Sierra Nevada Gold (ASX:SNX) identified silver, gold, copper, and antimony mineralization, from drilling at its Endowment mine, part of its Blackhawk Project in Nevada, according to a Tuesday filing with the Australian bourse.

Phase 1 drilling yielded up to 4.88 meters at 481 grams per tonne grade of silver, 0.61g/t gold, 0.6% copper & 0.4% antimony from 87.78 meters, the filing said.

Shares of the mining firm plummeted 23% in recent trade.