Gold mining company St Barbara (ASX:SBM) is set to raise AU$100 million via the placement of about 263 million shares priced at AU$0.38 apiece, according to a Tuesday filing with the Australian bourse.

In tranche one, 87.3 million shares will be issued, while the remaining 175.9 million shares will be issued in tranche two, subject to shareholder approval, the filing said.

The company will also offer eligible shareholders on the register as of Monday the opportunity to participate in a share purchase plan for up to AU$30,000 worth of shares at AU$0.38 apiece, capped at AU$10 million.

Proceeds will be used to advance the development of the Simberi Sulfide Expansion project in Papua New Guinea, according to the filing.

Shares fell almost 22% in morning trade Tuesday.

Price (AUD): $0.36, Change: $-0.10, Percent Change: -21.74%