* TSX rises 29.79 points, or 0.24 percent, to 12,312.15 * Gold companies Barrick, Goldcorp lead rally * Seven of 10 main sectors advance By John Tilak TORONTO, Dec 12 (Reuters) - Canada's main stock index hit a one-month high on Wednesday, led by the materials sector and higher resource prices, and supported by expectations that the U.S. Federal Reserve will announce a fresh round of bond buying to boost the economy. The Fed's anticipated move overshadowed concerns about ongoing U.S. congressional negotiations aimed at averting steep tax hikes and spending cuts due to kick in early in 2013. The U.S. central bank looked certain both to extend its purchases of mortgage-backed debt and replace another expiring stimulus program with a new bout of money creation. "Everyone is waiting to see what the Fed is going to say this afternoon. There is a general feeling that the U.S. economy is going to be okay," said David Baskin, president of Baskin Financial Services. In midmorning trading, the Toronto Stock Exchange's S&P/TSX composite index was up 29.79 points, or 0.24 percent, at 12,312.15, after earlier climbing to 12,331.53, its highest since Nov. 7. "It's the December rally. The TSX had a terrible month in November. It's a rebound from that," Baskin said. Seven of the 10 main sectors on the index advanced. Commodity prices rose, driving a rally in the materials sector, which includes mining companies. Barrick Gold Corp rose 1.4 percent to C$34.02, and Goldcorp Inc gained 1.5 percent to C$37.11. Gold prices were up about 0.5 percent. The financial sector, the index's largest, climbed 0.4 percent. Toronto Dominion Bank was up 0.6 percent at C$81.11, and Bank of Nova Scotia added 0.6 percent to C$56.81.