306,000 oz Au Average Annual Full Year Production

C$1.2B After-Tax NPV and 34% After-Tax IRR (Unlevered) at US$1,600/oz Au

C$257M Average Annual After-Tax Free Cash Flow per Full Year of Production

(Toronto, November 28, 2022)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide the results of its independent feasibility study (“FS”) prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-10”) on its 100% owned Windfall gold project (“Windfall”, or the “project”) located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec. Windfall is situated on the traditional lands of the Cree First Nation of Waswanipi (“CFNW”).

The FS provides a robust base case assessment for developing Windfall as an underground dual ramp-access mine with a central processing mill on site, and reflects drill results available as of June 7, 2022, as included in the Windfall MRE (2022) (as defined herein).  Osisko has begun detailed engineering work on the project, and is progressing towards delivering the Environmental Impact Assessment (the “EIA”) study in Q1 2023 and initiating the mine permitting process.

 

Highlights^(1-6) 

• Full year average production of 306,000 oz Au, 8.1 g/t Au average grade fully diluted 
• Peak production of 374,000 oz Au in year two 
• Average after-tax free cash flow of C$257 Million per full year of production (C$2.3 Billion cumulative free cash flow) 
• Capex of US$607 Million (includes US$38 Million as contingency in direct and indirect costs), NPV/Capex ratio of 1.5
• All-in sustaining cost (“AISC”) of US$758/oz; Cash cost of US$587/oz
• 3,400 tonne per day milling operation
• Average recovery of 93%; all in mining cost of US$136/tonne
• C$6.2 Billion of gross revenue
• Creation of over 1,000 direct and indirect jobs during construction and over 670 direct permanent jobs during operation

Notes:

(1) Cautionary Statement: Readers are advised that the FS summarized in this news release is intended to provide only an initial, high-level          overview of the project potential and design options. The FS mine plan and economic model include numerous assumptions. There is no guarantee the project economics described herein will be achieved.

(2) Full years of production refer to Years 1 to 9.

(3) AISC is presented within the meaning defined by the World Gold Council (“WGC”), less corporate G&A.

(4)  The FS relating to the disclosure in this news release will be filed on SEDAR (www.sedar.com) under Osisko’s issuer profile within 45-days.

(5) Total cash costs and cash costs per ounce, and AISC and AISC per ounce are non-IFRS financial measures. See “Non-IFRS Financial Measures” for a discussion of non-IFRS financial measures.

(6) References to C$ and US$ are to Canadian and United States dollars, respectively.

Osisko Chief Executive Officer John Burzynski commented: “We are very pleased to deliver the Windfall feasibility study, outlining the supporting economics indicating Windfall can become a significant and highly profitable new gold mine in Québec. Using the grades defined in our most recent mineral resource estimate (being the Windfall MRE (2022) reflecting drill results available as of June 7, 2022), the numbers are robust, with a C$1.2 Billion after-tax net present value (“NPV”) and 34% after-tax unlevered internal rate of return (“IRR”), using US$1,600 oz gold.  As we move to complete the EIA study in Q1 2023 and begin the permitting process, we expect to advance our underground exploration and continue to grow the scale and quality of the deposit. The Corporation anticipates the announcement of project financing plans in H1 2023 and a production decision in early 2024.

Osisko would like to thank our employees and contractors for their tremendous work over the past seven years to arrive at this important point in our project, and express our gratitude to our hosts the Cree First Nation of Waswanipi, as well as the community of Lebel-sur-Quévillon, and the many Québec government agencies for their continuous support.”

Feasibility Study Details

The FS was integrated by BBA Inc. under the supervision of Ms. Kim-Quyên Nguyên, P. Eng., MBA, Project Director for Osisko Mining, and the Osisko technical team. This independent FS was prepared in collaboration with the following firms: A2GC − Andrieux & Associates Geomechanics Consulting L.P. (Montréal, QC), BBA Inc. (Montréal, QC), GCM Consultants (Montréal, QC), Entech Mining Ltd. (Toronto, ON), PLR Resources Inc. (Montréal, QC) and WSP Canada Inc. (Montréal, QC).  These firms provided mineral resource estimates, reserve estimates, design parameters and cost estimates for mine operations, process facilities, major equipment selection, waste and tailings storage, reclamation, permitting, and operating and capital expenditures. Contributors and their area of responsibility are summarized in Table 5.

Project economics were evaluated based on a forecast date to receive the construction permit in Q1 2024. Unless stated otherwise, all costs are in Canadian dollars.

 

Table 1: FS Summary

Total mineralized material mined (t)	12,183,405
Average mill feed diluted gold grade (Au g/t)	8.06
Total gold contained (oz)	3,158,713
Total gold produced (oz)	2,942 339
Total gold payable (oz)	2,940,868
Gold payable recovery (%)	93.1%
Average annual gold produced (Au oz per year)	294,234
Average mill feed diluted silver grade (Ag g/t)	4.18
Silver payable recovery (%)	83.3%
Total silver payable (oz)	1,366,537
Total initial CAPEX (C$Million)	788.6
Sustaining capital (C$Million)	587.6
Operating cost (per tonne milled)
Mining (C$)	82.21
Processing (C$)	40.76
Waste & water management (C$)	6.30
General & administration (C$)	32.81
Electrical transmission line lease (C$)	14.59
Total unit operating costs (per tonne milled) (C$)	176.67

 

Table 2: Summary Economics at US$1,600 Au

LOM net smelter return (“NSR”) revenue (C$Million)	6,134
Total LOM pre-tax cash flow (C$Million)	2,432
Average annual pre-tax cash flow (C$Million)	243
LOM income taxes (C$Million)	721.8
Total LOM after-tax free cash (C$Million)	1,710.2
Average annual after-tax free cash flow (C$Million)	171
Discount rate (%)	5.0%
Pre-tax NPV (C$Million)	1,685
Pre-tax IRR	40.1%
Pre-tax payback after start of production (years)	2.0
After-tax NPV (C$Million)	1,168.4
After-tax IRR	33.8%
After-tax payback after start of production (years)	2.0

 

Table 3: All-In Sustaining Cost

Adjusted operating costs
Mining cost(1)	993.0
Processing cost(1)	492.3
Tailing & water management cost(1)	76.1
General & administrative cost(1)	396.3
Electrical transmission line lease cost(1)	176.2
Royalties(1)	127.4
Transport and refining costs(1)	20.0
Ag by-product credit(1)	(37.3)
Adjusted operating costs(1)	2,244.1
Sustaining costs
LOM sustaining costs(1)	587.6
Salvage value credit(1)	(18.7)
Reclamation and closure costs(1)	83.3
Total(1)	2,896.4
All-in sustaining costs (US$/oz)	757.6
All-in sustaining costs (C$/oz)	984.9

Notes:

(1)    All-in sustaining costs are presented as defines by the WGC less corporate G&A

(2)    Millions of Canadian dollars

Table 4: Gold Price⁽¹⁾ and Exchange Rate⁽²⁾ Sensitivity

	Gold Price (US$/oz)
	1,300	1,400	1,500	1,600(1)	1,700	1,800	1,900	2,000
Pre-tax NPV 5% (C$Million)	836.2	988.6	1,350.7	1,685.1	1,968.0	2,217.7	2,444.6	2,654.3
After-tax NPV 5% (C$Million)	640.4	739.2	964.6	1,168.4	1,338.7	1,485.3	1,618.1	1,740.5
Pre-tax IRR	24.7%	27.6%	34.3%	40.1%	44.8%	48.8%	52.4%	55.6%
After-tax IRR	21.5%	24.0%	29.3%	33.8%	37.5%	40.6%	43.3%	45.8%
Pre-tax payback after start of production (years)	2.88	2.64	2.21	1.95	1.79	1.66	1.56	1.49
After-tax payback after start of production (years)	3.03	2.78	2.32	2.03	1.86	1.74	1.64	1.57

	Foreign Exchange Sensitivity
	0.90	0.85	0.80	0.77(2)	0.70	0.65	0.60	0.55
Pre-tax NPV 5% (C$M)	1,025.4	1,952.2	1,268.0	1,685.1	2,134.1	2,034.3	2,549.9	2,478.8
After-tax NPV 5% (C$M)	762.5	1,329.2	913.4	1,168.4	1,436.4	1,377.9	1,679.4	1,638.1
Pre-tax IRR	28.3%	44.5%	32.8%	40.1%	47.5%	45.9%	54.0%	52.9%
After-tax IRR	24.5%	37.3%	28.1%	33.8%	39.6%	38.3%	44.6%	43.8%

Notes:

(1) The base case uses a gold price of US$1,600/oz.

(2) The base case uses an exchange rate of US$1.00 = C$1.30 (or US$0.77 = C$1.00).

 

Table 5: Consulting Firms and Area of Responsibility

Consulting Firm	Area of Responsibility
A2GC − Andrieux & Associates Geomechanics Consulting L.P.	–         Rock mass characterization and rock engineering in support of the underground mine design
BBA Inc.	–         Metallurgical test work management and analysis –         Crusher and process plant mass and water balance –         Electrical distribution infrastructure design and costs (on-site) –         Electrical Transmission Line Leasing Costs –         Integrated Operations Centre (IOC) design and costs –         General and administration (G&A) operating costs –         Project execution plan and schedule –         IT and communications infrastructure design and costs (supply and on-site) –         Financial Analysis –         NI 43-101 integration
Entech Mining Ltd.	–         Underground mine design, underground infrastructure, ventilation, paste backfill distribution; Production scheduling –         Underground capital costs and operating costs –         Mineral Reserve Estimate
PLR Resources Inc.	–         Historical data review –         Current and historical geology, exploration, drilling –         Sample preparation, QA/QC, and data verification –         Geological modelling and mineral resource estimate
WSP Canada Inc.	–         Site utilities & services, design and costs –         Off-site access road to Windfall, inspection and costs –         On-site roads and pads, design and costs –         Site utilities & services electrical, design and costs –         Surface mineralized material, waste rock, overburden and topsoil management facility, design and costs –         Surface water management infrastructure, design and costs –         Regulatory context, social considerations, and anticipated environmental issues –         Geotechnical input for infrastructure design –         Geotechnical input for TSF design –         Geochemical characterization of waste rock, tailings, and ore –         Surface tailings management facility, design and costs –         Site wide water balance –         Hydrogeology and groundwater quality input for environmental studies –         Hydrogeology input to underground mine design –         Tailings filtration plant and dry tailings storage / handling, design and costs –         Environmental studies, permitting and closure costs
GCM Consultant	–         Water treatment plant design, capital and operating costs

 

Mineral Resource Estimate

The FS mineral reserve estimate is based on the Windfall MRE (2022), which is summarized below in Table 6. This mineral resource estimate uses a base cut-off of 3.5 g/t Au in the measured mineral resource, indicated mineral resource and inferred mineral resource categories.

