Osisko Infill Drilling Continues to Intersect High-grade at Lynx

TORONTO, June 17, 2019 - Osisko Mining Corp. Inc. (OSK:TSX. "Osisko" or the "Corporation") is pleased to provide new infill drilling results from the ongoing definition and expansion program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec. The program is currently focused on infill drilling within the main Windfall gold deposit and the adjacent Lynx deposit (located immediately NE of Windfall), exploration and expansion drilling on the main mineralized zones, and deep exploration in the central areas of the intrusive system. Significant new analytical results from 19 intercepts in 7 drill holes and 6 wedges from surface focused on Lynx infill drilling are presented below. Additionally, 69 intercepts in 43 underground drill holes focused on 5 metre infill drilling, including the pending Lynx bulk sample area, are included in a second table below.

Highlights from new infill drilling results at Lynx include: 132 g/t Au over 5.0 metres in WST-19-0117; 51.0 g/t Au over 6.3 metres in OSK-W-19-909-W7; 56.2 g/t Au over 4.7 metres in WST-19-0106; 106 g/t Au over 2.0 metres in WST-19-0119; 82.9 g/t Au over 2.3 metres in WST-19-0113; 85.3 g/t Au over 2.0 metres in WST-19-0125; 36.0 g/t Au over 4.1 metres in OSK-W-18-1785-W1; 23.4 g/t Au over 6.3 metres in OSK-W-18-1539; 63.6 g/t Au over 2.1 metres in WST-19-0137; 59.3 g/t Au over 2.2 metres in WST-19-148; 37.0 g/t Au over 3.5 metres in WST-19-0130 and 42.1 g/t Au over 3.0 metres in WST-19-0093. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Surface Drilling

Underground drilling

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See "Quality Control and Reporting Protocols" below.

Surface Drilling

Underground drilling

OSK-W-18-1539 intersected 23.4 g/t Au over 6.3 metres. Mineralization is composed of local visible gold, up to 20% disseminated pyrite, up to 10% disseminated sphalerite, 3% chalcopyrite, 3% molybdenite and traces of arsenopyrite within a moderate silica, sericite and fuchsite altered rhyolite.

OSK-W-18-1785-W1 intersected two intervals: 36.0 g/t Au over 4.1 metres and 27.4 g/t Au over 2.3 metres. The first interval contains local visible gold, up to 15% finely disseminated pyrite, up to 1.5% sphalerite within pervasive silica flooding with quartz-tourmaline veins. The mineralization is at the contact between a moderate fuchsite and sericite altered rhyolite and a felsic porphyritic dike. The second interval contains local visible gold, up to 15% finely disseminated pyrite, trace sphalerite and pyrite tourmaline stringers within a strong silica and moderate sericite altered felsic porphyritic dike.

OSK-W-19-1181-W5 intersected three intervals: 19.6 g/t Au over 2.2 metres, 6.50 g/t Au over 2.0 metres and 13.4 g/t Au over 4.7 metres. The first interval contains up to 3% stringer, clustered, and disseminated pyrite and quartz-tourmaline veins at the contact between a moderate sericite altered gabbro and a moderate fuchsite and sericite altered rhyolite. The second interval contains 1% pyrite in clusters and stringers within a strong sericite altered rhyolite. The last interval is composed of up to 5% pyrite clusters within a moderate sericite altered rhyolite.

OSK-W-19-1181-W8 intersected 20.5 g/t Au over 2.2 metres. The mineralization is composed of 4% pyrite stringers with a tourmaline breccia and quartz-carbonate veins hosted in a moderate chlorite and weak fuchsite altered rhyolite.

OSK-W-19-1850 intersected 16.8 g/t Au over 3.0 metres. The mineralization is composed of up to 2% pyrite stringers within a strong chlorite and moderate carbonate altered gabbro.

OSK-W-19-1852 intersected 13.7 g/t Au over 2.1 metres. The mineralization is composed of up to 5% disseminated, clustered, and stringer pyrite, and trace sphalerite with pervasive silica flooding hosted in a moderate sericite altered rhyolite.

