Osisko Windfall Update on Discovery 1 Deep Drill Hole

Wide Zones of Anomalous Gold Intercepted As Hole Nears Interpreted Source Area

TORONTO, Dec. 10, 2019 (GLOBE NEWSWIRE) -- Osisko Mining Inc. (OSK:TSX. "Osisko" or the "Corporation") is pleased to provide an update on the Discovery 1 (OSK-W-19-1970) drill hole. Discovery 1 is a planned 3000 metre to 3500 metre deep drill hole, designed to target two down plunge extensions of known gold zones and investigate the projected source area of the Windfall deposit at depth. The working model for the Windfall deposit interprets an outer shell and centre of a possible porphyry intrusion feeding the Windfall-Lynx gold system.

Prior results from Discovery 1 included successful intersections in the targeted Underdog Zone (500 metre extension:  14.1 g/t Au over 2.1 metres), and the Triple 8 Zone (100 metre extension:  9.58 g/t Au over 7.6 metres) (see Osisko news release dated September 11, 2019).

Discovery 1 completed approximately 2275 metres before requiring a wedge at 2170 metres to drill past blocked rods.  To date, the hole has progressed to 3225 metres of the planned 3500 metres.

The drill hole has intersected several wide zones of anomalous gold mineralization between 2300 metres - 2900 metres down-hole. Analytical results below 2900 metres are pending. The newly detected anomalous gold zones range up to 116 metres in length, and occur in chlorite, sericite, and biotite altered andesites.  Wide zones of anomalous gold have similarly been observed in the proximity of Triple 8, Triple Lynx, and Lynx zones.

Osisko President and Chief Executive Officer John Burzynski commented: “Discovery 1 gave early dividends with the discovery of the Underdog and Triple 8 extensions. As we approach the main target depth, these wide intercepts of anomalous gold values are a positive indication that we may be approaching another mineralized zone. We are at the really interesting part of this hole as Discovery 1 continues its voyage to the hypothetical roots and feeder system of the Windfall deposit.”

Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Hole No.	From (m)	To (m)	Interval (m)	Au (ppb)	Host
OSK-W-19-1970-W1	2290.0	2305.0	15.0	790	Andesite
	2358.2	2360.7	2.5	4010	Felsic intrusive
	2377.0	2392.0	15.0	1340	Andesite
	2437.4	2520.6	83.2	320	Andesite
	2650.2	2670.0	19.8	750	Andesite
	2681.0	2738.0	57.0	460	Andesite
	2738.0	2740.0	2.0	7410	Felsic intrusive
	2760.0	2856.0	116.0	420	Andesite
	2879.3	2900.0	20.7	540	Andesite