LONDON, Aug 8 (Reuters) – Copper ended mostly unchanged on Wednesday as the United States geared up to begin collecting tariffs on a further $16 billion of Chinese goods later this month but a weaker dollar stemmed losses. Benchmark copper on the London Metal Exchange slipped 0.1 percent to $6,168 per tonne in final open outcry trading. The metal used in power and construction rose 0.6 percent in the previous session on short-covering and optimism that China will prop up its economy with stimulus measures. News of the looming tarfiffs overshadowed data showing exports from top metals consumer China surged more than expected in July despite U.S. duties. “Copper is still a metal that is suffering under the trade conflict between the U.S. and China,” said Quantitative Commodity Research consultant Peter Fertig. „Any new message in this trade conflict which is not pointing towards de-escalation has a negative impact on risky assets including commodities and base metals,” he said, adding that support for the metal was near $6,000 per tonne.

CHINA COPPER: China’s imports of copper concentrate rose to an all-time high last month as Chinese smelters ramped up purchases to feed their growing capacity and take advantage of high processing charges.

CHINA ALUMINIUM: China’s aluminium exports rose to their second-highest level on record in July, as a weaker yuan and a still-favourable price arbitrage to international markets outweighed the imposition of U.S. import tariffs and growing trade tensions.

ALUMINIUM JUMPS: Aluminium jumped more than 3 percent to a two-week high of $2,113.50 per tonne, in a flurry of activity in afternoon trade that saw volumes double within a couple hours, one trader said.

The metal closed at $2,106 per tonne.

“Aluminium was held down by fund selling and now that has turned around,” another trader said, adding the softer dollar had helped the metal push higher.

DOLLAR: A weaker greenback makes dollar-denominated commodities cheaper for non-U.S. firms, a relationship used by funds to generate buy and sell signals.

ESCONDIDA: The union at Chile’s Escondida copper mine, the world’s largest, said BHP must alter its negotiating strategy and improve its contract offer during the final phase of talks if it hoped to avoid a strike.

ALUMINIUM STOCKS: On-warrant stocks of aluminium available to the market in LME-registered warehouses touched their lowest since August 2007 at 833,075 tonnes. MALSTX-TOTAL

Stocks monitored by the Shanghai Futures Exchange are down 8 percent to 905,924 tonnes from this year’s peak but still up over 20 percent in 2018.

ALCOA WALKOUT: Alcoa workers in Western Australia have walked out indefinitely over an enterprise agreement dispute with the aluminium maker, the Australian Workers’ Union said.