UPDATE 2-Peru mining unions plan to strike before election
* Workers want better benefits, smelter open
LIMA May 20 (Reuters) - Peru's federation of mining unions said Friday it plans to hold a nationwide strike starting on May 30, just days before the June 5 presidential run-off vote, to pressure the government to improve benefits.
Workers want Congress to lift caps on profit-sharing paid by companies, lower the retirement age, and find a way to reopen the vast La Oroya smelter, which has been shut for nearly two years, said Luis Castillo, the head of the federation.
"We will turn in the plans to strike to the labor ministry today (Friday) at 4 p.m.," Castillo told Reuters.
Workers at the Ucucchacua silver mine, owned by Buenaventura (BVN.N), Peru's largest precious metals miner, had agreed to the strike, union leader Segundino Romero said.
"We have approved the start of the indefinite strike because Congress has not resolved the issue of retirement for miners," said Romero. "It's unfortunate that the government does not hear our requests."
But workers at Antamina, a major copper-zinc pit, were not planning to participate, a union spokesman said.
The success of the national strike rests on the approval of local unions. The last two previous calls for a national walk-out from the federation of mining unions did not come to fruition because member unions could not agree on terms.
Miners last downed their tools in a national strike in the top metals producer in October 2009, also demanding Congress pass laws lowering the retirement age and raising salaries, but workers stayed on the job at key mines.
They can currently receive payments in profit-sharing plans each year equal to up to 18 monthly salaries. During periods of windfall profits, workers think they should be entitled to more.
The candidates in Peru's tight election, left-wing former army officer Ollanta Humala and right-wing lawmaker Keiko Fujimori, defeated three seasoned moderate politicians in the first-round vote mainly by promising to lower poverty with a better distribution of Peru's vast mineral wealth.
Both candidates support taxing the windfall profits of lucrative international mining firms to fund social programs in a country with a high 32 percent poverty rate despite one of the world's fastest economic growth rates.
Previous national strikes have slowed the production of minerals, which account for 60 percent of the country's exports. Peru is the world's No. 2 producer of silver, zinc and copper and the No. 6 gold producer.
International firms operating in Peru include Southern Copper (SCCO.N), Xstrata Copper (XTA.L) and Newmont Mining (NEM.N). The idled La Oroya smelter was run by Doe Run Peru, a unit of U.S.-based Renco Group, which the government accuses of failing to finish an environmental cleanup project.
(Reporting by Patricia Velez; Editing by Lisa Shumaker)