Outback search resumes for missing SA teen

Police will resume scouring the mines of an outback South Australian town for the body of a teenage girl missing since 1990.

Karen Williams was last seen alive in the early hours of August 4, 1990 after spending the night with friends in Coober Pedy.

She was 16 at the time.

A major search of the town's opal mines last year failed to find her body.

However, police said crucial new evidence from two witnesses has prompted them to resume the search this week.

"The information they have provided is significant to the investigation," Detective Superintendent Des Bray said on Saturday.

"In addition, we're grateful that someone has come forward with a large number of historical photos that shows the layout and buildings in the town at the time of Karen's disappearance. That has helped enormously.

Nikola Novakovich, 42, has pleaded not guilty to the teenager's murder and is awaiting trial in the South Australian Supreme Court.