Month: October 2017

(Toronto, October 31, 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 twenty-four new intercepts in eighteen holes are reported in this release, with significant assay results presented in the table below.

Significant new results include:  4.96 g/t Au over 13.5 metres in OSK-G17-414; 2.01 g/t Au over 21.5 metres and 3.10 g/t Au over 17.0 metres in OSK-G17-395; 3.60 g/t Au over 9.0 metres and 4.45 g/t Au over 5.5 metres in OSK-G17-423; 6.12 g/t Au over 6.0 metres and 10.6 g/t Au over 3.5 metres in OSK-G17-438; 2.13 g/t Au over 17.0 metres in OSK-G17-380; 8.14 g/t Au over 2.7 metres in OSK-G17-426; 7.69 g/t Au over 4.5 metres in OSK-G17-427; 1.34 g/t Au over 22.2 metres in OSK-G17-388; 1.24 g/t Au over 20.9 metres in OSK-G17-391.

The new results continue to confirm the extent of known mineralization in the Garrcon zone. The 2017 drill program is exploring the 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-G17-336	6.0	7.0	1.0	37.1	30.0	Garrcon
OSK-G17-380	226.4	243.4	17.0	2.13		Garrcon
OSK-G17-388	56.1	78.3	22.2	1.34		Garrcon
OSK-G17-391	69.9	90.8	20.9	1.24		Garrcon
OSK-G17-395	25.50	47.0	21.5	2.01		Garrcon
Including	35.8	38.1	2.3	9.78
	75.0	92.0	17.0	3.10		Garrcon
OSK-G17-401	35.0	54.8	19.8	1.16		Garrcon
OSK-G17-402	155.7	165.5	9.8	2.86		Garrcon
	256.0	266.0	10.0	1.72		Garrcon
OSK-G17-403	79.0	94.0	15.0	1.50		Garrcon
OSK-G17-405	91.6	98.5	6.9	4.28		Garrcon
OSK-G17-409	82.1	91.0	8.9	1.57		Garrcon
OSK-G17-410	55.0	63.8	8.8	1.16		Garrcon
OSK-G17-414	42.0	55.5	13.5	4.96		Garrcon
OSK-G17-419	35.8	45.8	10.0	1.44		Garrcon
	128.8	132.3	3.5	4.63		Garrcon
OSK-G17-423	50.0	59.0	9.0	3.60		Garrcon
	162.0	167.5	5.5	4.45		Garrcon
OSK-G17-426	48.5	50.5	2.0	6.30		Garrcon
	222.0	224.7	2.7	8.14		Garrcon
OSK-G17-427	210.5	215.0	4.5	7.69		Garrcon
Including	212.0	214.0	2.0	15.6
	244.0	245.0	1.0	58.1	30.0	Garrcon
OSK-G17-438	113.0	119.0	6.0	6.12		Garrcon
Including	113.9	115.5	1.6	19.8
	599.5	603.0	3.5	10.6		Garrcon

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-G17-336	337	-55	970	578439	5373928	1400W
OSK-G17-380	339	-47	465	578690	5373821	1200W
OSK-G17-388	281	-45	147	578592	5373861	1300W
OSK-G17-391	280	-60	216	578592	5373861	1300W
OSK-G17-395	280	-60	192	578583	5373886	1300W
OSK-G17-401	278	-61	186	578591	5373906	1275W
OSK-G17-402	340	-45	685	578714	5373764	1200W
OSK-G17-403	277	-45	162	578598	5373941	1250W
OSK-G17-405	280	-59	189	578598	5373941	1250W
OSK-G17-407	282	-45	90	578577	5373970	1250W
OSK-G17-409	282	-60	93	578577	5373970	1250W
OSK-G17-410	281	-45	101	578665	5373876	1200W
OSK-G17-414	281	-46	156	578701	5373894	1175W
OSK-G17-419	282	-45	144	578712	5373917	1175W
OSK-G17-423	280	-45	183	578685	5373950	1175W
OSK-G17-426	280	-60	244	578685	5373950	1175W
OSK-G17-427	270	-90	575	578691	5374046	1125W
OSK-G17-438	243	-90	777	578627	5373858	1250W

 

OSK-G17-388, 391, 395, 401, 403, 405, 407, 409 were drilled as part of a program to test the extension of a mineralized zone bulk sampled in prior work.  During a bulk sample program conducted in 2014 – 2015 by the previous property operator, testing focused on a N-NE trending mineralized corridor marked by zones of quartz-iron carbonate breccias. The mineralized corridor was found to dip shallowly to the east. New drilling involved a series of shallow west oriented holes designed to intersect the mineralized corridor at high angles to its strike.