Table 6: Windfall Deposit Mineral Resource Estimate ⁽¹⁾

Area	Measured					Indicated					Inferred
	Tonnes(1) (000)	Grade Au (g/t)	Grade Ag (g/t)	Ounces Au(1) (000)	Ounces Ag(1) (000)	Tonnes(1) (000)	Grade Au (g/t)	Grade Ag (g/t)	Ounces Au(1) (000)	Ounces Ag(1) (000)	Tonnes(1) (000)	Grade Au (g/t)	Grade Ag (g/t)	Ounces Au(1) (000)	Ounces Ag(1) (000)
Lynx(2)	671	11.4	7.2	247	154	6,638	13.2	6.7	2,814	1,426	4,774	10.8	6.9	1,663	1,063
Underdog	–	–	–	–	–	928	9.5	3.4	284	101	4,072	7.7	3.0	1 011	397
Main(3)	109	9.4	4.4	33	16	2,685	7.6	4.8	655	412	2,799	5.8	3.3	518	296
Triple 8	–	–	–	–	–	–	–	–	–	–	642	7.0	6.6	145	136
Total in situ	780	11.1	6.8	279	170	10,250	11.4	5.9	3,754	1,939	12,287	8.4	4.8	3,337	1,892
Stockpiles	32	16.9	4.3	17	4	–	–	–	–	–	–	–	–	–	–
Total	811	11.4	6.7	297	174	10,250	11.4	5.9	3,754	1,939	12,287	8.4	4.8	3,337	1,892

Notes:

(1) Values are rounded to nearest thousand which may result in apparent discrepancies.

(2) Lynx area includes: Lynx Main, Lynx HW, Lynx SW, Lynx 4, and Triple Lynx.

(3) Main area includes: Zone 27, Caribou 1, Caribou 2, Caribou Extension, Bobcat, Mallard, Windfall North, and F-Zones

 

Mineral Reserve Estimate

The mineral reserve estimate on which the FS is based was completed by Patrick Langlais (P.Eng.) of Entech Mining Ltd. (summarized below in Table 7) and consists of probable reserves using a 3.5 g/t operating, 2.5 g/t incremental, and 1.7 g/t development cut-off grade.

Table 7: Windfall Mineral Reserve

 

			Tonnes (000s)	Grade (g/t)	Contained Oz Au (000s)
Probable mineral reserves(1)(2)(3)(4)(5)			12,183	8.06	3,159
Notes:
	(1)	Patrick Langlais, P.Eng. (Entech Mining Ltd.) is the “qualified person” (within the meaning of NI 43-101) for the mineral reserve estimate and is considered to be “independent” of Osisko under Section 1.5 of NI 43-101.
	(2)	Mineral reserve estimate has an effective date of September 1, 2022 and is based on the mineral resource block model dated June 7, 2022.
	(3)	Estimated at US$1,600/oz Au using an exchange rate of US$1.00 = C$1.30
	(4)	Mineral reserve tonnage and mined metal have been rounded to reflect the accuracy of the estimate and numbers may not add due to rounding.
	(5)	Mineral reserves presented include both internal and external dilution along with mining recovery. The external dilution is estimated to be 20%. Assumed mining recoveries are 98% for development and an average of 91% for production.

 

Capital and Operating Costs Estimate

The overall capital cost estimate developed in the FS generally meets the AACE Class3 requirements and has an accuracy range of between -10% and +15%. Contingency was calculated based on Monte Carlo simulation, using a P₅₀ value.

 

Table 8: Capital Cost Summary⁽¹⁾⁽²⁾

Capital Costs (Millions of Canadian dollars)	Pre-Production	Sustaining	Total
Mining	80.2	556.7	636.9
Mineral processing and filtration plant	273.8	0.0	273.8
Mine surface facilities	0.0	3.7	3.7
Electrical and communication	14.7	0.0	14.7
Plant surface facilities	63.9	0.0	63.9
Tailings and water management	69.5	26.0	95.5
Indirect and owner’s costs	237.0	1.3	238.3
Site reclamation and closure restoration	0.0	83.3	83.3
Salvage value	0.0	(18.7)	(18.7)
Subtotal	739.1	652.3	1,391.3
Contingency (P50)	49.5	0.0	49.5
Total capital costs(2)	788.6	652.3	1,440.8
Production revenue NSR		6,134.3	6,134.3

Notes:

(1) Totals may differ due to rounding.

(2) Total capital costs exclude: (i) sunk costs for pre-ordered grinding mills (C$5.6 million) and EIA (C$1.1 million); (ii) long-lead items,                including engineering studies (C$34.6 million), logistics and warehousing (C$2.1 million), mechanical and electrical packages (C$57.0            million), camp (C$32.2 million), material opportunity purchase (C$8 million), mining fixed equipment (C$2.9 million) and contingency         (C$3.0 million).

Table 9: Operating Cost Summary

Operating costs (Millions of Canadian dollars)
Mining	993.0
Processing	492.3
Waste and water management	76.1
General & administration	396.3
Electrical transmission line lease	176.2
Total operating costs	2,134.0

Mining

The mineral resources used in the mine plan are contained in three different zones over a strike length of 2,300 metres and span from surface to a depth of approximately 1,100 metres. Each zone is characterized by multiple tabular panels, which mainly trend ENE and dip vertically to sub-vertically.

The planned underground mine will have a targeted production rate of 3,400 tonnes per day (“tpd”). The selected mining method is longitudinal longhole open stoping. Stope dimensions are 20 metres in height, median of 25 metres in strike length, and have a median thickness of 4.4 metres with a minimum thickness of 3.0 metres. Mineralized material will be extracted using a fleet of 14 and 18 tonne load-haul-dumps (“LHDs”) and 54 tonne haul trucks using a ramp to surface.

 Processing

A total of 3,400 tpd run-of-mine will be processed at the Windfall site. The process plant consists of primary crushing, followed by a grinding circuit consisting of a SAG mill (24’ x 11’, in closed circuit with a pebble crusher) and ball mill (17’ x 31’, in closed circuit with cyclones – SABC circuit). A gravity circuit followed by leaching recovers coarse gold from the cyclone underflow, while the cyclone overflow, at a P₈₀= 37 microns, is treated in a carbon-in–pulp (“CIP”) circuit, followed by SO2/air cyanide destruction. Gold and silver are recovered in an adsorption-desorption-recovery (“ADR”) circuit and electrowinning (‘’EW’’) cells, with gold room recovery and production of doré bars.

The process plant is followed by a tailings filtration plant with filter press to produce paste backfill to send underground and/or dry material for filtered tailings stack storage.

The process plant is estimated to average 93.1% payable gold recovery and 83.3% for silver over the LOM.

The process plant building also includes mine and mill offices, a dry, warehouse, and first aid office.

 Surface Infrastructure and Indirects

The mine envisions using existing exploration camp surface infrastructure: site access road; underground exploration ramp portal; underground ventilation and services; waste rock stockpile; ponds; water treatment plant; power line and substation; telecommunication tower; storage domes; and diesel generators. The project will include the construction of the following infrastructure: camp complex; First Nations cultural centre; potable water and sewage systems; gatehouse; truck shop; core shack; process plant complex including crushing line, offices, dry and warehouse; waste rock stockpile extension; overburden and ore stockpiles; tailings filtration and paste backfill plant; fire protection system; water treatment plant upgrade; surface water management facility including ditches, ponds and pumping stations; overhead power lines; service and hauling roads; Lynx portal and services; exhaust ventilation systems; fuel storage and distribution; and tailings storage facility.

Indirect costs such as owner’s costs, and construction management, temporary facilities for construction and other related items are estimated at C$237 million. An additional C$49.5 million has been budgeted as contingency for specific direct and indirect costs.

Environment and Closure

The Windfall mining project is located north of the 49^th parallel in the administrative region of Nord-du-Québec, on Category III lands of the Eeyou Istchee Baie-James territory. The mine site is located approximately 270 kilometres from the city of Val-d’Or and 115 kilometres east of the town of Lebel-sur-Quévillon.

The project is subject to the provincial EIA and review procedure under Section 153 of chapter II of the Environment Quality Act (Québec) (LQE; L.R.Q., c. Q 2 ), which documents the provisions applicable to the James Bay and Northern Québec region, in connection with the agreement of the same name.

Inventories have been carried out since 2010. Additional data is being collected and the results will be integrated into the ongoing EIA study.

In addition to provincial EIA approval, the project will require permits and authorizations prior to construction and operation of the proposed mine. Requests for these approvals will be submitted following the EIA.

A closure plan for the Windfall project has been developed, the closure costs are estimated at C$83.3 million (excluding salvage value). The objective of site closure is to return the site to a fully satisfactory state that includes eliminating all unacceptable health hazards and ensuring public safety, eliminating the production and spread of contaminants that could damage the receiving environment and, in the long term (aiming to cease the necessity of maintenance and monitoring) returning the site to an environmentally sound condition. This cost estimate includes site restoration as well as post-closure monitoring, 10% of direct costs for engineering and a contingency of 18%. In accordance with Québec mining legislation, the Corporation will post a bond as a guarantee for 100% of the anticipated site closure costs.

Stakeholder Engagement

The Windfall project is located on the traditional lands of the CFNW. Osisko has taken a proactive approach toward stakeholder consultation, holding more than 250 communication activities since 2015, primarily with in CFNW and Lebel-sur-Quévillon.  Consultation on the project with First Nation and non-First Nation communities was initiated in 2015 and has continued with frequent updates on project activities, meetings, open house presentations, committees and employment and contracting opportunities.

Concerns raised by communities include land disturbance, water quality, impacts to wildlife and the cumulative effects of all projects in the area. Osisko is committed to continuing the dialogue with potentially affected communities through the environmental assessment process.

The CFNW and non-First Nation communities have expressed strong support for the project. Osisko’s understanding of their main interest in the project is the maximization of local economic benefits – specifically with a focus on employment and entrepreneurial opportunities throughout the various phases of the project. In 2022 more than 95 First Nations community members worked at the Windfall site. Since 2016, Osisko has invested over C$256 million dollars in the purchase of goods and services from First Nations-owned companies or joint ventures.

Royalties

A 2.1% NSR royalty on all metals produced from the Windfall project has been applied in the FS based on existing royalty agreements and reflecting the mine plan.

Opportunities

The FS mining plan includes 1.3 million tonnes of inferred mineral resources located within mineral reserve blocks, for which a zero-grade value has been assigned. Through a limited amount of underground drilling, the Corporation believes that it could potentially convert most of the 1.3 million tonnes, grading between 4.0-6.0 g/t Au and representing between 160,000 – 250,000 ounces Au of inferred resource material.

Based on bulk sample results from Windfall, the Corporation believes additional recovery could be achieved by optimizing gravity circuit.

Ongoing studies and continuous improvement in waste and water management approaches may result in the reduction of the surface footprint and impacts.

The Corporation will continue to investigate opportunities that may arise to allow electrification of the mining fleet as a way of further reduction of the project carbon footprint.

 

Conference Call

Osisko will host a conference call on Tuesday, November 29, 2022, at 8:00am ET.