OSK-W-19-1855 intersected 4.67 g/t Au over 2.0 metres. The mineralization is composed of 2% disseminated pyrite and tourmaline ptygmatic veins within a strong silica altered felsic fragmental intrusion.

OSK-W-19-1857-W1 intersected two intervals: 3.94 g/t Au over 2.5 metres and 3.31 g/t Au over 2.2 metres. The two intervals contain up to 7% pyrite stringers and clusters, quartz-tourmaline veins and trace chalcopyrite at the contact between a moderate silica and weak sericite altered rhyolite with a strong sericite altered gabbro. Both units have weak fuchsite alteration.

OSK-W-19-1860 intersected two intervals: 6.39 g/t Au over 2.8 metres and 13.0 g/t Au over 3.9 metres. The first interval contains up to 3% disseminated pyrite and quartz-tourmaline veins hosted in a moderate silica and sericite altered felsic fragmental intrusion. The second interval contains up to 4% finely disseminated pyrite, smoky quartz veins and local visible gold within a strong silica and weak sericite altered rhyolite.

OSK-W-19-1915 intersected 7.84 g/t Au over 2.1 metres. The mineralization is composed of local visible gold with pervasive silica flooding, 2% pyrite stringers and clusters hosted in a weak sericite and carbonate altered felsic fragmental intrusion.

OSK-W-19-1939 intersected 4.47 g/t Au over 2.2 metres. The mineralization is composed of 3% pyrite stringers and clusters hosted in a moderate sericite and weak silica altered felsic intrusion.

OSK-W-19-909-W7 intersect two intervals: 51.0 g/t Au over 6.3 metres and 14.3 g/t Au over 2.1 metres. The first interval contains local visible gold and electrum with pervasive silica flooding, 20% pyrite clusters, trace chalcopyrite and smoky quartz veins hosted at the contact between a strong silica altered rhyolite and a felsic porphyritic intrusion. The second interval contains 1% pyrite stringers within a strong silica, strong sericite and weak fuchsite altered felsic porphyritic dike.

OSK-W-19-961-W1 intersected 5.11 g/t Au over 2.0 metres. The mineralization is composed of 5% pyrites clusters and smoky quartz veins within a silica altered rhyolite.

