SHANGHAI, Sept. 20 (SMM) –As LME copper prices slumped nearly 4% on the previous trading day, SHFE 1112 copper contract prices, the most active one, opened down RMB 670/mt at RMB 63,200/mt on Tuesday. After the opening, short investors tried again to dampen copper prices by increasing positions. In this context, SHFE three-month copper contract prices posted weak performance, with prices moving lower after a down open and setting a yearly low of RMB 62,480/mt. However, as some long investors began to come into the market after prices falling below RMB 62,500/mt, and since LME copper prices stopped falling and Chinese stock markets rebounded slightly, the moving band of SHFE three-month copper contract prices immediately returned above RMB 62,500/mt, and narrowly fluctuated around RMB 62,700/mt in the afternoon business. Position closings at the tail of trading helped copper prices break the resistance at the daily moving average. Finally, SHFE 1112 copper contract prices closed at RMB 62,960/mt, down RMB 910/mt or a loss of 1.42%. Positions for SHFE 1112 copper contracts were up 4,770 lots, and trading volumes were up 39,178 lots. Short investors reported great profits during the whole trading day, but their willingness in keeping up with falling copper prices weakened. Markets were awaiting the US Federal Reserve meeting to be held on the evening of September 20th.