Toll-free dial-in number (Canada/US): 1 855-343-6177

Local dial-in number: 416-933-3854

Conference ID: 1418200

 

Notes for Mineral Resource Estimate (being the Windfall MRE (2022)) on Windfall Deposit

	(1)	The effective date of the Windfall MRE (2022) is June 7, 2022. The Windfall MRE (2022) was prepared by Pierre-Luc Richard, P. Geo. (OGQ#1119) and Mathieu Bélisle, P. Eng. of BBA Inc., each of whom is a “qualified person” within the meaning of NI 43-101 and considered to be “independent” of Osisko under Section 1.5 of NI 43-101.
	(2)	The Windfall MRE (2022) has been prepared in accordance with the “Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines”, adopted by the CIM Council on November 29, 2019.
	(3)	The mineral resources referred to in the Windfall MRE (2022) are not mineral reserves and they do not have demonstrated economic viability.  The quantity and grade of reported inferred mineral resources are uncertain in nature and there has been insufficient exploration to define these inferred mineral resources as indicated mineral resources or measured mineral resources; however, it is reasonably expected that most of the inferred mineral resources could be upgraded to indicated mineral resources with continued exploration.  Resources are presented undiluted and in situ and are considered to have reasonable prospects for economic extraction.  Isolated and discontinuous blocks above the stated cut-off grade are excluded from the mineral resource estimate.  Must-take material (i.e., isolated blocks below cut-off grade located within a potentially mineable volume) was included in the mineral resource estimate.
	(4)	Mineral resources are reported inclusive of those mineral resources converted to mineral reserves.
	(5)	As of June 7, 2022, being the effective date of the Windfall MRE (2022), the drill database comprises a total of 4,834 drill holes for 1,852,861 metres of drilling in the area extent of the mineral resource estimate, of which 4,152 drill holes (1,665,282 metres) were completed and assayed by Osisko. The drill hole grid spacing is approximately 12.5 metres x 12.5 metres for definition drilling, 25 metres x 25 metres for infill drilling and larger for extension drilling.
	(6)	All core assays reported by Osisko were obtained by analytical methods described below under “Technical Information and Quality Control & Quality Assurance – Quality Control and Reporting Protocols”.
	(7)	Geological interpretation of the deposit is based on lithologies, mineralization style, alteration, and structural features.  Most mineralization envelopes are subvertical, striking NE-SW and plunging approximately 40 degrees towards the North-East.  The 3D wireframing was generated in Leapfrog Geo, a modelling software, from hand selections of mineralization intervals.  The mineral resource estimate includes a total of 579 tabular, mostly sub-vertical domains defined by individual wireframes with a minimum true thickness of 2.0 metres.
	(8)	Assays were composited within the mineralization domains into 2.0 metre length composites.  A value of 0.00125 g/t Au and 0.0025 g/t Ag (¼ of the detection limit) was applied to unassayed core intervals.
	(9)	High-grade composites were capped.  Capping was determined in each zone from statistical studies on groups of lenses sharing similar mineralization characteristics.  Capping varies from 6 g/t Au to 200 g/t Au and from 5 g/t Ag to 150 g/t Ag.  A three-pass capping strategy defined by capping values decreasing as interpolation search distances increase was used in the grade estimations.
	(10)	Block models were produced using Datamine™ Studio RM Software. The models are defined by parent cell sizes of 5 metres EW, 2 metres NS and 5 metres height, and sub-blocked to minimum sub-cell sizes of 1.25 metres EW, 0.5 metres NS and 1.25 metres height.
	(11)	Ordinary Kriging (OK) based interpolations were produced for gold estimations in each zone of the Windfall deposit, while silver grade estimations were produced using Inverse Distance Squared (ID2) interpolations. Gold estimation parameters are based on composite variography analyses. The gold estimation parameters were used for the silver estimation.
	(12)	Density values between 2.74 and 2.93 were applied to the mineralized lenses.
	(13)	The mineral resource estimate included in the Windfall MRE (2022) uses the measured mineral resource, indicated mineral resource and inferred mineral resource categories, as follows:
		(a)	The measured mineral resource category is manually defined and encloses areas where:
			(i)	drill spacing is less than 12.5 metres;
			(ii)	blocks are informed by mostly four drill holes;
			(iii)	geological evidence is sufficient to confirm geological and grade continuity; and
			(iv)	lenses have generally been accessed by underground workings.
		(b)	The indicated mineral resource category is manually defined and encloses areas where:
			(i)	drill spacing is generally less than 25 metres;
			(ii)	blocks are informed by mostly three drill holes; and
			(iii)	geological evidence is sufficient to assume geological and grade continuity.
		(c)	The inferred mineral resource category is manually defined and encloses areas where:
			(i)	drill spacing is less than 100 metres;
			(ii)	blocks are informed by a minimum of two drill holes;
			(iii)	geological evidence is sufficient to imply, but not verify geological and grade continuity.
	(14)	Tonnage and gold grade of the stockpiles were estimated using the grade control model.  Densities by lithologies, ranging from 2.76 to 2.84, were used in the estimation of the tonnages.  Gold grades were estimated with an average of muck samples results for every round tonnage, based on muck samples with an average sample weight of 3.4 kilograms taken every 8-yard scoop bucket.  The sampling capping varying between 60 g/t Au to 80 g/t Au was applied on the muck gold grade results.  An average per silver grade estimates in the stockpiles was reported from the resource block model as silver was not analyzed in the muck samples.
	(15)	The mineral resource is reported at 3.5 g/t Au cut-off.  The cut-off grade is based on the following economic parameters: gold price at US$1,600/oz, exchange rate at US$1.28 = C$1.00, 93% mill recovery; payability of 99.95%; selling cost at US$5/oz, 2% NSR royalties, mining cost at C$125/t milled, G&A cost at C$39/t milled, processing cost at C$42/t, and environment cost at C$4/t.
	(16)	Estimates use metric units (metres (m), tonnes (t), and g/t).  Metal contents are presented in troy ounces (metric tonne x grade / 31.103475).
	(17)	The independent qualified person is not aware of any known environmental, permitting, legal, title-related, taxation, socio-political or marketing issues, or any other relevant issue that could materially affect the mineral resource estimate.

Technical Information and Quality Control & Quality Assurance

Independent Qualified Persons

This FS was prepared for Osisko by BBA Inc. and other industry consultants, each of whom is a “qualified person” within the meaning of NI 43-101 and considered to be “independent” of Osisko under Section 1.5 of NI 43-101, including the following:

• Patrick Andrieux, P.Eng. (A2GC − Andrieux & Associates Geomechanics Consulting L.P.)
• Colin Hardie, P.Eng., Mathieu Bélisle, P.Eng. (BBA Inc.)
• Patrick Langlais, P.Eng. (Entech Mining Ltd.)
• Pierre-Luc Richard, P. Geo. (PLR Resources Inc.)
• Andréanne Hamel, P. Eng., Aytaç Göksu, P. Eng., Eric Poirier, P. Eng., PMP, Frédéric Choquet, P.Eng., Isabelle Larouche, P.Eng., Ken DeVos, P. Geo., Yves Boulianne, P. Eng. (WSP Canada Inc.)
• Mélissa Tremblay, P. Eng. (GCM Consultants)

Each “qualified person” noted above has reviewed and approved the scientific and technical content in this news release relating to the FS.

Qualified Person

The scientific and technical content in this news release has been reviewed and approved by Mr. Mathieu Savard, P.Geo (OGQ #510), President of Osisko, who is a “qualified person” within the meaning of NI 43-101.

 

Quality Control and Reporting Protocols

NQ core assays were obtained by either 1 kilogram screen fire assay or standard 50 gram fire assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/ Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

 

About Windfall

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The MRE for Windfall is supported by the technical report titled “NI 43-101 Technical Report, Mineral Resource Estimate for the Windfall Project”, dated September 14, 2022 (with an effective date of June 7, 2022), prepared for the Corporation by BBA Inc. and PLR Resources Inc. (the “Windfall MRE (2022)”), and assuming a cut-off grade of 3.50 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the MRE for Windfall are further described in the Windfall MRE (2022), being the full technical report for this updated MRE prepared in accordance with NI 43-101 and is available on SEDAR (www.sedar.com) under Osisko’s issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main, and Underdog. Mineralization is generally comprised of sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The resources excluding TP8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

The FS relating to the disclosure of this news release will be filed on SEDAR (www.sedar.com) under Osisko’s issuer profile within 45-days. Reference should be made to the full text of the FS for the assumptions, qualifications and limitations relating thereto.

 

Non-IFRS Financial Measures

The Corporation has included certain non-IFRS financial measures in this news release, such as capital cost, sustaining capital cost, total capital cost and AISC, which are not measures recognized under IFRS and do not have a standardized meaning prescribed by IFRS. As a result, these measures may not be comparable to similar measures reported by other corporations. Each of these measures used are intended to provide additional information to the user and should not be considered in isolation or as a substitute for measures prepared in accordance with IFRS. Non-IFRS financial measures used in this news release and common to the gold mining industry are defined below.

Total Cash Costs and Total Cash Costs per Ounce

Total cash costs are reflective of the cost of production. Total cash costs reported in the FS include mining costs, processing, general and administrative costs of the mine, silver by-product credit, refining costs, transportation costs and royalties. Total cash costs per ounce is calculated as total cash costs divided by payable gold ounces.

AISC and AISC per Ounce

AISC (all-in sustaining cost) is reflective of all of the expenditures that are required to produce an ounce of gold from operations. AISC reported in the FS includes total cash costs, sustaining capital, closure costs and salvage, but excludes corporate general and administrative costs, waste and water management costs, electrical transmission line lease costs. AISC per ounce is calculated as AISC divided by payable gold ounces.

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the FS providing a robust base case assessment for developing Windfall as an underground dual ramp-access mine with a central processing mill at the mine site; the results of the engineering work being undertaken on the project; reliance on third-parties for infrastructure, including power lines; the timing and progress of the EIA study; the timing and progress of the mine permitting process; the results of the FS, including NPV, IRR, production, tax-free cash flows, capex, AISC, milling operations, average recovery, job creation; the key assumptions, parameters and methods used to estimate the mineral resource estimate relating to the FS; the prospects of Windfall being a highly-profitable gold mine; the ability of the Corporation to obtain project financing in H1 2023 (if at all); the basis for the Corporation making a production decision early in 2024 (if at all); the prospects, if any, of the Windfall gold deposit; timing and ability of Osisko to file a technical report for the FS disclosed in this news release; the trend of grade increase; the Lynx zone remaining open to expansion down plunge; upgrading a inferred mineral resource to a measured mineral resource or indicated mineral resource category; future drilling at the Windfall gold deposit; the significance of historic exploration activities and results. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; the timing and ability, if at all, to finalize the EIA study; the timing and ability, if at all, to obtain permits; the FS’ reliance on third-parties for infrastructure critical to build and operate the project, including power lines; our ability to obtain power for the project, if at all or on terms economic to the Corporation; the status of third-party approvals or consents; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including (infill) drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the Canadian/United States dollar exchange rate; the global economic climate; metal (including gold) prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

CONTACT INFORMATION:

John Burzynski
Chief Executive Officer
Telephone (416) 363-8653

 

169% Reconciliation vs Grade in Mineral Resource Estimate

10,135 ounces Gold and 4,378 ounces Silver Contained within 4,809 tonnes

 

(Toronto, Oct 27, 2022) Osisko Mining Inc. (OSK:TSX “Osisko” or the “Corporation”) is pleased to provide new results from the continuing exploration program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

 

Highlights

• Average grade of 65.5 g/t Au (2.11 ounces per Ton Au) for the bulk sample, 169% positive reconciliation
• 4,809 tonnes bulk sample contained 10,135 ounces Au and 4,378 ounces of Ag
• 93.1% Au recovery (including 52.2% Au recovery in gravity concentrates) from floatation processing circuit
• Windfall bulk samples processed to date (Zone 27, Lynx 311, and Lynx 600) using floatation processing comprised an aggregate of 16,025 tonnes containing 14,914 ounces of gold and 8,004 ounces of silver, with the average gold recovery for the three samples of 94.1%

 

Results from processing 4,809 tonnes mined from Triple Lynx (the “bulk sample”) presented in Table 1 and Table 2, have exceeded technical expectations. The sample produced a positive reconciliation of 169%, returning an average grade of 65.5 g/t Au, well above the predicted capped grade based on the 12.5-metres infill model using the same block model parameters as the current mineral resource estimate “MRE” (technical report filed on SEDAR under Osisko’s issuer profile on September 14, 2022). Significant visual gold mineralization was encountered along the length of the mined stope.  Highlights and full results are presented below, diagrams and sections can be found at www.osiskomining.com. Map: Bulk TLX-3161 Long section Final

 

Table 1: Lynx Bulk Sample Reconciled Results

tonnes (dry)	Head Grade		Contained Ounces		Gravity Concentrate		Flotation Concentrate		Overall Recovery		Recovered Ounces
	Au (g/t)	Ag (g/t)	Au	Ag	t (dry)	Au Rec (%)	t (dry)	Au Rec (%)	Au (%)	Ag (%)	Au	Ag
4,809	65.5	28.3	10,135	4,378	11.5	52.2	316.5	85.7	93.1	88.2	9,439	3,864

Mill feed tonnages used in the sample processing reconciliation were provided by Northern Sun. Day and night shift daily composite samples collected during the processing of the bulk sample were assayed by external independent laboratories. Bulk sample results were reconciled by Soutex Inc., an external independent consultant using Bilmat.

