercepts from these holes have never been followed up on, and these represent significant exploration targets for future exploration programs.
An estimate of mineable material, including tons and grade, which is based on non-NI 43-101 compliant historical reserves and resources, provided a basis around which a conceptual mine was designed. Subsequently, SRK’s underground mine team based in Sudbury, Ontario, was used to review the company’s analysis.
“The resultant mine plan indicates good economic returns at current commodity prices,” said Bruce Reid, president and CEO, Bunker Hill Mining Corp. “[We have an] experienced mine operations team at the mine site, with most individuals possessing decades of local experience. This team includes a mining engineer, chief mine geologist, mine superintendent, logistics manager, and mine maintenance manager.”
The main capital cost components of the mine plan include rehabilitation/repair of underground access, which includes the Kellogg and Russell tunnels, Nos. 1 and 2 hoists), additional underground development (inter-level ramps, etc.), civil engineering/construction (surface buildings, roads), and process plant and tailings facility construction. The total cost of these items, preproduction, are estimated at approximately $75 million.
A total of 90 years of processing history has provided an extensive metallurgical database, which shows that excellent recoveries and good concentrates can be produced from a simple flowsheet. Recoveries averaged 93% for zinc, and 92% for lead. Concentrates were of high grade (56% zinc, 64% lead) and were clean with no deleterious elements. These results were obtained with more than 50-year-old technology, as the plant was last upgraded in the 1940s (producing up to the 1980s). Bunker Hill will tender for an engineering study (bulk sample, metallurgical testing, flowsheet design, feasibility study, engineering design, EPC contract) to be completed for an on-site 1,500 tpd modular processing facility, which would allow for a potential future doubling of throughput rate. This tender process is expected to conclude during the second half of 2018.
Bunker Hill is currently searching for partners to help finance the restart of the mine.