Bunker Hill Announces Prefeasibility Study FOR First Phase of MINE Restart
BUNKER HILL ANNOUNCES PREFEASIBILITY STUDY FOR FIRST PHASE OF MINE RESTART
Bunker Hill to Host Live Interactive 6ix Summit on Thursday, September 8 @ 2:00pm ET / 11:00am PT
HIGHLIGHTS:
• Average annual FCF of >$25 million, EBITDA of >$40 million, and zinc-equivalent production of >90 million pounds
• Attractive financial returns, including $52 million NPV8 ($63 million NPV5), 36% IRR, and 2.1 year pay-back
• Initial capex of $55 million achieves expanded 1,800 tpd operation, leveraging mineral endowment of the largest-
scale and shallowest major mine in Idaho’s Silver Valley, and one of the most prolific mines in US history
• Rapid restart of 16 months to commercial production for ‘Stage 1’ five-year mine plan on M&I Resources only
• All-in Sustaining Cost position of $0.77 per payable pound of zinc, net of by-products
• ‘Phase 1’ mine plan zinc equivalent production of 475 million pounds at a zinc equivalent grade of 8.5%, including
317 million pounds of zinc, 146 million pounds of lead, and 3 million ounces of silver
• ‘Phase 2’ opportunities include resource conversion to unlock value from Inferred Resources which remain open
for expansion, further increased scale, ongoing metallurgical optimization, and ore sorting
• Silver Valley-based, experienced operating team, on-site construction-ready mill, no permitting constraints
• Executive Chairman Richard Williams, CEO Sam Ash, and CFO David Wiens to host live interactive 6ix virtual
investor event on Thursday, September 8th at 2:00PM ET / 11:00AM PT to discuss the PFS results and next steps.
Investors are invited to register for this event at: [LINK]
TORONTO, Canada, September 6, 2022 – Bunker Hill Mining Corp. (CSE: BNKR) (“Bunker Hill” or the “Company) is pleased
to report the results of a Prefeasibility Study (“PFS”) for the first phase of the restart of the Bunker Hill Mine in Idaho’s
Silver Valley, USA.
The PFS plan describes a $55 million (including contingency) initial capital cost to rapidly restart the mine by the end of
2023, generating over $25 million of annual average free cash flow from an initial 5-year mine plan based on Probable
Mineral Reserves to produce over 315 million pounds of zinc, 145 million pounds of lead, and 3 million ounces of silver
at an estimated All-in Sustaining Cost of $0.77 per payable pound of zinc (net of by-products).
Sam Ash, CEO of Bunker Hill, stated: “We are very pleased to announce our Prefeasibility Study for ‘Phase 1’ of our multi-
phase value-generation plan for the Bunker Hill Mine outlining how we intend to commence profitable, sustainable,
modern operations by the end of 2023 . As demonstrated in our PFS, Bunker Hill is a sustainable low-risk, high-margin
asset with the potential to generate free cash flow of over $25 million per year while contributing to strategic metal
production in the United States beginning in 2024 and providing a significant economic boost to our many community
partners in the Silver Valley of Northern Idaho. We are now focused on driving forward to a formal construction decision
while maintaining momentum with ongoing restart activities.”
The PFS was prepared in accordance with National Instrument 43 -101 (“NI 43-101”). MineTech USA, LLC (Mine Tech)
developed the mine infrastructure, capex and opex related portions of the PFS as well as portions of the mine plan and
operating schedules in coordination with Bunker Hill’s team who directed Patterson & Cooke North America for the
tailing backfill components, YaKum Consulting Inc for metallurgy and processing and Barr Engineering for process design
and milling. The Company plans to file the complete d PFS report on SEDAR at www.sedar.com within 45 days of this
press release. All “t” and “ton” references in this press release are to short tons and “$” references are in U.S. dollars.