 

Osisko Chairman and Chief Executive Officer John Burzynski commented: “On the back of our strongly positive MRE announced in late August and the significant new high-grade down plunge intercepts in September (Osisko news release dated September 27, 2022), today’s bulk sample results underscore the potential for Windfall to become one of the largest and highest-grade underground gold deposits in Canada. The grade has – for the third time in as many bulk samples – significantly exceeded expectations based on capped drilling block models. The empirical results from our bulk samples have consistently returned strong positive reconciliations, and give strong support to the existing geological model.  They have proved invaluable in increasing our confidence in the grade, continuity and predictability of the mineralized zones at Windfall.”

Geology

The Triple Lynx wireframe 3161 bulk sample is characterized by a West-South-West oriented mineralization corridor moderately dipping to the north, with an average width of 3.3 metres. Banded grey quartz veins contain 5 – 15% pyrite, trace chalcopyrite and local visible gold. The mineralization is hosted within a granodiorite dyke and gabbro, both showing strong sericite and silica alteration.

 

Processing

A total of 4,809 tonnes of mineralized material were processed in September 2022 at the Northern Sun Redstone concentrator, producing gravity and flotation concentrates. The reconciled head grade obtained from the processed sample is 65.5 g/t Au and 28.3 g/t Ag. The sample contained 10,135 oz Au and 4,378 oz Ag, with a total of 9,439 oz Au and 3,864 oz Ag recovered.  Reconciled recoveries are 93.1% for gold and 88.2% for silver. The Windfall MRE metallurgical test work considered a communition, gravity and leaching circuit process flowsheet, giving an average recovery of 96.4% for the Lynx zone. Test mill availability dictated the use of a mill with a communition, gravity and flotation flowsheet. The reconciled results from the processing of the bulk sample material are presented in Table 1.

 

Block Model

The bulk sample was taken from Triple Lynx mineralization wireframe 3161 of the Windfall MRE. The sample area was infill drilled at 12.5-metres spacings and predicted to contain 4,800 tonnes averaging 38.9 g/t Au, and 6,009 ounces of gold (Table 2).

 

Table 2: Infill Resource Block Model Predictions vs. Processed Material

Block Model – Predictions			Processed Material – Actual
Tonnes	Au g/t	Au Ounces	Tonnes	Au g/t	Au Ounces
4,800	38.9	6,009	4,809	65.5	10,135

 

Concentrates

Both the gravity concentrates and flotation concentrate produced from the sample are considered high- grade.  The gravity concentrate averaged 14,339 g/t Au (461.0 oz/t Au), while the flotation concentrate averaged 408.2 g/t Au (13.1 oz/t Au).

 

Mining and Grade Control

The Triple Lynx bulk sample was mined using long hole mining methods. Two development drifts were mined conventionally at 20 metres floor-to-floor vertical intervals between 580 and 600 metres below surface. While mining the development drifts, sampling of the face was completed to test the width and grade of the mineralization. A V30 borehole was used in the slot raise and three-inch production holes were drilled down and blasted. The blasted ore was retrieved using a remote scoop tram, sampled, trucked to a surface stockpile, then trucked to the Northern Sun mill site.

 

Previous Bulk Samples

All three bulk samples completed by Osisko have reconciled positively. Table 3 summarizes Windfall’s three bulk sample results, which have returned in aggregate 14,914 ounces gold and 8,004 ounces silver from a combined 16,025 tonnes, or an average of 0.93 ounces Au per tonne and 0.50 ounces Ag per tonne, with an average gold recovery of 94.1 percent, and average silver recovery of 90.8 percent.

 

 

Table 3: Bulk Samples Completed at Windfall

Bulk Sample		Predicted	Actual	Reconciliation
Zone 27*	Tonnage (t)	5,512	5,500	100%
	Au g/t	6.8	8.5	126%
	Au oz	1,198	1,508	126%
Lynx 311*	Tonnage (t)	5,717	5,716	100%
	Au g/t	9.4	17.8	189%
	Au oz	1,736	3,271	189%
Lynx 600	Tonnage (t)	4,800	4,809	100%
	Au g/t	38.9	65.5	169%
	Au oz	6,009	10,135	169%

*See Osisko news releases dated June 11, 2019, and December 11, 2019, respectively.

 

Qualified Person

The scientific and technical content of this news release has been reviewed, prepared and approved by Kim-Quyên Nguyên, MBA., P.Eng. (OIQ 146014), Project Director for Osisko, who is a “qualified person” within the meaning of National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”). The block model in the bulk area of the Triple Lynx zone, with an effective date of February 3, 2022, was prepared by Judith St-Laurent, P.Geo (OGQ #1023), Director of Mineral Resource Estimation of Osisko Mining, who is a “qualified person” within the meaning of NI 43-101. The scientific and technical content in this news release has been reviewed and approved by Mr. Mathieu Savard, P.Geo (OGQ #510), President of Osisko Mining, who is a “qualified person” within the meaning of NI 43-101.

 

Technical Info, Quality Control and Reporting Protocols

Process reconciliation was performed using Bilmat software by Soutex Inc., an external consultant. A reconciled balance was calculated for each day and night shift as well as for the overall bulk sample processing. Day and night shift mill throughput was estimated using the load cell on the Redstone primary ball mill feed conveyor. Composite samples were taken each day and night shift on the streams required for the reconciliation. The total quantity of material processed was estimated based on the Redstone Mill truck scale which has been calibrated before the bulk sample processing. The flotation concentrate was bagged and weighed on the same truck scale and drill samples were taken from each bag. The gravity concentrate bags were weighed on a scale and each bag was drill sampled. The material remaining in the equipment at the end of the bulk processing after the clean-up was collected in bags, weighed, and sampled. All samples were sent out to an external independent lab for preparation and assaying. All shift samples were assayed for gold, silver, iron, sulfur, and moisture. The drill samples from the bags were assayed for gold, silver and moisture. Gold assay from all streams except the rougher flotation feed and tails was obtained by screened metallics fire assay. Remaining process cleaning bags data was redistributed through the flotation concentrate.

 

About Windfall

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The MRE for Windfall is supported by the technical report titled “NI 43-101 Technical Report, Mineral Resource Estimate for the Windfall Project”, dated September 14, 2022 (with an effective date of June 7, 2022), prepared for the Corporation by BBA Inc. and PLR Resources Inc. (the “Windfall MRE (2022)”), and assuming a cut-off grade of 3.50 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the MRE for Windfall are further described in the Windfall MRE (2022), being the full technical report for this updated MRE prepared in accordance with NI 43-101 and is available on SEDAR (www.sedar.com) under Osisko’s issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main, and Underdog. Mineralization is generally comprised of sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The resources excluding TP8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

 

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. The information in this news release about the potential for Windfall to become one of the largest and highest-grade underground deposits in Canada; the Windfall gold deposit being one of the highest grade resource-stage gold projects in Canada; the significance of the results from the bulk sample described in this news release; the bulk sample having a higher than expected grade; any prediction arising from the bulk sample; the average grade of the bulk sample having any predictive value; the MRE for Windfall being possibly conservative on the grade of the deposit; the geology of the bulk sample; the deposit remaining open along strike and at depth; potential depth extensions of the mineralized zones down-plunge and at depth; potential mineralization; the ability to realize upon any mineralization in a manner that is economic; the ability to complete any proposed exploration activities and the results of such activities, including the continuity or extension of any mineralization; and any other information herein that is not a historical fact may be “forward-looking information”. Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This forward- looking information is based on reasonable assumptions and estimates of management of the Corporation at the time such assumptions and estimates were made, and involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Osisko to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, risks relating to the ability of exploration activities (including drill results and bulk samples) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall project; the ability of the Corporation to obtain required approvals and complete transactions on terms announced; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions. Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information, Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

 

For further information please contact:

John Burzynski Chairman and Chief Executive Officer Telephone: (416) 363-8653

Intercepts Confirm Potential for Significant Expansion of Windfall

81.8 g/t Au Over 3.5 Metres; 22.3 g/t Au Over 4.1 metres

(Toronto, September 27, 2022) Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new exploration results from its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

Hole OSK-22-1109-W2 targeted the projected down plunge extension of Lynx 4 at a vertical depth from surface of 1,670 metres. The hole successfully intercepted significant widths of high-grade gold mineralization, including 81.8 g/t Au over 3.5 metres (2.39 ounces per ton over 11.5 feet) and 22.3 g/t Au over 4.1 metres (0.65 ounces per ton over 13.4 feet). These intercepts confirm potential for a major down-plunge extension of the Lynx 4 high-grade zone, which could have significant implications for the future potential expansion of the Windfall deposit.

The new intercepts are 625 metres (2,050 feet) down plunge from the nearest resource block (Lynx 4 wireframe 3449) included in the most recent Mineral Resource Estimate (“MRE”) for Windfall (see Windfall MRE (2022) (as defined herein). The technical report was filed on SEDAR (www.sedar.com) under Osisko’s issuer profile on September 14, 2022). The new mineralization is typical of Lynx 4 wireframe 3449, including disseminated pyrite associated with strong pervasive silica alteration hosted in a sericitized gabbro, with local visible gold.

Osisko Chief Executive Officer John Burzynski commented: “Windfall has scale and grade unparalleled in the global near-term development category. With the recent on-time delivery of our Windfall MRE (based on approximately 1.7 million metres of drilling since 2015), we have now focused on completion of the definitive feasibility study which is on schedule for delivery before the end of the year. Today’s down-plunge results are a strong indication of a much larger deposit, underscoring the consistency and predictability of the geology model we have developed for Windfall over the past six years. The addition of 625 metres length to one of our highest-grade Lynx 4 zones shows there is great potential for Windfall to move to the top of the class, when compared to other significant Canadian long-life, high-grade gold deposits.”

Maps showing hole locations and full analytical results are available at www.osiskomining.com. Maps: 20220927_Lynx 4_EXT_EN MRE, 20220927_Lynx 4_EXT_EN plan, 20220927_Lynx 4_EXT_EN long section, PR_EN_20220927_Surface.

Exploration drilling

Hole No.	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t)         cut to 100 g/t	Zone	Corridor
OSK-W-22-1109-W2	1993.0	1997.1	4.1	22.3	19.6	LX4-3449	Lynx 4
including	1993.4	1994.0	0.6	119	100
	2001.8	2005.3	3.5	81.8	31.0	LX4-3449	Lynx 4
including	2004.4	2005.3	0.9	298	100
OSK-W-19-1992-W1*	1708.4	1714.3	5.9	14.3		Lynx 4	Lynx 4
OSK-W-20-2251-W1**	2112.0	2114.0	2.0	8.45		Lynx 4	Lynx 4

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. * See Osisko news released dated October 21, 2019, ** see Osisko news release dated January 11, 2021.

