Author: lboivin

(Toronto, October 5, 2017).  Osisko Mining Inc. (OSK:TSX, “Osisko” or the “Corporation”) is pleased to announce new results from the ongoing drill program at its 100% owned Garrison gold project located in Garrison Township, Ontario.  Over 70,000 metres of new drilling have been conducted by Osisko on the Garrison Project to date.  A total of seventeen new intercepts in sixteen holes are reported in this release, with significant assay results presented in the table below.

Significant new results include: 7.14 g/t Au over 12.7 metres in OSK-G17-420; 5.18g/t Au over 17.0 metres and 1.62 g/t Au over 16.1 metres in OSK-G17-412; 1.37g/t Au over 30.2 metres in OSK-G17-408; 2.84 g/t over 7.1 metres in OSK-G17-415.

The new results continue to demonstrate the potential to expand the extent of known mineralization in the 903 Zone. The 2017 drill program will continue to explore extensions of the mineralized zones within the Garrcon, Jonpol and 903 zones.  Maps and sections showing hole locations and complete drilling results are available at www.osiskomining.com. 

Hole No.	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 30 g/t	Zone
OSK-G17-367	186.9	202.2	15.3	1.20		903
	229.8	240.8	11.0	2.03		903
OSK-G17-370	179.6	188.7	9.1	2.65		903
	310.0	322.0	12.0	1.33		903
OSK-G17-371A	203.6	216.6	13.0	1.65		903
	305.8	317.2	11.4	2.00		903
OSK-G17-379	249.3	251.3	2.0	5.37		903
OSK-G17-396	48.6	64.6	16.0	1.03		903
OSK-G17-400	177.0	179.0	2.0	6.44		903
OSK-G17-406	122.7	130.7	8.0	2.44		903
	155.9	171.0	15.1	1.43		903
OSK-G17-408	47.8	78.0	30.2	1.37		903
OSK-G17-412	170.9	187.0	16.1	1.62		903
	264.0	281.0	17.0	5.18		903
including	264.0	269.0	5.0	14.6		903
	289.0	291.0	2.0	10.4		903
OSK-G17-415	92.5	99.6	7.1	2.84		903
OSK-G17-420	114.0	126.7	12.7	7.14		903

Notes:  True Widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.

 

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-G17-345	346	-51	180	576870	5373421	3050W
OSK-G17-367	339	-47	372	577307	5373101	2750W
OSK-G17-370	331	-47	516	577594	5373044	2500W
OSK-G17-371A	339	-50	551	576899	5372903	3200W
OSK-G17-374A	334	-45	354	576661	5372970	3400W
OSK-G17-382	340	-60	429	576587	5372885	3500W
OSK-G17-379	339	-53	504	577048	5373076	3000W
OSK-G17-396	338	-45	297	576986	5373248	3000W
OSK-G17-400	340	-47	361	577027	5373284	2950W
OSK-G17-404	340	-45	240	576764	5373116	3250W
OSK-G17-406	340	-46	246	577010	5373183	3000W
OSK-G17-408	339	-45	282	577387	5373317	2600W
OSK-G17-411	341	-47	414	577355	5373113	2700W
OSK-G17-412	339	-45	396	577069	5373168	2950W
OSK-G17-415	340	-46	417	577260	5373080	2800W
OSK-G17-420	341	-45	303	577228	5373169	2800W

 

OSK-G17-367 was drilled in the central section of the 903 Zone targeting extensions of the main 903 syenite body to depth. Two intervals in the 903 syenite intersected 1.20 g/t Au over 15.3 metres and 2.03 g/t Au over 11.0 metres. The two broad zones are hosted in syenite showing a porphyritic texture and significant fracturing containing specular hematite and pyrite mineralization.

OSK-G17-370 targeted the eastern extension of the main 903 Zone and 903 South Zone along strike. The hole intersected a new shallow mineralized zone along the flow contact between an ultramafic volcanic and mafic volcanic. This horizon contains limited syenite surrounded by a broad quartz carbonate veining over 10 metres and averaging 2.65 g/t Au over 9.1 metres. A second mineralized zone was intersected along the eastern extension of the 903 South Zone horizon characterized by intense quartz and iron carbonate fracturing adjacent to diabase and hosted within ultramafic volcanic. This interval reported a average of 1.33 g/t Au over 12.0 metres.

OSK-G17-371A, 374A and 382 were drilled southwest of the main 903 syenite, targeting a linear magnetic low that may represent a fault offset extension of the main 903 Zone extending west. All three holes intersected a zone of mariposite alteration ranging from 50 to 75 metres in width containing syenite coincident with the magnetic low. Anomalous gold grades were reported from holes 374A and 382. OSK-G17-371A intersected two separate syenite dykes ranging in width from 15 to 40 metres. The first syenite dyke showed a brick red hematite alteration and limited quartz veining which averaged 1.65 g/t Au over 13.0 metres. The second broader syenite contained considerable quartz – iron carbonate veining up to 1 metre in width a long with minor hematite alteration and disseminated pyrite; this interval averaged 2.00 g/t Au over 11.4 metres.

OSK-G17-379, 396, 406 were drilled along section 3000W in the western section of the main 903 Zone. Each of the holes intersected syenite within the 903 Zone. A strong interval of quartz – iron carbonate veining and hematite alteration was found in OSK-G17-396 reporting a shallow intercept averaging 1.03 g/t Au over 16.0 metres. Drilling 55 metres below this intercept hole OSK-G17-406 also intersected syenite containing significant iron – carbonate veining along with a moderate hematite alteration believed to be the extension of the zone found in OSK-G17-396. Within the syenite dykes two mineralized zones averaged 2.44 g/t Au over 8.0 metres and 1.43 g/t Au over 15.1 metres.  Below this interval (110 metres) OSK-G17-379 intersected syenite dykes hosted within mariposite schist. An interval within the dyke assayed 5.37 g/t Au over 2.0 metres also coincident with veining and hematite alteration.

OSK-G17-400, 412 were drilled along section 2950W within the main 903 Zone. Drill hole OSK-G17-400 was drilled north of the main syenite body and did not intersected any significant dykes; drilling into the footwall metasediment the hole intersected a 5 cm quartz-iron carbonate vein and surrounding fracturing that averaged 6.44 g/t Au over 2.0 metres. Testing 120 metres below OSK-G17-400,OSK-G17-412 intersected a broad zone of syenite along the main trend of the 903 Zone. Within the syenite was quartz-iron carbonate veining with moderate hematite alteration of the syenite as well as along fractures and showing disseminated pyrite within the syenite; this interval averaged 1.62 g/t Au over 16.1 metres. This hole also intersected the footwall metasediment within which a broad chlorite alteration zone containing quartz and iron carbonate veining from 2-40 cm in width and showing disseminated pyrite within the metasediment, averaging 5.18 g/t Au over 17.0 metres. A second interval within the metasediment showing only limited quartz-iron carbonate fracturing to 1 cm width averaged 10.4 g/t Au over 2.0 metres.

OSK-G17-408 was drilled along the eastern strike extension of the 903 Zone targeting the up dip extension of syenite intersected in OSK-G17-332 (1.09 g/t Au over 17.0 metres, March 15, 2017). The hole intersected syenite 35 metres up dip of OSK-G17-332. The syenite contained moderate quartz – iron carbonate veins from 10 to 20 cm in width along with hematite alteration and disseminated pyrite. This shallow interval averaged 1.37 g/t Au over 30.2 metres. 

OSK-G17-415, 420 were drilled along section 2800W in the central 903 Zone. OSK-G17-415 was drilled 50 metres down dip of OSK-G17-335 (1.57g/t Au over 10.0 metres and 1.49 g/t Au over 9.0 metres, March 15, 2017). The hole successfully intersected the main 903 syenite dyke at a vertical depth of 185 metres but reported limited mineralization. The upper part of hole OSK-G17-415 intersected the southern 903 Zone within highly altered metasediment containing sericite and iron carbonate alteration. Very fine disseminated pyrite along with 1-2 cm quartz – iron carbonate veins contained within the metasediment averaged 2.84 g/t Au over 7.1 metres.  OSK-G17-420 was drilled 50 metres up dip from OSK-G17-335, intersecting a 75 metre wide syenite body. Within the upper contact of the syenite there is considerable strong hematite alteration along with limited quartz – iron carbonate veining and 2-3% coarse disseminated pyrite; this interval returned 7.14 g/t Au over 12.7 metres.

OSK-G17-345, -404, -411 did not intersect significant mineralization.