Highlights of the PFS are presented in Table 1 below:
Table 1: Phase 1 Prefeasibility Study Results Summary
16 months Years 1-5
Year Initial
Capex 1 2 3 4 5 TOTAL ANNUAL
AVERAGE
Metal Prices
Zinc ($/lb) 1.50 1.40 1.30 1.25 1.25 1.25 1.29 1.29
Lead ($/lb) 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
Silver ($/oz)
22.00 22.00 22.00 21.50 21.50 21.50 21.70 21.70
Mine plan
Ore mined (kt)
77 652 655 655 655 665 3,360 657
Zinc grade (%) 5.9% 5.6% 4.7% 5.7% 5.7% 5.9% 5.5% 5.5%
Lead grade (%) 2.1% 2.4% 2.7% 2.9% 2.4% 1.9% 2.5% 2.5%
Silver grade (oz/t)
0.5 0.7 1.3 1.4 1.2 0.8 1.1 1.1
Zinc eq grade (%)
7.7% 8.0% 8.1% 9.4% 8.8% 8.2% 8.5% 8.5%
Production
Zinc concentrate (t) 6,671 53,504 44,852 54,997 55,061 57,909 272,995 53,265
Lead concentrate (t) 2,091 20,945 23,577 25,078 20,955 16,605 109,251 21,432
Zn grade - Zn conc (%) 58.0% 58.0% 58.0% 58.0% 58.0% 58.0% 58.0% 58.0%
Pb grade - Pb conc (%) 67.0% 67.0% 67.0% 67.0% 67.0% 67.0% 67.0% 67.0%
Ag grade - Pb conc (oz/t) 14.4 18.6 31.5 30.1 31.0 27.4 27.6 27.7
Zn prod. - Zn conc (klbs) 7,738 62,065 52,029 63,796 63,871 67,174 316,674 61,787
Pb prod. - Pb conc (klbs) 2,802 28,067 31,593 33,605 28,080 22,251 146,397 28,719
Ag prod. - Pb conc (koz) 30 390 742 754 649 455 3,020 598
Zinc eq produced (klbs)
9,954 87,233 87,679 102,310 96,375 91,909 475,460 93,101
Cost metrics
Mining ($/t) 35 38 37 35 41 37 37
Processing ($/t) 21 21 21 21 21 21 21
G&A ($/t) 9 9 9 9 6 9 9
Opex - total ($/t) 65 68 67 65 69 67 67
Sustaining capex ($/t)
18 22 19 41 8 21 21
Cash costs: by-prod. ($/lb Zn payable) 0.61 0.42 0.36 0.45 0.64 0.50 0.50
AISC: by-prod. ($/lb Zn payable)
0.82 0.74 0.59 0.95 0.73 0.77 0.77
FCF & Valuation ($000's)
Zinc revenue 73,857 57,492 67,784 67,863 71,373 338,368 67,674
Lead revenue 25,330 28,513 30,328 25,342 20,081 129,595 25,919
Silver revenue 7,900 15,515 15,406 13,256 9,260 61,337 12,267
Gross revenue 107,087 101,520 113,518 106,461 100,714 529,300 105,860
TC - Zinc conc (16,257) (11,138) (13,657) (13,673) (14,380) (69,105) (13,821)
TC - Lead conc (3,698) (4,162) (4,428) (3,700) (2,932) (18,919) (3,784)
RC - Lead conc (449) (882) (896) (771) (538) (3,535) (707)
Land freight (2,193) (2,019) (2,360) (2,239) (2,192) (11,002) (2,200)
Net smelter return 84,491 83,319 92,178 86,079 80,672 426,739 85,348
Mining costs (22,828) (24,592) (23,971) (22,927) (27,454) (121,772) (24,354)
Processing costs (13,766) (13,842) (13,842) (13,842) (14,053) (69,346) (13,869)
G&A costs (6,050) (6,063) (6,063) (6,063) (4,257) (28,496) (5,699)
EBITDA 41,847 38,822 48,302 43,247 34,908 207,126 41,425
Sustaining capex (11,475) (14,127) (12,651) (26,982) (5,215) (70,450) (14,090)
Initial capex (54,853) (54,853) -
Land & salvage value 12,281 12,281 12,281
Pre-tax free cash flow (54,853) 30,372 24,695 35,650 16,266 41,974 94,103 29,791
Taxes (511) (1,394) (1,382) (2,218) (1,155) (1,224) (7,884) (1,475)
Free cash flow (55,364) 28,978 23,313 33,432 15,111 40,750 86,219 28,317
NPV (5%) 62,826
NPV (8%) 51,813
IRR (%) 36.0%
Payback (years) 2.1 `
Mineral Resource Estimate
Mineral Resources for the Bunker Hill Mine are Inclusive of Mineral Reserves. Metallurgical recoveries and concentrate
grade specifications reflect the current data supported by the PFS. Mineral Resources are reported at an NSR cutoff of
$70/ton. Mineral Resources are reported in situ and undiluted. Mineral Resources meet the reasonable prospects of
eventual economic extraction due to the fact that the entire vertical extents of the mineralization have been developed
on mining levels every two -hundred-feet. High grade capping was applied to the assays prior to grade estimation.