Drill hole location

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Elevation	Section
OSK-W-22-1109-W2	131	-56	2100	454385	5436238	402	5025
OSK-W-19-1992-W1	106	-61	1875	454007	5436004	401	4575
OSK-W-20-2251-W1	96	-53	2278	453262	5435936	407	3900

Lynx Zone

Mineralization occurs as grey to translucent quartz-carbonate-pyrite-tourmaline veins and pyrite replacement zones and stockworks. Vein-type mineralization is associated with haloes of pervasive sericite-pyrite ± silica alteration and contain sulphides (predominantly pyrite with minor amounts of chalcopyrite, sphalerite, galena, arsenopyrite, and pyrrhotite) and local visible gold. Replacement mineralization is associated with strong pervasive silica-sericite-ankerite ± tourmaline alteration and contains disseminated pyrite from trace to 80% with local visible gold. Pyrite stockworks can form envelopes that reach several tens of metres thick. Fuchsite alteration is common and is spatially constrained to near the gabbros. Mineralization occurs at or near geological contacts between felsic porphyritic or fragmental intrusions and the host rhyolites or gabbros and locally can be hosted along the gabbro-rhyolite contact.

 

Qualified Person

The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Louis Grenier, M.Sc.A., P.Geo. (OGQ 800), Director of Exploration for Osisko’s Windfall gold project, who is a “qualified person” within the meaning of National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

 

Quality Control and Reporting Protocols

True width determination is estimated at 55-80% of the reported core length interval for the zone. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.5 g/t Au diluted over core lengths of at least 2.0 metres. NQ core assays were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at: (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos; and (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

About the Windfall Gold Deposit

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The MRE for Windfall is supported by the technical report entitled “Mineral Resource Estimate Update for the Windfall Project” dated September 14, 2022 (with an effective date  of June 7, 2022) (the “Windfall MRE (2022)”), and assuming a cut-off grade of 3.50 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the MRE for Windfall are further described in the Windfall MRE (2022), being the full technical report for this updated MRE prepared in accordance with NI 43-101, and is available on SEDAR (www.sedar.com) under Osisko’s issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main, and Underdog.  Mineralization is generally comprised of sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The resources excluding TP8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

 

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the significance of the Lynx 4 high-grade extension; the significance of any resource described herein; the potential of expanding Windfall beyond the current known deposit; any scientific and technical information not supported by the Windfall MRE (2022); the key assumptions, parameters and methods used to estimate the MRE disclosed in this news release; the prospects, if any, of the Windfall gold deposit; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; the amount and type of drilling to be completed and the timing to complete such drilling; the focus of the remaining infill drilling; the trend of grade increase; the Lynx zone remaining open to expansion down plunge; upgrading a inferred mineral resource to a measured mineral resource or indicated mineral resource category; future drilling at the Windfall gold deposit; the significance of historic exploration activities and results. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including (infill) drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

CONTACT INFORMATION:

John Burzynski
Chief Executive Officer
Telephone (416) 363-8653

Including 203 g/t Au over 5.2 metres and 93.9 g/t Au over 7.6 metres

(Toronto, September 15, 2022) Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new analytical results from the ongoing drill program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

Significant new analytical results presented below include 103 intercepts in 46 drill holes (4 from surface, 42 from underground) and 6 wedges. The infill intercepts are located inside defined mineral resource estimate (“MRE”) blocks (see Osisko news release dated August 30, 2022). The expansion intercepts are located outside the MRE blocks and either expand resource wireframes or are in a defined zone or corridor not yet correlated to a specific wireframe.

A new Lynx 4 zone announced earlier this year (see Osisko news release dated March 23, 2022) was included in the recent MRE as Lynx 4 wireframe 3466. Two expansion holes confirmed the growth potential of this wireframe with intercepts 56.9 g/t Au over 2.4 metres and 14.0 g/t Au over 2.9 metres, 170 metres and 80 metres below the current MRE blocks, respectively.

Expansion intercepts extending wireframes include: 29.1 g/t Au over 5.8 metres, a 231-meter extension of Triple Lynx wireframe 3155 below the MRE blocks, 203 g/t Au over 5.2 metres, a 33-meter extension of Triple Lynx wireframe 3120 to the west, and 51.4 g/t Au over 2.1 meters, a 39-meter extension of Triple Lynx wireframe 3161 to the east.

Infill results in this release were received after the June 7, 2022 database closed for use in the recently released MRE, and were not included. These infill results will be used in future mine planning.

Osisko Chief Executive Officer John Burzynski commented: “Our drill program continues to deliver significant high-grade results. The expansion holes continue to clearly demonstrate additional potential growth of the resource base at Windfall. As the focus shifts to engineering and the pending feasibility study, we are reducing the number of active drills at site, however we will maintain exploration work on high-potential expansion areas as well as drilling on key infill areas for mine planning.”

Select infill high-grade intercepts include: 93.9 g/t Au over 7.6 metres in WST-22-1040, 127 g/t Au over 5.7 metres in WST-22-1032; 112 g/t Au over 5.9 metres in WST-22-1033; 57.0 g/t Au over 9.3 metres in OSK-W-22-2601-W7; 53.4 g/t Au over 8.2 metres in WST-22-1026; 214 g/t Au over 2.0 metres in WST-22-1029; 176 g/t Au over 2.1 metres in WST-22-1048; 151 g/t Au over 2.2 metres in WST-22-1068 and 155 g/t Au over 2.0 metres in WST-22-1071A. Maps showing hole locations and full analytical results are available at www.osiskomining.com. Maps: Long Section_Infill EN 20220915, Long Section_LX4-3466 EN 20220915, Long Section_Expan EN 20220915, PR_EN_20220915_Surface, PR_EN_20220915_UG.

 

Expansion Drilling

Hole No.	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t)         cut to 100 g/t	Zone	Corridor
OSK-W-19-2108-W2	1736.9	1739.3	2.4	56.9	36.3	LX4_3466	Lynx 4
including	1737.9	1738.7	0.8	162	100
OSK-W-22-2540-W13	1293.8	1296.0	2.2	7.08		LX4	Lynx 4
	1374.0	1376.4	2.4	4.57		LX4_3463	Lynx 4
	1471.1	1474.0	2.9	14.0		LX4_3466	Lynx4
including	1471.1	1472.2	1.1	27.4
OSK-W-22-2601-W7	1061.3	1067.1	5.8	29.1		TLX_3155	Triple Lynx
including	1062.2	1063.3	1.1	69.3
	1091.0	1093.0	2.0	16.3		TLX	Triple Lynx
including	1091.0	1092.0	1.0	30.1
	1126.0	1128.7	2.7	4.49		TLX	Triple Lynx
including	1127.4	1127.8	0.4	15.7
OSK-W-22-2646-W8	1037.9	1043.8	5.9	7.27		TLX_3148	Triple Lynx
	1137.5	1139.5	2.0	6.18		TLX_3162	Triple Lynx
OSK-W-22-2655	310.6	313.3	2.7	10.7		BCT	Bobcat
including	310.6	311.4	0.8	23.6
	344.0	346.0	2.0	3.64		BCT	Bobcat
	385.0	387.0	2.0	80.8	50.0	LXM	Lynx
including	385.0	386.0	1.0	162	100
	432.0	434.0	2.0	6.10		LXM	Lynx
	653.0	655.0	2.0	3.82		LSW_3508	Lynx SW
including	653.9	654.4	0.5	15.0
OSK-W-22-2656	579.0	581.2	2.2	4.57		LSW_3500	Lynx SW
WST-22-1024	160.0	162.0	2.0	5.74		TLX	Triple Lynx
including	160.0	160.6	0.6	18.9
WST-22-1025	135.4	137.7	2.3	4.10		LXM_3357	Lynx
including	137.0	137.7	0.7	11.9
WST-22-1026	351.8	354.0	2.2	4.82		TLX	Triple Lynx
including	353.1	354.0	0.9	10.8
WST-22-1032	109.0	111.1	2.1	6.17		TLX	Triple Lynx
including	109.8	110.1	0.3	17.1
	189.7	191.7	2.0	43.8	25.3	TLX	Triple Lynx
including	190.2	190.7	0.5	174	100
	205.9	208.1	2.2	24.6		TLX_3148	Triple Lynx
including	206.3	206.9	0.6	59.3
WST-22-1040	242.8	248.0	5.2	203	43.8	TLX_3120	Triple Lynx
including	246.3	248.0	1.7	586	100
WST-22-1047	41.0	43.0	2.0	125	25.2	LXM	Lynx
including	41.6	42.1	0.5	498	100
WST-22-1049	224.0	226.0	2.0	8.88		TLX	Triple Lynx
including	225.0	226.0	1.0	17.6
WST-22-1052	446.0	448.0	2.0	7.83		LX4	Lynx 4
including	447.1	447.7	0.6	25.8
WST-22-1053A	50.0	52.0	2.0	6.64		LXM	Lynx
including	50.0	50.4	0.4	33.0
WST-22-1061	142.6	144.7	2.1	51.4	43.2	TLX_3161	Triple Lynx
including	143.3	144.0	0.7	125	100
and	144.4	144.7	0.3	60.8
WST-22-1073	211.7	214.8	3.1	4.85		LHW_3216	Lynx HW
WST-22-1085	254.0	256.1	2.1	4.23		TLX_3163	Triple Lynx
including	255.2	255.5	0.3	29.2

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below., BCT = Bob Cat, LHW = Lynx Hangingwall, LSW = Lynx South West, LXM = Lynx Main, LX4 = Lynx 4 and TLX = Triple Lynx.

