With a big international trade agreement in play, a member of Maine’s congressional delegation met with US Trade Representative Ron Kirk in Norridgewock to visit that town’s New Balance shoe plant. US Representative Mike Michaud, a Democrat, visited the plant with Kirk Thursday so they could learn more about the company’s concerns as Kirk’s office helps negotiate the proposed Trans-Pacific Partnership Agreement with several other nations that border the Pacific Ocean. Senators Olympia Snowe and Susan Collins could not attend because of their Senate schedules. New Balance is currently the only athletic shoe company manufacturing in the United States, with 25 percent of its footwear shipments produced at five New England facilities.