WST-19-0089 intersected 4.05 g/t Au over 2.2 metres. The mineralization is composed of 1% pyrite stringer and 2% disseminated pyrite within a moderate silica and sericite altered rhyolite. WST-19-0089 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0090 intersected 5.23 g/t Au over 2.4 metres. The mineralization includes 1% pyrite stringers and 2% disseminated pyrite within a moderate silica and sericite altered rhyolite. WST-19-0090 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0091 intersected 21.5 g/t Au over 4.3 metres. The mineralization is composed of local visible gold, 2% pyrite stringers and 15% sphalerite hosted in sericite, silica and fuchsite altered rhyolite. WST-19-0091 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0092 intersected 3.33 g/t Au over 2.0 metres. The mineralization is composed of 1% pyrite stringers with pervasive silica flooding within a moderate sericite and silica altered rhyolite. WST-19-0092 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0093 intersected 42.1 g/t Au over 3.0 metres. The mineralization is composed of local visible gold in fracture filling, up to 2% pyrite stringers with pervasive silica flooding, hosted in a moderate silica and weak fuchsite altered felsic fragmental intrusion. WST-19-0093 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0097 intersected 14.2 g/t Au over 2.1 metres. The mineralization is composed of trace pyrite stringers and clusters within a weak silica and sericite altered rhyolite. WST-19-0097 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0098 intersected 38.7 g/t Au over 2.7 metres. The mineralization is composed of local visible gold, up to 3% disseminated and stringer pyrite, and trace chalcopyrite and sphalerite hosted in a moderate fuchsite and silica altered rhyolite. WST-19-0098 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0099 intersected 28.5 g/t Au over 2.0 metres. The mineralization is composed of local visible gold, 1% disseminated pyrite and trace chalcopyrite with pervasive silica flooding hosted in a moderate sericite and silica altered rhyolite. WST-19-0099 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0100 intersected 34.1 g/t Au over 3.1 metres. The mineralization is composed of local visible gold, 1% pyrite stringers and clusters with pervasive silica flooding hosted in a weak silica and sericite altered rhyolite. WST-19-0100 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0101 intersected 7.66 g/t Au over 2.0 metres. The mineralization is composed of 2% pyrite-tourmaline stringers, 1% pyrite clusters and trace chalcopyrite within pervasive silica flooding and hosted in a weak silica and sericite altered rhyolite. WST-19-0101 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0102 intersected 6.12 g/t Au over 2.5 metres. The mineralization is composed of 2% pyrite clusters and 1% pyrite-tourmaline stringers hosted at the contact between a weak silica and sericite altered rhyolite and a weak sericite altered felsic porphyritic intrusion. WST-19-0102 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0106 intersected three interval: 10.2 g/t Au over 3.0 metres, 5.04 g/t Au over 2.3 metres and 56.2 g/t Au over 4.7 metres. The first interval is composed of up to 5% disseminated, clustered, and stringer pyrite associated with pervasive silica flooding hosted in a sericitized felsic porphyritic intrusion. The second interval contains trace disseminated and clustered pyrite within a moderate sericite and weak silica altered rhyolite. The last interval contains local visible gold, 3% pyrite clusters, trace sphalerite and chalcopyrite associated with pervasive silica flooding hosted in a moderate silica and sericite altered felsic porphyritic intrusion. WST-19-0106 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0107 intersected 9.94 g/t Au over 2.6 metres. The mineralization is composed of up to 3% pyrite clusters and stringers, traces sphalerite with pervasive silica flooding hosted in a moderate sericite altered rhyolite. WST-19-0107 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0108 intersected 22.5 g/t Au over 2.3 metres. The mineralization is composed of up to 5% pyrite-tourmaline stringers and clusters hosted in a weak sericite and silica altered rhyolite. WST-19-0108 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0111 intersected 13.3 g/t Au over 2.1 metres. The mineralization is composed of local visible gold, 1% disseminated pyrite with pervasive silica flooding hosted in a moderate silica and fuchsite altered felsic porphyritic intrusion. WST-19-0111 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0112 intersected 16.0 g/t Au over 2.3 metres. The mineralization is composed of 7% pyrite clusters with pervasive silica flooding hosted at the contact between a felsic porphyritic intrusion and a rhyolite. WST-19-0112 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0113 intersected 82.9 g/t Au over 2.3 metres. The mineralization is composed of local visible gold, 3% pyrite clusters and stringers with trace sphalerite in pervasive silica flooding hosted in a moderate sericite altered rhyolite. WST-19-0113 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0114 intersected 5.89 g/t Au over 2.3 metres. The mineralization is composed of up to 5% finely disseminated pyrite with pervasive silica flooding hosted in weak fuchsite, sericite and silica altered rhyolite. WST-19-0114 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0115 intersected 17.1 g/t Au over 2.4 metres. The mineralization is composed of up to 5% finely disseminated and clustered pyrite hosted in a moderate silica, and weak sericite and fuchsite altered rhyolite. WST-19-0115 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0116 intersected 26.9 g/t Au over 3.5 metres and 3.91 g/t Au over 5.2 metres. The first interval contains 3% pyrite clusters and stringers with pervasive silica flooding hosted in a moderate sericite altered rhyolite. The second interval contains trace disseminated, clustered, and stringer pyrite within a moderate sericite and weak silica altered rhyolite. WST-19-0115 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0117 intersected 132 g/t Au over 5.0 metres. The mineralization is composed of local visible gold, 2% pyrite stringers and clusters, traces chalcopyrite and quartz-tourmaline veins hosted in a weak sericitized and silica altered felsic intrusion. WST-19-0117 was drilled from underground drill station RA-180-190-E located 180 metres below surface from section 3450E.

