(Updates at market close) By Utkarsh Hathi and Fergal Smith TORONTO, Oct 22 (Reuters) - Canada's main stock index pulled back from a four-week high on Thursday as a drop in gold and copper prices weighed on metal mining stocks, while technology fell on renewed concerns over AI spending. The S&P/TSX Composite Index ended down 351.54 points, or 1%, at 35,973.45. It posted on Wednesday its highest closing level since September 22 after Canada unveiled a multi-billion support package for sectors hit hard by US tariffs.