LIMA, April 10 (Reuters) - Peru's largest mining union on Friday approved an indefinite strike beginning on May 18 to demand better working conditions for workers, a union boss said.
Ricardo Juarez, president of the national mining workers federation, said some 70 unions representing 20,000 miners backed the strike, which would be the first nationwide walkout to hit the industry in the world's No. 3 copper producer this year.
"The miners are tired of abuse. We want better conditions," Juarez said, adding that the unions' demands included lifting a cap on the workers' share of company profits.
They were also seeking stricter regulation of the outsourcing mining-related services to companies outside of the industry.
The strike threat puts more pressure on mining companies operating in Peru, which is also the world's third biggest zinc producer, who are grappling with low international metal prices.
Juarez said there was also support for industrial action from some unions within the petroleum sector as well as port workers. (Reporting by Teresa Cespedes; Writin by Richard Lough; Editing by Robert Birsel)