Kongsberg Silver Mines
The silver mines of Kongsberg, in Buskerud county in Norway, constitute the largest mining field in Norway, with over 80 different mines. It was the largest pre-industrial working place in Norway, with over 4,000 workers at its peak in the 1770s and supplied over 10% of the gross national product of the Danish–Norwegian union during its 335-year-long history: over 450,000 man-years were expended in the production.
Mining in North Korea
The Hyesan Mine, located in Masan-dong, Hyesan-si, and Ryanggang-do, has been in operation since 1970 and is the largest copper mine in the country. It was flooded and hence closed from 1994 to 2009 and has been partially reopened, after bailing out water, since 2010. Other products from the mine are chalcocite, chalcopyrite, galena, and sphalerite. The plant has a capacity to handle 1,200,000 tons of copper ore annually. According to a 1993 report, the mine produced about 90,000 tons of concentrate of 16% grade of copper.