Osisko Windfall Drilling Intercepts Wide High-Grade in Expansion Holes


163 g/t Au over 8.8 metres in Lynx 4

32.4 g/t Au over 5.7 metres in Triple Lynx

TORONTO, Dec. 08, 2021 (GLOBE NEWSWIRE) -- 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 97 intercepts in 31 drill holes (12 from surface, 19 from underground) and 22 wedges. The infill intercepts are located inside defined February 2021 mineral resource estimate (“MRE”) blocks (see Osisko news release dated February 17, 2021). The expansion intercepts are located outside the February 2021 MRE blocks and either expand resource wireframes or are in a defined zone or corridor but do not yet correlate to a specific wireframe.

Osisko Chief Executive Officer John Burzynski commented: “Today’s results underscore once again how much room there is to grow at Windfall with the headline holes located outside the resource released in February earlier this year. Targeted infill drilling also returned high-grade intercepts highlighting the robust grade of the deposit.”

Selected high-grade intercepts include: 163 g/t Au over 8.8 metres in OSK-W-21-1462-W11; 178 g/t Au over 2.9 metres in OSK-W-21-2551-W5; 135 g/t Au over 2.0 metres in OSK-W-21-1871-W1; 104 g/t Au over 2.4 metres in OSK-W-21-1949-W6; 95.2 g/t Au over 2.1 metres in OSK-W-21-2287-W7; 32.4 g/t Au over 5.7 metres in OSK-W-21-2540-W5, 49.4 g/t Au over 2.0 metres in WST-21-0903, 35.7 g/t Au over 2.4 metres in WST-21-0901, 21.5 g/t Au over 4.0 metres in OSK-W-21-2544-W2 and 42.7 g/t Au over 2.0 metres in WST-21-0879. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Infill Drilling

