METALS-Shanghai copper hits 3-month high on supply concerns

(Adds analyst comment, updates prices) BEIJING, June 6 (Reuters) - Shanghai base metals rose on Wednesday, with copper and lead gaining ground on fears of a supply squeeze, while nickel and zinc tracked the ferrous complex higher after a blast at an iron ore mine in China and amid falling inventories. The most-traded July copper contract on the Shanghai Futures Exchange rose for a fourth straight session, climbing as much as 1.8 percent to 53,020 yuan a tonne, its highest since March 7,