Aug. 5 (Bloomberg) --Minmetals Resources Ltd. (1208), a unit of China’s largest metals trader, said zinc production fell 13 percent in the second quarter because of lower grades at the Golden Grove mine in Western Australia.

Concentrate production was 156,475 metric tons, compared with 178,979 tons a year earlier, the Hong Kong-based company said today in a statement.

The price of zinc, used to galvanize steel, has gained 9 percent from this year’s low in May. Minmetals cut its zinc production forecast for 2011 from the Golden Grove mine, it’s second largest, by as much as 20 percent.

Output from the mine may be between 70,000 and 77,000 tons this year, it said today. It had earlier forecast production would be between 83,000 and 87,000 tons.

Production at its Century operation, Australia’s largest open pit zinc mine, gained 5 percent from a year earlier in the quarter to 128,388 tons. Lead concentrate output fell 4 percent to 16,273 tons and gold declined to 23,025 ounces from 31,481 ounces. Copper concentrate production more than doubled to 5,754 tons after it resumed mining at the Scuddles deposit at Golden Grove.