Grades are estimated using Inverse Distance Cubed (ID3) interpolation techniques. A bulk density of 11.3 cubic feet per
ton was applied to the entire Mineral Resource based upon historic density values from production records at Bunker
Hill. Historic mining voids, stopes and development drifting have been accounted for in the Mineral Resource Estimate.
Table 2: Bunker Hill Mine Mineral Resource Estimate – NSR $70/ton cutoff – Ag selling price of $20/oz (troy), Lead
selling price of $1.00/lb, Zn selling price of $1.20/lb. Effective date of August 29, 2022.
Classification Ton (x1,000) NSR
($/Ton)
Ag
Oz/Ton
Ag Oz
(x1,000) Pb % Pb Lbs.
(x1,000) Zn % Zn Lbs.
(x1,000)
Measured (M) 2,374 $ 119.60 1.01 2,404 2.46 116,574 5.37 254,811
Indicated (I) 4,662 $ 119.81 1.00 4,657 2.37 221,295 5.48 510,964
Total M & I 7,036 $ 119.74 1.00 7,061 2.40 337,869 5.44 765,774
Inferred 6,943 $ 126.28 1.52 10,532 2.87 398,901 4.96 688,482
(1) The Qualified Person for the above estimate is Scott Wilson, C.P.G., SME; effective August 29, 2022
(2) Measured, Indicated and Inferred classifications are based on the 2014 CIM Definition Standards.
(3) Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability
(4) Net smelter return (NSR) is defined as the return from sales of concentrates, expressed in US$/t, i.e.: NSR = (Contained metal) * (Metallurgical
recoveries) * (Metal Payability %) * (Metal prices) – (Treatment, refining, transport and other selling costs). For the Mineral Resource Estimate, NSR
values were calculated using updated open-cycle metallurgical results including recoveries of 85.1%, 84.2% and 88.2% for Zn, Ag and Pb respectively,
and concentrate grades of 58% Zn in zinc concentrate, and 67% Pb and 12.13 oz/ton Ag in lead concentrate.
(5) Mineral Resources are estimated using a zinc price of $1.20 per pound, silver price of $20.00 per ounce, and lead price of $1.00 per pound.
(6) Historic mining voids, stopes and development drifting have been depleted from the Mineral Resource Estimate
(7) Totals may not add up due to rounding
Mineral Reserve Estimate
Mineral Reserves are reported from the Quill, Newgard and UTZ sections of the Project. Measured and Indicated
Mineral Resources were converted to Probable Mineral Reserves for the mine. Due to the distribution of mineralization,
a portion of Inferred Mineral Resources has been included in the estimation of internal dilution at zero grade. Ongoing
metallurgical work, minimal bulk mining / sampling of material in the Mineral Resource Estimate and current
development advancement, were considered for the est imation of Probable Mineral Reserves. Continued technical
evaluations and advancement of mine development are required to estimate Proven Mineral Reserves.
Optimized stope envelopes contain internal planned waste at zero value. External unplanned wasted was applied at 5%
additional tons at zero grade for all planned tons. A minimum 5 -foot buffer was placed around the worked -out stope
areas. Delineation drilling is planned prior to mining in support of the short-term production mine plan and to identify
areas that will require back fill prior to mining adjacent areas.
Mineral Reserves are estimated at an NSR cutoff of $80/ton at the reference point of salable mill concentrates.
