Street battles erupt in Guinea refinery town CONAKRY (Reuters) - Street clashes broke out on Sunday in the Guinean industrial town of Fria, home to RUSAL's huge alumina refinery, after local youths armed with knives and guns attacked suspected black market fuel salesmen, witnesses and officials said. At least 20 people were injured in the fighting which ran for several hours before regional security forces arrived in the afternoon to break it up, witnesses said. "Some youths ... were angry at some traders who, according to them, were selling diesel stolen from the refinery on the black market," a resident told Reuters, on condition of anonymity. Several of them were attacked and the merchants retaliated. Guinea is the world's top supplier of the aluminum ore bauxite and holds rich iron ore deposits, but is struggling to attract investment due to political turmoil, rampant labor strife, and a government review of mining contracts. The 630,000 metric tons per year refinery in Fria, owned by Russia's RUSAL, the world's largest aluminum producer, has been shut since April following a labor dispute. "The youths find it unacceptable that people are taking advantage of this difficult period for the community by stealing diesel and reselling it," said an official at the plant, asking not to be named. A government official was not immediately available to comment on the clashes in Fria, about 160 kilometers (99 miles) north of the capital Conakry. Canadian gold miner Semafo Inc. said on Sunday it had resumed some administrative work at its Kiniero mine in Guinea, around a year after locals attacked the operation, forcing it to shut and employees to be evacuated. Reporting by Saliou Samb; Writing by Richard Valdmanis; Editing by Sophie Hares