Hole No.From (m)To (m)Interval (m)Au (g/t) uncutAu (g/t) cut to 100 g/tZoneCorridor
OSK-W-21-1871-W1888.6891.02.412.5 UDD_4106Underdog
 1008.01010.02.013550.1UDD_4501
Underdog
including1008.01009.01.0270100
OSK-W-21-1871-W3491.0493.12.17.90 CA2_2211
Caribou
including491.5491.90.418.8 
 549.0551.02.05.32 CA2_2233Caribou
OSK-W-21-1949-W6747.2749.62.410427.6LXM_3345
Lynx
including748.1748.60.5466100
OSK-W-21-2287-W71213.91216.02.195.2 LX4_3449Lynx 4
OSK-W-21-2407-W2802.0805.03.08.55 UDD_4106
Underdog
including802.8803.50.721.1 
OSK-W-21-2416-W71018.01020.02.041.315.8TLX_3162
Triple Lynx
including1019.31019.60.3270100
 1032.01034.02.036.823.9TLX_3162
Triple Lynx
including1032.91033.20.3186100
OSK-W-21-2512-W2433.0435.02.07.24 CA2_2211Caribou
 687.6690.02.428.2 UDD_4100
Underdog
including688.3689.31.065.8 
 694.0696.02.06.01 UDD_4100Underdog
 715.0720.05.05.04 UDD_4102Underdog
 724.0726.02.04.28 UDD_4102Underdog
OSK-W-21-2531-W3810.0813.03.011.4 UDD_4110Underdog
 873.0877.04.010.3 UDD_4101Underdog
 913.0916.43.410.2 UDD_4100Underdog
OSK-W-21-2531-W4845.3847.32.06.79 UDD_4101
Underdog
including845.3845.60.335.3 
OSK-W-21-2532-W3828.0833.05.08.29 UDD_4100
Underdog
including832.0833.01.024.0 
 837.8842.04.219.016.1UDD_4100
Underdog
including840.0840.40.4131100
OSK-W-21-2537-W3938.0940.02.012.6 TLX_3183Triple Lynx
OSK-W-21-2544-W2774.9777.02.14.22 TLX_3171Triple Lynx
 783.0787.04.021.5 TLX_3171
Triple Lynx
including784.5785.20.762.8 
 793.0795.02.019.0 TLX_3184
Triple Lynx
including794.0794.40.493.3 
 989.0991.02.017.5 TLX_3195
Triple Lynx
including989.4990.00.658.1 
OSK-W-21-2551-W5941.3943.52.217.3 LX4_3430
Lynx 4
including942.0942.40.478.6 
 958.4961.32.917836.3LX4_3430
Lynx 4
including958.8959.70.9556100
OSK-W-21-2578-W3604.7606.92.27.71 UDD_4100
Underdog
including606.1606.90.820.9 
OSK-W-21-2587-W11030.01032.02.020.5 TLX_3163Triple Lynx
 1038.01040.02.05.36 TLX_3164
Triple Lynx
including1038.71039.00.327.1 
 1046.01049.03.03.99 TLX_3164Triple Lynx
 1089.01091.02.05.66 TLX_3162
Triple Lynx
including1089.01089.40.416.6 
 1105.61109.03.48.17 TLX_3170Triple Lynx
OSK-W-21-2600475.8478.02.25.70 Z27_1115Zone 27
OSK-W-21-26051312.01314.02.05.62 LX4_3445Lynx 4
OSK-W-21-2612-W1382.6384.92.34.02 Z27_1115
Zone 27
including382.6383.00.414.4 
OSK-W-21-2613916.2922.05.814.6 TLX_3161
Triple Lynx
including916.2916.60.438.1 
and918.7919.30.641.0 
 967.9970.02.119.8 TLX_3163
Triple Lynx
including967.9968.30.460.9 
and968.9969.30.442.5 
 994.0996.02.03.77 TLX_3164
Triple Lynx
including994.4995.00.68.21 
OSK-W-21-2621628.0630.02.018.6 UDD_4101Underdog
OSK-W-21-2625814.9817.32.410.9 LX4_3437
Lynx 4
including814.9815.20.355.1 
OSK-W-21-2631133.0135.02.026.5 F11_6001F-11
OSK-W-21-2632103.0105.02.03.66 F11_6000F-11
 139.0141.52.519.6 F11_6009
F-11
including139.6140.50.947.7 
OSK-W-21-2635568.0570.42.44.21 CA2_2211
Caribou
including570.1570.40.324.2 
OSK-W-21-2636365.0367.02.04.26 CA1_2551
Caribou
including366.0366.40.412.4 
 550.0552.02.013.0 Z27_1107
Zone 27
including551.0551.70.735.6 
OSK-W-21-2641118.4124.05.64.04 F11_6001F-11
WST-21-0649456.0458.02.06.23 TLX_3165Triple Lynx
WST-21-0875510.0512.72.720.718.8LX4_3450
Lynx 4
including512.2512.70.5111100
WST-21-0878346.0348.32.37.43 TLX_3131
Triple Lynx
including348.0348.30.337.7 
WST-21-0879510.0512.02.042.725.8LX4_3450
Lynx 4
including510.5511.00.5168100
 612.5615.02.524.0 LX4_3429
Lynx 4
including612.5613.00.578.8 
WST-21-0900272.9275.42.55.33 LHW_3215
Lynx HW
including275.0275.40.422.2 
WST-21-0901308.0310.42.435.724.5LHW_3215
Lynx HW
including309.6309.90.3189100
WST-21-0907509.5512.53.019.8 LX4_3430
Lynx 4
including509.5511.01.539.5 
 644.0646.12.138.835.1LX4_3448
Lynx 4
including645.0645.50.5116100
WST-21-0912603.0605.12.138.6 LX4_3429
Lynx 4
including603.6604.50.974.9 
WST-21-0920B301.1303.22.14.08 LHW_3215Lynx HW
WST-21-0922102.0104.02.03.57 LXM_3304Lynx

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See "Quality Control and Reporting Protocols" below. CA1 and CA2 = Caribou, LX4 = Lynx 4, LHW = Lynx Hanging Wall, LXM = Lynx Main, TLX = Triple Lynx, UDD = Underdog, F11 = F-Zones, Z27 = Zone 27.

