Mining company Freeport-McMoRan Copper & Gold Inc. on Monday lowered second-quarter guidance for its copper production, hurt by high clay content found in a section of a mine.

The company said it expects to mine about 235 million pounds of copper and 275,000 ounces of gold in the second quarter. Previously, the company said it expected to mine 280 million pounds of copper. Gold guidance remains unchanged.

The shortfall is due to a section of a mine with abnormally high clay content, which has hurt ore flow, mill recoveries and concentrate grades, the company said.

The company said it was taking steps to offset the shortfall such as blending the material found in the high clay-content mine with ore from other sections of the mine.