A unit of Egypt's Orascom Construction Industries (OCI) has won a $675 million contract to build an additional phase of Doha Convention Center and Tower in Qatar. The contract was awarded recently to Six Construct Qatar - which is fully owned by BESIX Group, itself a 50-50 venture between OCI and Belgian construction group Besix - in a joint venture with Midmac Contracting company, OCI said in a statement quoted by Reuters. The group has been previously working on an earlier phase of the project since early 2009 and will now finish the project by the end of October 2012 for the Qatari Diar Real Estate Investment Company, the statement said. The firm already won a contract in June worth $750 million to expand Qatar's international airport.