** Shares of Sunstone Metals STM.AX drop as much as 13.6% to A$0.019, their lowest level since mid-November

** Mineral explorer to raise A$8 million ($5.31 million) through placement

** Offer price of 1.9 Australian cents per share represents a 13.6% discount, as of last trading close

** Placement to fund scoping study on the Bramaderos Gold-Copper Project in Ecuador

** Stock has risen ~178.7% this year, including session's moves

($1 = 1.5053 Australian dollars)

(Reporting by Aamir Sheik Khalid in Bengaluru)

((Aamir.SheikKhalid@thomsonreuters.com))