Qualified Person
The scientific and technical content of this press release has been reviewed, prepared and approved by Mr. Greg Matheson, P.Geo. Senior Project Manager of the Garrison 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
True widths of the new exploration intercepts reported in this press release have yet to be determined, but are  typically 65 – 90% of reported core lengths. Additional drilling is planned for the immediate area which will enable the true width determination. Assays are uncut except where indicated, and calculated intervals are reported over a minimum length of 2 metres using a lower cutoff of 1.0 g/t Au. All HQ core assays reported were obtained by either whole sample rock metallic screen/fire assay or standard 30 gram fire-assaying with ICP finish at SGS Minerals Services in Cochrane, Ontario. The whole sample metallic screen assay method is selected by the geologist when samples contain coarse gold or any samples displaying gold initial fire assay values greater than 4g/t. Drill program design, Quality Assurance/Quality Control and interpretation of results is performed by qualified persons employing a Quality Assurance/Quality Control program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for Quality Assurance/Quality Control purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assays.

About the Garrison Project
The Garrison Project area is comprised of 214 mineral claims, 25 mining leases, and 87 patent claims encompassing approximately 8,000 hectares.  Both Garrcon and Jonpol have resource estimates that are described in a technical report prepared in accordance with NI 43-101, which was completed by a previous operator Northern Gold Mining Inc. (entitled “Technical Report on the Golden Bear Project – Garrison Property: Larder Lake Mining Division, Garrison Township, Ontario, Canada”) dated December 30, 2013, with an effective date of December 30, 2013 (the “Garrison Technical Report”). The Garrison Technical Report was prepared by A.C.A. Howe International Limited for Northern Gold Mining Inc. (a wholly-owned subsidiary of Osisko) and is available on Osiskos website at www.osiskomining.com and on SEDAR under Northern Gold Mining Inc.s issuer profile at www.sedar.com.

Resource estimates were conducted by A.C.A. Howe International Limited according to CIM standards. The Garrcon Zone estimates showed 15.1 million tonnes with an average grade of 1.07 g/t Au (521,000 oz) in measured resources; 14.1 million tonnes averaging 1.16 g/t Au (526,000 oz) in indicated resources; and 1.7 million tonnes averaging 0.72 g/t Au (39,000 oz) in inferred resources. Potential underground resources of 5.1 million tonnes averaging 3.49 g/t Au (577,000 oz) in the inferred category were also outlined. Resources were reported at a cut-off grade of 0.4 g/t Au for open pit extraction and 1.5 g/t in a bulk underground mining scenario using a gold price of US$1,250/oz.

At the Jonpol Zone, resources were estimated as 0.87 million tonnes averaging 5.34 g/t Au (150,000 oz) in the indicated category; and 1.07 million tonnes averaging 5.56 g/t Au (192,000 oz) in inferred resources. Resources were reported at a cut-off grade of 3.0 g/t Au and assume an underground extraction scenario using a gold price of US$1,250/oz.

Readers are cautioned that inferred resources have a great amount of uncertainty as to their existence and as to whether they can be mined economically. It cannot be assumed that all or any part of the inferred resources will ever be upgraded to a higher category. Mineral resources are not mineral reserves and do not have demonstrated economic viability.

Garrcon Zone
The Garrcon Zone has a shallow plunge eastward along the footwall of the Destor-Porcupine Fault Zone with the bulk of the resource in the western, more densely drilled area. The zone is exposed at surface and has potential for open pit bulk mining at an estimated overall stripping ratio of 1.8:1. There is potential for additional underground resources below the pit and along the easterly plunge of the zone, which is open for further exploration down dip and along strike.

The Garrcon shaft was sunk in 1935 and 1936 by the Consolidated Mining and Smelting Co. of Canada (“Cominco”) and the Shaft and South Zones were tested for high grade gold mineralization. Cominco drove approximately 1,430 metres of drifts and cross cuts, mining underground veins. Diamond drilling by Cominco and Lac Minerals Ltd. in the mid-to-late 1980s identified broad sections of low grade mineralization. In 2006-2007, ValGold Resources Ltd. conducted additional drilling confirming these zones. From 2009-2013 Northern Gold Mining Inc. conducted 97,000 metres of diamond drilling which delineated the current resource.

In 2014, Northern Gold Mining Inc. was granted a trial mining permit allowing the extraction of up to 150,000 tonnes. Northern Gold Mining Inc. mined 73,534 dry tonnes which was processed at the nearby Holt mill facility recovering 3,516 oz at an average head grade of 1.55 g/t and recovery of 95.9%. The trial production permit remains active.

Jonpol Zone
Jonpol is situated in the Munro Fault Zone, a west striking splay off the north side of the Destor-Porcupine Fault. Hosted in a shear zone tens of metres wide in altered mafic volcanic rocks, the deposit consists of four high grade gold mineralized zones (JP, JD, RP and East) over a strike length of 1.7 kilometers. Gold mineralization is hosted in quartz carbonate veins, in mafic and ultramafic host rocks, and is associated with intense albite and/or sericite alteration and pyrite mineralization.

In 1997, a 49,087 tonne bulk sample was extracted from the central part of the JP zone by Hillsborough Resources Limited with an average grade of 6.7 g/t which produced 9,476 ounces Au. From 1985-2013, over 130,000 metres of drilling was completed on the property by previous operators. Development work on the JP zone included the sinking of a 184 metre shaft as well as development of a ramp to the 150 metre level with mining on six sublevels. The Jonpol infrastructure underwent reclamation in the late 1990s and was closed out in 2001, but the existing ramp and shaft are preserved.

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% in the high-grade Windfall Lake gold deposit located between Val-dOr and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area (82,400 hectares), a 100% interest in the Marban project located in the heart of Québecs prolific Abitibi gold mining district, and properties in the Larder Lake Mining Division in northeast Ontario, including the Garrcon and Jonpol zones on the Garrison property, the Buffonta past producing mine and the Gold Pike mine property. The Corporation also holds interests and options in a number of additional properties in northern Ontario.  Osisko continues to be well financed and has approximately $246 million in cash and equity investment.

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 ongoing drill program at the Garrison gold project; results of the current drill program; the significance of new drill results reported in this press release; the ability of new drill results to demonstrate potential for expansion of the previously defined Garrcon, Jonpol and 903 mineralized zones at the Garrison project; the scope of the 2017 drill program; that the 2017 drill program will follow new extensions of these mineralized zones to further define the scale of mineralization at the Garrison project; 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; 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”, “managements 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 it was made, 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) to accurately predict mineralization; errors in managements geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests; 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, President and Chief Executive Officer
Telephone: (416) 363-8653

High Grade Lynx Deposit Expanded Additional 210 Meters to NE

(Toronto, October 3, 2017)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec.  The 800,000 metre drill program combines definition, expansion and exploration drilling in and around the main Windfall gold deposit and the adjacent Lynx deposit (located immediately NE of Windfall).  Significant new analytical results from 23 intercepts in 17 drill holes focused on infill and expansion drilling in the Lynx deposit are presented below.

Highlights from the new results include: 27.0 g/t Au over 2.7 metres in OSK-W-17-906; 11.6 g/t Au over 4.4 metres in OSK-W-17-1039; 13.0 g/t Au over 3.6 metres in OSK-W-17-1102; 23.4 g/t Au over 2.0 metres in OSK-W-17-918; and 22.0 g/t Au over 2.0 metres in OSK-W-17-958. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Hole Number	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 100 g/t	Zone	Corridor
OSK-W-17-899	243.0	245.0	2.0	4.46		Lynx 2	Lynx
OSK-W-17-906	169.3	172.0	2.7	27.0		Lynx HW	Lynx
including	169.3	170.2	0.9	76.9
	174.0	176.5	2.5	4.25		Lynx HW	Lynx
including	174.6	175.0	0.4	21.9
	276.0	280.0	4.0	5.05		Lynx 2 FW	Lynx
OSK-W-17-909	869.0	872.7	3.7	4.33		VNCR	Lynx
including	872.0	872.7	0.7	18.6
OSK-W-17-918	238.0	240.0	2.0	23.4		Lynx 2	Lynx
including	238.7	239.3	0.6	61.3
OSK-W-17-929	936.5	938.5	2.0	18.9		Lynx 1	Lynx
including	937.2	937.6	0.4	62.6
OSK-W-17-939	246.0	248.0	2.0	12.1		Lynx 1	Lynx
including	246.0	247.0	1.0	20.6
	296.0	298.0	2.0	4.71		Lynx 2	Lynx
OSK-W-17-958	500.0	502.0	2.0	22.0		Lynx 1	Lynx
including	500.0	500.5	0.5	87.0
	712.0	717.0	5.0	5.74		Lynx 4	Lynx
	1070.0	1072.0	2.0	5.36		TBD	Lynx
OSK-W-17-986	317.0	320.1	3.1	5.69		VNCR	Lynx
including	317.0	318.0	1.0	15.9
OSK-W-17-987	270.2	272.2	2.0	5.77		VNCR	Lynx
including	270.7	271.9	1.2	9.06
OSK-W-17-1021	68.0	70.2	2.2	9.72		VNCR	Lynx
OSK-W-17-1039	436.9	441.3	4.4	11.6		Lynx 1	Lynx
including	436.9	437.9	1.0	34.4
OSK-W-17-1044	242.0	244.1	2.1	3.03		Lynx 1	Lynx
OSK-W-17-1068	451.9	454.3	2.4	4.77		Lynx HW	Lynx
OSK-W-17-1091	60.4	62.7	2.3	11.3		Lynx 1	Lynx
including	61.0	62.0	1.0	25.2
OSK-W-17-1102	280.9	284.5	3.6	13.0		Lynx 2	Lynx
including	280.9	281.6	0.7	55.4
OSK-W-17-1121	303.0	305.0	2.0	4.29		Lynx 1	Lynx
	309.5	313.5	4.0	7.78		Lynx 1	Lynx
including	309.5	311.2	1.7	14.9
OSK-W-17-1169	573.0	576.5	3.5	4.23		Lynx 2	Lynx
including	575.6	576.5	0.9	12.6

Notes:

1. True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.
2. Definitions: HG = Hanging wall; FW = Foot Wall; VNCR = crustiform vein; TBD = to be determined.

