Rio Tinto (RIO.AX) rejected a merger approach from smaller rival Glencore Plc (GLEN.L) to create a $160 billion mining and trading giant in August just as the price of its most profitable product, iron ore, slid toward a five-year low. The miner said on Tuesday Glencore had contacted it about a potential merger in July, adding that it turned Glencore down in August and there had been no further contact between the companies on a deal. A merger would have created the world’s biggest miner, supplanting BHP Billiton (BHP.AX).