Serbia is selling its sprawling, semi-bankrupt and polluting copper mining complex RTB Bor. Workers at the run-down mine are hoping are hoping a new mine will see an improvement in their pay and conditions. Once a socialist-era success story, Serbia's bankrupt copper miner RTB Bor is now hoping for a new owner with the cash to reverse the fortunes of the sprawling complex and the dusty town beyond. In Yugoslav times, Bor had 20,000 employees and sold copper to East and West. But a decade of isolation in the war-torn 1990s and zero investment since brought the firm to its knees, burdened with 500 million USD debts and sky-high production costs. Despite the boom in copper prices, currently around 7,800 USD a tonne, RTB is losing 45 million USD annually. In the second privatisation attempt this year, Serbia has set the minimum price for two surface mines, one underground mine and the smelting and refining unit at 340 million USD. State reports have confirmed that RTB Bor has the ore reserves of over a billion tonnes that is waiting for a new owner. Zoran Baberovic has worked at the mine for 27 years, through three different political regimes. He said conditions have deteriorated severely since his early days at the mine. "We used to have better salaries and working conditions," said RTB miner Zoran Baberovic. But Baberovic says he has hopes things will improve with a new owner. "I expect a higher salary, good working conditions and new equipment from a new owner so we can finally start working properly," Baberovic added. Five investors are interested in the mine, with the deadline for binding bids expiring on October 31st: Britain's Vedanta Resources , Montanwerke Brixlegg, the copper producer of Austria's A-Tec Industries , Cyprus-based East Point, a Russian fund called Strike Force and Russia's Solvej, which runs several mines in FYR Macedonia. In RTB's golden era in the 1980's, annual production stood at 140,000 tonnes of copper per year. It fell to 10,000 in the 1990s, when Serbia was punished with sanctions for its role in the bloody Yugoslav wars. "The new owner will have to modernise the rusty, creaking complex, and invest in research and development opening a new mine alone is estimated to cost 200 million USD," said Branislav Mihajlovic, RTB's deputy manager. "But at the same time trends in the world copper market have turned RTB from a company with low prospects into a company with a future," Mihajlovic added. After nationalist strongman Slobodan Milosevic was ousted in 2000 and the country started making tentative steps towards the West, RTB's massive furnaces were again fired up. Production reached 45,000 tonnes in 2006, and for the first time in 25 years, the firm bought a new bulldozer this month. But the expectations go beyond cash and production figures. The town of Bor, home to 65,000 people, was built around the mine in the early 20th century. It was once one of Yugoslavia's richest towns, a multinational hub buzzing around the company. RTB's decline shows on the town, now one of Serbia's poorest, and the most polluted. The air smells of sulphur, creating an acrid metal taste in the mouth. Workers in the smelting hall where red-hot molten copper ore is stirred in massive vats do not even wear masks. RTB's technology is 80 years old, and considered obsolete in most European countries. In a recent study the World Bank said the high levels of pollution in the air, earth and water made the environment the region's biggest problem.