first explored in the 1960s, hyesan mine produces 10,000 tons of copper concentrates annually. this area has 80% of north korea's available copper, and the north had estimated that it will be able to continue mining copper there for the next forty years. when kapsan tongjum mine, explored during the japanese colonial period, was finally depleted and closed in 1990, hyesan mine became the lifeline of the nation’s copper production. at that time, the mine flooded because the pumping device stopped operating due to the lack of electricity across the country. although the workers at the mine did their best to pump the water, they could not stop the water flowing into the mine at a speed of 480㎥/hour. in 1996, during the north's 'arduous march', electricity was not provided to the mine, leading to flooding in the mineshafts in january 1997. hyesan mine flooded again, as did other mines throughout the country, and lost all mining facilities. since 1998, kim jong il budgeted 8.2 million usd to dewater the mine, and the mine was recovered using electricity and equipment provided by china.