UPDATE 1-Rainy River ups 2010 exploration budget by 33 pct

* Raises budget by C$6.1 mln to C$24.8 mln for 2010

* To spend C$3 mln on its JV with Northern Superior Resources

Aug 19 (Reuters) - Rainy River Resources Ltd RR.V raised its exploration budget for 2010 by about 33 percent to C$24.8 million as the Canadian gold miner continues to see higher mineral grades at its flagship project in Northern Ontario.

The company, which is considering both underground and open-pit mining options for its Rainy River gold project, said the increased budget will help it extend its drilling activities to 90,000 metres by end of the year from present 53,000 metres.

The stepped up exploration program will provide detailed information to determine the best and most value accretive development approach for the project, it said in a statement.

In addition, the company will be spending C$3 million on its joint venture with Northern Superior Resources Inc (SUP.V) in Northern Ontario, it added.

Shares of the Toronto, Ontario-based company have fallen over 10 percent after hitting a 52-week high of C$6.85 in June.

They were up 10 Canadian cents at C$6.25 Thursday morning on the Toronto Stock Exchange. (Reporting by Ashutosh Joshi in Bangalore; Editing by Prem Udayabhanu)