DAKAR (Reuters) -Niger's main mine workers' union has thrown its support behind the military government's planned nationalisation of Somair, one of the world's largest uranium mines, saying output will continue, despite tensions with French operator Orano. Niger, which seized the Somair mine in December, announced its plan to nationalise it last week, accusing Orano of taking a disproportionate share of production. French state-owned Orano did not respond to a request for comment on the allegations that it has taken more than its fair share.