Southern Copper Corp., the largest producer of the metal in Peru and Mexico, fell for a third day in four as earnings failed to meet investor expectations and the company postponed the startup of a copper mine.

Southern Copper, a unit of Grupo Mexico SAB, declined 0.5 percent to $34.80 at 12:41 p.m. in Lima after earlier falling as much as 1.4 percent.

“The earnings report wasn’t as favorable as the market had hoped,” said Leoncio Altamirano, a trader at Lima-based brokerage Juan Magot y Asociados SAB. “Investors also feel the company won’t recover what they invested in the stalled Tia Maria project.”

Southern said fourth-quarter net income climbed 9 percent to $537 million, or 64 cents a share, from $492 million, or 58 cents, in the year-earlier period. Analysts expected a profit of 70.4 cents a share, according to data compiled by Bloomberg.

A drop in copper prices offset a 24 percent gain in Southern’s output. Average copper prices fell 13 percent in the quarter from a year earlier on investor concern the slowing global economy and escalating European debt crisis will pare Chinese demand.

The company today delayed the startup of its $900 million Tia Maria mine in Peru to 2015 as the company prepares a new environmental impact study for the project, suspended last year by environmental protests.