Table 3: Bunker Hill Mine Mineral Reserves Estimate
Area Description Tons (t) Zn (%) Pb (%) Ag (opt) Contained
Ag (koz)
Contained
Zn (klbs)
Contained
Pb (klbs)
NSR
(US$/t)
Newgard and
Quill
Probable 3,111,344 5.87% 2.56% 1.12 3,492 365,118 159,326 133.53
Plan Dilution 94,997 - - - - - - -
Unplanned Dilution 155,567 - - - - - - -
UTZ
Probable 89,117 3.93% 3.74% 1.35 95 7,002 6,658 122.66
Plan Dilution 794 - - - - - - -
Unplanned Dilution 4,445 - - - - - - -
Total Probable 3,200,461 5.81% 2.59% 1.12 3,587 372,120 165,984 133.23
Total Plan 3,360,473 5.30% 2.40% 1.02 3,587 372,120 165,984 126.88
(1) Plan Dilution is zero grade waste included in the designed stope shapes and probable tonnages
(2) Unplanned dilution is 5% external dilution added at zero grade
(3) Mineral Reserves stated are inclusive of all above mentioned dilutions and are factored for ore loss due to mining activities
(4) Net smelter return (NSR) is defined as the return from sales of concentrates, expressed in US$/t, i.e.: NSR = (Contained metal) * (Metallurgical
recoveries) * (Metal Payability %) * (Metal prices) – (Treatment, refining, transport and other selling costs). For the Mineral Reserve Estimate, NSR
values were calculated using updated open-cycle metallurgical results including recoveries of 85.1%, 84.2% and 88.2% for Zn, Ag and Pb respectively,
and concentrate grades of 58% Zn in zinc concentrate, and 67% Pb and 12.13 oz/ton Ag in lead concentrate.
(5) Mineral Reserves are estimated using a zinc price of $1.20 per pound, silver price of $20.00 per ounce, and lead price of $1.00 per pound.
(6) Historic mining voids, stopes and development drifting have been depleted from the Mineral Reserve Estimate
(7) Totals may not add up due to rounding
Initial Capital Costs & Infrastructure Overview
The PFS contemplates the technical and investment requirements for , and demonstrates the robust economics of a
potential restart to a sustained mining and milling rate of 1,800 ton per day. The utilization of pre-existing infrastructure
and expenditures already made through August 2022 allows for a low remaining capital investment required, as detailed
in the table below.
Table 4: Initial Capital Costs
($000’s) Initial Capital
Process plant 26,764
Capital development 6,370
Paste plant 6,206
Construction management & Indirects 4,034
Detailed engineering 2,798
Power feed & distribution 1,693
Mobile equipment 954
Surface upgrades & other 795
Pre-commercial production revenue (695)
Capital Costs - Total (pre-contingency) 48,920
Contingency 5,933
Capital Costs - Total 54,853
The majority of the initial capital cost relate s to construction of the processing plant at an estimated pre -contingency
cost of $26.8 million and harnessing the extensive mill equipment and components from Teck’s Pend Oreille site. These
costs include labor, refurbishment of equipment, costs of a new mill building inclusive of clearance, geotechnical and
foundational work, and costs of additional mechanical equipment and components (to ensure all aspects of the
processing plant are capable of an 1,800 ton per day run rate). The layout and design of th ese new facilities are
envisaged to be on surface and located in the main yard in an area currently occupied by the historic Bunker Hill
maintenance shop. Costs related to the purchase of the process plant from Teck are not included, nor are the costs
associated with its demobilization, as this activity had been completed as of August 2022.
Approximately $6.4 million has been budgeted for capital development, a moderate estimate considering the extensive,
intact, pre-existing infrastructure at the mine and surface including underground workings, surface portals and shaft
access points as well as the main mine office and adjacent surface buildings. As an example, the Kellogg Tunnel adjacent
to the main mine office connects horizontally by ra il to the underground hoisting facilities on 9 -level approximately
9,500 feet from the portal . As such, pre -production capital development primarily relates to the development of an
underground decline from the Wardner yard (at the 5-level) to the back of the Kellogg Tunnel (at the 9-level) to provide
rubber tire access for mine equipment and all requisite access to initial stopes in readiness for commercial production,
and related rehabilitation activities.
