By Reuters Staff2 Min ReadFILE PHOTO: A Zimbabwean miner works underground at Metallon Gold mine in Shamva, about 80 km( 50 miles) north of the capital Hararre, June 14, 2011.... REUTERS/ Philimon Bulawayo HARARE( Reuters)-Zimbabwe’s central bank will allow large-scale gold mining companies to directly export a portion of their bullion, an official said, as the bank gradually eases its control of gold trading in the country. The central bank-owned Fidelity Printers and Refiners( FPR) is the sol