MONTREAL – Yamana Gold Inc. (TSX:YRI) has signed a deal to buy a 50 per cent share in Osisko’s mining and exploration assets in a stock-and-cash deal that values the gold miner at about $3.4 billion.

Montreal-based Osisko Mining Corp (TSX:OSK) has been fighting a hostile takeover attempt by Vancouver-based Goldcorp (TSX:G), which is one of Canada’s largest gold producers.

Under the agreement, Toronto-based Yamana will become an equal partner in all of Osisko’s mining and exploration assets including the Canadian Malartic gold mine in Quebec.

Osisko will continue to operate Canadian Malartic and all other projects under the guidance of a joint operating committee.

Its shareholders will receive $2.194 in cash, 0.2119 of a Yamana share and a new share of Osisko, which will continue to hold a 50 per cent stake in its assets.

Osisko valued the offer at $7.60 per share at the time of the announcement. Its shares gained 58 cents or 8.4 per cent to $7.46 on the Toronto Stock Exchange after the market opened.

The deal will require approval by a two-thirds majority vote by Osisko shareholders and optionholders.

Osisko also says it has signed a deal with the CPP Investment Board for an increase under its existing credit facility and with the Caisse de depot et placement du Quebec for the sale of a gold stream of 37,500 ounces per year from its Canadian Malartic mine.

Goldcorp has offered Osisko shareholders 0.146 of a Goldcorp share plus $2.26 in cash for each Osisko share.