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.
Norsk Hydro
Hydro is one of the largest aluminium companies worldwide. In Norway, Hydro has plants in Magnor, Rjukan, Raufoss, Vennesla, Karmøy, Høyanger, Årdal, Husnes, Sunndalsøra, and Holmestrand. Most of the employees in the company work in plants and offices located outside Norway, such as Germany and Brazil. Hydro has more employees in the United States than any other Norwegian company.