Infill Drilling

Hole No.	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t)         cut to 100 g/t	Zone	Corridor
OSK-W-22-2120-W4	1245.9	1248.0	2.1	16.4		LX4_3449	Lynx 4
including	1246.5	1247.0	0.5	65.8
	1251.9	1254.2	2.3	3.52		LX4_3449	Lynx 4
	1263.4	1265.6	2.2	24.1		LX4_3445	Lynx 4
including	1264.2	1264.7	0.5	78.6
OSK-W-22-2601-W7	1104.0	1106.0	2.0	5.59		TLX_3162	Triple Lynx
including	1104.0	1104.5	0.5	18.2
	1112.0	1114.6	2.6	6.07		TLX_3162	Triple Lynx
including	1113.1	1113.8	0.7	17.6
	1163.7	1173.0	9.3	57.0	24.9	TLX_3172	Triple Lynx
including	1166.1	1166.6	0.5	689	100
and	1170.3	1170.8	0.5	108	100
OSK-W-22-2605-W5	1339.7	1344.0	4.3	3.52		LX4_3445	Lynx 4
OSK-W-22-2651	534.0	536.0	2.0	5.35		LSW_3508	Lynx SW
including	535.0	536.0	1.0	10.4
	563.0	565.0	2.0	5.78		LSW_3500	Lynx SW
including	564.0	565.0	1.0	11.1
OSK-W-22-2652	599.6	601.7	2.1	9.69		LSW_3500	Lynx SW
including	600.0	600.4	0.4	45.4
OSK-W-22-2656	554.4	556.4	2.0	19.9		LSW_3508	Lynx SW
including	555.0	555.5	0.5	59.1
WST-22-1026	253.6	261.8	8.2	53.4	27.0	TLX_3158	Triple Lynx
including	257.6	258.2	0.6	214	100
and	258.2	258.8	0.6	347	100
WST-22-1027	234.4	236.7	2.3	19.8		TLX_3131	Triple Lynx
	403.0	405.0	2.0	9.17		LX4_3410	Lynx 4
including	403.4	404.2	0.8	22.7
WST-22-1029	143.1	145.1	2.0	214	53.4	LXM_3388	Lynx
including	143.1	143.4	0.3	1130	100
WST-22-1032	241.3	247.0	5.7	127	50.1	TLX_3158	Triple Lynx
including	243.4	244.9	1.5	370	100
WST-22-1033	324.9	327.3	2.4	37.8		TLX_3158	Triple Lynx
including	325.6	326.4	0.8	90.2
	373.0	376.0	3.0	3.52		TLX_3155	Triple Lynx
	467.4	473.3	5.9	112	44.5	TLX_3172	Triple Lynx
including	467.8	468.4	0.6	505	100
and	469.2	470.0	0.8	240	100
WST-22-1034	169.7	173.1	3.4	26.5		LXM_3388	Lynx
including	171.8	172.4	0.6	56.6
	579.0	581.9	2.9	54.1	41.7	LX4_3430	Lynx 4
including	581.0	581.9	0.9	140	100
WST-22-1035	212.2	215.0	2.8	12.2		TLX_3148	Triple Lynx
	277.0	279.2	2.2	23.3		TLX_3158	Triple Lynx
including	278.7	279.2	0.5	93.0
WST-22-1037	212.3	214.3	2.0	10.4		TLX_3120	Triple Lynx
including	212.9	213.4	0.5	36.4
	248.0	250.2	2.2	68.4	46.6	TLX_3158	Triple Lynx
including	248.9	249.9	1.0	148	100
	336.0	338.2	2.2	6.37		TLX_3162	Triple Lynx
including	336.6	337.0	0.4	29.6
WST-22-1038	272.0	275.3	3.3	5.62		TLX_3120	Triple Lynx
	277.9	280.2	2.3	28.4	18.9	TLX_3158	Triple Lynx
including	279.8	280.2	0.4	155	100
	455.4	459.0	3.6	6.28		TLX_3172	Triple Lynx
including	458.5	459.0	0.5	37.3
WST-22-1039	255.3	258.0	2.7	25.6		TLX_3158	Triple Lynx
including	256.6	257.0	0.4	58.8
WST-22-1040	310.7	318.3	7.6	93.9	61.0	TLX_3158	Triple Lynx
including	311.7	313.1	1.4	236	100
	361.3	366.7	5.4	11.2		TLX_3162	Triple Lynx
including	363.1	364.0	0.9	46.3
	374.0	376.3	2.3	40.7	25.6	TLX_3162	Triple Lynx
including	375.9	376.3	0.4	187	100
WST-22-1041B	170.0	172.5	2.5	15.6		LXM_3388	Lynx
including	170.6	171.1	0.5	66.8
	492.0	494.0	2.0	4.21		LX4_3404	Lynx 4
including	493.0	493.7	0.7	8.43
WST-22-1042	309.1	311.3	2.2	20.5		TLX_3158	Triple Lynx
including	309.1	309.5	0.4	47.6
WST-22-1043	501.4	503.5	2.1	130	26.7	LX4_3410	Lynx 4
including	502.7	503.2	0.5	536	100
	529.9	533.1	3.2	5.60		LX4_3411	Lynx 4
including	532.6	533.1	0.5	27.8
WST-22-1044	57.0	59.2	2.2	90.2	27.0	LXM_3388	Lynx
including	58.7	59.2	0.5	378	100
WST-22-1045	233.1	236.5	3.4	7.40		TLX_3148	Triple Lynx
including	236.2	236.5	0.3	16.4
WST-22-1046B	403.0	405.3	2.3	5.55		TLX_3162	Triple Lynx
including	403.5	403.8	0.3	29.7
WST-22-1047	47.0	49.0	2.0	9.49		LXM_3354	Lynx
including	48.0	49.0	1.0	18.7
WST-22-1048	39.5	41.5	2.0	144	20.4	LXM_3354	Lynx
including	40.0	40.4	0.4	718	100
	61.4	63.5	2.1	176	34.0	LXM_3388	Lynx
including	61.9	62.6	0.7	526	100
WST-22-1052	177.0	179.0	2.0	17.7		LXM_3388	Lynx
including	177.9	178.4	0.5	40.6
	514.5	517.0	2.5	28.1		LX4_3430	Lynx 4
including	515.1	515.8	0.7	92.2
	519.0	521.0	2.0	6.81		LX4_3430	Lynx 4
WST-22-1053	48.5	50.5	2.0	8.51		LXM_3388	Lynx
including	50.0	50.5	0.5	33.8
WST-22-1058C	402.2	412.5	10.3	6.41		TLX_3162	Triple Lynx
including	405.6	406.0	0.4	95.3
WST-22-1061	112.0	114.2	2.2	15.5		TLX_3121	Triple Lynx
including	113.1	114.2	1.1	30.9
WST-22-1063A	175.3	180.3	5.0	22.4		TLX_3148	Triple Lynx
including	175.3	176.3	1.0	93.6
and	179.9	180.3	0.4	27.7
	185.0	187.0	2.0	5.35		TLX_3148	Triple Lynx
	241.3	246.2	4.9	51.7	46.6	TLX_3158	Triple Lynx
including	242.0	243.0	1.0	125	100
WST-22-1065	156.0	158.1	2.1	7.44		LXM_3317	Lynx
including	157.5	158.1	0.6	18.4
WST-22-1066	77.9	80.0	2.1	29.9		LXM_3388	Lynx
including	78.5	78.8	0.3	78.4
WST-22-1068	190.0	192.0	2.0	45.9		TLX_3161	Triple Lynx
including	191.0	191.3	0.3	96.7
	580.3	582.5	2.2	151	27.6	LX4_3430	Lynx 4
including	580.3	580.9	0.6	554	100
	586.0	588.5	2.5	52.9	23.8	LX4_3430	Lynx 4
including	586.6	587.0	0.4	282	100
WST-22-1070	161.8	163.9	2.1	62.4	38.7	TLX_3121	Triple Lynx
including	162.1	162.8	0.7	171	100
WST-22-1071A	188.0	190.9	2.9	68.9	36.4	TLX_3161	Triple Lynx
including	189.2	190.2	1.0	194	100
	203.8	205.8	2.0	155	65.5	TLX_3161	Triple Lynx
including	203.8	204.6	0.8	131	100
and	204.6	205.1	0.5	408	100
	242.0	244.0	2.0	5.63		TLX_3163	Triple Lynx
including	243.3	243.7	0.4	18.4
	264.0	266.5	2.5	9.18		TLX_3149	Triple Lynx
including	264.0	265.0	1.0	20.0
WST-22-1073	64.5	67.0	2.5	5.62		LXM_3388	Lynx
WST-22-1076	156.6	159.4	2.8	10.9		TLX_3161	Triple Lynx
including	156.6	156.9	0.3	74.0
WST-22-1078	100.6	106.1	5.5	34.6	33.2	TLX_3161	Triple Lynx
including	100.6	101.2	0.6	101	100
WST-22-1083	117.0	119.0	2.0	29.5	15.5	LXM_3317	Lynx
including	118.0	118.3	0.3	193	100
WST-22-1085	225.0	231.6	6.6	6.98		TLX_3161	Triple Lynx
including	227.0	228.0	1.0	23.0
	296.0	299.0	3.0	4.66		TLX_3158	Triple Lynx
WST-22-1090	179.2	181.7	2.5	63.1	48.7	TLX_3161	Triple Lynx
including	179.9	180.7	0.8	145	100
WST-22-1091	64.5	67.0	2.5	3.54		LXM_3388	Lynx
WST-22-1092	275.0	277.1	2.1	6.26		LHW_3212	Lynx HW
including	276.2	276.8	0.6	20.8
WST-22-1095	464.0	466.0	2.0	13.4		TLX_3162	Triple Lynx
including	465.1	466.0	0.9	28.9
	508.0	512.0	4.0	45.0	30.4	TLX_3172	Triple Lynx
including	508.7	509.2	0.5	217	100

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below., LHW = Lynx Hangingwall, LSW = Lynx South West, LXM = Lynx Main, LX4 = Lynx 4 and TLX = Triple Lynx.

 

Drill hole location

Hole No.	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Elevation	Section
OSK-W-19-2108-W2	117	-53	2013	453215	5435858	414	3825
OSK-W-22-2120-W4	114	-60	1337	453800	5435747	401	4275
OSK-W-22-2540-W13	117	-60	1773	453466	5435639	410	3925
OSK-W-22-2601-W7	125	-61	1209	453425	5435656	412	3900
OSK-W-22-2605-W5	112	-55	1401	453551	5435669	408	4025
OSK-W-22-2646-W8	109	-58	1254	453326	5435648	414	3825
OSK-W-22-2651	146	-57	567	452988	5435242	417	3325
OSK-W-22-2652	143	-55	633	453010	5435274	416	3350
OSK-W-22-2655	146	-60	675	452976	5435277	411	3325
OSK-W-22-2656	147	-56	672	452941	5435243	411	3275
WST-22-1024	131	-57	271	453701	5435376	-198	4000
WST-22-1025	122	-20	189	453507	5435332	-47	3825
WST-22-1026	153	-65	361	453646	5435347	-189	3950
WST-22-1027	138	-30	468	453444	5435276	-99	3725
WST-22-1029	155	-40	180	453506	5435331	-47	3825
WST-22-1032	147	-61	268	453646	5435347	-188	3950
WST-22-1033	128	-63	508	453510	5435330	-127	3825
WST-22-1034	130	-45	625	453507	5435331	-48	3825
WST-22-1035	122	-60	325	453701	5435376	-198	4000
WST-22-1037	163	-63	342	453646	5435347	-188	3950
WST-22-1038	170	-67	490	453645	5435346	-189	3950
WST-22-1039	113	-55	312	453701	5435376	-198	4000
WST-22-1040	134	-60	480	453510	5435330	-127	3825
WST-22-1041B	127	-43	585	453507	5435331	-48	3825
WST-22-1042	108	-57	342	453701	5435376	-198	4000
WST-22-1043	133	-26	561	453344	5435312	-66	3650
WST-22-1044	138	-16	193	453647	5435347	-187	3950
WST-22-1045	104	-54	339	453702	5435376	-198	4000
WST-22-1046B	124	-58	436	453510	5435331	-127	3825
WST-22-1047	130	-12	226	453647	5435347	-187	3950
WST-22-1048	139	-1	169	453647	5435347	-187	3950
WST-22-1049	129	-44	621	453507	5435328	-90	3825
WST-22-1052	119	-42	613	453506	5435331	-48	3825
WST-22-1053	115	-13	64	453648	5435348	-187	3950
WST-22-1053A	115	-12	193	453648	5435348	-187	3950
WST-22-1058C	121	-60	520	453511	5435331	-127	3825
WST-22-1061	160	-59	166	453600	5435324	-181	3900
WST-22-1063A	119	-55	291	453702	5435377	-198	4000
WST-22-1065	106	-18	238	453648	5435348	-187	3950
WST-22-1066	104	-26	237	453648	5435348	-188	3950
WST-22-1068	122	-46	628	453507	5435328	-90	3825
WST-22-1070	167	-57	181	453645	5435346	-188	3950
WST-22-1071A	139	-59	393	453509	5435330	-127	3825
WST-22-1073	155	19	255	453701	5435376	-195	4000
WST-22-1076	177	-60	208	453599	5435324	-181	3900
WST-22-1078	186	-52	133	453599	5435324	-181	3900
WST-22-1083	123	-36	187	453702	5435377	-198	4000
WST-22-1085	134	-58	423	453509	5435330	-127	3825
WST-22-1090	145	-57	317	453509	5435330	-127	3825
WST-22-1091	152	30	254	453701	5435376	-195	4000
WST-22-1092	147	-7	349	453510	5435330	-126	3825
WST-22-1095	125	-66	561	453510	5435330	-127	3825

 

Bobcat

Mineralization most commonly occurs in gold-bearing quartz-pyrite veins controlled by northeast trending faults and shears and to a lesser extent in minor crustiform quartz-tourmaline-ankerite-pyrite veins and pyrite replacement zones and stockwork. Mineralization is hosted in sheared mafic volcanics, rhyolites near faults, or at the contact with felsic porphyritic intrusions.

