SINGAPORE, July 28 (Reuters) - London copper advanced on Tuesday after U.S. Senate Republicans proposed a $1 trillion coronavirus aid package, lifting risk sentiment.

Three-month copper on the London Metal Exchange rose 0.3% to $6,436.50 a tonne by 0703 GMT, while the most-traded September copper contract on the Shanghai Futures Exchange eased 0.3% to 51,520 yuan ($7,359.89) a tonne, having climbed as much as 1.1% earlier in the session.

Positive COVID-19 vaccine developments, with Moderna Inc and Pfizer Inc launching two late-stage vaccines trials that could achieve regulatory approval and widespread use by end-2020, also supported sentiment.

Meanwhile, supervisors at Antofagasta Minerals' Centinela copper mine in top copper producing country Chile have agreed to a new contract offer, avoiding the possibility of a strike, the union president said on Monday.

"The talks about stimulus packages in the United States .. is weakening the dollar and helping metals higher. Strike or no strike (in Chile), this is about the wall of money finding a home," said commodities broker Anna Stablum at Marex Spectron.

FUNDAMENTALS

* TIN: ShFE tin jumped as much as 6.7% to 154,400 yuan a tonne, its highest since June 2018 after ShFE tin stockpiles hit their lowest since April 2017 last week.

* ALUMINIUM: U.S. aluminium premium rose to 10.2 U.S. cents a pound, the highest level since April 20.

* ZINC STOCKS: LME zinc stocks hit their highest since October 2018 at 158,825 tonnes, while lead inventories jumped to their highest since September 2018 at 117,700 tonnes.

* OTHER PRICES: LME nickel fell 1% to $13,585 a tonne and LME aluminium rose 0.2% to $1,710.50 a tonne, while ShFE nickel fell 0.6% to 108,740 yuan a tonne and ShFE lead advanced 2.3% to 15,435 yuan a tonne.

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($1 = 7.0001 yuan) (Reporting by Mai Nguyen; Editing by Vinay Dwivedi and Louise Heavens)