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-W-17-899	334	-57	303	453219	5434913	3350
OSK-W-17-906	331	-56	441	453349	5434937	3475
OSK-W-17-909	131	-55	1119	453683	5435677	4125
OSK-W-17-918	335	-57	372	453387	5434953	3525
OSK-W-17-929	130	-58	1218	453871	5435782	4350
OSK-W-17-939	327	-51	414	453376	5434898	3475
OSK-W-17-958	143	-55	1212	453359	5435439	3725
OSK-W-17-986	328	-66	360	453447	5435019	3600
OSK-W-17-987	339	-60	327	453224	5434909	3350
OSK-W-17-1021	333	-55	621	452990	5434889	3150
OSK-W-17-1039	147	-49	513	453361	5435436	3725
OSK-W-17-1044	333	-70	381	453477	5435045	3650
OSK-W-17-1068	130	-45	513	453253	5435282	3575
OSK-W-17-1091	332	-51	246	453207	5434962	3375
OSK-W-17-1102	330	-50	345	453275	5434899	3400
OSK-W-17-1121	335	-64	465	453436	5434958	3550
OSK-W-17-1169	129	-55	1437	453330	5435468	3725

 

OSK-W-17-899 intersected Lynx 2 returning 4.46 g/t Au over 2.0 metres. Mineralization includes up to 6% pyrite as disseminations and clusters and pyrite stringers hosted within weak to moderate chloritized rhyolite, and 1-3% pyrite within weakly developed crustiform veins occurring near the contact between the rhyolite and gabbro. This interval expands the Lynx 2 corridor 35 metres north-east of OSK-W-17-805 (12.4 g/t Au over 5.0 metres previously reported June 16, 2017).

OSK-W-17-906 intersected three intervals:  27.0 g/t Au over 2.7 metres, 4.25 g/t Au over 2.5 metres, both related to Lynx HW and finally 5.05 g/t Au over 4.0 metres related to Lynx 2 FW. Mineralization is hosted in a felsic volcanic cut by quartz veins (pervasive silica flooding) with 30% disseminated pyrite and local visible gold. The second interval is in a porphyritic felsic intrusion cut by small quartz veins with 5-7% disseminated pyrite. Mineralization for the third interval consists of up to 2% disseminated pyrite hosted in a weak sericitized and strong silicified felsic volcanic. This intersection extends Lynx 2 corridor 35 metres north-east of OSK-W-17-803 (5.23 g/t Au over 2.3 metres previously reported April 11, 2017).

OSK-W-17-909 intersected 4.33 g/t Au over 3.7 metres related to crustiform veins containing 3% disseminated pyrite.  The crustiform veins do not correlate to a known zone within the Lynx corridor.

OSK-W-17-918 intersected 23.4 g/t Au over 2.0 metres in Lynx 2. The interval includes 10-15% pervasive silica flooding, 3-5% pyrite tourmaline stringers within a sericitized fragmental felsic intrusion. It is located 10 metres below OSK-W-17-825 (4.06 g/t Au over 2.0 metres previously reported May 10, 2017).

OSK-W-17-929 intersected 18.9 g/t Au over 2.0 metres in Lynx 1, containing locally 8% disseminated pyrite within a moderately to strongly silicified gabbro. It is 210 metres down plunge and north-east of OSK-W-17-909 (11.8 g/t Au over 2.0 metres previously reported September 18, 2017).

OSK-W-17-939 intersected two intervals: 12.1 g/t Au over 2.0 metres in Lynx 1 and 4.71 g/t over 2.0 metres in Lynx 2. The first interval includes trace pyrite and 5% pyrite tourmaline stringers within a weakly sericitized felsic intrusion. The second interval is similar but hosted at the contact between a felsic dike and a volcanic. This interval is 35 metres up plunge and north-east of OSK-W-17-788 (17.0 g/t Au over 17.3 metres, previously reported April 5, 2017).

OSK-W-17-958 intersected three intervals: 22.0 g/t Au over 2.0 metres in Lynx 1, 5.74 g/t Au over 5 metres in Lynx 4  and 5.36 g/t Au over 2.0 metres. The first interval, weakly bleached by sericite and moderate patchy silica alteration, contains 5-7% pyrite stringers, traces of chalcopyrite and quartz-tourmaline veining.  It correlates 25 metres east to OSK-W-17-887 (24.3 g/t Au over 2.6 metres previously reported July 25, 2017). The second interval is strongly altered by fuchsite and locally strongly altered by pervasive silica flooding with up to 10-15% disseminated pyrite and traces of chalcopyrite. This interval contains 20% crustiform veins. The second interval corresponds to a new extension of the Lynx 4 HW and correlates 170 metres north-east of OSK-W-17-817 (13.3 g/t Au over 2 metres previously reported July 12, 2017).  The third interval contains trace pyrite in a quartz vein hosted by a weak silicified and sericitized and strong chloritized gabbro. This interval is within the Lynx corridor, zone to be determined.

OSK-W-17-986 intersected 5.69 g/t Au over 3.1 metres related to a crustiform vein in the Lynx Corridor. Mineralization consists of crustiform quartz-carbonate veins (20-60 centimetres) with pervasive silica flooding hosted in a bleached gabbro with 15% disseminated pyrite, tourmaline-pyrite stringers and local visible gold. The crustiform veins are located 30 metres below and northeast of another crustiform vein previously reported in OSK-W-17-859 (73.5 g/t Au over 2.2 metres, July 12, 2017).

OSK-W-17-987 intersected 5.77 g/t Au over 2.0 metres. Mineralization contains 2% pyrite stringers associated with quartz carbonate and tourmaline veins hosted in a fuschitized and chloritized gabbro, and correlates to a crustiform vein in the Lynx 2 corridor above another crustiform vein in OSK-W-16-740 (5.69 g/t Au over 4.6 metres previously reported January 11, 2017).

OSK-W-17-1021 intersected 9.72 g/t Au over 2.2 metres. Mineralization consists of two crustiform veins with 1% pyrite silicified bands surrounded by felsic intrusion with 2% disseminated pyrite.

OSK-W-17-1039 intersected 11.6 g/t Au over 4.4 metres. The interval is a strongly silicified fragmental felsic intrusion which contains 5% disseminated pyrite and 5% pyrite in a quartz-tourmaline vein (over 10 centimetres). It is located 30 metres north-east of OSK-W-17-912 (6.65 g/t Au over 2.8 metres previously reported August 24, 2017).

OSK-W-17-1044 intersected 3.03 g/t Au over 2.1 metres in Lynx 1. Mineralization is hosted in a bleached, chloritized and epidotized mafic volcanic containing 2% pyrite clusters and 3% pyrite stringers. The hole is 50 metres north-east of OSK-W-17-790 (11.3 g/t Au over 3.6 metres previously reported March 28, 2017).

OSK-W-17-1068 intersected 4.77 g/t Au over 2.4 metres in the Lynx HW Zone. This interval contains pervasive silica flooding with 20% pyrite clusters and 10% pyrite stringers. Both lower and upper contacts are ptygmatic tourmaline veins, hosted in a sericitized large quartz eye felsic intrusion. The interval is 80 metres south-west of OSK-W-17-848 (15.1 g/t Au overs 2.1 metres previously released September 18).

OSK-W-17-1091 intersected 11.3 g/t Au over 2.3 metres in Lynx 1. The interval is within a strongly sericitized felsic volcanic with trace pyrite clusters and traces of pyrite stringers, located 5 metres up plunge and west of OSK-W-16-755 (11.8 g/t Au over 6.0 metres previously reported January 11, 2017).