WST-19-0118 intersected 18.0 g/t Au over 3.0 metres. The mineralization is composed of up to 10% pyrite stringers and clusters and 1% sphalerite in fracture filling at the contact between a sericite altered felsic intrusion and a sericite altered rhyolite. WST-19-0118 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0119 intersected 3.94 g/t Au over 2.2 metres, 106 g/t Au over 2.0 metres and 4.09 g/t Au over 2.1 metres. The first interval contains up to 30% fine disseminated, clustered, and stringer pyrite with quartz-tourmaline veins hosted in a moderate sericite altered rhyolite. The second and third intervals contains local visible gold, 1% fine disseminated pyrite and quartz-carbonate veins hosted in a weak sericite and silica altered rhyolite. WST-19-0119 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0120 intersected 7.34 g/t Au over 4.0 metres and 10.5 g/t Au over 2.4 metres. The first interval contains up to 3% disseminated and clustered pyrite, trace sphalerite and tourmaline ptygmatic veins within a weak fuchsite and moderate sericite altered rhyolite. WST-19-0120 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0121 intersected 8.66 g/t Au over 3.6 metres. The mineralization is composed of up to 3% disseminated and stringer pyrite and up to 10% quartz-tourmaline ptygmatic veins within a sericite altered felsic intrusion. WST-19-0121 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0122 intersected 32.9 g/t Au over 2.0 metres and 50.8 g/t Au over 2.0 metres. The first interval contains up to 20% finely disseminated pyrite with pervasive silica flooding hosted in a moderate sericite and strong silica altered rhyolite. The second interval is composed of 10% pyrite stringers and smoky quartz veins within a moderate sericite altered rhyolite. WST-19-0122 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0123 intersected 3.51 g/t Au over 2.7 metres. The mineralization is composed of 3% pyrite stingers and clusters with pervasive silica flooding hosted in a strong silica and sericite altered rhyolite. WST-19-0123 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0125 intersected 85.3 g/t Au over 2.0 metres and 7.36 g/t Au over 2.0 metres. The first interval contains local visible gold and up to 10% finely disseminated pyrite with pervasive silica flooding hosted in a strong fuchsite and silica altered rhyolite. The second interval is composed of 20% finely disseminated pyrite within a strong sericite, silica and a moderate fuchsite altered rhyolite. WST-19-0125 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0126 intersected 6.60 g/t Au over 2.0 metres and 11.7 g/t Au over 2.5 metres. The first interval contains 4% disseminated and clustered pyrite hosted in a weak sericite and silica altered rhyolite. The second interval contains local visible gold, 4% pyrite tourmaline veins, up to 20% finely disseminated pyrite and trace sphalerite hosted in a moderate silica and weak sericite altered rhyolite. WST-19-0126 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0128 intersected 10.7 g/t Au over 3.0 metres. The mineralization is composed of up to 3% pyrite clusters and stringers with pervasive silica flooding and quartz-carbonate veins hosted in a weak silica and sericite altered rhyolite. WST-19-0128 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0129 intersected 4.59 g/t Au over 2.1 metres. The mineralization is composed of 1% pyrite clusters within a weak silica altered rhyolite. WST-19-0129 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0130 intersected 37.0 g/t Au over 3.5 metres. The mineralization is composed of up to 3% pyrite clusters and local visible gold with pervasive silica flooding and trace sphalerite hosted in strong silica and fuchsite altered rhyolite. WST-19-0130 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0132 intersected four intervals: 27.3 g/t Au over 2.0 metres, 3.03 g/t Au over 2.2 metres, 6.68 g/t Au over 2.7 metres and 4.17 g/t Au over 2.0 metres. The first interval contains 1% pyrite clusters within a weak sericite altered felsic fragmental intrusion. The second interval contains 2% pyrite clusters with pervasive silica flooding and up to 20% quartz-tourmaline ptygmatic veins within a sericitized felsic fragmental intrusion. The third interval is composed of 2% pyrite clusters hosted in a strong silica and weak sericite altered rhyolite. The last interval contains 1% pyrite clusters with 15% smoky quartz veins hosted in a strong sericite and silica altered rhyolite. WST-19-0128 