Bunker Hill’s long hole stoping method envisions the use of a paste (i.e., hydraulic) backfill plant to deliver binder-added
tailings product to backfill stopes. The paste plant will also deliver both binder-added and non-binder added thickened
tailings to open historic mining voids throughout the mine as a means of tailings deposition. Patterson & Cooke, North
America investigated several options to handle the backfill and tails placement requirements of the project. The option
with the greatest amount of operational flexibility is to locate the plan t on surface. The $6.2m of capital allocated for
this will include construction of a tailings thickening plant to be located in the mill/process building (in the main yard on
the 9 -level) and of a tailings filtration plant immediately adjacent to the buil ding. In addition, the paste plant and
pumping station will be constructed at the mine’s 5 -level laydown in the Wardner yard. Surface construction of the
plants will help expedite construction, lower labor costs and make binder delivery to the plant more efficient. Location
of the pumping station on the 5-level of the mine (highest accessible level) allows for gravity-assisted flow to the stoping
areas, almost all of which are lower in elevation. Tailings will be filtered into a filter cake material and backhauled up to
the Wardner plant from the mill/process location by means of the same haul trucks used for the overland ore haulage
to the mill. Once at the Wardner location, tailings filter cake material will be mixed with a binding agent and water and
then pumped through the reticulation line either to open void space for deposition or mined out stopes for backfill
requirements. Initial backfill test work indicates excellent backfill strengths can be produced at low binder content .
Further test work will provide optimization on binder addition requirements.
Construction management (EPCM and related costs) and detailed engineering costs have been estimated at $4.0 million
and $2.8m respectively. The EPCM partner is assumed to be selected and onboa rded at the beginning of the capital
schedule, enabling a rapid advance after a construction decision. The detailed engineering costs span the remaining
engineering work to enable construction across the processing plant (including crusher and loadout fac ilities), paste
plant (all parts) and other infrastructure requirements.
Bunker Hill has been working closely with Avista Utilities to upgrade the electrical supply infrastructure to both the main
Bunker Hill yard (9 -level) and Wardner (5-level) sites. As of September 2022, Avista is extending and upgrading three
phase power to the Wardner site. Additional capacity will be freed up at the main Kellogg/Bunker Hill substation by
redirecting loads to adjacent substations where feasible (either immediately or with minimal additional infrastructure).
Capital costs for these activities are funded by the project up front and then credited back to the operational power bill
over the life of the project.
Other initial capital costs include various mobile equipment (supplementing the mine contractor fleet) and
miscellaneous surface upgrades.
Mine water from all levels above the 9-level naturally drains out of the Kellogg Tunnel and then flows through existing
infrastructure into the Central Water Treatment Plant (CTP), owned by Idaho Department of Environmental Quality
(IDEQ), for treatment. The PFS envisages a long-term agreement between Bunker Hill and the IDEQ for use of the CTP
for mine water treatment requirements, and therefore does not therefore envision capital expenditure for an internal
water treatment plant.
Mining Methods
The Newgard/Quill resource was optimized and scheduled utilizing the long -hole open stoping (LHOS) mining method
with backfill, whereby stopes are accessed via lateral drifts driven off the Newgard ramp connecting the levels vertically.
The ramps and raise systems provide ventilation, utilities, and secondary escapeway, as well as connecting the entire
mine for rubber tire access. The LHOS areas are accessed primarily by new excavations and do connect to some existing
levels which will be rehabilitated. Backfill requirements are provided via the surface (5 -level) hydraulic fill plant and
distribution system.
Processing
The PFS envisages a mill throughput increase to 1,800 tons per day from a reconfiguration whereby two larger ball mills
are purchased to replace the existing ball mills procured from the Pend Oreille site; the Company has identified multiple
opportunities in this regard.
The plan entail s run-of-mine (ROM) ore delivered from underground to a mobile jaw crusher located at the surface
portal in Wardner. The crushed ROM will be delivered to the secondary crushing circuit via truck and overland haulage
route. The processing facility and secondary crushing facility will be located at surface in the Kellogg yard adjacent to
the Kellogg Tunnel. Crushed ore will be fed to a fine ore storage silo ahead of the new concentrator facility that will be
constructed where the existing Bunker Hill maintenance building now stands.
The PFS envisages usage of the surface footprint occupied by the existing storage building adjacent to the surface
administration buildings. Geotechnical and other technical work to finalize detailed engineering designs is currently
underway and will be followed by demolition of the existing surface building.
