July 31 (Reuters) - Sandfire Resources Nl SFR.AX
* Increased its ownership of high-grade black butte copper project in central Montana, USA
* Acquisition of 16.9 pct stake in North American-listed Tintina Resources Inc takes its holding in Tintina from 61.2 pct to 78.1 pct
* Purchase price for 54.6 million shares, is C$0.13 per share for a total purchase price of C$7.1 million