Kongsberg is particularly known for its old silver mines, from which roughly 1,350 tonnes (3,000,000 lb) of silver was extracted between the discovery of silver ore seams in 1623, and the last year of mining, in 1957. In 1770, the mines employed about 4,000 workers, and the town was the second largest in Norway, after Bergen (and thus larger than today's capital, Oslo).
Following several hard years with reduced silver output from the mines, the war of 1807�1814, and a severe town fire in 1810 where 56 houses on the west side were destroyed, mining was complemented by the government establishing a defense industry in 1814. During peaceful times, the defense industry gradually evolved into many other kinds of high tech activities as well, now dominating the town's employment.
In 1987, however, the state-owned Kongsberg Vaapenfabrikk (English: Kongsberg Weapons Factory) suffered a major financial crisis as well as accusations of breaching the CoCom rules by selling sensitive technology to the Soviet bloc. As a result the company was split into several smaller units and partly sold to private investors. Today, the separate firms thrive as one of Norway's main high-tech industrial clusters, centering on the defence and maritime company Kongsberg Gruppen which is listed on theOslo Stock Exchange.
Kongsberg is also home to the Mint of Norway (Norwegian: Det Norske Myntverket), which exclusively makes Norwegian coins. It was established in 1686, and was renamed from the Royal Norwegian Mint (Norwegian: Den Kongelige Mynt) in 2004 after having been sold to private investors (the Mint of Finland and Norwegian company Samlerhuset) in 2003
