Dec 9 (Reuters) - London copper prices fell on Thursday on a slightly firmer U.S. dollar and signs of easing tightness in nearby supplies of the metal, while investors weighed the uncertainties surrounding the impact of the Omicron variant of the coronavirus.

Three-month copper on the London Metal Exchange was down 0.3% at $9,624.5 a tonne, as of 0800 GMT, while the most-traded January copper contract on the Shanghai Futures Exchange closed flat at 69,710 yuan a tonne.

The dollar index inched 0.1% higher, making the greenback-denominated commodity more expensive for those holding other currencies.

On-warrant LME inventories rose to 72,975 tonnes, their highest since Oct. 8. They were, however, down 69% from August high of 238,725 tonnes.

The premium for LME cash copper over the three-month contract fell to $2.30 a tonne, its lowest since Sept. 17, indicating easing tightness in nearby supplies.

This came as cancelled warrants of copper in LME warehouses , or metal earmarked for delivery, fell to 2,200 tonnes, the lowest since December 2009.

Earlier this week, customs data showed China's copper imports in November rose for a third straight month, with arrivals of copper concentrate at its highest since at least December 2007.

"Volatility in copper prices is likely to persist for a while more, but the trend is still likely to have a bullish bias due to unresolved problems in fundamentals caused by ongoing COVID situation," said Wong Min Hao, a commodities manager with Phillip Futures.

"Attention will be on any fresh news on monetary policy coming from U.S. or China, the top copper consumer, as well as new developments about the Omicron variant, which may add further uncertainty to the market," he added.

FUNDAMENTALS

* LME aluminium was up 0.1% at $2,630 a tonne, zinc edged 0.3% higher to $3,319, nickel fell 1.8% to $19,865 a tonne and lead rose 0.5% to $2,295 a tonne.

* ShFE aluminium dipped 0.5% to 18,770 yuan a tonne, zinc climbed 1.7% to 23,505 yuan a tonne, lead gained 2.9% to 15,520 yuan a tonne and tin was steady at 284,330 yuan a tonne.

* Ecuador's mining industry is threatened by legal uncertainty, the sector's guild said on Wednesday, citing a decision by the country's top court to withdraw environmental permissions for a project in a protected forest.

* China's factory-gate inflation slowed in November, driven by a government crackdown on runaway commodity prices and an easing power crunch, amid Beijing's efforts to bolster the faltering economy.

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($1 = 6.3443 Chinese yuan)

(Reporting by Eileen Soreng in Bengaluru; Editing by Subhranshu Sahu, Sherry Jacob-Phillips and Alexander Smith)