(MB) Base metals prices on the Shanghai Futures Exchange were mixed during Asian morning trading on Thursday, with lead and sister-metal zinc the only two to record significant gains, while the rest were little changed to weaker. Zinc premiums became firmer across Asia over the past week, with an open import arbitrage to China sending Shanghai premiums to nine-month highs. The Aluminum Association wants US and Chinese officials to address the issue of Beijing’s aluminium overcapacity at meetings on August 22-23 with an eye towards a long-term solution. Tin premiums were stable across the board on Tuesday August 21, with a recent swing in the metal’s London Metal Exchange cash/three-month spread having little effect on the physical market. Click here for the global tin wrap. In the battle between macro and fundamental copper price drivers, copper bears hold the strongest of all trump cards – trade war. The depreciation of the South African rand since early August has sparked a debate in the chrome ore market over whether South African suppliers should be expected to cut offers prices into China.