Copper loses two per cent on the LME COPPER has settled at its lowest price in over three months one the London Metal Exchange (LME) as concerns over China's growth and the longevity of US economic stimulus sent investors heading for the exits. LME three-month copper on Wednesday was changing hands for $US6,980 a metric ton at the close of open outcry trading - down two per cent on the day and its lowest daily settlement since August 5. Aluminium closed 0.3 per cent lower at $US1,794.50 a ton. Copper prices began sliding on Tuesday after China's Third Plenum -- a four-day meeting that set the course for the world's second-largest economy for the next 10 years -- failed to provide clear direction on policy over the coming decade. The statement that followed the meeting called for fewer investment restrictions and greater rights for farmers but was lacking in specifics. As such, expectations for economic growth in the country tend to have a bearing on prices. Concern the US Federal Reserve may start to rein in its economic stimulus measures sooner than expected also weighed on copper prices on Wednesday, said analysts and brokers. On Tuesday, Atlanta Federal Reserve President Dennis Lockhart said the Fed could start reducing stimulus in December. "There's still no firm policy from China and Fed tapering is a worry," said Rob Montefusco, a senior commodities broker at Sucden Financial. Copper's break below a key technical support level at $US7,120 a ton Tuesday set the scene for Wednesday's tumble as investors began to place bets that prices would fall further, said Montefusco. The metal's subsequent slide below its September low of $US7,030 a ton Wednesday then triggered a round of stop-loss orders -- or commands to sell at a certain level -- escalating copper's slide, he said.