SHANGHAI, Jun. 14 (SMM) – SMM's survey found that the average operating rate at China's scrap copper smelters inched down to 49.8% in May. The long-unfavorable SHFE/LME copper price ratio created losses for those trading in scrap copper, especially in high-quality material. This led directly to a tight market for high-quality scrap copper and sourcing difficulties for scrap copper smelters. The price spread between scrap and refined copper narrowed further during May, leaving scrap copper smelters nearly no margin for profit, forcing more SME smelters to cut production. Larger scrap copper smelters, however, were able to maintain stable production last month on the strength of their larger raw material stocks.