 

Lynx Zone

Mineralization occurs as grey to translucent quartz-carbonate-pyrite-tourmaline veins and pyrite replacement zones and stockworks. Vein-type mineralization is associated with haloes of pervasive sericite-pyrite ± silica alteration and contain sulphides (predominantly pyrite with minor amounts of chalcopyrite, sphalerite, galena, arsenopyrite, and pyrrhotite) and local visible gold. Replacement mineralization is associated with strong pervasive silica-sericite-ankerite ± tourmaline alteration and contains disseminated pyrite from trace to 80% with local visible gold. Pyrite stockworks can form envelopes that reach several tens of metres thick. Fuchsite alteration is common and is spatially constrained to near the gabbros. Mineralization occurs at or near geological contacts between felsic porphyritic or fragmental intrusions and the host rhyolites or gabbros and locally can be hosted along the gabbro-rhyolite contact.

 

Qualified Person

The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Louis Grenier, M.Sc.A., P.Geo. (OGQ 800), Director of Exploration for Osisko’s Windfall gold project, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

 

Quality Control and Reporting Protocols

True width determination is estimated at 55-80% of the reported core length interval for the zone. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.5 g/t Au diluted over core lengths of at least 2.0 metres. NQ core assays were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

 

About the Windfall Gold Deposit

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The Mineral Resource Estimate (“MRE“) defined by Osisko, as disclosed in the news release dated August 30, 2022, will be further described, including the key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the August 30, 2022, news release, in the full technical report being prepared for this updated mineral resource estimate in accordance with NI 43-101, and will be available on SEDAR (www.sedar.com) under the Corporation’s issuer profile within 45 days, and assumes a cut-off grade of 3.50 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main, and Underdog.  Mineralization is generally comprised of sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The resources excluding TP8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

 

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may”, “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in this news release; the prospects, if any, of the Windfall gold deposit; the timing and ability of Osisko to file a technical report for the mineral resource estimate disclosed in this news release; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; upgrading an inferred mineral resource to a measured mineral resource or indicated mineral resource category; future exploration activities, including drilling, at the Windfall gold deposit; the deposit remaining open along strike and at depth; the plunge potential of the Lynx and Underdog zones; expected grade and resource growth; cut-off grade and sensitivity analysis; and the significance of historic exploration activities and results. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

 

CONTACT INFORMATION:

John Burzynski
Chief Executive Officer
Telephone (416) 363-8653

(Toronto, September 14, 2022) Osisko Mining Inc. (OSK:TSX, “Osisko” or the “Corporation”) is pleased to announce that it has filed a technical report in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101“) to update the mineral resource estimate on its 100% owned Windfall gold deposit. The technical report entitled “ Mineral Resource Estimate Update for the Windfall Project, Eeyou Istchee James Bay, Québec, Canada” and dated September 14, 2022 (with an effective date of June 7, 2022) has been prepared for Osisko by BBA Inc. The technical report is available on SEDAR (www.sedar.com) under Osisko’s issuer profile.

 

The technical report contains a non-material change from the news release published on August 30, 2022. Sensitivity Table 1 has been corrected for the 2.5g/t cut-off grade. This change does not impact the results of the August 30, 2022 news release as the modification affects only numbers presented for reference purposes in the news release.  The NI 43-101 Technical Report cut-off grade has been determined with reference to a 3.5g/t cut-off grade.  The Table 1 below (which is included in the Technical Report) should replace the Table 1 from the August 30, 2022 news release.

 

Table 1: Windfall Gold Deposit Mineral Resource Estimate Sensitivity Table

Cut-off 2 (g/t Au)	Measured + Indicated					Inferred
	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Ounces Au1  (000 oz)	Ounces Ag1 (000 oz)	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Ounces Au1  (000 oz)	Ounces Ag1 (000 oz)
5.0	8,213	13.9	7.0	3,667	1,854	7,986	10.7	6.0	2,760	1,545
4.5	9,029	13.1	6.7	3,791	1,935	9,078	10.0	5.6	2,927	1,638
4.0	9,950	12.2	6.3	3,917	2,020	10,561	9.2	5.2	3,129	1,754
3.5	11,061	11.4	5.9	4,050	2,114	12,287	8.4	4.8	3,337	1,892
3.0	12,388	10.5	5.6	4,188	2,217	14,299	7.7	4.4	3,547	2,033
2.5	14,728	10.1	5.1	4,772	2,423	17,178	6.9	4.0	3,801	2,219

Notes:  ¹Values are rounded to nearest thousand which may cause apparent discrepancies.  ²MRE cut-off: 3.5 g/t Au. ³The cut-off grade variation is not applicable to the material in the Stockpiles.

 

Qualified Person

The technical report entitled, “Mineral Resource Estimate Update for the Windfall Project, Eeyou Istchee James Bay, Québec, Canada” and dated September 14, 2022 with an effective date of June 7, 2022, was prepared for Osisko by BBA Inc. (Pierre-Luc Richard, M.Sc., P.Geo (OGQ#1119) and Mathieu Belisle, P. Eng. (OIQ#128549)). Mr. Richard is an employee of PLR Resources Inc., subcontracted by BBA Inc.  for purposes of the technical report and Mr. Belisle is an employee of BBA Inc. Each of Pierre-Luc Richard and Mathieu Belisle is considered to be “independent” of Osisko for purposes of Section 1.5 of NI 43-101. The scientific and technical content in this news release has been reviewed and approved by Mr. Mathieu Savard, P.Geo (OGQ #510), President of Osisko, who is a “qualified person” (within the meaning of NI 43-101).

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

 Cautionary Statements Regarding Mineral Resource Estimate

Readers are cautioned that mineral resources are not mineral reserves and that the economic viability of mineral resources that are not mineral reserves has not been demonstrated. The mineral resource estimate described in this news release may be materially affected by geology, environmental, permitting, legal, title, socio-political, marketing or other relevant issues. The mineral resource estimate is classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum’s “CIM Definition Standards on Mineral Resources and Mineral Reserves” incorporated by reference into NI 43-101. Readers are cautioned not to assume that further work on the stated mineral resources will lead to mineral reserves that can be mined economically.

 

CONTACT INFORMATION:

John Burzynski
President & Chief Executive Officer
Telephone (416) 363-8653

4.1 Million Ounces Measured and Indicated Resource Averaging 11.4 g/t Au

3.3 Million Ounces Inferred Resource Averaging 8.4 g/t Au

 

(Toronto, August 30, 2022) Osisko Mining Inc. (OSK:TSX, “Osisko” or the “Corporation”) is pleased to provide an updated mineral resource estimate (“MRE”) for its 100% owned world-class high-grade Windfall gold deposit, located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

 

This robust MRE includes approximately 1.9 million metres of drilling, with 1.7 million metres completed by Osisko since October 2015, completed as of May 2022 and all analytical results received as of June 7, 2022.  The MRE will form the basis of the pending Windfall Project Feasibility Study, scheduled for delivery by YE2022.2022-08-30 MRE and upside potential_EN

 

HIGHLIGHTS

• 4.1 M oz Au measured & indicated (“M&I”) resource averaging 11.4 g/t Au
• M&I resource ounces increase of 26% (0.8 M oz Au)
• M&I resource grade increase of 8%
• Lynx contains 65% of MRE total (M&I 3.1 M oz averaging 13.0 g/t Au; Inferred 1.7 M oz averaging 10.8 g/t Au)
• 50% of the MRE is hosted in 26 wireframes; 75% of MRE is hosted in 97 wireframes
• 98% of MRE is located from surface to 1200 m vertical depth
• Exploration ramp access is currently at 635 m vertical depth in Lynx
• Extraction and transportation of the Lynx 600 bulk sample is completed, processing at custom mill pending and results on schedule for early Q4 2022
• Feasibility study on schedule for YE2022.

 

Chief Executive Officer of Osisko John Burzynski commented: “We’ve had a busy summer and have successfully completed another significant milestone at Windfall. With this final MRE update prior to our pending feasibility study, we have met and exceeded our objectives for the Windfall drill program:  a robust measured and indicated resource of over 4 million ounces with an average grade of over 10 g/t Au. The scale of Windfall and the deposit grade has steadily increased since Osisko’s discovery of Lynx in late 2016.  Lynx now represents almost two-thirds (65%) of the total gold in the MRE, and it continues to impress with a stand-alone total M&I resource of 3.1 M oz averaging 13.0 g/t Au.”

 

Mr. Burzynski continued: “Importantly, we completed the extraction and the transportation of the Lynx 600 (Triple Lynx) bulk sample in August, and the custom mill is being prepared for treating the test material.  We expect to have the processed results in hand for this high-grade sample by early October and anticipate that it will once again confirm a higher grade than indicated by drilling. As a reminder, the processing of the prior two bulk samples from the upper areas of the deposit returned results that were 26% and 89% higher grade than anticipated from drilling (please see Osisko news releases dated June 11 and December 11, 2019).  Finally, work is advancing well on the Windfall feasibility study, and we are on track for delivery by YE2022.”

 

The MRE tables below show the sensitivity to cut-off grades (Table 1) and the resources by area of the Windfall deposit (Table 2).

 

Table 1: Windfall Gold Deposit Mineral Resource Estimate Sensitivity Table

Cut-off 2 (g/t Au)	Measured + Indicated					Inferred
	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Ounces Au1  (000 oz)	Ounces Ag1 (000 oz)	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Ounces Au1  (000 oz)	Ounces Ag1 (000 oz)
5.0	8,213	13.9	7.0	3,667	1,854	7,986	10.7	6.0	2,760	1,545
4.5	9,029	13.1	6.7	3,791	1,935	9,078	10.0	5.6	2,927	1,638
4.0	9,950	12.2	6.3	3,917	2,020	10,561	9.2	5.2	3,129	1,754
3.5	11,061	11.4	5.9	4,050	2,114	12,287	8.4	4.8	3,337	1,892
3.0	12,388	10.5	5.6	4,188	2,217	14,299	7.7	4.4	3,547	2,033
2.5	18,526	9.8	4.8	5,848	2,849	20,397	7.0	3.8	4,583	2,496

Notes:  ¹Values are rounded to nearest thousand which may cause apparent discrepancies.  ²MRE cut-off: 3.5 g/t Au. ³The cut-off grade variation is not applicable to the material in the Stockpiles.

