Iron ore sank below $100 a ton, hitting the lowest level in more than two weeks, as China’s efforts to support growth underwhelmed investors, and miners continued to ramp up operations.

Iron ore futures traded 0.7% lower at $99.95 a ton at 2:11 p.m. in Singapore, after earlier sinking as low as $99.80. In China, yuan-priced contracts in Dalian dropped, and steel futures in ...