The new results include:

•  1.34 g/t Au over 22.2 metres in OSK-G17-388
•  1.24 g/t Au over 20.9 metres in OSK-G17-391
•  2.01 g/t Au over 21.5 metres and
•  3.10 g/t Au over 17.0 metres in OSK-G17-395
•  1.16 g/t Au over 19.8 metres in OSK-G17-401
•  1.50 g/t Au over 15.0 metres in OSK-G17-403
•  4.28 g/t Au over   6.9 metres in OSK-G17-405
•  1.57 g/t Au over   8.9 metres in OSK-G17-409

Previous reported holes (see August 22, 2017 press release) from this program included OSK-G17-386 (1.20 g/t Au over 33.8 metres), OSK-G17-393 (1.12 g/t Au over 59.3 metres) and OSK-G17-398 (1.13 g/t Au over 22.8 metres).

OSK-G17-410, 414, 419, 423, 426 were designed to test the mineralized zone dipping below the Garrcon east bulk sample pit. The east bulk sample pit tested in 2014 – 2015 showed a parallel zone to the west bulk sample pit trending N-NE and comprised mainly of multiple parallel 1-10 cm quartz-iron carbonate veins hosted within metasediment. Similar to the west bulk sample pit, the mineralized corridor has a shallow east dip.

The new results include:

•  1.16 g/t Au over   8.8 metres in OSK-G17-410
•  4.96 g/t Au over 13.5 metres in OSK-G17-414
•  1.44 g/t Au over 10.0 metres and
•  4.63 g/t Au over   3.5 metres in OSK-G17-419
•  3.60 g/t Au over   9.0 metres and
•  4.45 g/t Au over   5.5 metres in OSK-G17-423
•  6.30 g/t Au over   2.0 metres and
•  8.14 g/t Au over   2.7 metres in OSK-G17-426

In both bulk sample pits the mineralization is closely associated with the N-NE trending quartz iron carbonate veins, breccias and fractures showing a strong iron carbonate alteration of the host rock.  Mineralization consists of pyrite concentrations up to 2% along with local visible gold.

OSK-G17-336 was drilled north west of the Garrcon west bulk sample pit intersecting a fracture zone within metasediment near the collar of the hole, with local visible gold returning 37.1 g/t Au over 1.0 metre.

OSK-G17-402, 380 were infill holes in the Garrcon Zone along section 1200W, drilling across the host metasediment.  OSK-G17-380 intersected 2.13 g/t Au over 17.0 metres within a zone of quartz-iron carbonate fracturing showing moderate hematite alteration. OSK-G17-402 intersected two significant mineralized zones including 2.86 g/t Au over 9.8 metres comprised of a broad zone of quartz-iron carbonate veins from 1-5 cm containing 1-2% pyrite, and local visible gold within an iron carbonate alteration halo.  A second interval returned 1.71 g/t Au over 10.0 metres within a fractured zone including minor quartz-iron carbonate and disseminated pyrite.

OSK-G17-427 intersected 7.69 g/t Au over 4.5 metres within a broad quartz-iron carbonate breccia within iron carbonate altered metasediment. This zone correlates with historical drill hole GAR-11-70, 25 metres north which intersected 5.65 g/t Au over 3.0 metres and GAR-12-159 located 40 metres south which intersected 8.39 g/t over 2.0 metres. A second mineralized zone within the hole returned 58.1 g/t Au over 1.0 metre within a zone containing quartz-iron carbonate fracturing and pervasive hematite altered metasediment.

OSK-G17-438 was drilled vertically between the two bulk sample pits at Garrcon. The hole intersected the down dip extension of the mineralized zone in the west bulk sample pit averaging 6.12 g/t Au over 6.0 metres. This interval is hosted within iron carbonate altered metasediment containing multiple 1 cm quartz-iron carbonate. A second intercept of the Garrcon deep zone returned 10.6 g/t Au over 3.5 metres.

OSK-G17-407 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 work 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 or through AAS finish at Bureau Veritas Mineral Laboratories in Timmins, 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 $240 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

(Toronto, October 25, 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 18 intercepts in 11 infill holes (at 15 metre spacings) between section 2150E – 2450E, and 4 infill/expansion holes in Zone 27 of the Windfall deposit are presented below.

Highlights from the new results include: 39.4 g/t Au over 2.4 metres in OSK-W-17-1186; 18.8 g/t Au over 4.2 metres in OSK-W-17-1154; 25.7 g/t Au over 2.6 metres in OSK-W-17-903-W1;  and 7.90 g/t Au over 8.0 metres. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Osisko is performing definition drilling in Zone 27.  The definition program is focused on infilling a 200 metre wide by 200 metre deep area of Zone 27 with a 15 metres drill spacing.  The area is between section 2150E and 2350E.