Expansion Drilling

Hole No.From (m)To (m)Interval (m)Au (g/t) uncutAu (g/t) cut to 100 g/tZoneCorridor
OSK-W-21-1432-W11929.3938.18.816326.0LX4
Lynx
including929.3931.01.7811100
OSK-W-21-1871-W2754.0756.02.04.06 UDDUnderdog
OSK-W-21-2287-W71233.01235.02.024.2 LX4
Lynx 4
including1233.51234.40.949.0 
OSK-W-21-2407-W2769.3771.92.613.4 UDD
Underdog
including769.3769.70.457.1 
OSK-W-21-2465-W4765.6767.72.123.0 TLX
Triple Lynx
including766.8767.70.950.2 
OSK-W-21-2465-W6938.0940.02.04.61 TLXTriple Lynx
OSK-W-21-2540-W5948.0953.75.732.426.1TLX
Triple Lynx
including951.7952.71.0136100
OSK-W-21-2540-W6949.0951.02.011.8 TLX
Triple Lynx
including949.0950.01.023.3 
 955.0957.02.029.0 TLX
Triple Lynx
including955.6956.40.871.1 
OSK-W-21-2544-W2819.0821.02.05.18 TLX
Triple Lynx
including819.9820.20.329.7 
OSK-W-21-2578-W3589.5591.62.17.42 UDD
Underdog
including590.1590.70.624.7 
OSK-W-21-2587-W1967.0969.02.04.01 TLX
Triple Lynx
including967.0967.90.98.06 
OSK-W-21-2589131.6133.62.07.71 LNX
Lynx
including132.8133.20.431.0 
OSK-W-21-2599725.0727.02.024.7 CA2
Caribou
including725.0726.01.049.3 
 730.0732.02.05.92 CA2Caribou
 745.4748.32.95.42 CA2_2220Caribou
OSK-W-21-26131015.01017.02.05.65 TLXTriple Lynx
OSK-W-21-2635597.3600.02.712.0 CA2
Caribou
including598.1598.40.340.4 
WST-21-0649606.0608.02.05.94 LX4
Lynx
including606.4606.70.337.2 
WST-21-079374.076.02.03.72 LNX
Lynx
including74.375.10.88.11 
WST-21-0863336.3338.72.46.80 TLX
Triple Lynx
including338.3338.70.429.1 
WST-21-0878138.0140.52.53.93 TLXTriple Lynx
WST-21-0886231.0233.02.08.62 LSW
Lynx SW
including232.6233.00.442.8 
 319.2323.84.66.98 LSW
Lynx SW
including319.2319.50.335.7 
and320.1320.40.330.9 
 362.4364.42.04.74 LSW_3502
Lynx SW
including362.4362.70.331.0 
WST-21-0894B101.0103.02.04.94 BCT
Bobcat
including101.3101.80.519.0 
WST-21-0898239.5241.82.310.3 TLX
Triple Lynx
including240.7241.40.731.4 
WST-21-0903274.1276.12.049.4 TLXTriple Lynx
WST-21-0907567.0569.02.07.94 LX4
Lynx
including567.0567.80.819.5 
 583.0585.02.03.53 LX4
Lynx 4
including583.5584.00.513.5 
WST-21-0909366.4368.52.13.88 TLX
Triple Lynx
including367.8368.10.311.3 
 384.0386.42.45.94 TLX
Triple Lynx
including385.1385.50.432.1 
 409.0411.52.54.92 TLX
Triple Lynx
including411.1411.50.415.3 
WST-21-0915B247.0249.52.59.56 TLX
Triple Lynx
including247.0247.50.545.0 
 358.6361.22.622.2 TLX
Triple Lynx
including359.6360.30.763.7 
 368.2370.52.34.01 TLXTriple Lynx
WST-21-0916A386.0388.02.04.68 TLX
Triple Lynx
including387.2387.50.310.6 

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See "Quality Control and Reporting Protocols" below. BCT = Bobcat, CA2 = Caribou, LNX= Lynx, LSW = Lynx South West, LX4 = Lynx 4, TLX = Triple Lynx, UDD = Underdog.

