MINING Mining is considered to be the oldest of Norwe- gian export industries. Its origin can be traced back to the beginning of the sixteenth century; but it was not until the seventeenth century that it became an economic factor of great national importance. Silver was found at Kongsberg in 1623 and copper at Rgros in 1644. In the eigh- teenth century and early in the nineteenth iron works played the leading part in the mining industry. About the middle of last century, how- ever, several of these works had to be closed down because the working methods they then employed had lost them their competitive ability. In the ’sixties a considerable export trade was estab- lished in iron pyrites, and in the ’seventies nickel works enjoyed a brief period of great prosperity. Fluctuating prices in the world’s markets at a later period, at the close of the past and the beginning of the present century, have had a marked effect on this industry; but, taken all round, it may be said to have made considerable headway. It is estimated that up to 1814 the total value of all mining production from its beginning was approximately 330 million Kroner. From 1814 to 1899 the value of this output was 315 millions. In the first quarter of the twentieth century the value of mining production approximated 500 million Kroner, about half of which was accounted for by the sulphur mines. Since 1925 exports 94