MELBOURNE (Reuters) -The world's biggest mining company, BHP, touted its solid copper potential and flagged the investment appeal of the United States on Monday, but was silent on the prospect of major buyouts, as top executives briefed shareholders. CEO Mike Henry and Chief Financial Officer Vandita Pant answered select questions in the first major opportunity to talk to investors since last week's blockbuster tieup of one-time target Anglo American and Teck Resources. Their answers focused on growth po ...