OSK-W-17-1102 intersected 13.0 g/t Au over 3.6 metres in Lynx 2. This interval consists of a quartz-tourmaline vein (5 centimetres) with 7% pyrite and a pervasive silica flooding with 15% pyrite and 1% pyrite stringer in a sericitized and silicified rhyolite. The interval is 15 metres down plunge and north-east of OSK-W-17-899 (4.46 g/t Au over 2.0 metres, this press release).

OSK-W-17-1121 intersected two intervals: 4.29 g/t Au over 2.0 metres and 7.78 g/t Au over 4.0 metres, both in Lynx 1. The mineralization is hosted at a rhyolite and felsic intrusion contact and composed of 2-3% of pervasive silica flooding with up to 3% pyrite stringers and disseminated pyrite.  The intersection is 15 metres south-west of OSK-W-17-792 (42.1g/t Au over 9.2 metres, previously reported April 5, 2017).

OSK-W-17-1169 intersected 4.23 g/t Au over 3.5 metres in Lynx 2. Mineralization consists of 10% disseminated pyrite in silica altered gabbro. It is 120 metres down plunge and east OSK-W-17-958 (9.18 g/t Au overs 2.2 metres previously reported September 18, 2017).

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), Project Manager of the Windfall Lake 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 widths determinations are estimated at 65-80% of the reported core length intervals for most of the zones. 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 3.0 g/t Au diluted over core lengths of at least 2.0 metres. All NQ core assays reported were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at ALS Laboratories in Val dOr, Québec, Thunder Bay and Sudbury, Ontario or Vancouver, British Colombia or 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 an Aqua Regia-ICP-AES 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 Lake Gold Deposit
The Windfall Lake gold deposit is located between Val-dOr and Chibougamau in the Abitibi region of Québec, Canada. The mineral resource defined by the previous operator comprises 2,762,000 tonnes at 8.42 g/t Au (748.000 ounces) in the indicated category and 3,512,000 tonnes at 7.62 g/t Au (860,000 ounces) in the inferred category (sourced from a technical report dated June 10, 2015 entitled “Preliminary Economic Assessment of the Windfall Lake Gold Property, Québec, Canada” with an effective date of April 28, 2015, prepared in accordance with NI 43-101). The Windfall Lake gold deposit is currently one of the highest grade resource-stage gold projects in Canada. The bulk of the mineralization occurs in the Main Zone, a southwest/northeast trending zone of stacked mineralized lenses, measuring approximately 600 metres wide and at least 1.400 metres long. The deposit is well defined from surface to a depth of 500 metres, and remains open along strike and at depth. Mineralization has been identified only 30 metres from surface in some areas and as deep as 870 metres in others, with significant potential to extend mineralization up and 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% in the high-grade Windfall Lake gold deposit located between Val-dOr and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quevillon area (over 3,300 square kilometres), a 100% interest in the Marban project located in the heart of Québecs prolific Abitibi gold mining district, and properties in the Larder Lake Mining Division in northeast Ontario, including the Jonpol and Garrcon deposits on the Garrison property, the Buffonta past producing mine and the Gold Pike mine property. The Corporation also holds interests and options in a number of additional properties in northern Quebec and Ontario.  Osisko continues to be well financed with approximately $246 million in cash and investments (pro-forma recently announced financing).

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 Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the current 800,000 metre drill program; the significance of new results from the ongoing drill program at the Windfall Lake gold project; the significance of assay results presented in this press release; the type of drilling included in the drill program (definition drilling, expansion drilling to the NE of the main deposit and adjacent Lynx deposit, and exploration drilling on the greater deposit and Urban-Barry project area); potential mineralization; the potential to extend mineralization up and down-plunge and at depth at the Windfall Lake gold deposit; 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”, “managements 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 it was made, 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) to accurately predict mineralization; errors in managements geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall Lake gold 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. President and Chief Executive Officer
Telephone: (416) 363-8653

Additional High Grade Results from Caribou, Wolf, Zone 27 and Underdog

(Toronto. September 20, 2017)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec. The recently expanded 800,000 metre drill program combines definition, expansion and exploration drilling in and around the main Windfall gold deposit and in the adjacent Lynx deposit (located immediately NE of Windfall). Significant new analytical results from 42 intercepts in 28 drill holes and wedges focused on infill and expansion drilling in the Underdog, Caribou, Zone 27 and Mallard corridors of the Windfall deposit are presented below.
 
Highlights from the new results include: 611 g/t Au over 2.0 metres (15.4 g/t Au over 2.0 metres cut) in OSK-W-17-913; 297 g/t Au over 2.1 metres (14.5 g/t Au over 2.1 metres cut) in OSK-W-17-862-W1; 120 g/t Au over 2.0 metres (28.7 g/t Au over 2.0 metres cut) in OSK-W-17-871-W1; 60.5 g/t Au over 2.4 metres in OSK-W-17-973; 65.5 g/t Au over 2.0 metres in OSK-W-17-978; and 47.0 g/t Au over 2.3 metres in OSK-W-17-820-W1. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Hole Number	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 100 g/t	Zone	Corridor
OSK-EAG-13-494	738.5	740.6	2.1	6.52		Wolf	Caribou
Including	740.0	740.6	0.6	19.6
	749.0	751.0	2.0	4.56		Wolf	Caribou
OSK-OBM-16-601	657.6	659.6	2.0	16.2		FW3U	Underdog
OSK-W-17-820-W1	943.0	945.0	2.0	5.78		FW0 FW	Underdog
including	944.0	945.0	1.0	11.3
	949.0	951.0	2.0	9.02		FW0 FW	Underdog
	1109.2	1111.4	2.2	31.7	27.7	FW3 HW	Underdog
including	1110.8	1111.4	0.6	115	100
	1146.7	1149.0	2.3	47.0	18.1	Z14	Underdog
including	1147.1	1147.5	0.4	266	100
OSK-W-17-842	540.0	545.5	5.5	14.5	8.9	CS1	Caribou
including	540.0	540.4	0.4	182	100
OSK-W-17-847	831.0	833.0	2.0	6.87		FW0 HW	Underdog
	1085.1	1089.0	3.9	8.85		FW2	Underdog
OSK-W-17-855	166.6	169.4	2.8	3.93		Vein
OSK-W-17-855-W1	752.0	754.0	2.0	21.0		FW1	Underdog
including	752.0	753.0	1.0	41.2
OSK-W-17-855-W2	924.8	928.3	3.5	26.1		FW3	Underdog
including	924.8	925.5	0.7	33.5
including	925.5	925.9	0.4	66.2
including	927.0	928.3	1.3	31.5
	1095.8	1098.0	2.2	9.20		Z14	Underdog
including	1097.0	1098.0	1.0	18.6
OSK-W-17-858-W2	486.3	488.6	2.3	8.51		Wolf FW	Caribou
	630.1	632.5	2.4	32.6		VNCR	Underdog
including	631.6	632.5	0.9	76.6
	810.7	812.7	2.0	9.50		VNCR	Underdog
including	810.7	811.2	0.5	34.5
OSK-W-17-862	369.3	372.2	2.9	17.4			Caribou
including	369.3	370.8	1.5	30.8
OSK-W-17-862-W2	712.7	714.8	2.1	297	14.5	Vein	Z27
including	713.8	714.1	0.3	2080	100
OSK-W-17-864	790.3	793.0	2.7	14.0		FW3U	Underdog
including	792.0	793.0	1.0	28.6
OSK-W-17-871	152.0	156.8	4.8	17.9	13.4	Caribou	Caribou
including	155.5	156.0	0.5	143	100
OSK-W-17-871-W1	752.1	754.1	2.0	120	28.7	FW3U	Underdog
including	753.7	754.1	0.4	557	100
OSK-W-17-880-W1	464.0	466.5	2.5	4.57		Z27	Z27
including	466.0	466.5	0.5	12.1
OSK-W-17-885	1092.0	1100.0	8.0	6.69		FW0 FW	Underdog
including	1092.0	1093.0	1.0	22.3
	1366.0	1368.6	2.6	6.55		FW3	Underdog
including	1367.0	1367.8	0.8	18.2
OSK-W-17-889	386.5	388.5	2.0	16.2		Caribou	Caribou
including	388.0	388.5	0.5	58.0
OSK-W-17-901	137.0	139.0	2.0	13.8			Caribou
	209.0	211.0	2.0	7.12			Caribou
including	210.0	211.0	1.0	13.3
OSK-W-17-903	559.0	561.0	2.0	10.7		Z27	Z27
including	559.8	560.3	0.5	37.7
OSK-W-17-913	719.0	721.0	2.0	611	15.4	Wolf 2	Caribou
including	719.8	720.1	0.3	4070	100
	857.0	859.0	2.0	13.6		Wolf FW	Caribou
including	857.0	858.0	1.0	26.5
OSK-W-17-937	445.0	448.0	3.0	5.58		Vein	Z27
including	447.0	448.0	1.0	11.8
OSK-W-17-968	160.0	162.4	2.4	5.77		Z27	Z27
OSK-W-17-973	57.4	59.8	2.4	60.5	51.6	Z27	Z27
including	57.9	58.9	1.0	122	100
	64.0	66.1	2.1	5.12		Z27	Z27
including	65.7	66.1	0.4	25.2
OSK-W-17-977	269.5	271.7	2.2	12.0		Mallard	Mallard
including	270.8	271.7	0.9	25.4
OSK-W-17-978	98.0	100.0	2.0	65.5	20.1	VNCR	New
including	99.6	100.0	0.4	327	100
	108.0	110.0	2.0	14.0			New
including	109.1	109.4	0.3	92.2
OSK-W-17-989-W1	504.0	511.0	7.0	3.59		CS1 FW	Caribou
	514.0	517.0	3.0	7.74
including	515.0	516.0	1.0	20.5
OSK-W-17-1026	60.3	62.6	2.3	4.57		Z27	Z27
including	62.0	62.6	0.6	16.5
OSK-W-17-1051	857.1	859.8	2.7	5.36		Z14	Underdog

Notes:

1. True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.
2. Definitions: FW = foot wall; HW = hanging wall; VNCR = crustiform vein.