Hole Number	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 100 g/t	Zone	Corridor
OSK-W-17-864	516.0	524.0	8.0	7.90		Z27	Z27
OSK-W-17-903-W1	577.6	580.2	2.6	25.7		Z27 FW	Z27
including	577.6	578.5	0.9	73.7
OSK-W-17-1009	108.0	110.7	2.7	5.73		Z27 (15m infill)	Z27
including	109.0	110.0	1.0	13.7
OSK-W-17-1018	10.0	12.0	2.0	3.93		Z27	Z27
OSK-W-17-1023	134.4	138.0	3.6	4.00		Z27 (15m infill)	Z27
including	134.4	135.2	0.8	13.1
OSK-W-17-1038	97.4	99.7	2.3	16.4		Z27 (15m infill)	Z27
OSK-W-17-1050	76.5	80.0	3.5	6.55		Z27 (15m infill)	Z27
OSK-W-17-1103	79.8	82.0	2.2	15.4		Z27 (15m infill)	Z27
OSK-W-17-1106	19.0	21.2	2.2	3.02		Z27 (15m infill)	Z27
including	20.9	21.2	0.3	18.6
OSK-W-17-1122	63.0	65.2	2.2	7.05		Z27 (15m infill)	Z27
OSK-W-17-1129	206.8	209.0	2.2	8.20		Z27 (15m infill)	Z27
OSK-W-17-1154	91.0	95.2	4.2	18.8		Z27 (15m infill)	Z27
including	92.0	93.0	1.0	44.1
OSK-W-17-1164	132.0	139.8	7.8	7.12		Z27 (15m infill)	Z27
including	139.3	139.8	0.5	64.9
OSK-W-17-1180	71.0	74.0	3.0	5.04		Z27 (15m infill)	Z27
	80.0	85.0	5.0	18.0		Z27 (15m infill)	Z27
including	80.9	81.9	1.0	49.6
	142.8	146.0	3.2	3.98		Z27 (15m infill)	Z27
	156.5	158.7	2.2	3.47		Z27 (15m infill)	Z27
OSK-W-17-1186	522.0	524.4	2.4	39.4		Z27	Z27
including	523.0	524.0	1.0	87.8

Notes:

1. True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.
2. Definitions: FW = Foot Wall

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-W-17-864	330	-53	813	452467	5434581	2525
OSK-W-17-903-W1	329	-56	657	452539	5434692	2650
OSK-W-17-1009	147	-49	183	452107	5434809	2325
OSK-W-17-1018	333	-47	300	452247	5434865	2475
OSK-W-17-1023	145	-48	228	452033	5434796	2275
OSK-W-17-1038	147	-49	120	452067	5434773	2275
OSK-W-17-1050	148	-49	106	452053	5434749	2250
OSK-W-17-1103	148	-49	111	452016	5434722	2200
OSK-W-17-1106	330	-50	342	452152	5434730	2325
OSK-W-17-1122	150	-47	114	452063	5434736	2250
OSK-W-17-1129	325	-49	249	452213	5434606	2325
OSK-W-17-1154	149	-49	174	452020	5434762	2250
OSK-W-17-1164	143	-58	336	451960	5434752	2175
OSK-W-17-1180	322	-45	189	452066	5434618	2175
OSK-W-17-1186	331	-54	984	452419	5434554	2475

 

OSK-W-17-864 intersected 7.9 g/t Au over 8.0 metres. Mineralization is composed of up to 20% pyrite stringers within strong pervasive silica alteration. The andesite host is also sericite and fuchsite altered. Traces of chalcopyrite are observed along the interval.

OSK-W-17-903-W1 intersected 25.7 g/t Au over 2.6 metres in the Zone 27 Footwall. The mineralization is hosted in a strongly sericitized andesite, cut by the Red Dog intrusion, and composed of 3% pyrite stringers. The interval is 30 metre south-west of OSK-W-17-903 (10.7 g/t Au over 2.0 metres previously reported September 20, 2017).

OSK-W-17-1009 intersected 5.73 g/t Au over 2.7 metres. Mineralisation is in a porphyritic felsic intrusion and composed of massive pyrite stringers and pyrite-tourmaline veins. The intrusion is strongly sericitized and silicified.

OSK-W-17-1018 intersected 3.93 g/t Au over 2.0 metres. Mineralisation is composed of 6% semi-massive pyrite and 8% pyrite stringers within a strong silica and sericite altered rhyolite. The interval is 45 metres north-west of the main Zone 27.

OSK-W-17-1023 intersected 4.00 g/t Au over 3.6 metres. Mineralization is at the contact between the felsic intrusion and the rhyolite. Up to 4% pyrite stringers and few quartz-tourmaline veins are within a strong silica and sericite alteration envelope.

OSK-W-17-1038 intersected 16.4 g/t Au over 2.3 metres. Mineralization is composed of up to 5% pyrite stringers in a silica altered felsic porphyritic intrusion.

