In 2014, Osisko Mining was subject to a hostile takeover bid by Goldcorp but an alternative bid by white knights Yamana Gold and Agnico Eagle Mines Limited was accepted that, in addition to offering a higher price, created the spin-off Osisko Gold Royalties and turned Osisko Mining Corporation into the subsidiary company Canadian Malartic Corporation jointly owned by Yamana Gold and Agnico Eagle.

The company acquired an interest in the Canadian Malartic property in 2004 and after promising feasibility studies the mine was constructed with commercial production achieved in May 2011.

In August 2010 a superior court judge awarded the property to Osisko Mining Corporation after determining it was an obstacle for important preparation work at the project.

[3] The Malartic mine reached commercial production in May/June 2011 after processing averaged 33,300 tonnes (32,800 long tons) per day in the four weeks ended June 17, 2011.

As favourable exploration, feasibility and economic assessment results came in, re-development of the Malartic mine became the focus of the company.

[13][14][15][16] Later that year in December, in a joint venture with Clifton Star Resources Osisko acquired Quebec's Duparquet mining project, an area that produced 1 million troy ounces (69,000 lb; 31,000 kg) of gold between 1931 and 1957, when it was operated by Beattie Gold Mine.

[23][24][25][26] If all regulatory approvals are met, the mine was expected to open in 2015 when it would be capable of producing 463,000 troy ounces (14,400 kg) of gold annually.

[27] By March 2011 It owns at least 17.41 million troy ounces (1,194,000 lb; 542,000 kg) of gold reserves (including 10.71 in malartic and 6.7 at Hammond Reef, malartic reserves up 20% due to higher gold prices)[28][29] and over 230 square kilometres (89 sq mi) of land in the Malartic-Cadillac area.

The Dunn property is located 35 kilometres (22 mi) NE of Rouyn-Noranda, Quebec; it involves 1,990 hectares (4,900 acres) of land in Clericy and La Pause and ownership is shared with Midland Exploration, a tsx venture exchange listed exploration company focused on mining opportunities in Quebec.

The stake in the Mount Joy property in Timmins, Ontario is minor however, it has the option of becoming majority owner (up to 70%) by incurring project expenditures of 4-5 million dollars total in installments made on specific dates, by delivering a bankable feasibility study, and by securing additional financing.

The project, which covers 1,500 hectares (3,700 acres) of land, is controlled by Claim Post Resources, a company that in which Osisko owns stock.

[34] On March 21, 2011, Osisko finalized an agreement with Sparton Resources to acquire 60-70% of a gold property 7,500 hectares (19,000 acres) in area, in Atikokan, Ontario.