BHP was struggling to find common ground with Anglo American on Tuesday in talks over its takeover offer, with no new concessions as a deadline nears for the world’s biggest miner to submit a binding offer, five sources said. Anglo granted its bigger rival a one-week extension until 1600 GMT on Wednesday to its original May 22 deadline to submit a binding offer, after rejecting a third takeover proposal that had been dismissed as difficult to execute. It agreed to hold talks with BHP to iron out contentious issues over the structure of the deal.