Ханган нийлүүлэгчид –
Rio sounds copper warning from Mongolian steppe. HONG KONG (Reuters Breakingviews) – Rio Tinto has sounded a copper warning from the Mongolian steppe. The $104 billion mining giant says its flagship Oyu Tolgoi expansion in the country's south will be up to 30 months late, and could cost as much as a third more than planned.