Osisko Completes First Blast At Windfall Exploration Ramp

(Toronto, October 27, 2017) Osisko Mining Inc. (OSK:TSX “Osisko” or the “Corporation”) is pleased to announce it has completed its first underground blast on schedule at the exploration ramp at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec. 

Dewatering of the exploration ramp was completed at the end of August. Rehabilitation is on-going and is planned to be completed in the coming month. Underground infrastructure including construction of a powder magazine and various underground excavations is scheduled to be completed in December. The exploration ramp is expected to advance at a rate of approximately 200 metres per month towards the mineralized zones. Underground work, including bulk sampling (for metallurgical testing and grade confirmation) and underground exploration drilling, will commence in Q1 2018.

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.

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 underground blasts scheduled at the exploration ramp at the Windfall Lake gold project; ongoing rehabilitation efforts; the timing to complete rehabilitation efforts, if at all; the timing and ability, if at all, to complete the construction of underground infrastructure, including construction of a powder magazine and underground excavations; the expected advancement rate of the exploration ramp; the timing and ability to commence underground work (including bulk sampling and underground exploration drilling); the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada;  potential mineralization, including mineralization identified near the surface and at depth; 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 and underground work; property interests in the Windfall Lake gold project; 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