The new concentrator facility will consist of a standard primary ball milling circuit followed by a conventional differential
flotation circuit for lead and zinc. A lead concentrate will be produced first, followed by zinc concentrate in conventional
flotation cells with 3 stages of concentrate cleaning for each product. Concentrate dewatering and loadout will take
place on the north end of the concentrator to more easily accommodate the receiving and loading of concentrate trucks.
All tailings produced in the concentrator will be filtered to produce a tailings filter cake, consequently no surface tailings
pond will be required. All process water solution will be recovered and reused in the concentrator.
All freshwater makeup for the concentrator will either come from mine water sources or an internally operated water
treatment processes facility within the concentrator plant.
The zinc and lead concentrates are assumed to be transported by truck to the smelting facility owned by Teck Resources
Limited (“Teck”) in Trail, British Columbia, with Teck exercising its option (as announced by the Company on March 31,
2022) to acquire 100% of the zinc and lead concentrate production for an initial term of 5 years.
Metallurgy
SGS Lakefield was contracted to conduct additional metallurgical test work to optimize and improve previous
metallurgical results. Scoping level bulk flotation tests were conducted to affirm the mos t effective parameters to
maximize recovery and concentrate quality. This test work allowed for the establishment of ore hardness, mineralogical
characteristics, grind size vs. recovery, reagent profile, and repeatable flotation performance. Locked cycle testing of
representative Bunker Hill ores exhibited acceptable recovery profiles at varying head grades while producing
marketable grades of concentrates. Metallurgical variability and optimization test work will continue post PFS to further
refine and improve recovery and concentrate quality performance.
The current test work supports a traditional crushing and grinding circuit followed by lead and zinc flotation. The Bunker
Hill ore mineralogy requires a primary grind size of approximately 80% passing 74 microns for optimum flotation
recovery. Lead will be floated first while zinc is chemically depressed for recovery later in the process. The vast majority
of payable silver follows with the lead and reports to the lead concentrate. Zinc is chemically reactivated and recovered
post lead flotation. Test work has confirmed that 3 stages of cleaning is adequate to produce a marketable concentrate
grade for both lead and zinc.
Based on the metallurgical test work and an analysis of historical metallurgical performance, the performance criteria
used in the PFS consisted of the following: 1) 88.2% lead recovery to the lead concentrate at a grade of 67.0% lead, 2)
85.1% zinc recovery the zinc concentrate at a grade of 58% zinc, and 3) 84.2% silver recovery to the lead concentrate.
Operating Costs Summary
Operating cost estimates were prepared based on an 1,800 tons per day ore production rate, as summarized in the Table
below for the initial 5 years of mine life
.
Table 5: Summary of Operating Costs
Average
Mining ($/t) 37.09
Processing ($/t) 21.12
G&A ($/t) 8.68
Operating Costs - Total ($/t) 66.89
Operating costs are based on experienced local contract labor and equipment for mining operations. A zero -based
efficiency and cost estimate was completed based on the current underground contractors’ rates and guidance
benchmarked against current development activities . Electrical power costs are based on scheduled projected loads
applying an estimated power factor correction and applicable rates from Avista Utilities for all projected mine, milling
and site operations. Mining costs are based LHOS methods in the majority of the Newgard, Quill and UTZ ore zones.
There is a portion of limited cut-and-fill mining late in the mine plan, costs of which are reflected in total mine OPEX and
the mining schedule.
Mine production will be hauled using the Newgard ramp, exit the mine at the Russel portal and be trucked overland via
off-road haul trucks down to the Kellogg mill location. Thickened and filtered tails will be back hauled to the Russell site
for placement underground as engineered or straight backfill.
Operating costs in Table 5 do not include smelter charges or concentrate freight costs, which have been estimated based
on an outlook for the zinc and lead concentrate markets by a third -party consultant, and trucking quotes obtained.
These costs have been shown separately in Table 1 above.