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-EAG-13-494	330	-60	1197	452731	5434557	2750
OSK-OBM-16-601	332	-51	801	452476	5434677	2600
OSK-W-17-1026	129	-45	147	452119	5434787	2325
OSK-W-17-1051	138	-68	1248	452313	5435323	2775
OSK-W-17-820-W1	332	-66	1358	452670	5434484	2675
OSK-W-17-842	331	-59	948	452509	5434390	2475
OSK-W-17-847	334	-69	1347	452645	5434429	2625
OSK-W-17-855	334	-64	717	452309	5434384	2300
OSK-W-17-855-W1	334	-64	1197	452309	5434384	2300
OSK-W-17-855-W2	334	-64	1197	452309	5434384	2300
OSK-W-17-858-W2	331	-53	909	452524	5434616	2600
OSK-W-17-862	332	-55	993	452683	5434577	2725
OSK-W-17-862-W2	332	-55	759	452683	5434577	2725
OSK-W-17-864	330	-53	813	452467	5434581	2525
OSK-W-17-871	328	-54	533	452402	5434623	2500
OSK-W-17-871-W1	328	-54	840	452402	5434623	2500
OSK-W-17-880-W1	327	-50	801	452425	5434565	2500
OSK-W-17-885	335	-67	1458	452861	5434494	2850
OSK-W-17-889	333	-57	786	452695	5434564	2725
OSK-W-17-901	328	-55	810	452391	5434638	2500
OSK-W-17-903	329	-56	801	452539	5434692	2650
OSK-W-17-913	334	-52	954	452878	5434419	2825
OSK-W-17-937	333	-57	935	452897	5434430	2850
OSK-W-17-968	152	-51	201	451948	5434759	2175
OSK-W-17-973	150	-46	96	451969	5434707	2175
OSK-W-17-977	331	-51	540	452207	5434816	2425
OSK-W-17-978	335	-67	804	452851	5434803	2975
OSK-W-17-989-W1	336	-56	751	452660	5434497	2675

 

Underdog Corridor

OSK-OBM-16-601 intersected 16.2 g/t Au over 2.0 metres. Mineralization is composed of 5% pyrite stringers and ptygmatic tourmaline veins and disseminated pyrite hosted in a strongly sericitized andesite. The interval extends the FW3 upper 40 metres north-east of OSK-OBM-16-609 (63.2 g/t Au over 7.7 metres previously reported August 1, 2017).

OSK-W-17-820-W1 returned two intersections in the FW0 Footwall Zone: 5.78 g/t Au over 2.0 metres (including 11.3 g/t Au over 1.0 metre) and 9.02 g/t Au over 2.0 metres (including 12.0 g/t Au over 1.0 metre). Mineralization is composed of 1% disseminated pyrite or pyrite stringers within a fragmental felsic intrusion. The two intersections are 50 metres up-plunge and south-west of OSK-W-17-820 (5.79 g/t Au over 6.3 metres previously reported July 19, 2017). OSK-W-17-820-W1 also intersected the FW3 Zone returning 31.7 g/t Au over 2.2 meters, (including 115 g/t Au over 0.6 metres) (27.7 g/t Au over 2.2 metres cut) and the Z14 Zone, 47.0 g/t Au over 2.3 metres (including 266 g/t Au over 0.4 metres) (18.1 g/t Au over 2.3 metres cut). Both intersections are similar and associated with felsic porphyritic dikes with up to 2% pyrite stringers and local quartz veins. The interval in FW3 is 40 metres south-west of OSK-W-17-821 (9.27 g/t Au over 3.3 metres previously reported May 30, 2017).

OSK-W-17-847 intersected two intervals: 6.87 g/t Au over 2.0 metres and 8.85 g/t Au over 3.9 metres in the Underdog corridor. In the first interval, mineralization is within the fragmental felsic dike and composed of 1% pyrite stringers, and correlates with the FW0 hanging wall. In the second interval mineralization is composed of up to 20% pyrite stringers and pyrite-tourmaline stringers hosted in a strongly silicified felsic porphyritic intrusion. The interval correlates to the FW2 Zone 50 metres north-east of OBM-15-560 (11.0 g/t Au over 6.1 metres previously reported January 28, 2016).

OSK-W-17-855-W1 intersected 21.0 metres over 2.0 metres (including 41.2 g/t Au over 1.0 metre). Mineralization is composed of up to 30% pyrite in a fragmental felsic dike. The interval correlates to the FW1 Zone.

OSK-W-17-855-W2 intersected 26.1 g/t Au over 3.5 metres (including 66.2 g/t Au over 0.4 metres, 33.5 g/t over 0.7 metres and 31.5 g/t Au over 1.3 metres) in the FW3 Zone. Mineralization is composed of up to 7% pyrite stringers, traces of tourmaline-pyrite stringers, up to 5% disseminated pyrite, and local decimeter scale pyrite massive bands. It is hosted in a porphyritic felsic dike with quartz-eyes and strong silica alteration. This intersection is 50 metres north-east of OSK-W-17-807-W2 (32. 9 g/t Au over 2.0 metres previously reported August 14, 2017). OSK-W-17-855-W2 also intersected 9.2 g/t over 2.2 metres (including 18.6 g/t Au over 1.0 metre) in the Z14 Zone. Mineralization is composed of 1% disseminated pyrite associated to large quartz-eyes porphyritic dike. It is 70 metres north-east of OSK-W-17-807-W2 (4.29 g/t Au over 2.0 metres previously reported June 20, 2017).

OSK-W-17-864 intersected 14.0 g/t Au over 2.7 metres (including 28.6 g/t Au over 1.0 metre) in the FW3 Upper Zone. Mineralization is composed of up to 3% disseminated pyrite and up to 1% pyrite stringers hosted in the andesite. It is 25 metres south-west of OSK-W-17-854-W2 (18.6 /t Au over 3.5 metres previously reported August 1, 2017) and 15 metres north-east of OSK-W-17-871-W1 (120 g/t Au over 2.0 metres, this press release).

OSK-W-17-871-W1 intersected 120 g/t Au over 2.0 metres, (including 557 g/t Au over 0.4 metres) (28.7 g/t Au over 2.0 metres cut). Mineralization is composed of local visible gold, up to 10% disseminated pyrite, up to 10% pyrite tourmaline stringers and 2% pyrite stringers in a sericitized and chloritized rhyolite. The intersection is related to the FW3 Upper Zone and is 40 metres south-west of OSK-W-17-854-W2 (18.6 /t Au over 3.5 metres previously reported August 1, 2017).

OSK-W-17-885 returned two intersections: 6.69 g/t Au over 8.0 metres (including 22.3 g/t Au over 1.0 metre) and 6.55 g/t Au over 2.6 metres (including 18.2 g/t au over 0.8 metres). The first interval consists of a strongly sericitized and moderately silicified felsic intrusion with 2-5% disseminated pyrite and 1-2 % pyrite stringers in the FW0 Footwall Zone and is 100 metres north-east of OSK-17-780-W1 (5.97 g/t Au over 17.0 metres previously reported April 11, 2017). The second interval is a silica-rich zone with 3-5% tourmaline-pyrite stringers and 2% disseminated pyrite. This intersection is in the FW3 Zone and is 50 metres south-west of OSK-W-17-780 (9.38 g/t Au over 4.0 metres previously reported April 6, 2017).

OSK-W-17-889 intersected 4.35 g/t Au over 3.5 metres in the Wolf 2 Zone. Mineralization contains up to 20% pyrite stringers within a bleached andesite. It is 40 metres west-south-west of OSK-W-17-844 (8.14 g/t Au over 2.5 metres previously reported August 1, 2017).

