Gold bars
National Mining Corporation (NMiC), one of Ethiopia's mining companies, last week announced the discovery of a 568,000kg worth gold reserve in the African country's Oromia and Tigray regional states. The two regions reportedly hold the country's largest gold reserves, according to geological data from Ethiopia's Ministry of Mines. Lisi Niesner/Reuters

Falling copper prices and labor strife at some mines cut Freeport-McMoRan Copper & Gold Inc.'s third-quarter results by 11 percent.

Net income for the three months ended Sept. 30 fell to $1.05 billion, or $1.10 per share, compared to $1.18 billion, or $1.24 per share, in the year-earlier period.

Gold production fell to 385,000 ounces from 492 ounces, and gold sales fell to 409,000 ounces from 497,000 ounces in the previous year's third quarter.

Revenue rose to $5.2 billion from $5.15 billion, the U.S. mining company said.

The near-term economic outlook is uncertain and has resulted in a decline in copper prices over the last several weeks, James R. Moffett, CEO, said in a statement.

As we address union labor issues at our mines, our strategy continues to focus on effective execution of our operating plans, aggressive cost management and investing in projects with attractive rates of return to enhance our global portfolio of large-scale, long-lived and high-quality assets.

Shares rose 52 cents to $35.90 in midday trading.