Borsko jezero (Bor Lake) is an artificial lake in eastern Serbia (Bor District)The lake is a result of the construction of a dam of the rivers Valja Dzoni, Marec and part of Zlot (Zlotska reka) which took place in 1959 for the operation of the mining and smelting company RTB Bor (Rudarsko topioniÃÂarski basen Bor DOO)