TORONTO (Reuters) - Toronto's main stock index eked out a modest gain yesterday, led by gold-mining stocks and fertilizer producer Potash Corp, but pre-Christmas trading was light and stuck to a narrow range.

Six of ten TSX groups ended higher, after the index swung between positive and negative territory. The mining-dominated materials group gained 3.14 percent and the heavyweight energy group rose 1.27 percent despite lower prices for gold and oil futures contracts.

The Toronto Stock Exchange's S&P/TSX composite index rose 62.38 points, or 0.76 percent, to close at 8,311.91.

"Some of the strength today seems to be on the commodity side, I think it may be people just bargain-hunting near year-end or redeploying some of the funds from tax-loss selling," said Michael Sprung, president of Sprung & Co Investment Cousel.

Tax-loss selling, in which investors realise losses on securities to offset capital gains taxes, must settle before the last business day of the calendar year, making today the last day for such sales to count.

"Certainly we aren't seeing the kind of radical volatility that we've been used to lately," Sprung said. "I feel like it's a bit of a respite."

Potash Corp, the world's biggest fertilizer producer, rose 4.92 percent to C$83.23, after saying late on Monday that it had repurchased 2.95 million of its common shares.

Gold-mining issues gained ground even though gold futures fell one percent to $838.10 an ounce in New York.

Barrick Gold, which named former mining executive Aaron Regent its new president and chief executive yesterday, jumped 4.16 percent to C$41.30, and Agnico-Eagle Mines rose 3.92 percent to C$56.43.

"Although oil prices haven't been helping, the bulk of the oil stocks are up," said Paul Hand, managing director at RBC Capital Markets.

Crude oil futures slipped 2.3 percent to $38.98 a barrel in New York.

Yet EnCana Corp climbed 2.1 percent to C$52.07, and Canadian Natural Resources rose 3.09 percent to C$44.00.

Trading volume is expected to remain light as investors take time off for the Christmas holidays.

"In general, there are no broad themes other than people sneaking out here and there to do a little shopping, and a lot of people probably headed home early," Hand said.