* GRAPHIC-2019 asset returns: tmsnrt.rs/2jvdmXl
* Premium for cash copper over three-month contract slides (Adds Chile detail, updates prices)
By Pratima Desai
LONDON, Oct 21 (Reuters) - Copper prices rose to one-month highs on Monday as protests in major producer Chile fuelled concern about supplies and the prospect of easing trade tensions between China and the United States boosted sentiment.
Benchmark copper on the London Metal Exchange ended 0.4% up at $5,828 a tonne. Prices of the metal used in power and construction earlier touched a session high of $5,868.50.
"Some of it is a knee-jerk reaction to what's happening in Chile, but as far as we know copper production hasn't been affected," a trader said.
"Positive noises on resolving the U.S.-China standoff helped, but the market is still worried about demand, particularly in China."
CHILE: Chile is "at war" and the government will extend a state of emergency to more cities, President Sebastian Pinera said after at least seven people were killed in violent clashes and arson attacks over the weekend.
Chile's mining industry was running as normal despite the violent protests that have rocked the capital, Santiago, and other cities across the world's top copper producer, Mining Minister Baldo Prokurica said.
Union workers at BHP's Escondida copper mine will hold a day-long strike on Tuesday in a show of solidarity with protests in Chile.
TRADE: U.S. President Donald Trump thinks that a U.S.-China trade deal will be signed by the time of the Asia-Pacific Economic Cooperation meetings in Chile over Nov. 16-17.
DATA: China's property investment was buoyant in September, boosted by a rise in new construction activity, underlining hopes that resilience in the sector will help to cushion a broader slowdown in the world's second-largest economy.
"We've seen some stabilisation in Chinese data and some easing of trade tensions," said Danske Bank analyst Jens Pederson. "But metals markets haven't yet bought into the idea that prices may have bottomed."
China accounts for nearly half of global copper consumption estimated at about 24 million tonnes this year.
NICKEL: The premium for the cash over the three-month nickel contract hit $200 a tonne at the start of the month CMNI0-3. On Monday it turned to a discount as worries about supplies on the LME market receded. Traders expect stocks to rise over the coming days MNISTX-TOTAL.
Benchmark prices of the stainless steel ingredient were down 0.8% at $16,100 a tonne.
LEAD: Historically low stocks MPBSTX-TOTAL of the battery metal have helped to create a premium for cash lead over the three-month contract MPB0-3. It was last at $22 a tonne, matching the peak last week and the highest since early August.
Three-month lead rose 1.4% to $2,211 a tonne.
OTHER METALS: Aluminium slipped 0.5% to $1,729 a tonne, zinc added 0.7% to $2,473 and tin was down 1% at $16,775.
Reporting by Pratima Desai Editing by David Evans and David Goodman