From http://www.mint.ca/royalcanadianmintpublic/index.aspx?requestedPath=/en-CA/Home/default.htm:
On January 2, 1908 as an audience of dignitaries looked on, Governor General Earl Grey activated the press to strike a fifty-cent piece, the Dominion's first domestically produced coin. A few moments later, the Countess Grey closed the ceremony by striking Canada's first bronze cent.
In 1931 the heritage building on Sussex Drive, the surrounding land and the entire minting enterprise passed into Canadian hands, making the Mint a wholly Canadian institution.