(Updates with details on performance, metal prices, peso effect)
MEXICO CITY, Oct 28 (Reuters) - Mexican mining company Penoles on Wednesday reported a third-quarter net profit of 155.6 million pesos ($9.19 million), down 86.6 percent from the same period a year earlier as a slump in the peso pushed up costs.
In the July-September period of 2014, the company posted a profit of 1.16 billion pesos.
Sales at the company rose by 11.5 percent to 17.3 billion pesos from the third quarter of 2014.
The Mexican currency fell by 25.1 percent on average against the dollar during the third quarter from the same period a year earlier, the company said. Penoles suffered an 835 million peso exchange rate loss during the July-September period, it said.
Sales costs jumped by 29.4 percent to 14.4 billion pesos, the company said. The peso's slump also pushed up the firm's net financing expenses, which almost doubled to 669 million pesos.
Penoles also had to contend with sharp declines in metals prices, with gold down 12.3 percent, silver 24.7 percent, lead 21.5 percent, zinc 20.2 percent and copper 24.9 percent from the same period a year earlier, the company said.
$1 = 16.9330 Mexican pesos at end September Reporting by Christine Murray and Tomas Sarmiento; Editing by Cynthia Osterman