LONDON (Reuters) – The London Metal Exchange will not restart the trading of nickel contracts on Friday as it had anticipated because the criteria for restarting have not been met, the exchange said in a members notice on Thursday. LME was forced to halt nickel trading and cancel trades after prices soared over $100,000 per tonne on Tuesday in a surge blamed on short covering by one of the world’s top producers. “In relation to netting off long and short positions, the initial responses indicated limited potential uptake, particularly from those with short positions, and considerable differenc…