*TSX climbs 62.38 points

*Gold-mining shares jump 3.39 percent

*Potash Corp rises 4.92 percent

*Merrill Lynch sees market falling further (Adds details, comments on outlook)

By Lynne Olver

TORONTO, Dec 23 (Reuters) - Toronto's main stock index eked out a modest gain on Tuesday, led by gold-mining stocks and fertilizer producer Potash Corp (POT.TO: Quote, Profile, Research), but pre-Christmas trading was light and stuck to a narrow range.

Six of 10 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 .GSPTSE 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 yearend or redeploying some of the funds from tax-loss selling," said Michael Sprung, president of Sprung & Co Investment Counsel.