* Expands size of gold reserves and resources in Quebec
* Says expanded resource base will impact its mine plan
* Sees 2011, 2012 output below prior projected levels (Figures in U.S. dollars, unless noted)
TORONTO, March 31 (Reuters) - Osisko Mining OSK.TO said on Thursday it has expanded the size of its gold reserves and resources at its flagship Canadian Malartic gold deposit in Quebec.
But the company warned that projected production for 2011 and 2012 may be less than previously projected, as the increased reserves will impact its existing mine plan.
Montreal, Quebec-based Osisko said the proven and probable reserves at the open pit rose nearly 20 percent to 10.71 million ounces, while measured and indicated resources rose 5.4 percent to 11.8 million ounces.
The increased estimate is based on additional drill results and is calculated using a gold price of $1,000 an ounce.
The nearly $1 billion project is due to begin production in the second quarter. Osisko had forecast 688,000 ounces of gold production in 2012.
The new mine plan will be modified to include new ounces defined in lower grade zones that need to be included in the 2011 and 2012 mining schedule, said Osisko.
Osisko also said that noise level restrictions currently restrain it from being able to ramp up the mine to its full production capacity.
The company said it continues to implement noise reduction measures and is working to resolve noise level issues with the Quebec government to allow production ramp-up to full capacity by the third-quarter of 2011.
Osisko said details on updated costs, mine plan, production schedules and mine life will be provided in the coming quarter. ($1=$0.97 Canadian) (Reporting by Euan Rocha, editing by Dave Zimmerman)