A heated competition for copper among some of the biggest commodity traders is creating opportunities for miners to negotiate favorable terms ranging from huge upfront payments to extra-long contracts. Recent moves by cash-flush energy traders including Mercuria Energy Group Ltd. to expand in metals — a market long dominated by Glencore Plc and Trafigura Group — are raising tensions and sparking a scramble for contracts, at a time when the industry is already facing an unprecedented supply squeeze in copper ore. And mining companies are seizing the moment. One producer, Eurasian Resources Group, is seeking upfront ... (full story)