OSK-W-17-1050 intersected 6.55 g/t Au over 3.5 metres. Mineralization is composed of up to 4% pyrite stringers, 5% pyrite clusters and 1% quartz-tourmaline veins within a strongly sericitized and silicified rhyolite.

OSK-W-17-1103 intersected 15.4 g/t Au over 2.2 metres. Mineralization is composed of 10% pyrite-silica flooding at the contact between the andesite and the felsic porphyritic intrusion.

OSK-W-17-1106 intersected 3.02 g/t Au over 2.2 metres. Mineralisation is composed of trace disseminated pyrite and trace pyrite stringers hosted in a strongly sericitized rhyolite.

OSK-W-17-1122 intersected 7.05 g/t Au over 2.2 metres. Mineralization is composed of up to 10% pyrite stringers hosted in a strongly silicified and sericitized felsic dike.

OSK-W-17-1129 intersected 8.2 g/t Au over 2.2 metres. Mineralization is composed of up to 30% pyrite-silica flooding within a strongly sericitized rhyolite.

OSK-W-17-1154 intersected 18.8 g/t Au over 4.2 metres. Mineralization is composed of 10% semi-massive pyrite and 10% pyrite stringers within a strongly silicified and sericitized felsic intrusion.

OSK-W-17-1164 intersected 7.12 g/t Au over 7.8 metres. Mineralization is composed of trace pyrite stringers and trace pyrite clusters hosted in a sericite altered large quarts eyes, porphyritic felsic dike.

OSK-W-17-1080 intersected four intervals: 5.04 g/t Au over 3.0 metres, 18.0 g/t Au over 5.0 metres, 3.98 g/t Au over 3.2 metres and 3.47 g/t Au over 2.2 metres. The mineralization is composed of up to 15% pyrite stringers, 5% pyrites clusters and disseminated pyrite. Mineralization correlates with felsic intrusions, fragmental or porphyritic textured, hosted in strongly sericitized and silicified rhyolite or andesite.

OSK-W-17-1186 intersected 39.4 g/t Au over 2.4 metres. Mineralization is composed of 5% pyrite stringers and 5-10% disseminated pyrite within a strongly sericitized and silicified andesite.

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 $250 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

Drake Extended 100 Metres to NE

Caribou Extension Confirmed to NE

(Toronto, October 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 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 36 intercepts in 24 drill holes focused on infill and expansion drilling in the Underdog, Caribou, and Mallard corridors of the Windfall deposit are presented below.

Highlights from the new results include: 250 g/t Au over 2.0 metres and 73.6 g/t over 2.0 metres in OSK-W-17-903 in the Underdog corridor; 108 g/t Au over 2.3 metres in OSK-W-17-1179; 31.4 g/t Au over 6.0 metres in OSK-W-17-820 in the Caribou corridor; and 36.6 g/t Au over 3.4 metres in OSK-W-17-867 in the Wolf Zone footwall.  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-13-503	342.5	344.9	2.4	8.96		New	Underdog
including	343.5	344.9	1.4	13.3
OSK-OBM-16-601	795.0	797.8	2.8	5.26		FW4	Underdog
including	797.1	797.8	0.7	20.7
OSK-OBM-16-664	649.0	652.0	3.0	12.8		FW3U HW	Underdog
OSK-W-17-664-W1	754.0	756.4	2.4	4.89		FW3U	Underdog
including	754.9	755.8	0.9	12.8
OSK-W-17-820	558.5	564.5	6.0	31.4	25.4	CS1	Caribou
including	561.0	563.0	2.0	83.0	65.0
OSK-W-17-854-W1	489.6	492.0	2.4	7.97		Wolf FW	Caribou
including	491.3	492.0	0.7	15.1
	498.0	501.0	3.0	5.18		Wolf FW	Caribou
OSK-W-17-855-W2	759.9	762.0	2.1	11.1		FW1	Underdog
including	759.9	761.0	1.1	20.8
	861.0	863.0	2.0	8.88		FW2	Underdog
including	862.0	863.0	1.0	17.4
OSK-W-17-862-W2	640.0	643.0	3.0	13.4		Wolf FW	Caribou
including	642.0	643.0	1.0	38.9
OSK-W-17-867	714.1	717.5	3.4	36.6	29.9	Wolf FW	Caribou
including	715.0	716.0	1.0	123	100
OSK-W-17-871	23.2	25.8	2.6	5.39		TBD
including	24.1	25.0	0.9	15.2
	269.0	271.4	2.4	6.21		Caribou	Caribou
OSK-W-17-903	668.5	670.5	2.0	250	50.1	Vein	Underdog
including	668.5	669.5	1.0	501	100
	778.0	780.0	2.0	73.6	40.2	FW3U	Underdog
including	779.2	780.0	0.8	184	100
OSK-W-17-913	533.8	536.5	2.7	5.09		TBD	Caribou
including	533.8	535.0	1.2	11.1
	791.0	793.0	2.0	13.5		Wolf HW	Caribou
including	791.0	792.0	1.0	26.2
OSK-W-17-926	123.8	126.3	2.5	5.18		Mallard	Mallard
OSK-W-17-937	782.0	784.4	2.4	8.09		Wolf 2	Caribou
including	783.0	783.8	0.8	22.4
OSK-W-17-969	210.6	213.0	2.4	10.1		Mallard	Mallard
including	210.6	211.0	0.4	53.0
OSK-W-17-996	359.0	361.2	2.2	9.62		Mallard FW	Mallard
including	359.7	360.4	0.7	24.1
OSK-W-17-999	91.5	94.0	2.5	5.18		TBD NEW	Caribou
including	91.5	93.0	1.5	8.54
	400.7	403.9	3.2	3.68		Caribou ext.	Caribou
	432.9	436.4	3.5	5.79		Caribou ext.	Caribou
	459.4	462.0	2.6	5.19		Caribou ext.	Caribou
including	460.0	461.0	1.0	10.4
OSK-W-17-1031	182.0	184.0	2.0	3.14		Drake	Mallard
including	182.3	182.6	0.3	18.7
OSK-W-17-1051	303.0	305.1	2.1	7.85		TBD
	846.0	848.0	2.0	27.8		FW3	Underdog
including	847.0	848.0	1.0	53.8
OSK-W-17-1066	412.0	415.4	3.4	4.72		CS1 HW	Caribou
	458.6	460.9	2.3	4.48		CS1	Caribou
	514.0	517.0	3.0	7.98		CN1	Caribou
including	515.6	516.1	0.5	43.1
OSK-W-17-1079	597.0	599.3	2.3	108	17.5	CN1 FW	Caribou
including	597.6	598.0	0.4	618	100
OSK-W-17-1119	527.4	529.5	2.1	10.7		CN1	Caribou
including	528.3	528.7	0.4	44.4
	534.3	540.4	6.1	3.08		CN1	Caribou
including	539.2	540.4	1.2	9.48
OSK-W-17-1147-W1	1129.0	1131.0	2.0	7.52		Caribou ext.	Caribou
including	1130.0	1130.5	0.5	29.2
OSK-W-17-1189	718.5	723.7	5.2	6.58		Caribou	Caribou
including	718.5	719.0	0.5	49.8

