** Shares of PTR Minerals PTR.AX fall as much as 5.7% to A$0.25, their lowest level since May 5

** Mineral exploration co receives firm commitments to raise A$12 million ($7.85 million) via placement

** Issue price of A$0.25 represents a discount of 5.7% to co's last close

** Proceeds raised will be used primarily to progress the next stage of study work at the Rosewood Titanium Project, others

** 455,932 shares change hands, 2.3 times the 30-day average

** YTD, stock down 16.4%, including the day's moves

($1 = 1.5293 Australian dollars)

(Reporting by Sherin Sunny in Bengaluru)

((Sherin.Sunny@thomsonreuters.com))