(Montreal, April 22
2014) Osisko
Mining Corporation (the “Company” or “Osisko”) (OSK: TSX, EWX: Deutsche Boerse)
today announced that it has filed with the Canadian securities regulatory
authorities a notice of change to the directors’ circular (the “Notice of
Change”) in response to the Revised Goldcorp Offer (as defined herein).
The Notice of Change updates information contained in the directors’ circular
dated January 24, 2014 (the “Directors’ Circular”) issued by the
board of directors of Osisko (the “Osisko Board”) in connection with
the unsolicited proposal of Goldcorp Inc. (“Goldcorp”) dated January
14, 2014 to acquire all of the common shares of Osisko (the “Osisko
Shares”), as varied by the notice of extension dated February 18, 2014,
the notice of extension dated March 10, 2014, the notice of extension dated
March 21, 2014, the notice of extension dated April 3, 2014 and the notice of
extension and variation dated April 10, 2014 (the “Revised Goldcorp Offer“).
The Notice of Change will be mailed to Osisko’s shareholders and is currently
available under Osisko’s profile on SEDAR at www.sedar.com.

The Osisko Board has
thoroughly reviewed and considered the Revised Goldcorp Offer and the report
and recommendation of the special committee comprised of five independent
directors (the “Special Committee”) and has received advice from its
financial and legal advisors. Based upon the report of the Special Committee,
advice from each of BMO Capital Markets and Maxit Capital LP, and after
consultation with its legal advisors, the Osisko Board unanimously recommends
that Osisko’s shareholders reject the
Revised Goldcorp Offer and
not tender their Osisko Shares to the Revised Goldcorp
Offer. The Revised Goldcorp Offer is conditional and currently scheduled to
expire at 11:59 p.m. (Toronto time) on April 22, 2014.

The agreement (the “Agreement”)
announced on April 16, 2014 with Agnico Eagle Mines Limited (“Agnico Eagle”)
(TSX:AEM; NYSE:AEM) and Yamana Gold Inc. (“Yamana”) (TSX:YRI; NYSE:AUY)
provides superior value to Osisko’s shareholders. Additional details of the
Agreement will be described in a management information circular with respect
to the Arrangement (as defined herein). Osisko’s shareholders and optionholders
will be asked to consider and, if deemed advisable, to pass, with or without
variation, a special resolution authorizing and approving the Agreement
involving Osisko, Agnico Eagle and Yamana by way of a plan of arrangement (the
“Arrangement”).

About
Osisko Mining Corporation

Osisko
Mining Corporation operates the Canadian Malartic Gold Mine in Malartic, Québec
and is pursuing exploration on a number of properties, notably in Québec,
Ontario and Mexico.

Forward-Looking
Statements

Certain
statements contained in this press release may be deemed “forward-looking
statements”. All statements in this release, other than statements of
historical fact, that address events or developments that the Corporation
expects to occur, are forward looking statements. Forward looking statements
are statements that are not historical facts and are generally, but not always,
identified by the words “expects”, “plans”,
“anticipates”, “believes”, “intends”,
“estimates”, “projects”, “potential”,
“scheduled” and similar expressions, or that events or conditions
“will”, “would”, “may”, “could” or
“should” occur including, without limitation, the satisfaction of all
technical, economical, regulatory and financial conditions in order to complete
the Arrangement between Osisko, Agnico Eagle and Yamana, and the view on (i)
the value and the potential of this Arrangement for Osisko shareholders and (ii)
the value of the Goldcorp common shares and Revised Goldcorp Offer. Although
the Corporation believes the expectations expressed in such forward-looking
statements are based on reasonable assumptions, such statements are not
guarantees of future performance and actual results may differ materially from
those in forward looking statements. Factors that could cause the actual
results to differ materially from those in forward-looking statements include
gold prices, results of exploration and development activities, the
Corporation’s limited experience with production and development stage mining
operations, uninsured risks, regulatory changes or sanctions, defects in
titles, availability of personnel, materials and equipment, timeliness of
government approvals, actual performance of facilities, equipment and processes
relative to specifications and expectations, unanticipated environmental
impacts on operations market prices, continued availability of capital and
financing and general economic, market or business conditions. These factors
are discussed in greater detail in the Corporation’s most recent Annual
Information Form filed on SEDAR, which also provides additional general
assumptions in connection with these statements. The Corporation cautions that the
foregoing list of important factors is not exhaustive. Investors and others who
base themselves on the Corporation’s forward-looking statements should
carefully consider the above factors as well as the uncertainties they
represent and the risk they entail. The Corporation believes that the
expectations reflected in those forward-looking statements are reasonable, but
no assurance can be given that these expectations will prove to be correct and
such forward-looking statements included in this press release should not be
unduly relied upon. These statements speak only as of the date of this press
release.