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0133 intersected 16.2 g/t Au over 2.4 metres and 4.63 g/t Au over 2.1 metres. The first interval contains 2% pyrite clusters within a moderate sericite altered felsic fragmental intrusion. The second interval is composed of 3% disseminated pyrite with pervasive silica flooding within a weak sericite altered felsic fragmental intrusion. WST-19-0133 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0136 intersected four intervals: 8.51 g/t Au over 4.0 metres, 4.21 g/t Au over 2.0 metres, 15.9 g/t Au over 2.1 metres and 5.98 g/t Au over 7.4 metres. The first interval contains up to 5% disseminated pyrite, traces of sphalerite and smoky quartz veins within a weak silica and sericite altered felsic fragmental intrusion. The second interval contains 2% pyrite stringers hosted in a moderate silica altered felsic intrusion. The third interval is composed of 5% disseminated pyrite with pervasive silica flooding, local visible gold and quartz-tourmaline veins within a moderate silica and sericite altered felsic intrusion. The last interval contains local visible gold, 10% pyrite and smoky quartz veins hosted in a moderate sericite and silica altered felsic porphyritic intrusion. WST-19-0136 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0137 intersected two intervals: 17.5 g/t Au over 5.9 metres and 63.6 g/t Au over 2.1 metres. The first interval contains local visible gold, 1% disseminated and stringer pyrite within a moderate sericite and silica altered felsic fragmental intrusion. The second interval contains local visible gold and electrum, 4% finely disseminated pyrite and trace chalcopyrite within a fuchsite, silica and sericite altered rhyolite. WST-19-0137 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0139 intersected 4.08 g/t Au over 2.4 metres. The mineralization is composed of 5% disseminated pyrite with pervasive silica flooding within a moderate fuchsite, sericite and silica altered felsic intrusion. WST-19-0139 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0141 intersected four intervals: 3.91 g/t Au over 2.4 metres, 10.9 g/t Au over 2.1 metres, 18.4 g/t Au over 2.1 metres and 5.89 g/t Au over 2.2 metres. The first interval contains trace pyrite stringers within a moderate sericite altered rhyolite. The second interval contains local visible gold, 3% finely disseminated pyrite and quartz-tourmaline veins hosted in a sericite altered rhyolite. The third interval contains up to 5% finely disseminated and clustered pyrite hosted in a moderate silica altered rhyolite. The last interval is composed of 4% finely disseminated pyrite with pervasive silica flooding within a moderate sericite and silica altered rhyolite. WST-19-0141 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0142A intersected 5.92 g/t Au over 2.0 metres. The mineralization is composed of 5% disseminated pyrite and ptygmatic tourmaline veins within a strong silica altered rhyolite. WST-19-0142A was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0143 intersected three intervals: 16.1 g/t Au over 2.1 metres, 4.85 g/t Au over 2.0 metres and 3.27 g/t Au over 2.2 metres. The first interval contains local visible gold, trace pyrite clusters with pervasive silica flooding hosted in a moderate silica and sericite altered rhyolite. The second interval contain local visible gold with quartz-carbonate veins hosted in a moderate sericite altered rhyolite. The last interval contains 2% disseminated pyrite and quartz-carbonate veins hosted in a sericitized felsic fragmental intrusion. WST-19-0143 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0148 intersected four intervals: 10.5 g/t Au over 2.1 metres, 11.6 g/t Au over 2.3 metres, 59.3 g/t Au over 2.2 metres and 6.31 g/t Au over 2.4 metres. The first interval contains up to 2% pyrite stringers and ptygmatic tourmaline veins within a moderate sericite altered rhyolite. The second interval is composed of 4% disseminated, clustered, and stringer pyrite with pervasive silica flooding, quartz-tourmaline veins and trace sphalerite within a moderate sericite altered rhyolite. The third interval contains local visible gold, up to 9% disseminated and stringer pyrite and up to 3% sphalerite hosted in a strong fuchsite and silica altered rhyolite. The last interval contains up to 5% pyrite stringers and ptygmatic quartz-tourmaline veins at the contact between a felsic intrusion and a rhyolite. WST-19-0148 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

