BEIJING, March 27 (Reuters) - Most base metals gained ground on Wednesday, with Shanghai zinc touching a more than one-year high, as investors focused on tight inventories and the resumption of U.S.-China trade talks. The U.S. Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin are expected to arrive in Beijing later on Wednesday for talks aimed at resolving a long-running trade row that has weighed on metals prices. With London Metal Exchange zinc stocks falling to their lowest 28 years, the metal used to galvanise steel jumped 1.5 percent in London on Tuesday and prices in top zinc user China are also buoyant. Current zinc ingot inventories are "extremely low" and the next two-three months will see "intense destocking" as consumption in China recovers, Jinrui Futures said in a note. FUNDAMENTALS * SHANGHAI ZINC: The most traded May zinc contract on the Shanghai Futures Exchange rose as much as 2.1 percent to 22,450 yuan ($3,344.46) a tonne, its highest since March 7, 2018, and stood at 22,240 yuan a tonne at the end of the morning. Three-month zinc in London slipped 0.5 percent to $2,860 by 0450 GMT. * OPEN INTEREST: Market open interest in Shanghai zinc jumped to 632,310 lots of Tuesday, the highest since July 2017, pointing to greater bullishness. * ZINC SPREADS: The premium of cash LME zinc over the three-month contract stood at $47 a tonne on Tuesday, up $10.50 from Monday, indicating tighter near-term supply. * STOCKS: At 56,425 tonnes, LME zinc stocks are at their lowest since 1991, while copper inventories have fallen for seven straight days to 172,275 tonnes after spiking in the middle of the month. * OTHER METALS: Nickel, used to make stainless steel, added 1.5 percent in Shanghai to 101,040 yuan a tonne, while Shanghai copper nudged up 0.3 percent to 48,400 yuan a tonne. In London, copper also rose 0.3 percent to $6,349 while aluminium added 0.6 percent to $1,899.50. * COPPER: Polish miner KGHM and a union representing workers at its Sierra Gorda copper mine in Chile have agreed to extend contract talks, temporarily warding off the threat of a strike. * ALUNORTE: Norsk Hydro has agreed with Brazil's federal prosecutor to have a third-party technical assessment that, if positive, could lead to it resuming full production at the half-shut Alunorte alumina refinery.