METALS-Copper eases as investors cash in on strong week

* Zinc, nickel slip back from multi-year peaks

* LME/ShFE arb: http://bit.ly/2wZSAEz

* GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Releads, adds comment, updates with official prices)

LONDON, Feb 15 (Reuters) - Copper eased on Thursday and zinc and nickel pulled back from multi-year peaks as investors opted to cash in gains in this week's best performing metals in the face of a rally in other assets such as stocks.

Copper, chiefly used in construction, is still on track for its biggest weekly gain since November 2016, up nearly 6 percent so far on the back of optimism over global growth and dollar weakness, which benefits assets priced in the currency.

"Given that some prices have reached multi-year highs, (traders) are taking the opportunity to cash in and that is weighing on prices, especially in an environment with somewhat lower liquidity due to the absence of the Chinese traders," Commerzbank analyst Daniel Briesemann said.

Stocks and bond yields steamed higher as the dollar tumbled, as investors suddenly seemed to forget the inflation fears blamed for a brutal market sell-off in recent weeks.

The dollar slipped sharply on Wednesday after stronger than expected inflation and a weak retail sales report, and extended losses on Thursday to slide back towards last month's three-year low.

* COPPER PRICES: London Metal Exchange copper was down 0.4 percent in official midday trading at $7,133 a tonne.

* COPPER SUPPLY: Chilean mining company Antofagasta received environmental approval for a major $1.1 billion revamp of its Los Pelambres copper mine, the regional government of Coquimbo said on Wednesday.

* ZINC: Zinc was untraded in midday rings, but was last bid at $3,560 a tonne, down 0.2 percent. It hit its highest since July 2007 in earlier trade at $3,595.50 a tonne.

* ZINC SPREADS: The premium for cash over three-month zinc <CMZN0-3> slipped to $23.50 a tonne from a three-month high of $55.50 at the end of January, suggesting near-term tightness in the market is easing.

* NICKEL: LME nickel was also untraded in official rings. It was last bid at $14,180 a tonne, up 0.6 percent but off an earlier peak of $14,420 a tonne, its highest since May 2015. The metal, used in stainless steel, is set to be supported by strong Chinese demand and supply tightness.

* ALUMINIUM STOCKS: LME aluminium stocks <MALSTX-TOTAL> stocks rose by 31,275 tonnes, adding to Tuesday's 158,925-tonne increase. Stocks have climbed 187,250 tonnes so far this week, on track for their biggest weekly gain since May 2009.

* ALUMINIUM PRICES: Aluminium, also untraded in official rings, was last bid down 0.6 percent at $2,164 a tonne.

* CHINA HOLIDAY: The Shanghai Futures Exchange is closed from the evening session on Wednesday until Feb. 22, reducing trading activity and increasing price volatility.

* OTHER METALS: The other metals were also untraded in official midday rings. LME lead was last bid up 0.7 percent at $2,596 a tonne, while tin was last 0.2 percent lower at $21,500 a tonne.

(Additional reporting by Melanie Burton in Melbourne; Editing by Matthew Mpoke Bigg)