Petratherm (ASX:PTR) encountered a heavy mineral sand discovery during a recent drill program at the Rosewood prospect in South Australia, according to a Wednesday filing with the Australian bourse.

The program yielded up to 22 meters at over 19% heavy minerals from 8 meters, including 4 meters at about 28% heavy minerals from 9 meters, and 1 meter at nearly 40% heavy minerals from 11 meters.

Petratherm's shares surged past 73% in recent Wednesday trade and earlier reached their highest since August 2013.

Price (AUD): $0.36, Change: $+0.15, Percent Change: +73.17%