St Barbara Ltd. said May 31 that it slashed consolidated gold production guidance for its fiscal 2019 to about 355,000 ounces, from between 365,000 and 375,000 ounces, due to lower production volumes at the Gwalia gold mine in Western Australia.

Shares closed almost 6% lower on the ASX following the announcement.

Gwalia is now expected to produce about 220,000 ounces, compared to between 235,000 and 240,000 ounces previously expected. Meanwhile, output from the Simberi mine in Papua New Guinea is expected to hit the upper end of its guidance of between 130,000 and 135,000 ounces.

This is the second time the Australia-listed miner has revised its guidance. It cut its full-year guidance from its initial projection of between 365,000 and 385,000 ounces in April due to forecast revisions at Gwalia and Simberi.

A delay in the operation start of the mine's paste aggregate fill circuit from the December 2018 quarter to the June 2019 quarter resulted in the April reduction in Gwalia's output guidance.