OSK-W-17-1051 intersected 5.36 g/t Au over 2.7 metres. The strongly sericitized felsic dike hosts 3% pyrite stringers and trace tourmaline stringers. The interval correlates to Z14 Zone, a division of the FW3 Zone, 30 metres north-east of OSK-W-16-708-W1 (3.74 g/t Au over 3.0 metres previously reported August 31, 2016).

Caribou Corridor

OSK-EAG-13-494 intersected two intervals in Wolf: 6.52 g/t Au over 2.1 metres (including 19.6 g/t Au over 0.6 metres) and 4.56 g/t Au over 2.0 metres. Both intersectiions follow a contact between the andesite and a large quartz-eye porphyritic intrusion, with mineralization comprising up to 2% disseminated pyrite and pyrite stringers and associated with strong sericite alteration. The intersections infill 35 meters north-east of OSK-W-16-708-W1, and 25 meters south-west of OSK-16-708-W2 (12.5 g/t Au over 3.8 metres and 4.47 g/t Au over 2.8 metres, previously reported August 31 and September 12, 2016).

OSK-W-17-842 intersected the CS1 Zone within the Caribou Corridor and returned 14.5 g/t Au over 5.5 metres (including 182 g/t Au over 0.4 metres) (8.90 g/t Au over 5.5 metres cut). Mineralization is composed of 10% pyrite stringers and tourmaline-pyrite veins hosted in a fragmental andesite strongly sericitized, and is 50 metres north-east of OSK-W-16-749 (12.7 g/t Au over 5.4 metres previously reported January 23, 2017).

OSK-W-17-858-W2 intersected three intervals: 8.51 g/t Au over 2.3 metres; 32.6 g/t Au over 2.4 metres (including 76.6 g/t Au over 0.9 metres) and 9.50 g/t Au over 2.0 metres (including 34.5 g/t Au over 0.5 metre). The first interval correlates to the Wolf Zone and is composed of 2% pyrite and carbonate veins in a strongly sericitized felsic dike. The second and third intervals consists of a crustiform quartz carbonate vein in the Red Dog intrusion and in the andesite. Local visible gold, 5% pyrite stringers and tourmaline-pyrite stringers are also observed. The deepest vein is within the FW3 Upper Zone, 25 metres north-east of OSK-OBM-16-697 (29.1 g/t Au over 2.6 metres previously reported May 30, 2017).

OSK-W-17-862 intersected 17.4 g/t Au over 2.9 metres (including 30.8 g/t Au over 1.5 metres). Mineralization is at a contact between a gabbro and rhyolite with up to 4% disseminated pyrite in the silica altered zone. The interval is 30 metres above OSK-W-17-889 (16.2 g/t Au over 2.0 metres in this press release).

OSK-W-17-871 was previously reported on August 1,2017 with a cut value of 13.4 g/t Au over 4.8 metres. Additional analysis was done on the samples greater than 100 g/t and the interval has been recalculated to 17.9 g/t Au over 4.8 metres (including 143 g/t Au over 0.5 metres). The cut value remains unchanged. The mineralized zone is in a bleached to strongly sericitized large quartz-eye felsic intrusion containing 7% pyrite stringers. The intersection is 25 metres north-east of OSK-W-17-901 (16.2 g/t Au over 2.1 metres previously reported August 1, 2017) within the Caribou Corridor.

OSK-W-17-889 intersected 16.2 g/t Au over 2.0 metres (including 58.0 g/t Au over 0.5 metres) in the main Caribou Zone. Mineralization is at a contact between the gabbro and the rhyolite. The 1% pyrite stringers are associated with strong sericite alteration and a quartz-tourmaline vein. The interval is 30 metres below OSK-W-17-862 (17.4 g/t over 2.9 metres in this press release).

OSK-W-17-901 intersected two intervals: 13.8 g/t Au over 2.0 metres and 7.12 g/t Au over 2.0 metres (including 13.3 g/t Au over 1.0 metre). In both intervals, mineralization is composed of up to 1% disseminated pyrite and 1% pyrite stringers. The host rhyolite is strongly alterated in silica, sericite and carbonates. The first interval correlates to Caribou Main Zone and the second interval to Caribou footwall, 65 metres below OBM-16-660 (7.25 g/t Au over 6.9 metres previously published July 11, 2016).

OSK-W-17-913 intersected 611 g/t Au over 2.0 metres (including 4070 g/t Au over 0.3 metres) (15.4 g/t Au over 2.0 metres cut). The high-grade zone contains local visible gold and 1% pyrite stringers associated with pervasive silica flooding within a felsic dike. The host rock is strongly sericitized. The intersection correlates to the Wolf 2 Zone, 50 metres east-north-east of OSK W-16-718 (8.5 g/t Au over 4.7 metres previously reported September 19, 2016). The hole also intersected 13.6 g/t Au over 2.0 metres (including 26.5 g/t Au over 1.0 metre) in the Wolf footwall. Mineralization is associated with a large quartz-eyes porphyritic dike and composed of disseminated pyrite and trace of pyrite stringers. The interval is 40 metres north-east of OSK-W-16-718 (4.78 g/t Au over 2.6 metres previously reported September 19, 2016).

OSK-W-17-989-W1 intersected two proximate intervals in Caribou South 1 Zone: 3.59 g/t Au over 7.0 metres and 7.74 g/t Au over 3.0 metres (including 20.5 g/t Au over 1.0 metre). Mineralization is associated to a porphyritic felsic intrusion crosscutting a strongly sericitized and silicified andesite. Up to 20% pyrite stringers are observed. The interval is 65 metres south-west of OSK-W-16-709 (4.90 g/t Au over 3.7 metres previously reported August 23, 2016).

Zone 27

OSK-W-17-862-W2 intersected 297 g/t Au over 2.1 metres (including 2080 g/t Au over 0.3 metres) (14.5 g/t Au over 2.1 metres cut). The mineralization correlates to Zone 27 along the Red Dog intrusion contact, with visible gold associated with disseminated pyrite and pervasive silica alteration in a strongly silicified andesite.

OSK W-17-903 intersected 10.7 g/t Au over 2.0 metres (including 37.7 g/t Au over 0.5 metres). Mineralization consists of 2% pyrite stringers, 3% pyrite-tourmaline stringers and 5% disseminated pyrite hosted in silica and sericite altered andesite. The intersection correlates to Zone 27, 45 metres above OSK-W-16-746 (16.5 g/t Au over 3.7 metres previously reported January 5, 2017).

OSK-W-17-968 intersected 5.77 g/t Au over 2.4 meters in Zone 27. Mineralization consists of 3% quartz-tourmaline veins and 5% pyrite stringers in a strongly sericitized felsic dike. This intersection is 15 meters above OBM-16-600 (12.9 g/t Au over 4.2 metres previously reported March 16, 2016).

OSK-W-17-973 intersected two intervals in Zone 27: 60.5 g/t Au over 2.4 metres (including 122 g/t Au over 1.0 metre) (51.6 g/t Au over 2.4 metres cut) and 5.12 g/t Au over 2.1 metres (including 25.2 g/t Au over 0.4 metres). The first interval is composed of semi-massive pyrite in a silica altered porpyritic felsic dike. The second interval is at the contact between two felsic dikes and is composed of 1% pyrite in clusters or stringers.

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(Toronto, September 18, 2017)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec. The recently expanded 800,000 metre drill program combines definition, expansion and exploration drilling in and around the main Windfall gold deposit and in the adjacent Lynx deposit (located immediately NE of Windfall). Significant new analytical results from 29 intercepts in 21 drill holes focused on infill and expansion drilling in the Lynx deposit are presented below.