 

Table 2: Windfall Gold Deposit Mineral Resource Estimate by Area (3.5 g/t Au cut-off)

Area	Measured					Indicated					Inferred
	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Gold1 (000 oz)	Ag1 (000 oz)	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Gold1 (000 oz)	Ag1 (000 oz)	Tonnes1 (000 t)	Gold (g/t)	Ag (g/t)	Gold1 (000 oz)	Ag1 (000 oz)
Lynx2	671	11.4	7.2	247	154	6,638	13.2	6.7	2,814	1,426	4,774	10.8	6.9	1,663	1,063
Underdog	–	–	–	–	–	928	9.5	3.4	284	101	4,072	7.7	3.0	1,011	397
Main3	109	9.4	4.4	33	16	2,685	7.6	4.8	655	412	2,799	5.8	3.3	518	296
Triple 8	–	–	–	–	–	–	–	–	–	–	642	7.0	6.6	145	136
Total (in situ)	780	11.1	6.8	279	170	10,250	11.4	5.9	3,754	1,939	12,287	8.4	4.8	3,337	1,892
Stockpiles4	32	16.9	4.3	17	4	–	–	–	–	–	–	–	–	–	–
Total	811	11.4	6.7	297	174	10,250	11.4	5.9	3,754	1,939	12,287	8.4	4.8	3,337	1,892

Notes:  ¹Values are rounded to nearest thousand which may cause apparent discrepancies. ²Lynx area includes: Lynx Main, Lynx HW, Lynx SW, Lynx 4 and Triple Lynx. ³Main area includes: Zone 27, Caribou 1&2, Caribou Extension, Bobcat, Mallard, Windfall Nord, and F-Zones. ⁴Cut-off grade is not applicable to the stockpiles. See Windfall Gold Deposit Mineral Resource Estimate notes further below.

 

This MRE is the result of 4,834 drill holes (1,852,861 metres of core) in the resource area, including 4,152 drill holes (1,665,282 metres of core) completed by Osisko from October 2015 to May 2022 with assays up to June 7, 2022. The Windfall MRE (with an effective date of June 7, 2022) was prepared by Osisko and reviewed and audited by BBA Inc., Montréal, Québec. The full technical report, which is being prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI-43-101”), will be available on SEDAR (www.sedar.com) under the Corporation’s issuer profile within 45 days.

 

This mineral resource estimate reflects the current status of the geological interpretation supported by infill drilling, underground mapping and bulk sample results. Most mineralized envelopes in the Main area are associated with pyritic stringers. Lynx and Underdog mineralized lenses predominantly form an extensive anastomosed network of quartz-rich and pyrite-rich veins. The mineralization system is located near contacts between volcanic and pre-mineral intrusive rocks in the Main and Lynx areas, and more specifically, within pre-mineral intrusive units in Underdog.

 

The MRE is 50% contained within 26 wireframes, and 75% contained within 97 wireframes. The MRE considers a total of 579 mineralized lenses defined by individual wireframes with a minimum true thickness of 2.0 metres. The MRE reports grade blocks inside volumes potentially mineable by underground methods at a cut-off grade of 3.5 g/t Au (Table 3).

 

Table 3: Parameters used to estimate the underground cut-off grade

for the Windfall Gold Deposit Mineral Resource Estimation

Parameters	Unit	Value
Gold Price	USD/oz	1,600
Exchange Rate	USD/CAD	1.28
Mill Recovery	%	93.0
Payability	%	99.95
Sell Cost	USD/oz	5
Royalties (NSR)	%	2
Mining Cost	CAD/t milled	125
G&A Cost	CAD/t milled	39
Processing Cost	CAD/t milled	42
Environment	CAD/t milled	4
Calculated Cut-off Grade	g/t Au	3.5
MRE Cut-off Grade	g/t Au	3.5

 

Windfall Gold Deposit Mineral Resource Estimate Notes

 

1. The independent qualified person for the 2022 MRE, as defined by NI 43-101 guidelines, is Pierre-Luc Richard, P. Geo. (OGQ#1119), of PLR Resources Inc. The effective date of the estimate is June 07, 2022.

 

2. The Windfall mineral resource estimate follows the November 29, 2019, CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines.

 

3. These mineral resources are not mineral reserves as they have not demonstrated economic viability. The quantity and grade of reported Inferred mineral resources in this news release are uncertain in nature and there has been insufficient exploration to define these resources as Indicated or Measured; however, it is reasonably expected that the majority of Inferred mineral resources could be upgraded to Indicated mineral resources with continued exploration. Resources are presented undiluted and in situ and are considered to have reasonable prospects for economic extraction. Isolated and discontinuous blocks above the stated cut-off grade are excluded from the mineral resource estimate. Must-take material, i.e., isolated blocks below cut-off grade located within a potentially mineable volume, was included in the mineral resource estimate.

 

4. As of June 07, 2022, the database comprises a total of 4,834 drill holes for 1,852,861 m of drilling in the area extent of the mineral resource estimate, of which 4,152 drill holes (1,665,282 m) were completed and assayed by Osisko. The drill hole grid spacing is approximately 12.5 m x 12.5 m for definition drilling, 25 m x 25 m for infill drilling and larger for extension drilling.

 

5. All core assays reported by Osisko were obtained by analytical methods described below under “Quality Control and Reporting Protocols”.

 

6. Geological interpretation of the deposit is based on lithologies, mineralization style, alteration, and structural features. Most mineralization envelopes are subvertical, striking NE-SW and plunging approximately 40 degrees towards the North-East. The 3D wireframing was generated in Leapfrog Geo, a modelling software, from hand selections of mineralization intervals. The mineral resource estimate includes a total of 579 tabular, mostly sub-vertical domains defined by individual wireframes with a minimum true thickness of 2.0 m

 

7. Assays were composited within the mineralization domains into 2.0 m length composites. A value of 0.00125 g/t Au and 0.0025 g/t Ag (¼ of the detection limit) was applied to unassayed core intervals.

 

8. High-grade composites were capped. Capping was determined in each zone from statistical studies on groups of lenses sharing similar mineralization characteristics. Capping varies from 6 g/t Au to 200 g/t Au and from 5 g/t Ag to 150 g/t Ag. A three-pass capping strategy defined by capping values decreasing as interpolation search distances increase was used during grade estimation.

 

9. Block models were produced using Datamine™ Studio RM Software. The models are defined by parent cell sizes of 5 m EW, 2 m NS and 5 m height, and sub-blocked to minimum sub-cell sizes of 1.25 m EW, 0.5 m NS and 1.25 m height.

 

10. Ordinary Kriging (OK) based interpolations were produced for gold estimations in each zone of the Windfall deposit, while silver grade estimations were produced using Inverse Distance Squared (ID2) interpolations. Gold estimation parameters are based on composite variography analyses. The gold estimation parameters were used for the silver estimation.

 

11. Density values between 2.74 and 2.93 were applied to the mineralized lenses.

 

12. The Windfall mineral resource estimate is categorized as Measured, Indicated, and Inferred mineral resource as follows:

The Measured mineral resource category is manually defined and encloses areas where:

12. drill spacing is less than 12.5 m;
13. blocks are mostly informed by four drill holes;

• geological evidence is sufficient to confirm geological and grade continuity;

1. lenses have generally been accessed by underground workings.

The Indicated mineral resource category is manually defined and encloses areas where:

1. drill spacing is generally less than 25 m;
2. blocks are informed by mostly three drill holes;

• geological evidence is sufficient to assume geological and grade continuity.

The Inferred mineral resource category is manually defined and encloses areas where:

1. drill spacing is less than 100 m;
2. blocks are informed by a minimum of two drill holes;

• geological evidence is sufficient to imply, but not verify geological and grade continuity.

 

13. Tonnage and gold grade of the stockpiles were estimated using the grade control model. Densities by lithologies, ranging from 2.76 to 2.84, were used in the estimation of the tonnages. Gold grades were estimated using muck samples weighted average results for every round tonnage, based on muck samples with an average sample weight of 3.4 kg taken every 8-yard scoop bucket. Capping varying between 60 g/t Au to 80 g/t Au was applied on the muck gold grade results. Silver grade in the stockpiles was reported from the resource block model as silver was not analyzed in the muck samples.

 

14. The mineral resource is reported at 3.5 g/t Au cut-off. The cut-off grade is based on the following economic parameters: gold price at 1,600 USD/oz, exchange rate at 1.28 USD/CAD, 93.0% mill recovery; payability of 99.95%; selling cost at 5 USD/oz, 2% NSR royalties, mining cost at 125 CAD/t milled, G&A cost at 39 CAD/t milled, processing cost at 42 CAD/t, and environment cost at 4 CAD/t.

 

15. Estimates use metric units (metres (m), tonnes (t), and g/t). Metal contents are presented in troy ounces (metric tonne x grade / 31.103475).

 

16. The independent qualified person is not aware of any known environmental, permitting, legal, title-related, taxation, socio-political or marketing issues, or any other relevant issue, that could materially affect the mineral resource estimate.

 

Qualified Person

The Windfall mineral resource estimate, with an effective date of June 7, 2022, was (i) prepared by Judith St-Laurent, P.Geo (OGQ #1023), Director of Resource Estimation at Osisko, and (ii) reviewed and approved by Pierre-Luc Richard, M.Sc., P.Geo (OGQ#1119,) , each of whom is a “qualified person” within the meaning of NI 43-101. Mr. Richard is an employee of PLR Resources Inc., subcontracted by BBA Inc. and is considered to be “independent” of Osisko for purposes of section 1.5 of NI 43-101. The scientific and technical content in this news release has been reviewed and approved by Mr. Mathieu Savard, P.Geo (OGQ #510), President of Osisko, who is a “qualified person” within the meaning of NI 43-101.

Quality Control and Reporting Protocols

NQ core assays were obtained by either 1 kilogram screen fire assay or standard 50 gram fire assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/ Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

 

About the Windfall Gold Deposit

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec, Canada. The mineral resource defined by Osisko, as disclosed in this news release and assuming a cut-off grade of 3.5 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in this news release, certain of which are described in this news release, will be further described in the full technical report being prepared for this updated mineral resource estimate in accordance with NI 43-101, and will be available on SEDAR (www.sedar.com) under the Corporation’s issuer profile within 45 days. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main, and Underdog.  Mineralization is generally comprised of sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The resources excluding TP8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,400 square kilometres).

Cautionary Statements Regarding Estimates of Mineral Resources

This news release uses the terms measured, indicated and inferred mineral resources as a relative measure of the level of confidence in the resource estimate. Readers are cautioned that mineral resources are not mineral reserves and that the economic viability of resources that are not mineral reserves has not been demonstrated. The mineral resource estimate disclosed in this news release may be materially affected by geology, environmental, permitting, legal, title, socio-political, marketing or other relevant issues. The mineral resource estimate is classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum’s “CIM Definition Standards on Mineral Resources and Mineral Reserves” incorporated by reference into NI 43-101 (“CIM”). Under NI 43-101, estimates of inferred mineral resources may not form the basis of feasibility or pre-feasibility studies or economic studies except for preliminary economic assessments. Readers are cautioned not to assume that further work on the stated resources will lead to mineral reserves that can be mined economically.

 

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may”, “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in this news release; the prospects, if any, of the Windfall gold deposit; the timing and ability of Osisko to file a technical report for the mineral resource estimate disclosed in this news release; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; upgrading an inferred mineral resource to a measured mineral resource or indicated mineral resource category; future exploration activities, including drilling, at the Windfall gold deposit; the deposit remaining open along strike and at depth; the plunge potential of the Lynx and Underdog zones; expected grade and resource growth; cut-off grade and sensitivity analysis; and the significance of historic exploration activities and results. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

 

CONTACT INFORMATION:

John Burzynski
Chief Executive Officer
Office Telephone (416) 363-8653