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; TBD = To Be Determine.

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-EAG-13-503	330	-56	918	451969	5434525	2075
OSK-OBM-16-601	332	-51	801	452476	5434677	2600
OSK-OBM-16-664	329	-55	810	452396	5434618	2500
OSK-W-17-664-W1	329	-55	996	452394	5434619	2500
OSK-W-17-820	332	-66	1106	452670	5434484	2675
OSK-W-17-854-W1	331	-53	844	452485	5434592	2550
OSK-W-17-855-W2	334	-64	1197	452309	5434384	2300
OSK-W-17-862-W2	332	-55	759	452683	5434577	2725
OSK-W-17-867	315	-50	1029	452800	5434550	2825
OSK-W-17-871	328	-54	533	452402	5434623	2500
OSK-W-17-903	329	-56	801	452539	5434692	2650
OSK-W-17-913	334	-52	954	452878	5434419	2825
OSK-W-17-926	329	-54	216	451981	5434828	2225
OSK-W-17-937	333	-57	935	452897	5434430	2850
OSK-W-17-969	328	-48	324	452200	5434867	2425
OSK-W-17-996	328	-56	393	452270	5434844	2500
OSK-W-17-999	330	-61	516	452861	5434813	3000
OSK-W-17-1031	336	-62	390	452296	5434867	2525
OSK-W-17-1051	138	-68	1248	452313	5435323	2775
OSK-W-17-1066	332	-56	585	452488	5434436	2475
OSK-W-17-1079	332	-58	615	452541	5434452	2550
OSK-W-17-1119	331	-55	609	452541	5434452	2550
OSK-W-17-1147-W1	335	-52	1212	453241	5434381	3125
OSK-W-17-1189	335	-47	1005	452945	5434561	2950

 

OSK-EAG-13-503 intersected 8.96 g/t Au over 2.4 metres (including 13.3 g/t Au over 1.4 metres). Mineralization is composed of semi-massive pyrite stringers and up to 3% disseminated pyrite within a sericitized felsic intrusion. The interval occurs directly under the Red Dog intrusion on section 2075E.

OSK-OBM-16-601 intersected 5.26 g/t Au over 2.8 metres (including 20.7 g/t Au over 0.7 metres). Mineralization is composed of 1% disseminated pyrite within a strongly chloritized andesite. The interval is 60 metres north-west of and parallel to FW3 and aligns with FW4 projections.

