Barrick said it will receive about $300 million from the sale, which is subject to customary closing conditions, including approval by Australia's Foreign Investment Review Board.
The company said the three mines that comprise the Yilgarn South assets produced a total of 452,000 ounces of gold in 2012 and a further 196,000 ounces in the first half of this year.
Kerry Smith, an analyst at Haywood Securities, said selling the higher-cost mines will reduce Barrick's operating expenses and have only a minimal impact on the company's production volumes.
"By eliminating those three mines out of their portfolio, it frees their management up to spend more time on other assets that actually make more cash," Smith said.
He estimated the mines are responsible for about five per cent of Barrick's total production.
"I'm sure they're selling them at less than they paid for them, but they've also had the assets for a long time generating cash," Smith said.
Elizabeth Collins, an analyst at Morningstar said Barrick is taking a "tiny" step towards reducing its debt burden by divesting the "troubled mines."
"They're getting rid of higher-cost mines that have low remaining reserves on a proven basis, and giving them to a company that is smaller and therefore can focus on smaller mines," Collins said.
The transaction is expected to close on Oct. 1, 2013. Proceeds will be used for general corporate purposes, including debt repayment, and will be recorded in the fourth quarter of 2013.
"The agreement to divest Yilgarn South demonstrates further progress as we work to optimize the company's portfolio and maximize free cash flow," said Barrick president and CEO Jamie Sokalsky.
"I'd like to extend my gratitude and appreciation to our Yilgarn South employees, who have made a significant contribution to Barrick over many years."
Barrick, one of the world's largest gold producers, has been taking steps to decrease operating costs by lowering capital spending and staffing levels. It has said it will trim $1.5 billion to $1.8 billion from its costs over 2013 and 2014 by cutting capital spending, including laying off staff, at its project in Argentina.
Excluding unusual items, Barrick had adjusted earnings of US$663 million or 66 cents in the quarter ended June 30 — 10 cents better than analysts had been expecting but down from 82 cents per share last year.
Barrick shares have plummeted over the past year, falling to $14.22 from a peak of $42.08 in trading on the Toronto Stock Exchange. They closed Wednesday at $19.96.