Drill hole location

Hole NumberAzimuth (°)Dip (°)Length (m)UTM EUTM NElevationSection
OSK-W-21-1432-W11132-55114945381154357794004300
OSK-W-21-1871-W1331-56111945249654343974022475
OSK-W-21-1871-W2331-5691545249654343974022475
OSK-W-21-1871-W3331-5690645249654343974022475
OSK-W-21-1949-W6105-57122745344054354794013825
OSK-W-21-2287-W7116-53132045360754357144044075
OSK-W-21-2407-W2347-5584345231554344203992325
OSK-W-21-2416-W7123-54110445316954356244123650
OSK-W-21-2465-W4123-61105345339854355564133825
OSK-W-21-2465-W6123-6199345339854355564133825
OSK-W-21-2512-W2331-5483445244854344654002475
OSK-W-21-2531-W3344-62132945256654344154032550
OSK-W-21-2531-W4344-62120345256654344154032550
OSK-W-21-2532-W3341-60119145247854344304012475
OSK-W-21-2537-W3114-54102445298154355494203450
OSK-W-21-2540-W5117-60131145346554356404103925
OSK-W-21-2540-W6117-60154145346554356404103925
OSK-W-21-2544-W2128-50104445296054355394193425
OSK-W-21-2551-W5120-55102345362254356354054050
OSK-W-21-2578-W3350-5372345217854343973992200
OSK-W-21-2587-W1127-59117645335054356734183850
OSK-W-21-2589130-4966345296054355394203425
OSK-W-21-2599328-6277445278754345263972800
OSK-W-21-2600329-5078945247054346264032550
OSK-W-21-2605112-55140145355254356694084025
OSK-W-21-2612-W1333-5169045239154346384022500
OSK-W-21-2613114-53109245298154355494203450
OSK-W-21-2621344-53100145227254343963992275
OSK-W-21-262533-7789145413554350583964225
OSK-W-21-2631158-4716545233654358504063050
OSK-W-21-2632141-4415345236354358574063075
OSK-W-21-2635327-5670845268454344754022675
OSK-W-21-2636337-5280145249954346194032575
OSK-W-21-2641177-4616545243654358844073150
WST-21-0649136-477904532585435211983525
WST-21-0793125-151214534635435327323775
WST-21-0863135-644034535085435327-73800
WST-21-0875144-475774533225435235543600
WST-21-0878128-407114533755435297-263675
WST-21-0879139-447244532585435209963525
WST-21-0886128-5137545295454350042533175
WST-21-0894B132-5241745295554350042533175
WST-21-0898141-614024535085435327-73800
WST-21-0900122-133164534625435326333775
WST-21-0901116-183404534625435327323775
WST-21-0903120-613224535095435328-73800
WST-21-0907130-407014533745435296-263675
WST-21-0909151-594264535075435328-73800
WST-21-0912141-416404532585435209963525
WST-21-0915B143-634904535075435328-73800
WST-21-0916A146-525864533215435235543600
WST-21-0920B135-243484534625435326323775
WST-21-0922146-3511445331454351641243550

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.

Caribou Zone
Mineralization most commonly occurs in gold-bearing pyrite stockworks as well as semi-massive pyrite replacement zones associated with phyllic alteration (sericite-pyrite ± silica) with sulphides, pyrite dominated with minor chalcopyrite and sphalerite ranging from trace to up to 20%, and local visible gold. Mineralization is hosted in rhyolites or mafic-intermediate volcanics frequently at or near faults or the contact with felsic porphyritic intrusions.

F-Zones
Mineralization is hosted in sheared andesites with carbonate replacement or quartz veining and occurs as quartz ± ankerite veinlets or as replacement type in shear zones and is characterised by trace to 10% pyrite with local visible gold. Alteration is dominated by sericite-fuchsite-tourmaline-pyrite.

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.

Underdog
Mineralization most commonly occurs in gold-bearing quartz-pyrite (± tourmaline) veins and as disseminated, stringer, semi-massive to massive pyrite with minor sphalerite, chalcopyrite and molybdenite associated with strong sericite and silica alteration. Mineralization is hosted along the intrusive contacts of a three-phase composite felsic porphyritic unit which cross-cuts felsic and mafic volcanic sequences.

Zone 27
Mineralization most commonly occurs as replacement-type characterized by 5% to 50% disseminated, stringer, semi-massive or stockwork pyrite, ptygmatic tourmaline veins, quartz-tourmaline crustiform veins, local quartz-carbonate veins, and local visible gold. Mineralization is associated with moderate to strong sericite, weak to strong silica, weak chlorite and carbonate and locally weak fuchsite and is hosted in strongly altered andesites, in or at the contact of the rhyolite, or along the contacts with felsic porphyritic intrusions.

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 February 17, 2021 is supported by the technical report entitled “Preliminary Economic Assessment Update for the Windfall Project” dated April 26, 2021 (that includes Windfall Mineral Resource Estimate with an effective date  of November 30, 2020), and assuming a cut-off grade of 3.50 g/t Au, comprises 521,000 tonnes at 11.3 g/t Au (189,000 ounces) in the measured mineral resource category, 5,502,000 tonnes at 9.4 g/t Au (1,668,000 ounces) in the indicated mineral resource category and 16,401,000 tonnes at 8.0 g/t Au (4,244,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the February 17, 2021 news release are further described in the full technical report prepared by BBA Inc. in accordance with NI 43-101 and is available on SEDAR (www.sedar.com) under the Corporation'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 zones: Lynx, Main Zone, and Underdog. Mineralization is generally comprised of sub-vertical zones following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres as it now includes the Triple 8 (T8) zone. The resources excluding T8 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 gold 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 2,600 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 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; 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; 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