OSK-OBM-16-664 intersected 12.8 g/t Au over 3.0 metres in FW3U HW. Mineralization is composed of trace pyrite stringers and small quartz-tourmaline-pyrite veins hosted in rhyolite.

OSK-W-17-664-W1 intersected 4.89 g/t Au over 2.4 metres (including 12.8 g/t Au over 0.9 metres). Mineralization is composed of 2% pyrite stringers within a strongly sericitized andesite.

OSK-W-17-820 intersected 31.4 g/t Au over 6.0 metres uncut (including 83.0 g/t Au over 2.0 metres). Mineralization occurs with strong silica, chlorite and fuchsite alteration in a sheared andesite with up to 25% pyrite clusters and 15% interstitial sphalerite. The interval correlates to CS1 Zone.

OSK-W-17-854-W1 intersected two intervals within the Wolf FW: 7.97 g/t Au over 2.4 metres (including 15.1 g/t Au over 0.7 metres) and 5.18 g/t Au over 3.0 metres. Both intervals occur at the sericite, chlorite and silica altered contact between the felsic porphyritic intrusion and andesite. Mineralization is composed of up to 20% disseminated pyrite, up to 3% pyrite stringers and local quartz-tourmaline ptygmatic veins.

OSK-W-17-855-W2 intersected two intervals: 11.1 g/t Au over 2.1 metres (including 20.8 g/t Au over 1.1 metres) in FW1 and 8.88 g/t over 2.0 metres (including 17.4 g/t Au over 1.0 metre) in FW2. Both intervals contain up to 1% disseminated pyrite and pyrite stringers within and at the contacts along felsic porphyritic dikes.

OSK-W-17-862-W2 intersected 13.4 g/t Au over 3.0 metres (including 38.9 g/t Au over 1.0 metre) in the Wolf Footwall. The mineralization is composed of semi-massive pyrite within a strongly sericitized andesite.

OSK-W-17-867 intersected 36.6 g/t Au over 3.4 metres uncut, (including 123 g/t Au over 1.0 metre) in the Wolf footwall. Trace pyrite mineralization is hosted in weak sericite alteration at the contact between a felsic porphyritic dike and andesite. Two quartz-carbonate veins occur along the contact.

OSK-W-17-871. Intersected a new zone returning 5.39 g/t Au over 2.6 metres (including 15.2 g/t Au over 0.9 metres). The interval is 70 metres south-east of the main Caribou Corridor. Mineralization is composed of disseminated pyrite at the contact between a felsic porphyritic dike and a sericitized andesite. A second intersection returned 6.21 g/t Au over 2.4 metres in the main Caribou Zone. Mineralization is composed of up to 7% pyrite stringers and 3% disseminated pyrite hosted in a strongly sericitized rhyolite.

OSK-W-17-903 intersected two intervals. The first interval returned 250 g/t Au over 2.0 metres uncut (including 501 g/t Au over 1.0 metres) in a tension quartz vein within the Red Dog intrusion. The second interval returned 73.6 g/t Au over 2.0 metres uncut (including 184 g/t Au over 0.8 metres) in FW3.  Mineralization is composed of up to 2% pyrite stringers and disseminated pyrite and local quartz-carbonate veins within a chloritized andesite.

OSK-W-17-913 intersected two intervals: 5.09 g/t Au over 2.7 metres (including 11.1 g/t Au over 1.2 metres) and 13.5 g/t Au over 2.0 metres (including 26.2 g/t Au over 1.0 metre). The first interval is composed of disseminated pyrite at the contact between the rhyolite and the andesite, 55 metres south-east of the main Caribou Corridor. The second interval is within the Wolf hanging wall and is composed of disseminated pyrite and pyrite stringers within a large quartz eyes porphyritic felsic intrusion.

OSK-W-17-926 intersected 5.18 g/t Au over 2.5 metres in Mallard. Mineralization is in a strongly sericitized andesite containing 1% disseminated pyrite, pyrite stringers and local quartz-tourmaline veins.  Mineralization follows a porphyritic felsic dike contact and extends the Mallard Zone 35 metres north-east from OSK-W-17-919 (4.32 g/t Au over 2.5 metres previously reported August 14, 2017).

OSK-W-17-937 intersected 8.09 g/t Au over 2.4 metres (including 22.4 g/t Au over 0.8 metres). Mineralization occurs at the contact between a felsic intrusion and a sericitized rhyolite, with 15% pyrite stringers. The interval correlates to Wolf 2.

OSK-W-17-969 intersected Mallard returning 10.1 g/t Au over 2.4 metres (including 53.0 g/t Au over 0.4 metres).  Mineralization is within a sericitized andesite as 2% pyrite and up to 55% pyrite stringers. Interval is located 60 metres above the OSK-W-17-977 (12.0 g/t Au over 2.2 metres, previously reported September 20, 2017).