Cash Flow & Valuation
The project is expected to generate pre-tax free cash flow of $137 million over the initial Phase 1 mine plan (average of
$27 million per year) and $1 30 million on an after -tax basis (average of $26 million per year) before consideration of
sale proceeds from land and salvage equipment, after the initial capital expenditure period of 16 months. In addition,
total estimated cash flows include approximately $1 1 million (net of tax) from estimated proceeds of sale of
undeveloped land, processing and mobile equipment at the end of the five-year mine plan. Estimated cash flows do not
include the impact of potential financing arrangements. Tax estimates include federal and state income tax, mine license
tax, and property tax after consideration of Bunker Hill Mining Corp.’s existing estimated net operating loss position and
other tax attributes, and were estimated by Mining Tax Plan LLC.
The ’Phase 1’ Prefeasibility Study results yield an after-tax Net Present Value (“NPV”) of $52 million using an 8.0%
discount rate, or $63 million using a 5.0% discount rate, and an after-tax Internal Rate of Return (“IRR”) of 36.0%.
Table 6 below summarizes the after-tax sensitivities of NPV and IRR to metal prices, operating and capital costs.
Table 6: NPV (8%) & IRR Sensitivities
Metal Prices
Operating & Capital Costs
NPV (8%)
($M)
Zinc Price ($/lb) Operating Costs (+/- %)
(0.20) (0.10) - 0.10 0.20 (20%) (10%) - 10% 20%
Lead
Price
($/lb)
(0.20) (7) 13 32 51 68 Total
Capital
Costs
(+/-
%)
(20%) 102 87 72 56 40
(0.10) 4 23 42 60 78 (10%) 92 77 62 46 30
- 14 33 52 69 87 - 82 67 52 36 19
0.10 24 43 61 78 96 10% 72 57 42 25 9
0.20 34 53 70 87 105 20% 62 47 31 15 (1)
IRR (%)
Zinc Price ($/lb) Operating Costs (+/- %)
(0.20) (0.10) - 0.10 0.20 (20%) (10%) - 10% 20%
Lead
Price
($/lb)
(0.20) 4% 16% 26% 35% 44% Total
Capital
Costs
(+/-
%)
(20%) 71% 62% 53% 44% 34%
(0.10) 10% 21% 31% 40% 49% (10%) 60% 52% 44% 35% 26%
- 16% 26% 36% 45% 53% - 51% 44% 36% 28% 19%
0.10 22% 32% 41% 49% 57% 10% 44% 37% 29% 21% 13%
0.20 27% 37% 45% 54% 62% 20% 37% 30% 23% 15% 7%
Next Steps & Opportunities
Key next steps for the project include the completion of detailed engineering for the process plant and paste plant, prior
to commencement of construction. In parallel, underground development should continue in order to establish initial
mining areas. Thereafter, construction is expected to commence along with the purchase of long lead time capital items
and additional mining equipment.
Opportunities to further enhance financial returns include resource conversion to unlock value from Inferred Resources
which remain open for expansion, further increased scale beyond the contemplated 1,800 tpd throughput rate, ongoing
metallurgical optimization, and ore sorting. These opportunities are not included in the PFS economic analysis.
QUALIFIED PERSON
MineTech USA, LLC (MineTech) developed the mine infrastructure, capex and opex related portions of the P FS as well
as portions of the mine plan , reserves and operating schedules in coordination with Bunker Hill’s team who directed
Paterson & Cooke North America for the tailings and backfill components and Barr Engineering for milling and process
design. Robert Todd, P.E. is a Principal of MineTech, a registered engineer in Idaho, consultant to the Company and an
Independent “Qualified Person” as defined by NI 43 -101. Peter Kondos Ph.D., CEO of YaKum Consulting Inc was
responsible for the processing and metallurgical testing and sections of this release and subsequent technical report and
is an independent “Qualified Person” as defined by NI 43-101.
Mr. Scott E. Wilson, CPG, President of Resource Development Associates Inc. and a consultant to the Company, is an
independent qualified person as defined by NI 43 -101 and is acting a s the qualified person for the Company. He has
reviewed and approved the technical information summarized in this news release.
ABOUT BUNKER HILL MINING CORP.
Under new Idaho-based leadership, Bunker Hill Mining Corp. intends to sustainably restart and develop the Bunker Hill
Mine as the first step in consolidating a portfolio of North American precious -metal assets with a focus on silver.
Information about the Company is available on its website, www.bunkerhillmining.com, or under the Company’s profile
on SEDAR at www.sedar.com and on EDGAR at www.sec.gov.
For additional information contact: