By Mike Yamamoto of OptionMonsterNEW YORK -- The bulls are piling into Rio Tinto ahead of its earnings report in two weeks. More than 7,000 September 60 calls traded for 90 cents to $1.15 on Thursday, according to OptionMonster's tracking system. These are new positions, as open interest in the strike was just 72 contracts before the trades appeared. These long calls lock in the price where the stock can be purchased through mid-September no matter how far it might climb.