OSK-W-17-996 intersected 9.62 g/t Au over 2.2 metres (including 24.1 g/t Au over 0.7 metres). The interval correlates to the Mallard footwall and is composed of 4% disseminated pyrite, 5% crustiform veins and 1% ptygmatic tourmaline veins, occurring along the Red Dog contact within a moderate sericite altered andesite. It extends the Mallard zone 60 metres northeast of OSK-W-17-977 (12.0 g/t Au over 2.2 metres, previously reported September 20, 2017).

OSK-W-17-999 intersected four interval:  the first returned 5.18 g/t Au over 2.5 metres (including 8.54 g/t Au over 1.5 metres) 100 metres south-east of the main Caribou Corridor, mineralization within a fragmental felsic intrusion, with disseminated pyrite correlating with strong sericite alteration. The three other intervals are in the north-east extension of the Caribou Corridor, 50 metres north-east of OBM-16-580 and OBM-16-701 (4.30 g/t Au over 5.4 metres and 4.82 g/t Au over 7.0 metres, respectively reported February 18 and August 25, 2016). The three intervals returned 3.68 g/t Au over 3.2 metres; 5.79 g/t Au over 3.5 metres; and 5.19 g/t Au over 2.6 metres (including 10.4 g/t Au over 1.0 metre). Mineralization occurs in a strongly sericitized and silicified andesite with up to 40% pyrite stringers.

OSK-W-17-1031 intersected 3.14 g/t Au over 2.0 metres (including 18.7 g/t Au over 0.3 metres). Mineralization includes 4% pyrite stringers and 1% disseminated pyrite within a strongly silicified and sericitized andesite. This interval extends the Drake Zone 100 metres northeast of OSK-W-17-969 (7.39 g/t Au over 3.3 metres, previously reported August 24, 2017).

OSK-W-17-1051 intersected a new mineralized contact between a felsic intrusion and the andesite, returning 7.85 g/t Au over 2.1 metres. The interval is 160 metres north-west of the Mallard Corridor, along strike of the F-17 and F-51 zones.  OSK-W-17-1051 also intersected FW3 returning 27.8 g/t Au over 2.0 metres (including 53.8 g/t Au over 1.0 metre). Local visible gold is found with pervasive silica alteration and within a large quartz eyes porphyritic dike, as 8% disseminated pyrite and 4% pyrite-tourmaline stringers.

OSK-W-17-1066 intersected three intervals: 4.72 g/t Au over 3.4 metres; 4.48 g/t Au over 2.3 metres; and 7.98 g/t Au over 3.0 metres (including 43.1 g/t Au over 0.5 metres). The first two zones correlate to CS1 with up to 20% pyrite stringers in a chloritized rhyolite and strongly sericitized andesite. The third interval correlates to CN1 and includes up to 10% pyrite clusters along the contact between a sericitized andesite and a large quartz eyes porphyritic dike.

OSK-W-17-1079 intersected 108 g/t Au over 2.3 metres uncut (including 618 g/t Au over 0.4 metres). Mineralization is included in a sericitized gabbro with local visible gold and 1% pyrite. The interval correlates to CN1, just above the Red Dog contact.

OSK-W-17-1119 intersected two intervals in CN1: 10.7 g/t Au over 2.1 metres (including 44.4 g/t Au over 0.4 metres) and 3.08 g/t Au over 6.1 metres (including 9.48 g/t Au over 1.2 metres). Mineralization is composed of up to 20% pyrite stringers and 5-10% disseminated pyrite within a strongly sericitized andesite.

OSK-W-17-1147-W1 intersected 7.52 g/t Au over 2.0 metres (including 29.2 g/t Au over 0.5 metres) at the contact between an andesite and a porphyritic felsic dike with up to 5% disseminated pyrite and 1% pyrite stringers. The interval is in the north-east extension of the Caribou Corridor.

OSK-W-17-1189 intersected 6.58 g/t Au over 5.2 metres (including 49.8 g/t Au over 0.5 metres). Mineralization is composed of 5% disseminated pyrite, 2% pyrite clusters, in a strongly sericitized andesite in contact with a felsic intrusion. The interval is in the north-east extension of the Caribou Corridor.

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 $250 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

Lynx 4 Extended 235 Metres to NE

(Toronto, October 12, 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 19 intercepts in 11 drill holes focused on infill and expansion drilling in the Lynx deposit are presented below.

Highlights from the new results include: 61.8 g/t Au over 2.5 metres in OSK-W-17-953; 21.2 g/t Au over 4.3 metres in OSK-W-17-1169; 16.9 g/t Au over 4.0 metres in OSK-W-17-1190; and 29.8 g/t Au over 2.0 metres in OSK-W-17-881. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

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

 

OSK-W-17-856 intersected Lynx 2 returning 5.03 g/t Au over 5.6 metres (including 13.1 g/t Au over 0.6 metres and 15.2 g/t Au over 1.0 metre). Mineralization includes up to 18% pyrite, 5% quartz-carbonate veins and ptygmatic tourmaline veins related to rich silica bands.

