http://www.ft.com/cms/s/0/cce85326-6af9-11de-861d-00144feabdc0.html

Four employees of Rio Tinto, the Anglo-Australian mining group, have been detained in China without explanation, raising tensions as the company is locked in tough negotiations over iron ore prices.

detain 【法】〈人を〉留置[拘留，監禁]する

iron ore 鉄鉱石