Iron ore futures plummeted in Asia, with the contract in China tumbling to the lowest in three months as rising port inventories in the top user spurred concern global supplies are topping demand amid a resurgent dollar. Miners’ shares declined. Futures on the Dalian Commodity Exchange fell as much as 6.1 percent to 352 yuan ($53.78) a metric ton, the lowest since February, while the SGX AsiaClear contract for July settlement sank 4.6 percent to $46.58 a ton at 9:19 a.m. in Singapore. Miners’ shares retreated in Sydney as BHP Billiton Ltd. lost 2.2 percent, Rio Tinto Group dropped 1.9 percent and Fortescue Metals Group Ltd. fell 3.5 percent. The three are the country’s largest exporters. Iron ore has been on a wild ride in the past two months as investors sought to gauge conflicting economic signals from China against still-elevated port stockpiles and shifts in the U.S. currency. Inventories at ports have climbed above 100 million tons, offering fresh evidence of increased supplies in the world’s top user that may hurt prices. The port holdings may continue to rise, BHP forecast last week. “Stockpiles have once again broken the 100 million ton-level, indicating that supply pressure has increased significantly,” Fan Lu, an analyst at Sinosteel Futures Co., said in a note on Monday. “Mills’ margins have narrowed as steel output recovered,” suppressing demand for iron ore, she said. Iron ore with 62 percent content rose 2.7 percent to $54.89 a dry ton on Friday, according to Metal Bulletin Ltd. Prices have tumbled 22 percent since peaking at more than $70 a ton in April. The dollar has surged this month, hurting commodities priced in the U.S. currency, as several Federal Reserve policy makers signaled their willingness to raise interest rates further this year, possibly as soon as next month. The Bloomberg Dollar Spot Index rose for the past three weeks in its longest run of gains since January.