Highlights from the new results include: 36.0 g/t Au over 6.9 metres (29.9 g/t Au over 6.9 metres cut) in OSK-W-17-1006; 116 g/t Au over 2.3 metres (31.8 g/t Au over 2.3 metres cut) in OSK-W-17-873; 25.5 g/t Au over 4.0 metres in OSK-W-17-924; (27.1 g/t Au over 3.5 metres (20.5 g/t Au over 3.5 metres cut) OSK-W-17-922; 24.3 g/t Au over 3.5 metres in OSK-W-1010;  and 21.3 g/t Au over 3.0 metres in OSK-W-17-1048. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Hole Number	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 100 g/t	Zone	Corridor
OSK-W-17-848	363.0	365.5	2.5	7.95		Lynx 1	Lynx
Including	364.5	365.5	1.0	19.9
	518.5	520.6	2.1	15.1		Lynx HW	Lynx
Including	518.5	519.5	1.0	26.2
OSK-W-17-861	388.5	390.5	2.0	9.41		Lynx 2	Lynx
Including	388.5	389.5	1.0	18.7
	506.7	507.2	2.3	4.06		Lynx HW	Lynx
including	508.6	509.0	0.4	12.6
OSK-W-17-868	267.0	269.0	2.0	8.22		Lynx 1	Lynx
including	267.4	268.2	0.8	18.0
OSK-W-17-873	300.0	302.0	2.0	9.30		Lynx 2	Lynx
including	300.5	300.8	0.3	59.9
	306.2	308.5	2.3	116	31.8	Lynx 2	Lynx
including	307.8	308.5	0.7	375	100
	320.9	323.3	2.4	10.7		VNCR	Lynx
including	320.9	321.7	0.8	28.7
OSK-W-17-882	417.0	420.0	3.0	3.39		VNCR	Lynx
including	418.0	418.5	0.5	18.8
OSK-W-17-883	288.5	290.5	2.0	3.89		Lynx 2	Lynx
OSK-W-17-907	952.0	954.0	2.0	30.2		TBD	Lynx
including	952.4	953.1	0.7	85.2
OSK-W-17-909	908.0	910.0	2.0	11.8		Lynx 1	Lynx
including	908.5	909.0	0.5	37.0
	982.9	986.0	3.1	4.94		Lynx 1	Lynx
OSK-W-17-914	239.3	241.6	2.3	27.2	26.6	Lynx HW	Lynx
including	240.7	241.0	0.3	105	100
OSK-W-17-921	328.6	330.6	2.0	20.6		Lynx 1	Lynx
including	329.3	329.7	0.4	97.8
OSK-W-17-922	456.1	459.6	3.5	27.1	20.5	Lynx 2	Lynx
including	457.5	457.8	0.3	176	100
OSK-W-17-924	308.0	312.0	4.0	25.5		Lynx 2 FW	Lynx
OSK-W-17-928	376.2	378.3	2.1	9.1		Lynx 2	Lynx
including	376.7	377.6	0.9	20.0
OSK-W-17-945	481.0	483.0	2.0	5.38		Lynx 1	Lynx
OSK-W-17-949	196.0	200.0	4.0	5.18		Lynx HW	Lynx
including	196.5	196.9	0.4	28.3
	214.1	216.1	2.0	4.5		Lynx 1	Lynx
	236.3	238.3	2.0	10.4		Lynx 2	Lynx
including	236.9	237.3	0.4	49.1
OSK-W-17-957	193.7	197.9	4.2	6.02		Lynx 2	Lynx
including	197.6	197.9	0.3	64.1
	212.0	214.0	2.0	21.5		Lynx 2	Lynx
including	212.6	213.2	0.6	70.6
OSK-W-17-958	441.8	444.0	2.2	9.18		Lynx 2	Lynx
OSK-W-17-974	172.0	174.0	2.0	24.2		Lynx 2	Lynx
including	172.8	173.3	0.5	94.2
OSK-W-17-1006	383.3	390.2	6.9	36.0	29.9	Lynx 2	Lynx
including	383.3	384.2	0.9	147	100
including	384.6	385.7	1.1	62.3
including	389.3	390.2	0.9	41.4
OSK-W-17-1010	310.5	314.0	3.5	24.3		VNCR	Lynx
including	310.5	311.5	1.0	62.9
OSK-W-17-1048	216.0	219.0	3.0	21.3		Lynx 2	Lynx
including	217.8	219.0	1.2	37.4

Notes:

1. True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.
2. Definitions: HG = Hanging wall; FT = Foot Wall; VNCR = crustiform vein and TBD = To be determined.

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-W-17-848	135	-45	669	453311	5435357	3650
OSK-W-17-861	150	-45	726	453386	5435455	3775
OSK-W-17-868	332	-64	435	453428	5434977	3575
OSK-W-17-873	326	-61	393	453427	5434976	3575
OSK-W-17-882	331	-53	471	453369	5434846	3450
OSK-W-17-883	326	-60	396	453455	5434983	3600
OSK-W-17-907	134	-51	1317	453219	5435340	3575
OSK-W-17-909	131	-55	1119	453683	5435677	4125
OSK-W-17-914	332	-53	447	453390	5434852	3475
OSK-W-17-921	331	-57	447	453428	5434865	3525
OSK-W-17-922	144	-52	591	453360	5435437	3725
OSK-W-17-924	334	-54	375	453414	5434927	3550
OSK-W-17-928	333	-64	465	453433	5434905	3550
OSK-W-17-945	149	-50	557	453374	5435444	3750
OSK-W-17-949	333	-55	423	453434	5434969	3575
OSK-W-17-957	327	-56	228	453329	5434973	3475
OSK-W-17-958	143	-55	1212	453359	5435439	3725
OSK-W-17-974	330	-59	357	453302	5434978	3450
OSK-W-17-1006	136	-49	762	453281	5435348	3625
OSK-W-17-1010	330	-53	369	453313	5434908	3425
OSK-W-17-1048	333	-52	303	453215	5434914	3350

 

OSK-W-17-848 intersected two intervals: 7.95 g/t Au over 2.5 metres (including 19.9 g/t Au over 1.0 metre) and 15.1 g/t Au over 2.1 metres (including 26.2 g/t Au over 1.0 metre). In the first interval, the mineralization is composed of local tourmaline-pyrite stringers, tourmaline stringers and disseminated pyrite within a fragmental intrusion with sericite and silica alteration. The intersection correlates to Lynx 1, 40 metres above OSK-W-17-912 (19.8 g/t Au over 2.0 metres and 6.65 g/t Au over 2.8 metres previously reported August 24, 2017). In the second interval, the mineralization is composed of up 2% disseminated pyrite, 2% pyrite stringers and tourmaline veins. The interval correlates to Lynx HW, 120 metres south-west of OSK-W-17-836 (3.30 g/t Au over 2.3 metres).

OSK-W-17-861 intersected two intervals: 9.41 g/t Au over 2.0 metres (including 18.7 g/t Au over 1.0 metre), related to the Lynx 2, and 4.06 g/t Au over 2.3 metres (including 12.6 g/t Au over 0.4 metres), related to Lynx HW. The mineralization consists of 5% pyrite-tourmaline stringers within a silica altered rhyolite. The first intersection is 40 metres east-north-east of OSK W-17-912 (14.6 g/t Au over 2.2 meters previously reported August 24, 2017) and the second intersection is 40 metres down plunge of OSK-W-17-818.

OSK-W-17-868 intersected 8.22 g/t Au over 2.0 metres (including 18.0 g/t Au over 0.8 metres). The mineralization is composed of up to 10% pyrite stringers, up to 7% disseminated pyrite and local gold hosted in a strongly silicified and sericitized rhyolite.

OSK-W-17-873 intersected two intervals in the Lynx 2 Zone: 9.30 g/t Au over 2.0 metres (including 59.9 g/t Au over 0.3 metres) and 116 g/t Au over 2.3 metres (including 375 g/t Au over 0.7 metres) (31.8 g/t Au over 2.3 metres cut).  A third interval with a crustiform quartz vein averaged 10.7 g/t Au over 2.4 metres (including 28.7 g/t Au over 0.8 metres). In Lynx 2, the mineralization is composed of quartz-carbonate veins with up to 5% disseminated pyrite and up to 2% pyrite stringer cross cutting sericitized rhyolite and strongly silica altered gabbro, with local visible gold. The crustiform vein contains up to 3% disseminated pyrite.

OSK-W-17-882 intersected 3.39 g/t Au over 3.0 metres (including 18.8 g/t Au over 0.5 metres) in Lynx 2, contained in a weakly silicified gabbro with small crustiform veins and trace disseminated pyrite.

OSK-W-17-883 intersected 3.89 g/t Au over 2.0 metres in the Lynx 2 Zone. The mineralization consists of up to 2% pyrite stringers and ptygmatic tourmaline veins in a silica altered rhyolite. The interval is 30 metres east of OSK-W-17-873 (116 g/t Au over 2.3 metres, this press release).

OSK-W-17-907 intersected 30.2 g/t Au over 2.0 metres (including 85.2 g/t Au over 0.7 metres).  The mineralization is composed of up to 2% pyrite in a sericitized and silicified rhyolite.

OSK-W-17-909 intersected two intervals: 11.8 g/t Au over 2.0 metres (including 37.0 g/t Au over 0.5 metres) and 4.94 g/t Au over 3.1 metres. This interval consists of intense pervasive silica flooding hosted in a gabbro. Mineralization includes up to 7% pyrite stringers. The intersection correlates to Lynx 1, 400 metres down plunge and north-east of OSK-W-17-836.  The intersection is 200 metres vertically below OSK-W-17-908 (10.6 g/t Au over 4.2 metres, 7.34 g/t au over 4.1 metres and 12.6 g/t Au over 2.5 metres, previously reported August 9, 2017).

OSK-W-17-914 intersected 27.2 g/t Au over 2.3 metres, (including 105 g/t Au over 0.3 metres) (26.6 g/t Au over 2.3 metres cut). The intersection consists of pervasive silica flooding containing 10% pyrite stringers, 1% disseminated pyrite and local visible gold. Mineralization is hosted in a sericitized rhyolite with fuchsite. It correlates to the Lynx HW Zone, 50 metres south-east and sub parallel to the Lynx 1 Zone, and 75 metres down plunge of OSK-W-17-803 (5.23 g/t Au over 2.3 metres, previously reported April 11, 2017).