OSK-W-17-881 intersected two intervals: 6.54 g/t Au over 4.2 metres (including 15.1 g/t Au over 1.4 metres) and 29.8 g/t Au over 2.0 metres (including 59.4 g/t Au over 1.0 metre). Both intervals are related to Lynx 2 Footwall at the contacts between a rhyolite and a gabbro. Mineralization is composed of up to 1% pyrite stringers and quartz-tourmaline veins within sericite and fuchsite alteration.

OSK-W-17-923 intersected 4.33 g/t Au over 3.0 metres in a strongly sericite and fuchsite altered gabbro. The mineralization is composed of up to 2% pyrite, 2% pyrite stringers and small crustiform veins. The interval correlates to the Lynx 4 corridor, extending the zone235 metres north-east of OSK-W-17-836 (116 g/t Au over 2.4 metres, uncut, previously reported May 23, 2017).

OSK-W-17-953 intersected Lynx 2 returning 61.8 g/t Au over 2.5 metres, uncut, (including 189 g/t Au over 0.8 metres) or 33.3 g/t Au over 2.5 metres cut. The mineralization is within a strongly silicified, sericitized and fuchsitized gabbro with 3% pyrite stringers, 2% disseminated pyrite and small crustiform veins.

OSK-W-17-998 intersected a crustiform vein returning 4.78 g/t Au over 4.5 metres between the Lynx 2 and Lynx 3 Zones. The vein contains up to 7% disseminated pyrite, 3% tourmaline and ptygmatic veins.

OSK-W-17-1003 intersected two intervals: 5.18 g/t Au over 2.6 metres (including 16.8 g/t Au over 0.8 metres) in Lynx 1 and 19.5 g/t over 2.0 metres (including 46.3 g/t Au over 0.8 metres) in Lynx 2. The first interval includes up to 5% pyrite clusters, 5% chalcopyrite and crustiform veins within a strongly sericitized gabbro. The second interval is at the contact between a gabbro and a strongly sericitized rhyolite. Fuchsite is also observed. The mineralization is composed of 10% pyrite stringers and few tourmaline ptygmatic veins.

OSK-W-17-1121 contains three intervals in crustiform veins: 19.0 g/t Au over 2.3 metres (including 58.8 g/t Au over 0.7 metres), 3.34 g/t Au over 2.1 metres and 8.62 g/t Au over 2.7 metres (including 13.7 g/t Au over 1.7 metres). The first is between Lynx 1 and Lynx 2 and the second and third are inside Lynx 3 Zone. All are hosted in a silica altered gabbro and mineralization is composed of up to 6% disseminated pyrite, up to 2% disseminated sphalerite and pyrite stringers.

OSK-W-17-1123 intersected 11.6 g/t Au over 2.1 metres (including 47.5 g/t Au over 0.4 metres) in Lynx 2. Mineralization is composed of 20% pyrite stringers within a strong silica alteration at the contact between a rhyolite and an andesite.

OSK-W-17-1128 intersected three intervals: 3.85 g/t Au over 5.5 metres in Lynx 3, 5.00 g/t Au over 2.0 metres in Lynx 2 and 14.0 g/t Au over 2.3 metres (including 25.7 g/t Au over 1.2 metres) in Lynx 6. The first interval is composed of up to 2% smoky quartz veins within a strongly silicified rhyolite, the second interval is within the gabbro and the third interval composed of up to 1% disseminated pyrite is at the contact between a felsic porphyritic intrusion and a gabbro.

OSK-W-17-1169 intersected two intervals 7.14 g/t Au over 2.4 metres (including 21.8 g/t Au over 0.4 metres) and 21.2 g/t Au over 4.3 metres (including 42.4 g/t Au over 1.0 metre). Both intervals correlate to Lynx 4. The first interval is a felsic porphyritic dike crosscutting the hosting rhyolite. The mineralization is composed of up to 15% pyrite stringers and pyrite-tourmaline stringers. The second interval is composed of semi-massive pyrite and trace of sphalerite hosted in a strongly silicified rhyolite.

OSK-W-17-1190 intersected two intervals: 11.0 g/t Au over 2.5 metres and 16.9 g/t Au over 4.0 metres (including 57.2 g/t Au over 0.7 metres). The mineralization in both intervals is composed of up to 10% disseminated pyrite and quartz-tourmaline veins. The first interval is within a strongly sericitized rhyolite, and the second interval is at the contact between a rhyolite and a felsic porphyritic dike. Both intersections correlate to the Lynx 4 corridor  300 meters up plunge of OSK-W-17-827 (57.0 g/t Au over 2.7 metres previously reported July 25, 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 $250 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

(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