Residents of an Andean town that is home to a U.S.-owned metallurgical plant are stepping up pressure on the Peruvian government to grant an extension for completing environmental upgrades at the facility, the town's mayor said Thursday...Clemente Quincho, the mayor of smoke-choked La Oroya,...where St. Louis-based Doe Run Co. [part of Renco] operates a metallurgical plant...said the protest...also is directed at a consortium of grass roots groups, environmentalists and other non-governmental organizations that have lobbied against the company...