OSK-W-17-921 was previously reported on August 9, 2017, with a cut value of 3.05 g/t Au over 2.0 metres.  Additional analysis was done on samples greater than 10 g/t Au and the interval was upgraded to 20.6 g/t Au over 2.0 metres (including 97.8 g/t Au over 0.4 metres).  Mineralization consist of 5% pyrite stringers and 2% disseminated pyrite at a contact between gabbro and a large quartz-eye felsic dike. The intersection represents the Lynx 1 Zone, 20 metres south-west of OSK-W-17-839 (6.58 g/t Au over 8.3 metres previously reported July 12, 2017).

OSK-W-17-922 intersected 27.1 g/t Au over 3.5 metres, (including 176 g/t Au over 0.3 metres) (20.5 g/t Au over 3.5 metres cut). The intersection is hosted in a strongly silicified and fuschitized gabbro. The mineralization consists of 30% smoky quartz-carbonate-tourmaline-pyrite veins and up to 4% quartz-tourmaline veins. The high-grade sample intervals contain local visible gold, 10% pyrite-tourmaline stringers and 3-4% disseminated pyrite-tourmaline. The intersection is within the Lynx 2 Zone, 30 metres west of OSK-W-17-898 (23.5 g/t Au over 3.0 metres and 12.2 g/t Au over 2.5 metres respectively reported August 9, 2017 and July 25, 2017).

OSK-W-17-924 intersected 25.5 g/t Au over 4.0 metres in Lynx 2, with local visible gold and 1% disseminated pyrite, and pyrite stringers in a silica altered rhyolite. The interval is 25 metres south-west of OSK-W-17-873 (116 g/t Au over 2.3 metres, this press release).

OSK-W-17-928 intersected 9.1 g/t Au over 2.1 metres (including 20.0 g/t Au over 0.9 metres) in Lynx 2. Mineralization comprises 2% pyrite stringers at the contact between gabbro and a felsic porphyritic dike.

OSK-W-17-945 intersected 5.38 g/t Au over 2.0 metres in Lynx 1. The mineralization is composed of up to 1% disseminated pyrite in a chloritized gabbro. The interval is 45 metres north-east of OSK-W-17-898 (17.3 g/t Au over 2.3 metres previously reported July 25, 2017).

OSK-W-17-949 intersected three intervals: 5.18 g/t Au over 4.0 metres (including 28.3 g/t Au over 0.4 metres) in Lynx HW; 4.5 g/t Au over 2.0 metres in Lynx 1; and 10.4 g/t Au over 2.0 metres (including 49.1 g/t Au over 0.4 metres) in Lynx 2. The first interval is at a contact between the rhyolite and the gabbro; the second and the third intervals are in a strongly silicified rhyolite. Small fragmental felsic dikes crosscut the rhyolite. Mineralization is mainly composed of up to 5% pyrite stringers. The Lynx HW and Lynx 1 intersections are 25 metres north-east of OSK-W-17-870 (25.7 g/t Au over 2.7 metres and 18.9 g/t Au over 2.8 metres previously reported July 12, 2017). The Lynx 2 interval is 45 metres north-east of OSK-W-17-873 (10.0 g/t Au over 2.6 metres previously reported July 12, 2017).

OSK-W-17-957 intersected two intervals in Lynx 2 Zone: 6.02 g/t Au over 4.2 metres (including 64.1 g/t Au over 0.3 metres) and 21.5 g/t Au over 2.0 metres (including 70.6 g/t Au over 0.6 metres). Mineralization is composed of up to 3% pyrite fragments, up to 15% disseminated pyrite and local visible gold hosted in a strongly sericitized fragmental felsic intrusion. These intervals are 10 metres west of OSK-W-17-895 (8.98 g/t Au over 6.5 metres previously reported August 9, 2017).

OSK-W-17-958 intersected 9.18 g/t Au over 2.2 metres. Mineralization is composed of up to 3% disseminated pyrite and pyrite stringers in a strongly sericitized fragmental felsic intrusion. The intersection is 70 metres down plunge to the north-east of OSK-W-17-898 (12.2 g/t Au over 2.5 metres previously reported July 25, 2017).

OSK-W-17-974 intersected 24.2 g/t Au over 2.0 metres (including 94.2 g/t Au over 0.5 metres) in Lynx 2. The mineralization is composed of up to 20% disseminated pyrite and a quartz-tourmaline vein. The fragmental felsic dike host is strongly sericitized and silicified. The interval is 30 metres south-west of OSK-W-17-957 (6.02 g/t Au over 4.2 metres reported in this press release).

OSK-W-17-1006 intersected 36.0 g/t Au over 6.9 metres (including 147 g/t Au over 0.9 metres; 62.3 g/t Au over 1.1 metres; and 41.4 g/t Au over 0.9 metres) (29.9 g/t Au over 6.9 metres cut). Mineralization consists of two centimeter-scale smoky quartz veins at low core angles with 10% pyrite and local visible gold within a sericite and silica altered fragmental felsic unit. The intersection is related to the Lynx 2 Zone, 50 metres east of OSK-W-17-812 (26.0 g/t Au over 2.5 metres previously reported May 3, 2017).

OSK-W-17-1010 intersected 24.3 g/t Au over 3.5 metres (including 62.9 g/t Au over 1.0 metre). Mineralization is in a crustiform vein (quartz, carbonate and tourmaline) with local visible gold, 5% pyrite stringers and pyrite clusters hosted in a fragmental felsic volcanic. The vein is 20 metres north-east of OSK-W-17-877 (57.8 g/t Au over 2.3 metres previously reported July 25, 2017).

OSK-W-17-1048 intersected 21.3 g/t Au over 3.0 metres (including 37.4 g/t Au over 1.2 metres) in the Lynx 2 Zone. The mineralization is composed of up to 5% pyrite stringers and 2% quartz-tourmaline veins hosted in a strongly sericitized and silicified rhyolite. The intersection is 30 metres below OSK-W-17-849 (7.10 g/t Au over 2.0 metres previously reported July 12, 2017).

Quality Control and Reporting Protocols
True widths determinations are estimated at 65-80% of the reported core length intervals for most of the zones. 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 3.0 g/t Au diluted over core lengths of at least 2.0 metres. All NQ core assays reported were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at ALS Laboratories in Val dOr, Québec, Thunder Bay and Sudbury, Ontario or Vancouver, British Colombia or 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 an Aqua Regia-ICP-AES 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 Lake Gold Deposit
The Windfall Lake gold deposit is located between Val-dOr and Chibougamau in the Abitibi region of Québec, Canada. The mineral resource defined by the previous operator comprises 2,762,000 tonnes at 8.42 g/t Au (748.000 ounces) in the indicated category and 3,512,000 tonnes at 7.62 g/t Au (860,000 ounces) in the inferred category (sourced from a technical report dated June 10, 2015 entitled “Preliminary Economic Assessment of the Windfall Lake Gold Property, Québec, Canada” with an effective date of April 28, 2015, prepared in accordance with NI 43-101). The Windfall Lake gold deposit is currently one of the highest grade resource-stage gold projects in Canada. The bulk of the mineralization occurs in the Main Zone, a southwest/northeast trending zone of stacked mineralized lenses, measuring approximately 600 metres wide and at least 1.400 metres long. The deposit is well defined from surface to a depth of 500 metres, and remains open along strike and at depth. Mineralization has been identified only 30 metres from surface in some areas and as deep as 870 metres in others, with significant potential to extend mineralization up and 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% in the high-grade Windfall Lake gold deposit located between Val-dOr and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quevillon area (over 3,300 square kilometres), a 100% interest in the Marban project located in the heart of Québecs prolific Abitibi gold mining district, and properties in the Larder Lake Mining Division in northeast Ontario, including the Jonpol and Garrcon deposits on the Garrison property, the Buffonta past producing mine and the Gold Pike mine property. The Corporation also holds interests and options in a number of additional properties in northern Quebec and Ontario.  Osisko continues to be well financed with approximately $190 million in cash and investments.

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 Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the current 800,000 metre drill program; the significance of new results from the ongoing drill program at the Windfall Lake gold project; the significance of assay results presented in this press release; the type of drilling included in the drill program (definition drilling, expansion drilling to the NE of the main deposit and adjacent Lynx deposit, and exploration drilling on the greater deposit and Urban-Barry project area); potential mineralization; the potential to extend mineralization up and down-plunge and at depth at the Windfall Lake gold deposit; 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”, “managements 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 it was made, 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) to accurately predict mineralization; errors in managements geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall Lake gold 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. President and Chief Executive Officer
Telephone: (416) 363-8653