Miners, Ashtead support UK shares; AstraZeneca gains

(Reuters) - London's FTSE 100 edged higher on Tuesday with tool hire firm Ashtead gaining after an upbeat earnings report and miners boosted by a rise in copper prices driven by expectations of a global shortfall in production.The miner-heavy main index was up 0.1% while the FTSE 250 midcap index lost 0.2% by 0708 GMT.Ashtead rose nearly 3%, topping the FTSE 100 leader-board, while miners were up 1% as a key mine in Chile halved output due to a strike.Drugmaker AstraZeneca was the biggest boost..