Local voters approved a ballot measure intended to prevent construction of the controversial Pebble gold mine in Alaska's Bristol Bay.The vote, conducted by mail among residents of the Lake and Peninsula boroughs, was 280-246, according to a release from the Pebble Mine Partnership, a pro-mine group.The mine has sparked a storm of controversy, with critics saying the proposed project, which would also produce copper, will destroy the ­surrounding salmon habitat and the long-standing salmon fishing business that goes with it.Many jewelers, including Zale, signed a pledge crafted by environmental groups that commits them to never buying Pebble gold. Tiffany & Co. even screened an anti-Pebble documentary to members of the trade in 2008.In a statement, the Pebble Partnership said that it and the state of Alaska view the initiative as unconstitutional since it covers state-owned lands, a