Shares of Barrick Gold Corporation (NYSE:ABX) plunged Thursday after the world's largest gold producer cut its production outlook and increased its forecast operating costs as it reported a weaker-than-expected third-quarter profit.

The latest report by the Toronto-based company, which trimmed its estimated range of 2012 gold production from 7.3 million ounces to 7.8 million ounces to a range of 7.3 million ounces to 7.5 million ounces, marks its fourth-straight earnings disappointment as the cost of operating rises more quickly than the price of gold.


Barrick also increased its estimate of total cash costs for gold production from an earlier range of $550 to $575 per ounce to a current expected range of $550 to $575 per ounce, largely as a result of increased expenses from the Australia-Pacific region and from its African Barrick Gold affililate.


In the July to September period, Barrick reported net profit of $620 million, or 62 cents per share, compared with $1.37 billion in net profit, or 85 cents per share, in the year-earlier period. Excluding one-time events, earnings per share were 85 cents compared with $1.38 in the third quarter of 2011. Revenue fell to $3.44 billion from $3.97 billion.


Analysts polled by Bloomberg News expected, on average, 99 cents per share profit on revenue of $3.65 billion.


Shares slumped $2.62, or 6.47 percent, to $37.86 in morning trading.