WST-19-0149 intersected 4.03 g/t Au over 2.4 metres. The mineralization is composed of up to 1% pyrite stringers and clusters, and 3% quartz-carbonate veins hosted in a weak sericite altered rhyolite. WST-19-0149 was drilled from underground drill station RE-195-265-O located 195 metres below surface from section 3475E.

WST-19-0155 intersected 5.60 g/t Au over 2.3 metres and 13.8 g/t Au over 2.0 metres. The first interval contains 3% pyrite stringers with pervasive silica flooding and quartz-carbonate veins within a strong silica altered rhyolite. The second interval contains 1% pyrite stringers within a week silica altered rhyolite. WST-19-0155 was drilled from underground drill station AN-195-265-S located 195 metres below surface from section 3500E.

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 Osisko's 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 width determination is estimated at 55-80% of the reported core length interval for the zone. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.0 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 (i) ALS Laboratories in Val d'Or, Québec, Thunder Bay, Ontario, Sudbury, Ontario or Vancouver, British Colombia, or (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using 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-d'Or and Chibougamau in the Abitibi region of Québec, Canada. The mineral resource defined by Osisko, as disclosed in the Windfall Lake Technical Report (as defined below) and November 27, 2018 Lynx resource update, comprises 2,874,000 tonnes at 8.17 g/t Au (754,000 ounces) in the indicated mineral resource category and 10,352,000 tonnes at 7.11 g/t Au (2,366,000 ounces) in the inferred mineral resource category. For details regarding the key assumptions, parameters and methods used to estimate the Mineral Resources Ltd. presented in respect of the Windfall Lake gold project, please see the technical report entitled "Technical Report and Mineral Resource Estimate for the Windfall Lake Project, Windfall Lake and Urban-Barry Properties" and dated June 12, 2018 (effective date of May 14, 2018), which has been prepared by InnovExplo Inc. from Val-d'Or, Québec (the "Windfall Lake Technical Report") and the press release “Osisko Releases Mineral Resource Update for Lynx” dated November 27, 2018, which has been prepared by Osisko and reviewed and approved by Micon International, Ltd. from Toronto, Ontario. The Windfall Lake Technical Report and press release are available on Osisko's website at www.osiskomining.com and on SEDAR under Osisko's issuer profile at www.sedar.com. The Windfall Lake gold deposit is currently one of the highest-grade resource-stage gold projects in Canada. Mineralization occurs in four principal zones: Lynx, Zone 27, Caribou and Underdog. All zones comprise sub-vertical lenses following intrusive porphyry contacts plunging to the northeast. The deposit is well defined from surface to a depth of 900 metres and remains open along strike and at depth. Mineralization has been identified 30 metres from surface in some areas and as deep as 2,000 metres in others, with significant potential to extend mineralization down-plunge and at depth.

About Osisko Mining Inc.
Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall Lake gold deposit located between Val-d'Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Quévillon area (over 2,700 square kilometres).

Cautionary Note Regarding Forward-Looking Information
This news release contains "forward-looking information" within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. The information in this news release about the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the significance of results from the new infill drilling and ongoing drill definition and expansion program at the Windfall Lake gold project; the significance of assay results presented in this news release; the deposit remaining open along strike and at depth; potential depth extensions of the mineralized zones down-plunge and at depth; the actual mineralization of local visible gold; the current 800,000 metre drill program; the type of drilling included in the drill program; 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", "management's view", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This forward-looking information is based on reasonable assumptions and estimates of management of the Corporation at the time such assumptions and estimates were made, and involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Osisko to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management's geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall 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